Konferenciis krebuli

SoTa rusTavelis erovnuli samecniero fondi Shota Rustaveli National Science Foundation Íàöèîíàëüíûé Íàó÷íûé Ôîíä Øîòà Ðóñòàâåëè saqarTvelos mecnierebaTa erovnuli akademia Georgian National Academy of Sciences Íàöèîíàëüíàÿ Àêàäåìèÿ Íàóê Ãðóçèè ssi p saqarTvelos saxelmwifo samxedro samecniero– teqnikuri centri „delta“ LEPL State Military Scientific-Technical Center “DELTA” Ãîñóäàðñòâåííûé Âîåííûé Íàó÷íî-Òåõíè÷åñêèé Öåíòð “Äåëüòà” ssi p soxumis ilia vekuas fizika-teqnikis instituti LEPL Ilia Vekua Sukhumi Institute of Physics and Technology Ñóõóìñêèé Ôèçèêî-Òåõíè÷åñêèé Èíñòèòóò èì. Èëüè Âåêóà

saerTaSoriso Tanamedrove masalebi moxsenebaTa

konferencia da teqnologiebi krebuli

International conference ADVANCED MATERIALS AND TECHNOLOGIES Proceedings Ìåæäóíàðîäíàÿ êîíôåðåíöèÿ ÑÎÂÐÅÌÅÍÍÛÅ ÌÀÒÅÐÈÀËÛ È ÒÅÕÍÎËÎÃÈÈ Ñáîðíèê äîêëàäîâ

21–23 oqtomberi – October – Îêòÿáðü – 2015 Tbilisi, saqarTvelo Tbilisi, Georgia Òáèëèñè, Ãðóçèÿ

saorganizacio komiteti guram bokuCava – Tavmjdomare (saqarTvelo) klaus tiseni (germania), irakli Jordania (saqarTvelo), fernando markizi (aSS), uCa ZoZuaSvili (saqarTvelo), milton torikaCvili (aSS), arCil frangiSvili (saqarTvelo), ekaterine sanaia (saqarTvelo), patrik grei (didi briianaSvili (saqarTvelo), lukian taneTi), ivane nekliudovi (ukraina), aleqsi mir mirianaSvili anatiCuki (ukraina), vladimer kuWuxiZe (saqarTvelo), umar salixbaevi (uzbekeTi), anzor guldamaSvili (saqarTvelo), giorgi darsaveliZe (saqarTvelo), boris Sirokovi Sengelaia (saqarTvelo), nikoloz (ukraina), aleqsandre CixraZe (saqarTvelo), giorgi esaZe (saqarTvelo)

ORGANIZING COMMITTEE Guram Bokuchava – chairman (Georgia) Klaus Thiessen (Germany), Irakli Zhordania (Georgia), Fernando Marquis (USA), Ucha Dzodzuashvili (Georgia), Milton Torikachvili (USA), Archil Prangishvili (Georgia), Ekaterine Sanaia (Georgia), Patrick Gray (UK), Ivan Nekliudov (Ukraine), Alex Mirianashvili (Georgia), Lukyan Anatychuk (Ukraine), Vladimer Kuchukhidze (Georgia), Umar Salikhbaev (Uzbekistan), Anzor Guldamashvili (Georgia), Giorgi Darsavelidze (Georgia), Boris Shirokov (Ukraine), Alexander Shengelaya (Georgia), Nikoloz Chikhradze (Georgia), Giorgi Esadze (Georgia)

ÎÐÃÀÍÈÇÀÖÈÎÍÍÛÉ ÊÎÌÈÒÅÒ Ãóðàì Áîêó÷àâà – ïðåäñåäàòåëü (Ãðóçèÿ) Êëàóñ Òèññåí (Ãåðìàíèÿ), Èðàêëèé Äæîðäàíèÿ (Ãðóçèÿ), Ôåðíàíäî Ìàðêóñ (ÑØÀ), Ó÷à Äçîäçóàøâèëè (Ãðóçèÿ), Ìèëòîí Òîðèêà÷âèëè (ÑØÀ), Àð÷èë Ïðàíãèøâèëè (Ãðóçèÿ), Åêàòåðèíå Ñàíàÿ (Ãðóçèÿ), Ïàòðèê Ãðåé (Âåëèêîáðèòàíèÿ), Èâàí Íåêëþäîâ (Óêðàèíà), Àëåêñ Ìèðèàíàøâèëè (Ãðóçèÿ), Ëóêüÿí Àíàòû÷óê (Óêðàèíà), Âëàäèìèð Êó÷óõèäçå (Ãðóçèÿ), Óìàð Ñàëèõáàåâ (Óçáåêèñòàí), Àíçîð Ãóëäàìàøâèëè (Ãðóçèÿ), Ãåîðãèé Äàðñàâåëèäçå (Ãðóçèÿ), Áîðèñ Øèðîêîâ (Óêðàèíà), Àëåêñàíäð Øåíãåëàÿ (Ãðóçèÿ), Íèêîëîç ×èõðàäçå (Ãðóçèÿ), Ãåîðãèé Ýñàäçå (Ãðóçèÿ)

moxsenebaTa krebulis saredaqcio jgufi giorgi darsaveliZe anzor guldamaSvili roin Wedia avTandil siWinava marina qadaria

PROCEEDINGS EDITORIAL TEAM Giorgi Darsavelidze Anzor Guldamashvili Roin Chedia Avtandil Sichinava Marina Kadaria

ÐÅÄÀÊÖÈÎÍÍÀß ÃÐÓÏÏÀ ÑÁÎÐÍÈÊÀ ÄÎÊËÀÄΠÃåîðãèé Äàðñàâåëèäçå Àíçîð Ãóëäàìàøâèëè Ðîèí ×åäèÿ Àâòàíäèë Ñè÷èíàâà Ìàðèíà Êàäàðèà

saerTaSoriso samecniero konferencia „Tanamedrove masalebi da teqnologiebi“ organizebulia SoTa rusTavelis erovnuli samecniero fondis finansuri mxardaWeriT (proeqti N CF/72/11-811/15). moxsenebaTa krebuli gamocemulia konferenciis farglebSi da warmoadgens proeqtis ganuyofel nawils.

International conference “Advanced Materials and Technologies” is organized by financial support of the Shota Rustaveli National Science Foundation (project N CF/72/11-811/15). The Conference Proceedings are published within the framework of the conference and represents an inseparable part of the project. Ìåæäóíàðîäíàÿ êîíôåðåíöèÿ „Ñîâðåìåííûå ìàòåðèàëû è òåõíîëîãèè” îðãàíèçîâàíà ïðè ôèíàíñîâîé ïîääåðæêå Íàöèîíàëüíîãî Íàó÷íîãî Ôîíäà èì. Øîòà Ðóñòàâåëè (Ïðîåêò N CF/72/ 11-811/15). Ñáîðíèê äîêëàäîâ èçäàí â ðàìêàõ êîíôåðåíöèè è ÿâëÿåòñÿ íåîòüåìëåìîé ÷àñòüþ ïðîåêòà.

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Îñíîâíûå ýòàïû ðàçâèòèÿ èîííîé èìïëàíòàöèè â Ñóõóìñêîì ôèçèêîòåõíè÷åñêîì èíñòèòóòå èì. È. Âåêóà À.È. Ãóëäàìàøâèëè Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È. Âåêóà, óë. Ìèíäåëè 7, Òáèëèñè, Ãðóçèÿ, 0186, E-mail: sipt@sipt.org Ðåçþìå:  ñòàòüå ïðèâåäåí êðàòêèé îáçîð îñíîâíûõ ðåçóëüòàòîâ ìíîãîëåòíîé ðàáîòû àâòîðà, â îáëàñòè èîííîé èìïëàíòàöèè, ñîâìåñòíî ñ ñîòðóäíèêàìè, â îñíîâíîì ïî ðàññåêðå÷åííûì òðóäàì íåèçâåñòíûõ äî ñèõ ïîð øèðîêîìó êðóãó íàó÷íîé îáùåñòâåííîñòè.

Èñòîðèÿ ñîçäàíèÿ Ñóõóìñêîãî ôèçèêîòåõíè÷åñêîãî èíñòèòóòà èì. È. Âåêóà (ÑÔÒÈ) â 19451955 ãîäàõ è ðîëè íåìåöêèõ ó÷åíûõ â ðàçðàáîòêå ïðîìûøëåííîé òåõíîëîãèè ïîëó÷åíèÿ íóêëèäîâ óðàíà, äëÿ Ñîâåòñêîé àòîìíîé áîìáû ïîñâÿùåíà íå îäíà ìîíîãðàôèÿ, [1,2]. Îäíàêî, â ñèëó èçâåñòíûõ ïðè÷èí, íå èìååòñÿ äîñòàòî÷íàÿ èíôîðìàöèÿ î âûïîëíÿåìûõ, ïîñëå èñïûòàíèÿ àòîìíîé áîìáû ðàáîò. Äîñòèæåíèÿ ÑÔÒÈ â äðóãèõ îáëàñòÿõ íàóêè, òåõíîëîãèè è ïðèáîðîñòðîåíèÿ õîðîøî èçâåñòíû, ïî ìíîãî÷èñëåíûì ïóáëèêàöèÿì â íàó÷íûõ æóðíàëàõ è íåêîòîðûõ èçäàíèÿõ, íà÷èíàÿ ñ 1955 ãîäà, ïîñëå îòúåçäà íåìåöêèõ ñïåöèàëèñòîâ. Íàèáîëåå âàæíûå, íî íå âñå, ðàáîòû â îáëàñòè ôèçèêè, ïî íåêîòîðûì íàïðàâëåíèÿì ÑÔÒÈ â ïåðâûå âîøëè â êíèãó [3].  òîì ÷èñëå ñîâìåñòíûå ñ íåìåöêèìè ñïåöèàëèñòàìè ïóáëèêàöèè. Êíèãà äàåò ïðåäñòàâëåíèå î ïóòÿõ ðàçâèòèÿ è îöåíêè ñîñòîÿíèÿ, ôèçè÷åñêîé íàóêè â ÑÔÒÈ 1955-1970 ãîäîâ. Ïðåäñòàâëåíèå î ïðîâîäèìûõ ðàáîòàõ òîãî âðåìåíè, â áûâøåì Ñîâåòñêîì Ñîþçå, ìîæíî ïîëó÷èòü ïî èññëåäîâàíèÿì âëèÿíèÿ èîííîé áîìáàðäèðîâêè íà ñâîéñòâà ðàçðàáîòàííîãî â ÑÔÒÈ ïîëóïðîâîäíèêîãî äèîäà èç êðåìíèÿ [4]. Àâòîð äî îòúåçäà íåìåöêèõ ñïåöèàëèñòîâ â 1954 -1955 ãîäàõ ñ ãðóïïîé ñòóäåíòîâ Òáèëèññêîãî Ãîñóäàðñòâåííîãî Óíèâåðñèòåòà íàõîäèëñÿ â ÑÔÒÈ äëÿ ïðîõîæäåíèÿ ïðîèçâîäñòâåííîé ïðàêòèêè è âûïîëíåíèÿ äèïëîìíîé ðàáîòû. Èç ýòîé ãðóïïû, ó Âåðíåðà Øþòöå, íà ñîçäàíîì èì ïåðâîãî â Ñîâåòñêîì Ñîþçå ìàññïåêòðîãðàôå ñ äâîéíîé ôîêóñèðîâêîé, ïðîõîäèë ïðåääèïëîìíóþ ïðàêòèêó àâòîð ðàáîòû [4]. ×àñòü ñòóäåíòîâäèïëîìàíòîâ áûëà íàïðàâëåíà â ëàáîðàòîðèþ ïî èññëåäîâàíèþ ýëåêòðîôèçè÷åñêèõ ñâîéñòâ ïîëó÷àåìûõ â èíñòèòóòå ïîëóïðîâîäíèêîâ, ðóêîâîäèìîé È.Ä. Êèðâàëèäçå. Îíè èçó÷àëè èçìåíåíèå ñâîéñòâ ïîëóïðîâîäíèêîâ ïðè îáëó÷åííè, â âàêóóìíîì ãàçîâîì ðàçðÿäå, è ñîçäàëè ýëåìåíò ïîëóïðîâîäíèêîâîãî ïðåîáðàçîâàòåëÿ, ñîëíå÷íîé ýíåðãèè â ýëåêòðè÷åñêóþ. Òîãäà è â ïîñëåäñòâèè àâòîð, áóäó÷è ñîòðóäíèêîì èíñòèòóòà ñ 1955ã., èìåë âîçìîæíîñòü ïîñåùåíèÿ

ëàáîðàòîðèè, êîòîðàÿ áûëà îñíàùåíà ðàçðàáîòàííîé â èíñòèòóòå íåîáõîäèìîé àïïàðàòóðîé äëÿ èçìåðåíèÿ îñíîâíûõ ïîëóïðîâîäíèêîâûõ ïàðàìåòðîâ ïîëó÷àåìûõ îáðàçöîâ.  1953 ãîäó íà ñòåíäå ãëàâíîãî êîðïóñà â Ñèíîïå, áûëè âûñòàâëåíû âûðàùåííûå âïåðâûå â Ñîâåòñêîì Ñîþçå, íà óñòàíîâêàõ çîííîé ïëàâêè, ñîáñòâåííîé ðàçðàáîòêè, îáðàçöû ãåðìàíèÿ âûñîêîé ÷èñòîòû.  1955 ãîäó âïåðâûå â Ñîâåòñêîì Ñîþçå áûë ïîëó÷åí ìîíîêðèñòàëëè÷åñêèé êðåìíèé.  ïîñëåäñòâèè, ðàçðàáîòàííàÿ â èíñòèòóòå ïðîìûøëåííàÿ òåõíîëîãèÿ ïîëó÷åíèÿ êðåìíèÿ, áûëà âíåäðåíà â ïðîìûøëåííîñòü.  ïåðå÷íå îñîáåííî âàæíûõ ìèðîâûõ îòêðûòèé è èçîáðåòåíèé â îáëàñòè ïîëóïðîâîäíèêîâûõ ïðèáîðîâ è ìèêðîýëåêòðîíèêè, îñîáî îòìå÷åíî ïîëó÷åíèå â 1950 ã. ìîíîêðèñòàëëîâ ãåðìàíèÿ è 1952 ã. êðåìíèÿ. Èçâåñòíî, “÷òo â Ñóõóìñêîì ôèçèêî-òåõíè÷åñêîì èíñòèòóòå î÷åíü óñïåøíî, ñ ñåðåäèíû 50-õ ãîäîâ ðàçâûâàëèñü ðàáîòû ïî òåõíîëîãèÿì êðåìíèÿ” [5].  äàëüíåéøåì â èíñòèòóòå ïðîäîëæàëèñü ðàáîòû ïî èññëåäîâàíèþ, âëèÿíèÿ èîííîé áîìáàðäèðîâêè â òëåþùåì ðàçðÿäå íà õàðàêòåðèñòèêè ñîçäàííûõ ïîëóïðîâîäíèêîâûõ äèîäîâ [6]. Ïðîâîäèìûå ðàáîòû ñ íà÷àëà 50-õ ãîäîâ â îáëàñòè ðàäèàöèîííîé ôèçèêè ïîëóïðîâîäíèêîâ, çàëîæèëè îñíîâû èîííîé èìïëàíòàöèè.  äàííîé ñòàòüå ïðèâåäåí êðàòêèé îáçîð îñíîâíûõ ðåçóëüòàòîâ ìíîãîëåòíåé ðàáîòû àâòîðà, â îáëàñòè èîííîé èìïëàíòàöèè, ñîâìåñòíî ñ ñîòðóäíèêàìè, â îñíîâíîì ïî ðàññåêðå÷åííûì òðóäàì íåèçâåñòíûõ äî ñèõ ïîð øèðîêîìó êðóãó íàó÷íîé îáùåñòâåííîñòè. Îáçîð äàåò ïðåäñòàâëåíèå îá óðîâíå è ìàñøòàáàõ ïðîâîäèìûõ ðàáîò â ÑÔÒÈ ýòîãî ïåðèîäà. Èñòîðèÿ ñòàíîâëåíèÿ è ðàâèòèÿ èîííîé èìïëàíòàöèè, îòîáðàæåíî âî ìíîãî÷èñëåííûõ áèáëèîãðàôè÷åñêèõ è ìîíîãðàôè÷åñêèõ èçäàíèÿõ [15].  Ãðóçèè ðàáîòû â îáëàñòè èîííîé èìïëàíòàöèè íà÷àëèñü 1962 ã. àâòîðîì â Ñóõóìè ñîçäàíèåì, íå èìåóùåãî àíàëîãîâ â ÑÑÑÐ ýêñïåðèìåíòàëüíîãî êîìïëåêñà, âêëþ÷àþùåãî òðåõêàíàëüíóþ óñòàíîâêó

6 èîííîé èìïëàíòàöèè ñ âûñîêèìè ôëþåíñàìè è èîííîàñèñòèðîâàííîãî îñàæäåíèÿ, ñî ñïåêòðîìåòðîìåòðîì ðåçåôîðäîâñêîãî îáðàòíîãî ðàññåÿíèÿ (ÑÐÎÐ) ñ èñïîëüçîâàíèåì îðèåíòàöèîííûõ ýôôåêòîâ êàíàëèðîâàíèÿ è áëîêèðîâêè, ãåëèåâûé êðèîñòàò ñ ñâåðõïðîâîäÿùèìè îáìîòêàìè, èç íèîáèéãåðìàíèåâîãî ñïëàâà ñ íàïðÿæåííîñòüþ ìàãíèòíîãî ïîëÿ 15 Ò., è ìíîãèõ äðóãèõ ìåòîäèê äëÿ èññëåäîâàíèÿ ïðî÷íîñòíûõ, ôðèêöèîííûõ, ýìèññèîííîàäîñîðáöèîííûõ, ñâåðõïðîâîäÿùèõ, è äð. ñâîéñòâ ïîëóïðîâîäíèêîâûõ è ìåòàëëè÷åñêèõ ìàòåðèàëîâ. Óñòàíîâêà èîííîé èìïëàíòàöèè ÑÔÒÈ áûëà ñîçäàíà íà áàçå ýëåêòðîìàòèòà, äåìîíòèðîâàííîãî â êîìáèíàòå Ñâåðäëîâñê-45, óñòàíîâêè êàëüþòðîí (ÑÏ 30), ýëåêòðîìàãíèòíîãî ðàçäåëåíèÿ èçîòîïîâ óðàíà. Èçâåñòíî, ÷òî “â íà÷àëå 1946 ã. áûëà âûáðàíà ïëîùàäêà äëÿ ýëåêòðî ìàãíèòíîãî êîìáèíàòà â ñåâåðíîé Òóðå Ñâåðäëîâñê-45.  êîíöå 50-ûõ ãîäîâ, áûë ñíèæåí ïðèîðèòåò ýëåêòðîìàãíèòíîãî ðàçäåëåíèÿ. Áûëî ðåøåíî íå ñòðîèòü ïîëíîìàñøòàáíûé çàâîä ïî ýëåêòðîìàãíèòíîìó ðàçäåëåíèþ, à íåáîëüøîé çàâîä â Ñâåðäëîâñê-45, óæå çàâåðøåííûé, áîëüøå íå ðàññìàòðèâàëñÿ êàê ïåðâîî÷åðåäíîé” [1]. Ïåðâûé êàëüþòðîí â 1941 ã. áûë ñîçäàí Ý. Î. Ëîóðåíñîì â ðàìêàõ “Ìàíõåòåíñêîãî ïðîåêòà” íà áàçå äåìîíòèðîâàííîãî, èì æå ðàçðàáîòàííîãî 1931 ã.â Êàëèôîðíèéñêîì óíèâåðñèòåòå öèêëîòðîíà (îòñþäà íàçâàíèå êàëþòðîí) [1]. Íà çàâîäå ýëåêòðîìàãíèòíîãî ðàçäåëåíèÿ èçîòîïîâ óðàíà, â ïðîìûøåííûõ ìàñøòàáàõ, ïîñòðîåííîãî â 1943ã. â Îê-Ðèäæå, äî êîíöà âîéíû, áûëî ïîëó÷åíî íåîáõîäèìîå êîëè÷åñòâî óðàíà äëÿ ïåðâûõ àòîìíûõ áîìá.  äàëüíåéøåì ýòîò çàâîä íå èñïîëüçîâàëñÿ äëÿ ðàçäåëåíèÿ èçîòîïîâ â ïðîìûøëåííîì ìàñøòàáå, è ñëóæèë èñòî÷íèêîì ðàçäåëåííÿ èçîòîïîâ äëÿ íàó÷íî-èññëåäîâàòåëüñêèõ öåëåé. Ê òîìó âðåìåíè â Ñèíîïå ôóíêöèîíèðîâàëà, ðàçðàáîòàííaÿ 1947 ã. ãðóïïîé Ìàíôðåäà ôîí Àðäåíå, 30-òîííûé ýëåêòðîìàãíèòíûé ñåïàðàòîð èçîòîïîâ [1, 16]. Èçâåñòíî, ÷òî ó Ìàíôðåä ôîí Àðäåíå áûëà ÷àñòíàÿ ëàáîðàòîðèÿ â Áåðëèí-Ëèõòåðôåëüäå â êîòîðîì îí ñîçäàë ïðîòîòèï óñòðîéñòâà äëÿ ýëåêòðîìàãíèòíîãî ðàçäåëåíèÿ èçîòîïîâ”[1]. Íà ñåïàðàòîðå, â òî âðåìÿ, ïðîâîäèëèñü ðàáîòû, ïî èçãîòîâëåíèþ èçîòîïíûõ ìèøåíåé, äëÿ ÿäåðíûõ èññëåäîâàíèè, ïî âçàèìîäåéñòâèþ óñêîðåííûõ èîíîâ ñ òâåðäûì òåëîì è àòîìàìè â ìîëåêóëÿðíîì ïó÷êå [17,18]. Òðåõñîò òîííûé ýëåêòðîìàãíèò ñ âàêóóìíîé êàìåðîé, â êîíöå 50-ûõ ãîäîâ áûë ïåðåäàí ÑÔÒÈ, öåëüþ ñîçäàíèÿ êàñêàäà äëÿ ïîëó÷åíèÿ ýëåêòðîìàãíûòíûì ìåòîäîì èçîòîïîâ âûñîêîé ÷èñòîòû è îáîãàùåíèÿ. Îäíàêî ïðåäïî÷òåíèå áûëî îòäàíî áîëåå ïðèîðèòåòíîìó íàïðàâëåíèþ èîííîé èìïëàíòàöèè.  áûâøåì Ñîâåòñêîì Ñîþçå, ÑÔÒÈ áûë îäíèì èç èíèöèàòîðîâ ïðîâåäåíèÿ øèðîêîìàñøòàáíûõ ðàáîò â îáëàñòè èîííîé èìïëàíòàöèè. Íåîáõîäèìîñòü ïðîâåäåíèÿ ðàáîò áûëî ïðîäèêòîâàííî, îñòðîé íåáõîäèìîñòüþ ðàçâèòèÿ â Ñîâåòñêîì Ñîþçå, ïîëóïðîâîäíèêîâîé ýëåêòðîíèêè è ïîëóïðîâîäíèêîãî

ïðèáîðîñòðîåíèÿ. Áûëè ó÷òåíû ïîòðåáíîñòè ïðîâîäèìûõ ðàáîò â èíñòèòóòå, ïî ïðåîáðàçîâàíèþ ñîëíå÷íîãî, ÿäåðíîãî è ÿäåðíîãî òåïëîâîãî èçëó÷åíèÿ ôîòîýëåêòðè÷åñêèìè, òåðìîýëåêòðè÷åñêèìè è òåðìîýìèññèîííûìè ìåòîäàìè â ýëåêòðè÷åñêóþ. Ïðîâåäåíèå ðàáîò â ÑÔÒÈ áûëî îáóñëîâëåíî, ðåçóëüòàòàìè ðåøåíèÿ ïðîáëåì, ãîñóäàðñòâåííîãî çíà÷åíèÿ, èìåþùèìèñÿ íàó÷íî – òåõíè÷åñêèì ïîòåíöèàëîì, ñ îäíîé ñòîðîíû, è ïîëó÷åííîì ïðè ýòîì îïûòå. Ê íà÷àëó ðàáîò, ôèçè÷åñêèå îñíîâû èîííîé èìïëàíòàöèè äî êîíöà íå áûëè ðàçðàáîòàíû. Ìíîãîîáðàçèå ÿâëåíèé, ñîïðîâîæäàþùèõ èîííóþ èìïëàíòàöèþ, è èõ ñëîæíàÿ çàâèñèìîñòü îò ïàðàìåòðîâ èîííîãî ïó÷êà, ìèøåíè, è óñëîâèé èîííîãî îáëó÷åíèÿ, èçâåñòíûå îãðàíè÷åíèÿ òåîðåòè÷åñêèõ ïðåäñòàâëåíèé è ýêñïåðèìåíòàëüíîãî õàðàêòåðà, ñóùåñòâåííî ñäåðæèâàëè òåìïû èõ ïðàêòè÷åñêîãî ïðèìåíåíèÿ. Íàäî îòìåòèòü, ÷òî â íà÷àëå, ðàáîòû ïî íåäîïîíèìàíèþ âàæíîñòè òåõíîëîãèè èîííîé èìïëàíòàöèè â Ñîâåòñêîì Ñîþçå, èññëåäîâàíèþ ôèçè÷åñêèõ îñíîâ, è ðàçðàáîòêå òåõíîëîãèè óïðàâëÿåìîé èîííîé èìïëàíòàöèè, óäåëÿëîñü íåäîñòàòî÷íîå âíèìàíèå. Ïåðñïåêòèâíîñòü ïðîìûøëåííîãî ïðèìåíåíèÿ èîííîèìïëàíòàöèîííûõ ìàòåðèàëîâ, ñòèìóëèðîâàëè èññëåäîâàíèå ïðîèñõîäÿùèõ ðàäèàöèîííûõ ïðîöåññîâ, ôèçè÷åñêèõ îñíîâ ðàäèàöèîííîãî ôàçîîáðàçîâàíèÿ, ñâîéñòâ èîííîèìïëàíòàöèîííûõ ìàòåðèàëîâ è ñîçäàííûõ íà èõ îñíîâå óñòðîèñòâ è ïðèáîðîâ, ðàçðàáîòêó íîâûõ ýêñïåðèìåíòàëüíûõ ìåòîäîâ, ãîäíûõ äëÿ èññëåäîâàíèÿ ñâîéñòâ íàíîðàçìåðíûõ ñëîåâ. Îñîáåííî àêòóàëüíîé áûëà ðàçðàáîòêà òåõíîëîãèè óïðàâëÿåìîé èîííîé èìïëàíòàöèè ñ âûñîêèìè ôëþåíñàìè. Íåäîñòàòî÷íîå êîëè÷åñòâî óñòàíîâîê èîííîé èìïëàíòàöèè, ÷òî áûëî âûçâàíî ñëîæíîñòüþ èõ èçãîòîâëåíèÿ è ýêñïëóàòàöèè, ñóùåñòâåííî âëèÿëè íà õîä ðàáîò. Äëÿ èìïëàíòàöèè íà íà÷àëüíîì ýòàïå èñïîëüçîâàëèñü ýëåêòðîìàãíèòíûå, ýëåêòðè÷åñêèå ìàññàíàëèçàòîðû è óñêîðèòåëè èîíîâ. Îäíàêî ýòè óñòàíîâêè íå óäîâëåòâîðÿëè, ìåòîäè÷åñêèå è òåõíîëîãè÷åñêèå òðáîâàíèÿ óïðàâëÿåìîé èîííîé èìïëàíòàöèè. Ýòè òðåáîâàíèÿ ïðàêòè÷åñêè âûçâàëè íåîáõîäèìîñòü ñîçäàíèÿ íà áàçå ýëåêòðîìàãíèòà êàëüþòðîíà ñîâåðøåííî íîâîé óñòàíîâêè, ðàçðàáîòêó è ñîçäàíèå îòäåëüíûõ åå óçëîâ. Óñèëèÿ áûëè íàïðàâëåíû íà ñîçäàíèå íàäåæíîé è ïðîñòîé â îáñëóæèâàíèè, òåõíîëîãè÷åñêèìè ïðîöåññàìè, óñòàíîâêè èîíîé èìïëàíòàöèè îáåñïå÷èâàþùåé ñòðîãèé êîíòðîëü è óïðàâëåíèå ïàðàìåòðîâ èîííîãî ïó÷êà è ìûøåíè.  óñòàíîâêå áûëî ïðåäóñìîòðåííî óâåëè÷åíèå ýíåðãèè (äî 1 ÌýÂ), è ïëîòíîñòè òîêà èîíîâ (äî äåñÿòêè ìÀ·ñì-2), óëó÷øåíèå âàêóóìíûõ óñëîâûé èìïëàíòàöèè, îñîáåííî â ñèñòåìàõ òðàíñïîðòèðîâêè è äåðæàòåëÿõ îáðàçöîâ äî 6.5·10-5 Ïà. Òîëüêî, ñîçäàííàÿ â ÑÔÒÈ óñòàíîâêà ïîçâîëÿëà èìïëàíòèðîâàòü îáðàçöû, êàê íåêàíàëèðîâàíûìè èçîòîïíûìè èîííûìè ïó÷êàìè,

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Âèä óñòàíîâêè èîííîé èìïëàíòàöèè ÑÔÒÈ ïóáëèêóåòñÿ âïåðâûå) ïðàêòè÷åñêè âñåõ ýëåìåíòîâ, òàê è êàíàëèðîâàííûìè ïó÷êàìè èîíîâ, îðèåíòèðîâàííûõ ïî êðèñòàëëîãðàôè÷åñêèì íàïðàâëåíèÿì, ìîíîêðèñòàëëîâ ñ òî÷íîñòüþ 0.01î (âêëþ÷àÿ óãëîâóþ ðàñõîäèìîñòü ïó÷êà). Óñòàíîâêà èîííîé èìïëàíòàöèè, ñîçäàííàÿ â ÑÔÒÈ, èìååò ðÿä ñåðüåçíûõ ïðåèìóùåñòâ ïî ñðîâíåíèþ ñ ñåðèéíûìè ïðîìûøëåííûìè óñêîðèòåëÿìè, ïîçâîëÿþùèìè, êàê ïðàâèëî, ðåøàòü ëèøü âïîëíå îïðåäåëåííûå çàäà÷è, òèïè÷íûå, äëÿ òâåðäîòåëüíîé ýëåêòðîíèêè. Èìïëàíòàöèÿ íåêàíàëèðîâàíûìè èîíàìè îáðàçöîâ ñ ïëîùàäüþ 100-200 ñì2, ïðè òåìïåðàòóðàõ 100-1073 K, ôëþåíñàìè îáëó÷åíèÿ 1011-1018 èîí·ñì-2 è ïëîòíîñòüþ èîííîãî òîêà, â ïðåäåëàõ îò 1 ìêÀ·ñì-2 äî 10 ìÀ·ñì-2 îñóùåñòâëÿëàñü, íà ïåðâîì êàíàëå òðàíñïîðòèðîâêè óñòàíîâêè. Èìïëàíòàöèÿ êàíàëèðîâàííûìè èîíàìè îáðàçöîâ ñ ïëîùäüþ äî 2 ñì 2 ïðè òåìïåðàòóðàõ 180-873 K ïðîâîäèëàñü íà ÑÐÎÐ ñ ïîëóàâòîìàòè÷åñêèì óïðàâëåíèåì òðåõîñíîãî ãîíèîìåòðà ñ ïîìîùüþ ïîëóïðîâîäíèêîâîãî ìèíè ÝÂÌ. Íà ýòîé æå óñòàíîâêå îáðàòíî ðàññåÿííûìè ïðîòîíàìè ñ ýíåðãèåé 200 êý ñ ìåòîäàìè êàíàëèðîâàíèÿ è áëîêèðîâêè (èîííîãðàôèè) èçó÷åíû ýëåìåíòíûé ñîñòàâ, ñòðóêòóðû, ñòåïåíè ðàäèàöèîííîé ïîâðåæäàåìîñòè èîííîèìïëàíòèðîâàííûõ íàíîðàçìåðíûõ ñëîåâ êðèñòàëëîâ. Äëÿ ïîëó÷åíèÿ è óñêîðåíèÿ èîíîâ áûë ïðèìåíåí ïëàçìåííûé èñòî÷íèê ñ îäíîñòàäèèíûì óñêîðÿþùèì íàïðÿæåíèåì 200 êý è ïëîòíîñòüþ òîêà, äî äåñÿòêà ìÀ·ñì- 2, äîñòàòî÷íîé äëÿ óïðàâëÿåìîé èîííîé èìïëàíòàöèè è èçó÷åíèÿ êðèñòàëëîâ ìåòîäîì ÐÎÐ. Èñòî÷íèê èîíîâ ïîçâîëÿë ïîëó÷åíèå ÷åòûðåõçàðÿäíûõ èîííûõ ïó÷êîâ ôîñôîðà, âûñìóòà, òåëëóðà, öèíêà è íåêîòîðèõ äðóãèõ ýëåìåíòîâ ñ ïëîòíîñòüþ òîêà íå íèæå 10-20 ìêÀ·ñì-2. Ïîëîæèòåëüíûå ýêñïëóàòàöèîííûå õàðàêòåðèñòèêè ïëàçìåííûõ èñòî÷íèêîâ, âî ìíîãîì îïðåäåëÿëè áåñïåðåáîéíóþ ñòàáèëüíóþ ðàáîòó óñòàíîâêè, áåç ðàçãåðìåòèçàöèè âàêóóìíîé êàìåðû, â òå÷åíèå 100-150 ÷àñîâ (ðåñóðñîñïîñîáíîñòü êàòîäíîãî áëîêà).  ðàçðàáîòàííûõ è ñîçäàííûõ äåðæàòåëÿõ îáðàçöîâ, ñ âîäÿíûì îõëàæäåíèåì, íåîáõîäèìîå ðàññïðåäåëåíèå è îäíîðîäîñòü èìïëàíòàöèè (ìèêðîíåîäíîðîäíîñòü íå áîëåå 1%) äîñòèãàëîñü âðàùàòåëüíûì èëè âîçâðàòíî-

ïîñòóïàòåëüíûì äâèæåíèåì ìèøåíè â îòëè÷èå îò ïðèìåíÿåìûõ, â áîëüøèíñòâå ñëó÷àåâ, ðàçâåðòêîé èîííîãî ïó÷êà. Ñìåíà îáðàçöîâ, áåç îñîáîãî óõóäøåíèÿ âàêóóìíûõ óñëîâèé êàìåðû, ïðîâîäèëàñü ñ ïîìîùüþ øëþçîâ. Èññëåäîâàíèå âàêóóìíîé ðàáîòû âûõîäà ýëåêòðîíà ïðîâîäèëîñü ìåòîäàìè ïîëíîãî òîêà, è êîíòàêòíîé ðàçíîñòè ïîòåíöèàëîâ ïî ìåòîäó Êåëüâèíà. Èçìåðåíèÿ ðàáîòû âûõîäà ìåòîäîì ïîëíîãî òîêà ïðîâîäèëèñü íà ðàçðàáîòàííîì ïðèáîðå â âûñîêîâàêóóìíîé êàìåðå, áåç ìàñëüÿííîé îòêà÷êè ÂÂÊÁÌÎ 60 (Ðàçðàáîòà ÔÒÈÍÒ ã. Õàðüêîâ). Âàêóóìíàÿ êàìåðà ïðîãðåâàåìàÿ äî 570 K ñ òðåìÿ êðèîñîðáöèîííûìè è òðåìÿ êîíäåñàöèîííûìè íàñîñàìè ïîçâîëÿëà èçìåðåíèå äî äåñÿòè îáðàçöîâ çà îäèí öèêë, áåç ðàçãåðìåòèçàöèè âàêóóìíîé ñèñòåìû ïðè äàâëåíèÿõ 5.10-5 – 10-6 Ïà. Íà ñîçäàííîé ýêñïåðèìåíòàëüíîé áàçå, â ëàáîðàòîðèè áûëè ïðîâåäåíû øèðîêîìàñøòàáíûå ðàáîòû ïî èçó÷åíèþ íàó÷íûõ îñíîâ ðàäèàöèîííûõ ïðîöåññîâ, ïðîèñõîäÿùèõ ïðè èìïëàíòàöèè ìàòåðèàëîâ èîíàìè ñ âûñîêèìè ôëþåíñàìè è ïîâðåæäàþùèìè äîçàìè, èîííîé ìåòàëóðãèè, óñòàíîâëåíèþ îòëè÷èòåëüíûõ ïðåèìóùåñòâåííûõ îñîáåííîñòåé òåõíîëîãèè, èîííîé èìïëàíòàöèè â ôîðìèðîâàíèè ìàòåðèàëîâ, íîâîãî êëàññà â ðàâíîâåñíûõ, íåðàâíîâåñíûõ, ìåòàñòàáèëüíûõ è íàíîêðèñòàëëè÷åñêèõ ñîñòîÿíèÿõ, â çíà÷èòåëüíî îòëè÷àþùèõ óñëîâèÿõ ðàâíîâåñíîé òåðìîäèíàìèêè è âûÿñíåíèè âîçìîæíîñòè èõ èñïîëüçîâàíèÿ â ðàçëè÷íûõ îáëàñòÿõ íàóêè è òåõíèêè.  îñíîâíîì ïðîâîäèëèñü îáøèðíûå èññëåäîâàíèÿ ýëåêòðîôèçè÷åñêèõ, ôèçèêîìåõàíè÷åñêèõ è äðóãèõ ñâîéñòâ èîííîèìïëàíòàöèîííûõ ìàòåðèàëîâ ñ öåëüþ îïòèìèçàöèè òåõíîëîãèè è âûáîðà ìàòåðèàëîâ äëÿ ïîëóïðîâîäíèêîâîé ìèêðîýëåêòðîíèêè è ïîëóïðîâîäíèêîâîãî ïðèáîðîñòðîåíèÿ, ïðåîáðàçîâàòåëåé òåïëîâûõ è ÿäåðíûõ èçëó÷åíèé â ýëåêòðè÷åñêóþ ýíåðãèþ, äëÿ àòîìíîé íàóêè è òåõíèêè. Âïåðâûå, â áûâøåì Ñîâåòñêîì Ñîþçå, îáíàðóæeíû ÿâëåíèÿ êàíàëèðîâàíèÿ èîíîâ áîðà â êðåìíèè è óñòàíîâëåíî íàëè÷èå êàíàëèðîâàííûõ èîíîâ äàæå â òîì ñëó÷àå, êîãäà óãîë ïàäåíèÿ èîíîâ ïó÷êà â òðè-÷åòûðå ðàçà ïðåâûøàåò êðèòè÷åñêèé óãîë Ëèíäõàðäà.  ïåðâûå ýêñïåðè-

8 ìåíòàëüíî îáíàðóæåíû âàæíûå îñîáåííîñòè âçàèìîäåéñòâèÿ âûñîêîýíåðãåòè÷åñêèõ èîíîâ ñ êðèñòàëëàìè ñâÿçàííûå ñ ïðîÿâëåíèåì îðèåíòàöèîííûõ ýôôåêòîâ. Ïðåäëîæåíû ìåòîäû ó÷åòà âêëàäîâ êàíàëèðîâàííûõ è íåêàíàëèðîâàííûõ èîíîâ â ôîðìèðîâàíèè ïðîôèëÿ çàëåãàíèÿ èìïëàíòèðîâàííûõ èîíîâ, è ïðîôèëÿ ïîâðåæäàåìîñòè. Ïîëó÷åíû ñîîòíîøåíèÿ äëÿ ðàñ÷åòà âêëàäà íåêàíàëèðîâàííûõ, äåêàíàëèðîâàííûõ, õîðîøî êàíàëèðîâàííûõ è çàõâà÷åííûõ â êàíàëàõ èîíîâ â çàâèñèìîñòè îò ôëþåíñà èìïëàíòàöèè, ýíåðãèè, óãëà è ïëîñêîñòè ïàäåíèÿ èîíîâ, êðèñòàëëîãðàôè÷åñêîãî íàïðàâëåíèÿ. Óñòàíîâëåííûå çàêîíîìåðíîñòè èçìåíåíèÿ ñòðóêòóðû òâåðäûõ òåë ïðè èìïëàíòàöèè ïîçâîëèëè ðåàëèçîâàòü, íàïðàâëåííîå è êîíòðîëèðóåìîå èçìåíåíèå ýììèññèîííî-àäñîðáöèîííûõ è ìåõàíè÷åñêèõ ñâîéñòâ ìîëèáäåíà, íèîáèÿ è âîëüôðàìà.  ÷àñòíîñòè, âïåðâûå äîñòèãíóòîå ïðåöèçèîííîå èçìåíåíèå ðàáîòû âûõîäà ýëåêòðîíîâ â èíòåðâàëå 3,2 - 7,5 ýÂ, ÷òî ïîçâîëèëî ñîçäàòü ýôôåêòèâíûå ýëåêòðîäû äëÿ òåðìîýìèññèîííûõ ïðåîáðàçîâàòåëåé. Âïåðâûå ïðè îáëó÷åííèè òóãîïëàâêèõ ìåòàëëîâ â òåìïåðàòóðíîé îáëàñòè 100-600 K èîíàìè óãëåðîäà è àçîòà, ñèíòåçèðîâàíû âûñîêîïðî÷íûå ñïëàâû êàðáèäîâ è íèòðèäîâ.  ñåðåäèíå 60-õ ãîäîâ áûëà ñîçäàíà òðèãåðíàÿ ÿ÷åéêà íà êðåìíèåâûõ èîííîèìïëàòàöèîííûõ äèîäàõ, ñî âðåìåíåì ïåðåêëþ÷åíèÿ ìåíåå 0,1 ìêñ. Êîíäåíñàòîð ñ âûñîêîé åìêîñòüþ (èç ïåíòàîêñèäà òèòàíà), îìè÷åñêèå êîíòàêòû è òîêîâîäû ñîçäàâàëèñü ýëåêòðîííîëó÷åâûì èñïàðåíèåì â âàêóóìå. Ê 60-òûì ãîäàì îòíîñÿòñÿ, ñîçäàíèå: äèîäa ñ p-n ïåðåõîäîì ïðè îáëó÷åíèè ìîíîêðèñòàëëîâ êðåìíèÿ, ýëåêòðîííîé ïðîâîäèìîñòè, èîíàìè àðãîíà è êðåìíèÿ; ñèíòåç îêñèäîâ è íèòðèäîâ êðåìíèÿ ñ âûñîêèìè ïðîáûâíûìè íàïðÿæåíèÿìè è âûñîêîé äèýëåêòðè÷åñêîé ïðîíèöàåìîñòüþ.  íàñòîÿùåå âðåìÿ, íà ñîçäàííîé â Òáèëèñè ýêñïåðèìåíòàëüíîé áàçå, âåäóòñÿ ðàáîòû ïî ïðèìåíåíèþ è ðàçâèòèþ íàíîÿâëåíèè è íàíîòåõíîëîãèè. Ïðîâåäåíèå ðàáîò, âûçâàíî íåîáõîäèìîñòüþ ïîëó÷åíèÿ â èíñòèòóòå èíîâàöèîííûìè íàó÷íî - òåõíîëîãè÷åñêèìè ñïîñîáàìè ìàòåðèàëîâ íîâîãî êëàññà, è îïòèìèçàöèè òåõíîëîãèè ñîçäàíèÿ íà îñíîâå ýòèõ ìàòåðèàëîâ, óñòðîèñòâ ïðèáîðîâ ïîëóïðîâîäíèêîâîé ìèêðî - íàíîòåõíîëîãèè, îïòîýëåêòðîíèêè,  çàêëþ÷åíèè, îñîáî ñëåäóò îòìåòèòü ðîëü è âêëàä àêàäåìèêîâ È.Ã. Ãâåðäòöèòåëè, À.Ï. Àëåêñàíäðîâà è Ã.Í. Ôëåðîâà â ñòàíîâëåíèè è ðàçâèòèè èîííîé èìïëàíòàöèè â èíñòèòóòå. Ñëåäóåò îòìåòèòü âàæíîñòü ìíîãîëåòíåãî ñîòðóäíè÷åñòâà ÑÔÒÈ ñ Õàðüêîâñêèì ôèçèêî-òåõíè÷åñêèì èíñòèòóòîì, Ìèíèñòåðñòâîì ñðåäíåãî ìàøèíîñòðåíèÿ ÑÑÑÐ, ÍÈÈ Ïîëóïðîâîäíèêîâîé ýëåêòðîíèêè Ìèíèñòåðñòâà ýëåêòðîííîé ïðîìûøëåííîñòè ÑÑÑÐ “Ïóëüñàð”, ïðîô. Â.Ñ. Êóëèêàóñêàñîì èç ÍÈÈ ßÔ ÌÃÓ; à òàêæå ïîääåðæêà è ïîìîùü ÍÈÈ ÝÔÀ Ìèíèñòåðñòâà ñðåäíåãî ìàøèíîñòðåíèÿ ÑÑÑÐ â Ëåíèíãðàäå è Õàðêîâñêîãî ôèçèêî-òåõíè÷åñêîãî èíñòèòóòà íèçêèõ òåìïåðàòóð.

Ëèòåðòóðà

1. Äýâèä Õîëîâýé. Ñòàëèí è áîìáà. Ñîâåòñêèé Ñîþç è àòîìíàÿ ýíåðãèÿ 1939-1956. Ïåðåâîä ñ àíãëèéñêîãî. Ñèáèðñêèé õðîíîãðàô, Íîâîñèáèðñê, 1997. - 626 ñ.

2. Nikolaus Riehl, Frederick Seitz. Stalin’s Captive: Nikolaus Riehl and the Soviet Race for the Bomb. American Chemical Society and the Chemical Heritage Foundation. 1996. – 231p] 3. Ä.Ê. Äæèêèÿ. Èç èñòîðèè ôèçèêè â ñîâåòñêîé Ãðóçèè, Òáèëèñè, Òáèëèññêèé Ãîñóäàðñòåíèé Óíèâåðñèòåò.

1972.- 154 ñ.

4. È.Ä. Êèðâàëèäçå, Ê.Á.Ðåïèí. Âëèÿíèå èîííîé áîìáàðäèðîâêè â òëåþùåì ðàçðÿäå íà äèîäíûå ñâîéñòâà è äèôôóçèîííóþ äëèíó íåîñíîâíûõ íîñèòåëåé ýëåêòðîíîâ â êðåìíèè. Îò÷åò N 233 (À), ÑÔÒÈ, 1955. -17 ñ. (Áèáë., 4 ãëàâ).

5. Þ.À. Êîíöåâîé. Ìàòåðèàëû äëÿ òðàíçèñòîðîâ.  êí. Î÷åðêè èñòîðèè ðîññèéñêîé ýëåêòðîíèêè. Âûïóñê I. /Ïîä ðåä. Â.Ì. Ïðîëåéêî. Ì.: Òåõíîñôåðà, 2009. - 336 ñ. ñ. 59-72.

6. È.Ä. Êèðâàëèäçå, Ñ.Ò. ×åðíÿâñêàÿ. Î âëèÿíèè òåðìè÷åñêîé îáðàáîòêè è èîííîé áîìáàðäèðîâêè íà äèîäíûå ñâîéñòâà êðåìíèÿ â òî÷å÷íîì êîíòàêòå. ÔÒÒ, 1959, ò.1, âûï.1, ñ. 155-160 7. È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, À.Ã.Êóäçèåâ, Ã.È. Òêåøåëàøâèëè, Â.Ê. Öõàêàÿ, Ë.M. Öàêàäçå. Âëèÿíèå ðåëüåôà ïîâåðõíîñòè êàòîäà íà âîëüò-àìïåðíûå õàðàêòåðèñòèêè òåðìîýìèññèîííîãî ýëåìåíòà. Ïðÿìîå ïðåîáðàçîâàíèå òåïëîâîé ýíåðãèè â ýëåêòðè÷åñêóþ è òîïëèâíûå ýëåìåíòû (ÏÏÒÝÝ è ÒÝ), 1966, N 4(16), ñ.81-86.

8. È.Á. Àìèðõàíîâà, È.Ã. Ãâåðäöèòåëè, Â.Á. Ãîëóáêîâ, Ñ.À. Çàñëàâñêèé, Ò.Ò. Êàðïåíêî. Ïîëó÷åíèå è èññëåäîâàíèå ïëåíî÷íîãî òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà. Îò÷åò, ÑÔÒÈ, , èíâ. N 962, 1967. -21 p.

9. Í.Ï.Âîëîøèíà, È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàìøâèëè, Ý.Ì.Äèàñàìèäçå, Â.Ä. Æèðíîâ, Ñ.À Çàñëàâñêèé, À.Í. Êàëèíèí, Ò.Ò Êàðïåíêî, Ì.Êèíöóðàøâèëè, Ö.Ì Íåáèåðèäçå. Èçó÷åíèå ýëåêòðîôèçè÷åñêèõ ñâîéñòâ èîííîëåãèðîâàííûõ ìîíîêðèñòàëëîâ. Îò÷åò N ÃÐ 1320079 , ÑÔÒÈ, 1973.- 149 c.

10. È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ñ.À. Çàñëàâñêèé, Ì.Í. Êèíöóðàøâèëè, Ö.Ì. Íåáèåðèäçå. Ìåõàíè÷åñêèå ñâîéñòâà èîííî- ëåãèðîâàííîãî àçîòîì ìîëèáäåíà. Òðóäû II Âñåñîþçíîãî ñîâåùàíèÿ ïî ôèçèêå ðàäèàöèîííûõ ïîâðåæäåííèé òâåðäîãî òåëà. (Õàðüêîâ 25-28. 10.76, ÕÔÒÈ), Õàðüêîâ, ÕÔÒÈ, 1977, ñ, 41-49.

11. È.Ã. Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ñ.À. Çàñëàâñêèé, Ì. Êèíöóðàøâèëè Ö.Ì.Íåáèåðèäçå. Âëèÿíèå èîííîãî ëåãèðîâàíèÿ íà ýìèññèîííûå ñâîéñòâà ìîíîêðèñòàëëè÷åñêîãî ìîëèáäåíà, âîëüôðàìà è íèîáèÿ. ÏÏÒÝÝ è ÒÝ, 1977, N 2(76), ñ.146-49.

12. È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ý.Ì.Äèàñàìèäçå, À.Í.Êàëèíèí, Ò.Ò.Êàðïåíêî, Í.Ì.Êóöèÿ.Ñèíòåç ñîåäèíåíèé íèîáèÿ ïðè áîìáàðäèðîâêå èîíàìè àçîòà, óãëåðîäà è êðåìíèÿ. Òðóäû III Âñåñîþçíîãî ñîâåùàíèÿ ïî ôèçèêå ðàäèàöèîííûõ ïîâðåæäåííèé òâåðäîãî òåëà. (Õàðüêîâ 24-27.10.78, ÕÔÒÈ), ), Õàðüêîâ, ÕÔÒÈ, 19779, ñ. 56-64.

13. È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ñ.À.Çàñëàâñêèé, Ì.Ø.Êèíöóðàøâëè, Ö.Ì.Íåáèåðèäçå, Ì.À.Ñåêàíèÿ. Âëèÿíèå ðàäèàöèîííûõ äåôåêòîâ íà ðàáîòó âûõîäà ýëåêòðîíà Èíôîðìàöèîííûé áþëåòåí: Ïðÿìîå ïðåîáðàçîâàíèå ðàçëè÷íûõ âèäîâ ýíåðãèè â ýëåêòðè÷åñêóþ (ÈÁ ÏÏРÝÝ). 1980, 6 (98), ñ. 33-36.

9 14. È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ñ.À. Çàñëàâñêèé, Ö.Ì. Íåáèåðèäçå, Ì.À. Ñåêàíèÿ, Ø.À. ×îáîëàóðè. Èçìåðåíèå ðàáîòû âûõîäà èîííîëåãèðîâàííîãî êèñëîðîäîì ìîëèáäåíà ïî ìåòîäó Êåëüâèíà ñ âèáðèðóþùèì ýëåêòðîäîì. Ìàòåðèàëû çàñåäàíèÿ Êîîðäèíàöèîííîãî ÍÒÑ Ìèíèñòåðñòâà ñðåäíåãî ìàøèíîñòðåíèÿ ÑÑÑÐ “Ïî ôè-çèêå ðàäèàöèîííûõ ïîâðåæäåíèé òâåðäîãî òåëà” ïðè Õàðüêîâñêîì ôèçèêî-òåõíè÷åñêîì èíñòèòóòå (ÕÔÒÈ), (27-29.10.1980). Õàðüêîâ, ÕÔÒÈ, 1981, ñ. 67-76.

15. È.Ã. Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ñ.À. Çàñëàâñêèé, Â.Ê. Öõàêàÿ, Ë.Ì. Öàêàäçå. Èññëåäîâàíèå èîííîëåãèðîâàííîãî êèñëîðîäîì ìîíîêðèñòàëëà ìîëèáäåíà ãðàíåé <110> è <111> â êà÷åñòâå êîëëåêòîðà â ÒÝÏ. Òàì æå, ñ.77-84.

16. È.Ã.Ãâåðäöèòåëè, À.È.Ãóëäàìàøâèëè, Ñ.À.Çàñëàâñêèé, Ì.Ø.Êèíöóðàøâëè, Ö.Ì.Íåáèåðèäçå. Âëèÿíèå èîííîãî ëåãèðîâàííèÿ êèñëîðîäîì íà ýìèññèîííûå è ìåõàíè÷åñêèå ñâîéñòâà ìîíîêðèñòàëëîâ ìîëèáäåíà <110> âîëüôðàìà<110>, è íèîáèÿ <110>. ÈÁ ÏÏРÝÝ, 1983, N 1(111), ñ. 59-64.

17. For example. J.H.Freeman, MaTSU. INVITED REVIEW ARTICLE. Canal Rays to Ion Implantation 1886-1986. Radiation Effects, 1986, v.100, p.161-248.

18. Â.Ì.Ãóñåâ, Ä.Â.×êóàñåëè, Ì.È.Ãóñåâà, Ðàçäåëåíèå èçîòîïîâ ãåðìàíèÿ è ìàãíèÿ â ìàëîì ýëåêòðîìàãíèòíîì ñåïàðàòîðå. Àòîìíàÿ Ýíåðãèÿ, 1957, N 9, òîì.3, ñ.215-221.

19. Â.Ì.Ãóñåâ, Ì.È.Ãóñåâà, Â.Ï. Âëàñåíêî, Í.Ï. Åëèñòðàòîâ Èññëåäîâàíèå âçàèìîäåéñòâèÿ áûñòðûõ èîíîâ äåéòåðèÿ ñ ìåòàëëàìè. Ìàòåðèàëû I Âñåñîþçíîé êîíôåðåíöèè ïî ýëåêòðîííûì è èîííûì ñòîëêíîâåíèÿì (Ðèãà, 26 èþíÿ -3 èþëÿ 1959 ã.). Èçâ. ÀÍ ÑÑÑÐ, ñåð. ôèçè÷., 1960, ò. 24, N 6, 689-693.

20. Ä.Â.×êóàñåëè, À.È. Ãóëäàìàøâèëè, Ó.Ä. Íèêîëåèøâèëè. Ðåçîíàíñíàÿ ïåðåçàðÿäêà ïîëîæèòåëüíûõ èîíîâ ùåëî÷íûõ ìåòàëëîâ. Òàì æå ñ. 970 - 974.

Major stages of Ion implantation development in Ilia Vekua Sukhumi Institute of Physics and Technology A. I. Guldamashvili Ilia Vekua Sukhumi Institute of Physics and Technology (SIPT), N 7 Mindeli st., Tbilisi, Georgia, 0186, E-mail: sipt@sipt.org The paper presents brief survey of the years’ works in ion implantation performed by the SIPT employees, unknown for the scientific society, and basically according to the secret papers.

ionuri implantaciis ganviTarebis ZiriTadi etapebi soxumis fizika-teqnikis institutSi a.i. guldamaSvili

soxumis ilia vekuas fizika-teqnikis instituti, mindelis q. 7, Tbilisi, saqarTvelo, 0186, el-fosta: sipt@sipt.org moyvanilia ionuri implantaciis dargSi TanamSromlebTan erTad avtoris mravalwliani muSaobis ZiriTadi Sedegebis mokle mimoxilva, samecniero sazogadoebisaTvis aqamde ucnobi, ZiriTadad gansaidumloebuli Sromebis mixedviT.

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Historical aspects, state of the art and trends of further development of thermoelectricity L. Anatychuk Institute of Thermoelectricity NAS of Ukraine1, Nauky Str., Chernovtsi, 58029, Ukraine E-mail: anatych@gmail.com Abstract. In the paper the historical facts are presented that had an effect upon the development of thermoelectricity and the generalized approach applied to description of the thermoelectric energy conversion based on thermoelectric current induction resulting from them. The analysis of the thermoelectric material science problems is performed. The rational areas of thermoelectricity applications for the levels of figure of merit obtained are determined. The prospects of thermoelectricity development following from the informational and energetic theory are given attention to. The examples of mass thermoelectricity applications are provided.

Key words: thermoelectricity, generator, current, temperature.

Introduction Essentials of thermoelectricity are traditionally connected with the name of Seebeck, who is thought to be the author of the effect named after him. The effect is reduced to the emergence of thermoelectromotive forces in nonuniform electric circuits where the temperature balance is violated.

Actually, Seebeck was enchanted by the idea of the Earth’s magnetic field occurrence due to temperature difference between the Earth poles and the Equator (Fig.1).

It was reproduced in a great number of laboratories (Fig.3).

Fig.2. Schematic of the Seebeck’s experiment

Fig.1. Seebeck’s concept of the emergence of the magnetic field of the Earth

This idea led Seebeck to studying multiple couples of different materials which were brought to contact and heated to various temperatures. It finally resulted in his wellknown experiment (Fig.2) that confirmed the fact that, if the electric circuit consisted of two dissimilar materials and was heated to various temperatures, a magnetic field appeared inside such circuit that was registered by the deflection of the magnetic needle Seebeck called this effect thermomagnetism. He reported on it to Berlin Academy of Sciences on August 16, 1821. It was received with great enthusiasm.

The said effect attracted attention of Oersted, a famous physicist who discovered the magnetic interference of the electric current, as well. Apparently, Oersted paid attention to the fact that the Seebeck effect appears only at use of couples of materials that conduct electric current. He assumed, therefore, that the Seebeck effect had electrical nature and was caused by passing the electric current through the circuit of two dissimilar materials. To prove his assumption, Oersted broke the circuit in the Seebeck’s experiment and connected a galvanometer to the break.

The latter confirmed the presence of the electric current in the circuit (Fig.4).

Fig.3. Demonstration of the Seebeck’s experiment

11 Oersted reported on his discoveries to the French Academy of Sciences in 1823 in the following words: “I have the honour to present to the Assembly the amazing experiments that helped Seebeck prove the possibility of obtaining electric current in the circuit consisting of solid conductors exceptionally by distorting temperature balance in them”.

Fig.4. Oersted’s experiment

Oersted suggested that the Seebeck effect should be called thermoelectric which found its approval, though Seebeck was strongly against it. Further development of thermoelectricity followed a simple and easy to understand model of the Seebeck effect implementation in the form of a conventional thermocouple (Fig.5)

Fig.6. Use of Seebeck’sthermomagnetism for technologic processes control in blast furnaces

Secondly, the Seebeck’s experimental short-circuited model was closer to a generalized model of thermoelectric energy conversion, which will be described later.

Generalized theory of thermoelectric energy conversion The connection between the Seebeck’sthermomagnetism and a generalized model of thermoelectric energy conversion is given in Fig.7.

Fig.7. Development of the Seebeck’s experiment to a generalized thermoelectric energy converter model.

Fig.5. Thermocouple model

This very model served as a basis for both the theory of thermoelectricity and its various practical applications.

Nevertheless, Seebeck’s short- circuited circuit and the thermomagnetism effect occurring in it has not lost its topicality.

Firstly, the devices have been developed where Seebeck’s thermomagnetism is employed (Fig.6). In blast furnaces, for instance, it is used to control the steel fusion process. Short-circuited currents occurring in the melt caused magnetic fields creation that were registered by magnetometers and were used for obtaining information on the processes taking place inside furnaces.

1 – Seebeck’s experiment, 2 – optional conducting medium, 3 – thermoelectric eddy currents; external influences: – temperature, – electrical, – magnetic, – force fields.

The model is a free-form conducting medium with optional properties. The medium is influenced by the external physical fields. With the certain geometries and properties of the external fields, short-circuited currents due to heatto-electricity energy conversion are induced in it. The following condition serves as an indicator of such energy conversion

where is the electric current density vector, which can be determined from the Maxwell equations and heat and energy conservation laws:

12 Based on (6) and

all variants of thermoelectric

media and external fields where thermoelectric energy conversion takes place can be classified. The results of such classification are presented in Table 1. It is sometimes called a thermoelectricity periodic table.

From (2-4) the expression of the generalized Faraday law of electromagnetic induction can be found

The first member in the second part (5) describes the current induction in an alternating magnetic field, whereas the second one describes the current induction of the thermoelectric nature. In these expressions and are electric resistance and thermo EMF tensors; the rest of symbols are quite well-known ones.

In the absence of a magnetic field the expression (5) gives the law of thermoelectric currents induction

which provides the most generalized description of the thermoelectric energy conversion.

Here A is a medium influenced by physical fields thus causing the appearance of eddy currents in it; Î&#x2019; is a coil cut along the streamlines; C is a dynamo model; D is a generalized model of a thermoelectric energy converter; E is a particular case of a thermoelectric energy converter made of the material with dramatic inhomogeneity, a thermo couple.

Fig.8. Generalized model of energy converters development

As it is evident from the Table, there exist 124 variants of media and influences that favour thermoelectric energy conversion. Out of all, only 4 variants enjoy practical applications nowadays and 15 more are under study, whereas the rest have not been studied yet. The most interesting and functionally abundant variants of conversion are, though, the ones that have not been studied.

It is but natural to come to the conclusion based on this review that thermoelectricity is still at the initial stages of its development and practical applications.

At least one new type of a thermoelement can be found from every cell of the Table that differs from conventional ones, especially from thermocouples. A search in this direction is being carried out by way of computer methods of

Table1. Physical fields and media that favour thermoelectric energy conversion occurrence

13 solution of so-called inverse problems of thermoelectricity aimed at finding optimal temperature fields in thermoelements at the set current distributions in them (Fig.9).

Fig.9. Inverse problems of thermoelectricity

Over 20 novel types of such energy converters have already been found which extended the thermoelectricity elemental base. Let us consider some of those.

Spiral thermoelements Inhomogeneous media.

Based on the above approaches, a Bi-Te-based thermoelement was developed of functionally graded materials (Fig.10).

Fig.10. Spiral thermoelements 1 –spiral coils; 2 – spiral of coils (1); 3 –electromagnetic spiral

The inhomogeneity computed distribution is presented in Fig.10.1. A spiral was formed of such a coil (Fig.10.2).

The ability of building up voltage in a thermoelement by simple increasing the number of coils in a spiral similar to that in electrical devices is notable here (Fig.10.3). And it is but natural, as spiral thermoelements follow the generalization of the Faraday law for thermoelectric processes (4).

Fig.12. Thermoelectric generators based on spiral thermoelements

The method of this thermoelement fabrication seems also attractive (Fig.11).

The inhomogeneous rod with the central aperture is fabricated by the extrusion method; the spiral is formed by way of cutting the rod up to the middle on-the-mitre with the help of a diamond cutting tool.

The absence of junctions in such spiral devices makes them more reliable as compared to conventional soldered modules. However, a passive shunt spiral is mounted on the spiral to ensure its reliability. Such thermoelements open the possibility for applications of thermoelectric generators under conditions with very large shock loads up to 20000 - 80000 g. A set of such generators with the power of 0.2 to 10 W has been already developed (Fig.12).

Anisotropic media.

Spiral thermoelements can be developed from single crystals with the thermo EMF anisotropy. The heat source is situated inside the spiral and its outer surfaces are temperature-controlled. A spiral element fabricated of CdSbwith the material volume about 0.5 cm3 develops the voltage of nearly 1000 V at the temperature difference of 50 K. It replaces tens of thousands of thermocouples connected in-series.

Fig.13. Spiral element of anisotropic material

Fig.11. Spiral thermoelements technology 1 – extrusion, 2 – spiral preparation, 3 - spiral thermoelement, 4 – spiral redundancy

When used as sensitive heat flux sensors, such thermoelements appear to be of special interest. A set of microcalorimeters was fabricated on their basis whose ultimate sensitivity was up to 10-8 W (Fig.14). They find their application in microbiology, pharmaceutics, for substances degradation processes studies, combustible materials calorific power, at the environment bacterial pollution etc.

14

Fig.14. Microcalorimeter with anisotropic sensors

Fig.16. Reports at ITS conferences during 2012 â&#x20AC;&#x201C; 2015

And still new types of thermoelements have not found due applications, though the future, no doubt, belongs to them.

The majority of scientists and researchers dealing with thermoelectric equipment have been oriented at the application of the classical thermocouple element model within the last 70 years. Some tendencies of this trend development will be considered later.

Thermoelectricity based on thermocouples It is a common knowledge that energy applications of thermoelectricity are connected with applications of semiconductors.

Fig.17. Increase in semiconductor thermoelectric materials efficiency within the last 75 years

Fig.15. Semiconductor thermoelectricity development by academician Ioffeâ&#x20AC;&#x2122;s school

The Ioffe School created the theory of thermoelectric energy converters and requirements to semiconductor thermoelectric materials as for the figure of merit criterion Z, otherwise called the Ioffe criterion, were formulated (Fig.15).

It is the key factor the efficiency of thermoelectric devices depends on, so the efforts of the researchers were, naturally, concentrated on the improvement of its value.

This tendency is easy to trace if the number of presentations at the International Thermoelectric Society (ITS) be considered (Fig.16). The presentations on thermoelectric materials substantially outnumber those in other branches. Despite this, the successes in Z growth are very modest (Fig.17).

After the impetuous growth of the figure of merit in 1950s â&#x20AC;&#x201C; 1960s the saturation came notwithstanding the increase in the number of researches on thermoelectric material science. For practical purposes only materials developed as early as 50 years ago are used.

The results like these allow making a quite realistic prediction that dramatic increase in the figure of merit in the nearest future is not likely to happen, therefore there is every reason to pay more attention to prospects of practical applications of thermoelectricity where the level of the figure of merit of materials already obtained is considered.

Fig.18. Heat engines efficiency

15 Let us, hence, consider thermoelectric generators competitive ability with their additional advantages in reliability, lifetime, noiselessness etc. taken into account. A heat engine with a dynamo is the nearest competitor of a thermogenerator.

Fig.21. 2 W power thermogenerator

Fig.19. Thermoelectric generators for gas automation

Fig.18 provides the values of heat engines efficiency. It is evident that thermogenerators can compete against heat engines in efficiency at low powers, no more than 100 W only. If ZT increases to 3 even, competitive power can rise up to hundreds watts. For this reason preference should be given in the first turn to low-power generators at developing new thermogenerators. The demand for such generators is quite high. For automation of gas stoves, fireplaces power supply (Fig.19), for example, millions of items are required.

When free heat, such as solar energy, ocean energy, and industrial waste heat or like, is used, the approaches are entirely different. In this case it is not efficiency that is of primary importance but a thermoelectric generator specific cost S0 (Fig.22).

To estimate the generator efficiency, a coefficient K is introduced whose value is equal to the ratio between the cost of industrial electric energy and the generator specific cost. It is reasonable to apply the generator if K > 1. Here the generator lifetime N and the cost of competing industrial electricity m gain special importance.

These conditions considered, the industrial waste heat and that from heat engines utilization becomes rational.

Fig.23 demonstrates a 100-150 W thermogenerator utilizing a 6.8 MW gas turbine waste heat; exhaust gases temperature being 360-4200C. The thermogenerator is fabricated of sections, 100-200 W each, placed into the exhaust gasses flux.

Fig. 22.

Fig.20. Thermoelectric generators for boilers

Great is also the demand for 50 to 100 W generators for boilers (Fig.20). Their application enables operation of devices without electric energy from mains thus increasing their reliability and serviceability. Low-power (0.2 to 2 W) thermogenerators can become the alternative to chemical sources of electricity in many cases (Fig.21). Like gas lighters, they are filled up with propane-butane. The generator is repaid after three months of exploitation when it replaces chemical sources.

The surface temperature is 130-1800C, the generator power equals to 10 kW, and its specific cost is 2.5 $/W. The generators employ a heat concentrator and a liquid heat sink from modules. The expected lifetime is 20 years.

Thermogenerators installed in cogeneration sources of heat and electricity also seem to have good prospects (Fig.25). In the said generators exhaust gases heat energy is utilized and heat sink from the generator is carried out with liquid heat exchangers with the operating temperature of 900C which is used for heating. The generator electric power is 1.4 kW, expected profit in 10 years is ~ 40000 USD.

16 A thermogenerator mounted onto a rolling mill surface is shown in Fig.24.

Topical are developments of vehicular thermogenerators. A variant of such generator fabricated in the Institute of Thermoelectricity, Ukraine, is presented in Fig.26. It utilizes waste heat from a 9 W diesel. The generator electric power at the speed of 110 km per hour is 600 W. A liquid heat removal is used in the generator.

Fig.23. Thermoelectric generator utilizing gas turbine waste heat

Fig.26. Automobile thermoelectric generator

Fig.24. Thermoelectric generator utilizing rolling mill waste heat

Fig.25. Thermoelectric generator of cogeneration installation

The use of heat of the ocean to obtain electric energy by thermogenerators causes special interest. Such energy sources are treated as the alternative to solar power stations and, moreover, they possess significant advantages over the latter (Fig.27).

In such electric power stations temperature gradient providing nearly 20째 of temperature difference for its work is used. Cold and hot water pumping to the electric power station is a classical schematic for such installation. Despite significant losses connected with water pumping, the expected specific costs equal to about 25 $/W which is comparable But it should be taken into account that the growth rate of energy production is not that high (Fig.28) and increases annually by 4% only.

The predicted growth rate of information production, though, increases by 100% every two years. with solar power stations, their twenty-four-hour operation possibility considered.

17

Fig.27. Thermoelectric generators utilizing ocean temperature difference 1 â&#x20AC;&#x201C; ocean temperature gradient, 2 â&#x20AC;&#x201C; electric power plant with pipes for water pumping, 3 â&#x20AC;&#x201C; underwater electric power plant

This circumstance should be considered when thermoelectric products development is being planned. First of all those should be not energy devices but those of measurement technique. The attention of both researchers and developers should be duly concentrated on the latter. The information and energy theory of thermoelectric measuring devices created during last decades shows that the quality of thermoelectric measuring devices can be improved from one to three orders (Fig.29).

Fig.28. Energy and information development prediction

Great Mendeleev asserted that the increase in the measuring equipment resolution by one order only is a precondition for new discoveries in natural science. This statement should inspire those involved in novel thermoelectric measurement equipment development.

Fig.29. Opportunities of growth of thermoelectric measuring devices resolution

18 Conclusions Due to insignificant growth in the thermoelectric materials figure of merit Z, an opinion sometimes emerges about limited, if any, thermoelectricity chances.

The materials provided in the article give evidence it is quite the contrary.

1. From the generalized theory of thermoelectric energy conversion based on the law of thermoelectric induction of currents it is clear that thermoelectricity is at the initial stages of its development only. New trends in research and novel types of thermoelements will surely lead to new practical applications of thermoelectricity.

2. Limitations in the figure of merit of thermoelectric materials could in no way be an obstacle for further vast applications of thermoelectricity at powers which provide absolute advantages for thermoelectric energy conversion.

The demand for such devices is of mass character.

3. The application of thermoelectricity for industrial waste heat energy recuperators is very promising. Neither efficiency nor high figure of merit Z play a paramount role here, which enables vast use of the level of thermoelectric materials quality already obtained.

4. The prospect of use of thermoelectric generators with utilization of renewable heat sources, such as the ocean heat, soil temperature gradient, heat of human bodies etc. is of great importance as well.

5. Very attractive are also thermoelectric measuring devices, whose quality can be improved significantly (up to 10 to 100 times). Such devices can become topical as sensors, sources of information, which becomes more and more required.

istoriuli sakiTxebi, Tanamedrove mdgomareoba da Termoeleqtrobis Semdgomi ganviTarebis tendenciebi l. anatiCuki

Termoeleqtrobis instituti, 58000 naukis q. 1, Cernovci, ukraina elâ&#x20AC;&#x201C;fosta: anatych@gmail.com naSromSi warmodgenilia istoriuli faqtebi, romelTac gavlena iqonies Termoeleqtrobis ganviTarebaze. Termoeleqtruli gardaqmnis aRsawerad gamoyenebulia erTiani midgoma, romelic emyareba Termoeleqtruli denis inducirebas Termoeleqtruli gardaqmnis procesSi. Catarebulia Termoeleqtruli masalaTmcodnebis problemebis analizi. gansazRvrulia miRebuli gardaqmnis efeqturobis doneebis Sesabamisad Termoeleqtrobis gamoyenebis racionaluri sferoebi. yuradReba eTmoba Termoeleqtrobis ganviTarebis perspeqtiulobas, gamomdinare informaciuli da energetikuli Teoriebidan. naSromSi warmodgenilia Termoeleqrobis masiuri moxmarebis magaliTebi.

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The physics of carbon nanotube nanofluids and nanostructured materials for multifunctional applications F. Marquis1, G. Bokuchava2 Department of Mechanical Engineering, San Diego State University San Diego, CA 92182, USA 1 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli Str., 0186, Tbilisi, Georgia E-mail: fmarquis@mail.sdsu.edu 1

Abstract. The need for powerful and reliable thermal management systems has increased exponentially in the last two decades in order to sustain the performance of a very wide range of systems. Similarly there is a need for the development of lubricant fluids integrating increased lubricicity and increased thermal conductivity. Conventional heat transfer fluids such as water, ethylene glycol, water/ethylene glycol mixtures and lubricating oils are poor heat transfer fluids due to their low thermal conductivity. To overcome this limitation, nanofluids were first developed in 1995 by suspending spherical nanoparticles of metal and metal oxides in heat transfer fluids. It was later observed that these nanofluids showed significant limitations associated with the sphericity and agglomeration of the nanoparticles and lower values of thermal conductivity.

Later on in 2001 a new class of nanofluids consisting of colloidal suspensions of carbon nanotubes was developed. Carbon nanotube nanofluids have a much higher thermal conductivity then those based on metal and oxide particles, better stability, much increased lubricity, good fluidity, non-clogging properties and low chemical reactivness. In addition carbon nanotube nanofluids are most often the precursors for the development of advanced multifunctional and hybrid nano and nanostructured materials containing carbon nanotubes, such as: Nanolubricant Greases, Polymer Matrix Nano Composites and Ceramic Matrix Nano Composites. The values of the thermal conductivity of carbon nanotube nanofluids covers a wide range, depending on the base fluid, nano chemistry and nanophysics, processing routes and temperatures. Typical top range increments can exceed 175% for a 1vol% load. Higher increments have been achieved at higher loads but with significant increase in the viscosity. The best fluids have good fluidity, no significant settling in stationary mode over a period of several years and no significant separation in dynamic or flowing mode. This paper presents recent advances in the physics of carbon nanotube nanofluids and nanostructured materials for multifunctional applications.

Keywords: Carbon nanotubes (CNTs), carbon nanotube nanofluids (CNNFs), single wall carbon nanotubes (SWNTs), double wall carbon nanotubes (DWNTs) multi-wall carbon nanotubes (MWNTs), conventional heat transfer fluids (CHTFs), heat transfer nanofluids (HTNFs), nanolubricant fluids (NLFs), nanolubricant greases (NLGs), polymer matrix nanoncomposites (PMNCs), ceramic matrix nanocomposites (CMNCs), thermal conductivity (TC), heat capacity (HC), thermal diffusivity (TD), heat transfer performance (HTP).

Introduction Carbon nanotubes are near perfect molecules and have generated great interest since they were discovered in 1991.

The thermal conductivity of unroped single-wall carbon nanotubes have been theoretically calculated to be within the range 2000-6000 W/mK, although the thermal conductivity of SWNT multi-ropes is considerable lower and is observed to depend on the characteristics of the nanoropes, and usualy in the range of 200-400 W/mK [1-5]. The thermal conductivity of individual MWNTs is within the range of 1,000-3,000 W/mK, and the thermal conductivity of DWNTs is believed to be within the range of 1,000-4,000 W/mK. This means that the potential for enhancement of the thermal conductivity of carbon nanotube composites is much higher with SWNTs. However carbon nanotubes are very anisotropic and the transverse thermal conductivity is expected to be as low as that of fullerenes (0.4 W/ mK). Thus in principle SWNTs, DWNTs and MWNTs all have high thermal conductivity in the axial direction and the nano composite architecture can be designed in order to take full advantage of this behavior.

The electrical properties of carbon nanotubes vary from those typical of semiconducting to those typical of metal-

lic conductors depending on the type and chirality of the CNT. The average electrical resistivity of carbon nanotubes is approximately 100 micro Ohms, which is one order of magnitude lower then that of graphite.

The mechanical properties of carbon nanotubes are expected to equal or exceed the expected values of perfect materials. Since the C-C bond length in CNTs (0.142 nm) is shorter then that observed in diamond (0.152 nm), CNTs possess increased resistance against deformation. Theoretical predictions for SWNTs suggest that the Youngâ&#x20AC;&#x2122;s modulus to be in the range 1.3-1.5 TPa and the strength to be approximately of 200 GPa. For MWNTs the strength appears to be limited by the sliding of individual tubes in relation to each other and thus the strength is expected to be significantly lower, while the Youngâ&#x20AC;&#x2122;s modulus is expected to be in the range 1.0-1.1 TPa. Some of the major challenges that need to be overcome for the production of effective fully integrated carbon nanotube composites for multifunctional applications are carbon nanotube functionalization, dispersion, chemical and physical stability, integration into the appropriate matrix material and control of the tridimensional distribution of the nanotubes (nano architecture) within the composite [6-11].

20 The focus of this research is the application of robust carbon nanoparticles with superior thermal, electrical and mechanical properties and well established physical and chemical stability in order to design and manufacture new classes of very novel, unique and efficient carbon nanotube nanofluids, greases and nanocomposites, with much lower additive concentrations.

Experimental Materials Typically the nanomaterials used in this investigation have the following characteristics: SWNTs unroped (1-1.4 nm in diameter), SWNTs (roped) (10-50 nm), MWNTs (typically 10 to 50 nm, unroped), Vapor grown carbon fibers (30-200 nm and on average 100-150nm. This means that MWNTs and SWNT ropes have three orders of magnitude more surface area and unroped SWNTs have four orders of magnitude more surface area than conventional fibers.

Thus MWNTs, and roped SWNTs in a nanomaterial may produce what is still considered a solid percolated network while the unroped SWNTs (and possible DWNTs) have a chance to take on similar properties to the base material and thus induce thermal conduction by other means. In addition SWNTs are molecules on a similar scale to nanoceramics, polymers and fluid molecules. In this research we used two distinct paths for engineering carbon nanotube nanocomposites: (1) produce a mixture where the nanotubes are added in, in order to change the thermal conductivity, electrical conductivity, toughness and strength via the rule of mixtures starting conditions and, (2) produce hybrid nanomaterials where the nanotubes are fully integrated into the matrix in order to mimic the properties of the carbon nanotubes into the final nano composite. The second always generated the best performance with the highest degree of effectiveness and lowest carbon nanotube load.

Results and Discussion Types Nanofluids and Nano Composites Investigated.

Five types of advanced carbon nanotube nanocomposites have been developed, manufacture and tested for mulitifunctional applications: 1. Heat Transfer Nanofluids (HTNFs) or Nanocoolants.

These composites are based on three base fluids: a) Water, b) Water/ethylene glycol mixtures, and c) Water/antifreeze mixtures. The primary capability of these nanomaterials is to transfer heat due to their higher thermal conductivity, modified heat transfer coefficient and heat capacity which are the main design parameters. Typical applications of this type of nanomaterials are radiator coolants for all types of vehicles both military and domestic, air conditioning systems, cutting fluids, quenching fluids and many others based on heat transfer capabilities. In the case of radiator coolants one typical anticipated benefit will be the downsizing of the entire coolant system.

2.

Nanolubricant Fluids (NLFs). These composites are based on three types of base fluids: a) commercial oils, b) synthetic poly-alpha olefin oils, c) lubricant fluids under controlled specifications. The primary capabilities of this type of nanomaterials is to fold: (1) transfer heat due to the

control of the design parameters described above in number 1 and (2) higher lubricicity due to a lower friction coefficient. Typical applications are engine coolants for all types of engines both military and domestic. The anticipated benefits are: (1) downsizing engine blocks, (2) redesign of engine systems, (3) higher durability of engine components, (4) shorter engine downtime, (5) lower operation costs.

3.

Nanolubricant Greases (NLGs). These composites are based on fluids and grease such as bases: a) synthetic poly-alpha olefin oils and, b) controlled specifications greases. The primary capabilities of these nanomaterials are also two fold, as described above in number 2.

However in this case the carbon nanotube load is much higher typically between 1 and 6 volume percent. The typical carbon nanotube load in type 1 and type 2 of nanomaterials is typically between 0.05 and 1 volume per cent.

Typical applications of type 3 of nanomaterials are high stress contact gears for rotary crafts. In this case the anticipated benefits are three fold: (1) Higher torque being transmitted, (2) less heat being generated, (4) more heat being dissipated, (4) longer flight duration and (5) longer life of the metallic components.

4.

Polymer Matrix Nano Composites (PMNCs). In order to develop carbon nanocomposites for multifunctional applications requiring thermal, electrical and mechanical property enhancement a number of polymer matrix composites have been designed and manufactured. These matrices consist of both thermoplastic and epoxy matrices.

The focus of this research is the fully integration of unroped SWNTs and MWNTs in these matrices. Typical applications are aerospace and astronautical components.

5.

Ceramic Matrix Nano Composites (CMNCs). In order to develop carbon nanocomposites for multifunctional applications requiring thermal, electrical and mechanical property enhancement a number of nano ceramic matrix composites have been designed and manufactured.

These matrices consist of nano zirconia, nano stabilized nano zirconia and other nanoceramic matrices such as SiO2, TiO2, and LiO2. The focus of this research is the fully integration of the unroped SWNTs, DWNTs and MWNTs in these matrices and the control of the nano architecture through advanced processing.

Materials Processing Cutting of MWNTs and SWNT Multi Ropes and Exfoliation of SWNT Ropes. One of the major obstacles in the dispersion of SWNTs is the inability to resolve the entanglements of multi-ropes into single ropes and the inability to exfoliate the single ropes into single SWNTs. The magnitude of the entanglement of the multi-ropes is often magnified during purification of the as produced SWNTs. One of the most promising methods towards the exfoliation of these ropes is through their cutting. This process can both contribute to the exfoliation the ropes and help retard the process of agglomeration by shortening the nanotubes.

The ropes and the nanotubes can be cut through either physical or chemical means, leaving them open on the ends for end cap functionalization. Chemical and physical processes were used to cut and exfoliate the multi-ropes by

21 penetration between individual tubes in bundles. Exfoliation can be achieved through complex processes such as acid treatments used in conjunction with sonication and by high energy milling with nanoparticles. These sites at the end of nanotubes, once opened up, are inhabited by groups such as a â&#x20AC;&#x201C;COOH until replaced with a final group used to functionalize the nanotubes, leading to a higher colloidal suspend ability in a particular matrix. This is confirmed by the data presented in Figures 1 and 2. This data is in very good agreement with the insitu particle size distribution presented in Figure 3. Notice that the agglomerate size for the same base nanofluid is much smaller for MWNTs then for SWNTs due to their higher dispersibility.

Full Integration of CNTs in Nano Ceramic Matrices.

SWNTs, DWNTs and MWNTs were fully integrated in nanoceramic matrices using hydrothermal reactions at elevated temperatures and pressures, followed by sintering under hot isostactic compression. Typical results are shown in Figure 4

Modeling Thermal Conductivity The research carried out during the last seven years on carbon nanotube nanofluids confirms that the rule of mix-

tures is not adequate to describe the remarkable contributions of carbon nanotubes to thermal conductivity of CNNFs. Thus new approaches have been designed to quantitatively evaluate these contributions but none of them has yet been able to fully explain the mechanisms and model all the experimental data now available. In order to fully harvest the potential of CNNFs we need to develop robust physically based models that establish reliable relationships between the nanofluid architecture, temperature, the thermal conductivity and thermal performance. One of these approaches developed by the Marquis and co-workers is based on the morphologies of the agglomerates of the carbon nanotubes that they observed and on the Nielsen Model for conductive fillers in a matrix. These observed morphologies have been reported elsewhere [4,5,10]. We assume that most of the nanotubes in suspension are not individual CNTs but agglomerates of CNTs. Thus the CNTs would not remain straight and rigid, but would be in a dynamic folded state, thereby providing an effective agglomerate of various L/D shapes. These shapes are obtained by shuffling together a certain number of specific carbon nanotubes in a colloidal suspension of a CNNF in a specific stationary and or flow condition. It is important to notice

Fig. 1. left: as-produced HiPCo SWNTs bundled into ropes with amorphous carbon and metal catalysts adhering to the surface of the CNT ropes; right: partial exfoliation of SWNTs multi-ropes achieved through higher energy planetary milling with nano-zirconia particles.

Fig. 2. left: purified, HiPCo ESD SWNTs showing the multi-rope morphology. The striations running in the longitudinal direction of the ropes indicate the individual SWNTs. The diameter of the individual tubes is between 1 and 2 nm; right: partial exfoliation of multi-ropes of SWNTs.

22

Fig. 3. Intensity–weighted nanoparticle size distribution, left: .05% MWNTs in water/ethylene glycol (50/50) mixture; 0.01% ESD CNI SWNTs in water/ethylene glycol (50/50) mixture.

Fig. 4. Morphology of two nano-zirconia/MWNT composites showing homogeneous dispersion of fully coated MWNTs. The volume fraction of MWNTS is 34 %. The white spots indicate ends, nodes, and defects of CNTs

that CNNFs are non Newtonian shear thinning fluids, where the viscosity is strongly dependent on the shear rate. This is so because of the change in the the nanofluid architecture with shear rate. This model is based on Einstein’s viscosity model and can be represented by the following equations:

K =

k1 (1+A.B.ϕ2)/(1-B·ψ·ϕ2) (1)

B = (k2/k1-1)/(k2/k1+A)

(2)

ψ = 1+ (1-ϕm·ϕ2) /ϕm 2

(3)

K is the thermal conductivity of the CNNF, A quantifies the particle shape, k1 is the thermal conductivity of the base fluid, k2 is the thermal conductivity of the carbon nanotube , ϕ2 is the volume loading of carbon nanotubes, ψ is the packing efficiency and ϕm is the maximum packing efficiency. These constants A, B and ϕ m have been calculated and have been reported previously [5-9]. With this model we can explore various factors that can affect thermal conductivity of nanofluids such as the carbon nanotube aspect ratio (l/d), the carbon nanotube agglomerate aspect ratio (L/D), and decoupled orientation effects along nanotube axis Kl, and transverse to nanotube axis Kt, along with overall volume loading

This model is very effective in predicting that the architectural units are still primarily agglomerates of carbon nanotubes (and not individual carbon nanotubes) and the geometry of these agglomerates. This was further confirmed by electron microscopy (SEM and TEM) and by intensity weighted particle size analyses. An Excel program was written to investigate the above relations. An example of the output is shown in Figure 5, applied to the data presented in Figure 3. It is interesting to note that within the ranges of CNT loads presented there are non-linear portions to the model, which may assemble to link to the general nonlinear behavior observed. Further model development, synergistic with experimental nanofluid production and architecture quantification is needed. One of the limitations of this model is its inability to fully account for the remarkable effect of temperature on the thermal conductivity of the specific carbon nanotube nanofluid.

Conclusions This research work demonstrates the feasibility of developing fully integrated carbon nanotube nano fluids such as heat transfer fluids and lubricants fluids, greases, hybrid polymeric and hybrid nano polymeric and ceramic based composites with improved multifunctional properties such as strength, toughness, thermal and electrical conductivi-

23

Fig. 5. Left: MWNTs used in Fig. 5 showing the variation in nanotube size and the open nature of the network. Right: Effect of loading and architectural parameters on the thermal conductivity.

ty. In order to achieve the best multifunctional performance the carbon nanotubes must be fully integrated in liquid, greases, polymer and ceramic matrices and processing must be accomplished by looking behind the typical approaches used in the past for the development of more conventional composites.

References 1. F. D.S. Marquis and L.P.F. Chibante “Improving the Heat Transfer of Nanofluids and Nanolubricantes with Carbon Nanotubes”, Journal of Materials, 12 (2005) 32-44.

2. N. Canter “Preparing Heat-Transfer Nanofluids” Tribology & Lubrication Technology, 12 (2006)14-16.

3. J. A. Eastman, S.U.S. Choi, S. Li, W. Yu, and L.J. Thompson, “Anomalously Thermal Conductivity Enhancement in Nanotube Suspensions” “ Appl. Phys. Lett.79, no. 14 (2001), 2252-2254.

4. “Functional Composites of Carbon Nanotubes and Applications”, Lee, K-P, Gopalan, A.I. and Marquis, F.D.S. Marquis, Research Signpost (2009), ISBN 978-81-7895-413-4.

5. Marquis F.D.S, “The Nanotechnology of Carbon Nanotube Nanofluids” in “Functional Composites of Carbon Nanotubes and Applications”, Lee, K-P, Gopalan, A.I. and Marquis, F.D.S. Marquis, Research Signpost (2009), ISBN 97881-7895-413-4.

6. Holmes, A.C. 2007, Design and Manufacture of Fully-Integrated Carbon Nanotube Nanoceramic Composites for Multifunctional Applications, NPS Thesis.

7. Hicks, T.D. 2007, Development of Fully-Integrated Carbon Nanotube Nanogreases, NPS Thesis.

8. Marquis, F.D.S. “The Role of Powder Materials in Energy Efficiency in the Transportation Industry” JOM, 64, 3 (2012) 367-373.

9. Marquis, F.D.S. “Powder Materials and Energy Efficiency in Transportation: Opportunities and Challenges” JOM, Vol 64, 3 (2012) 365-367.

10. Marquis, F.D.S. “Carbon Nanotube Nanostructured Hybrid Materials Systems for Renewable Energy Applications” JOM, Vol 63, 1 (2011) 48-53 11. Marquis, F.D.S., “Carbon Nanotube Nano Composites for Multifunctional Applications”, Mater. Sci. Forum, 561-565 (2007) 1397-1402.

naxSirbadis nanomilakebiani nanosiTxeebis fizika da nanostruqturirebuli masalebi multifunqciuri gamoyenebisaTvis ferdinand d.s. markusi1, g. bokuCava2 1

san diegos saxelmwifo universiteti, meqanikuri inJineriis fakulteti, san diego, 92182, aSS 2 ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo el-fosta: fmarquis@mail.sdsu.edu ukanaskneli oci wlis manZilze geometriuli progresiiT gaizarda moTxovnileba sapoxi siTxeebis xarisxis mkveTri gaumjobesebis mimarTulebiT, gansakuTrebiT maTi lubrikantuli Tvisebebisa da Tbogamtarobis gazrdis TvalsazrisiT. 2001 wels SemoTavazebul iqna axali ti pis nanosiTxeebi naxSirbadis nanomilebis fuZeze, romlebsac aRmoaCndaT saukeTeso saeqspluatacio maxasiaTeblebi, vidre metalis an maTi oqsidebis nanofxvnilebze damzadebul sapox sistemebs. aRsaniSnavia is faqti, rom naxSirbadis nanomilebis nanosiTxeebma mTavari roli iTamaSes axali multifunqciuri masalebis misaRebad. aseT masalebs ganekuTvneba polimeruli da matriculi keramikuli nanokompozitebi. am sferoSi maTi gamoyeneba ganapiroba naxSirbadis nanomilakebis unikaluri Tburi, eleqtruli da meqanikuri Tvisebebis Sexamebam, fizikurma da qimiurma stabilurobam. maTi meqanikuri Tvisebebi eTanadeba an aRemateba arsebuli masalebis saeqspluatacio maxasiaTeblebs. warmodgenili statia warmoadgens uaxloesi miRwevebis mimoxilvas naxSirbadis nanomilebis fuZeze damzadebuli nanosiTxeebisa da multifunqciuri daniSnulebis nanostruqturuli masalebis Seqmnis Sesaxeb.

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High-pressure studies of novel superconducting and magnetic materials M.S. Torikachvili Department of Physics, San Diego State University, San Diego, CA 92182, USA, E-mail:miltont@mail.sdsu.edu Abstract. Hydrostatic pressure is a powerful experimental tool for the study of complex phenomena in condensed matter physics. By compressing the lattice in a controlled manner, pressure allows the fine-tuning of a number of physical properties, which in turn permits a detailed mapping of phase transformations, as well as bringing them about in some cases.

This is accomplished without the introduction of disorder, which frequently plagues substitutional studies. In this paper I will discuss 1) the fundamentals for pressure studies; 2) the basic techniques for the measurement of electrical, magnetic and thermal properties under pressure; and 3) present a few examples of the important pressure studies in superconductors (SC), magnetically ordered systems, structural transformations, and charge-density-wave (CDW) systems.

Keywords: magnetism, phase transitions, pressure, superconductivity.

Introduction Hydrostatic pressure (P) is a remarkable tool for experimental condensed matter physics, chemistry, and material sciences in general. Pressure is a thermodynamic parameter, and therefore it has a bearing on phase stability. Phase diagrams having P as one of the variables are of great interest in many fields of research. By pressurizing the lattice we can affect the electronic, magnetic, structural, and optical properties, in ways that can be helpful in the understanding of novel phenomena. Pressure has been an important factor in a number of remarkable discoveries, as the three examples given below. Even though Fe is regarded as toxic to superconductivity, i.e. even in small amounts it can suppress SC in the host compound, it becomes nonmagnetic and SC itself at high pressures.1-2At ambient pressure SmS displays poor reflectivity and the behavior if its electrical resistivityvs temperature is typical of semiconductors. However, in modest pressures near 0.5 GPa a semiconductor-metal phase transition takes place, its reflectivity increases manifold, and it acquires a metallic gold coloration.3Pressure experiments in Ba-La-Cu-O materials were found to raise the superconducting transition temperature Tc above its P = 0 values near 30 K. The substitution of Y for La generated “chemical” pressure, and ultimately lead to the discovery of SC near 90 K in YBa2Cu3O7.4-5It is predicted that some hydrogen compounds and pure ä hydrogen itself can become SC with high Tc’s at very high pressures.6 However, in addition to being technically very challenging, these experiments are perhaps beyond the limits of the current experimental capabilities, and these predictions remain to be tested.

Experimental Techniques There are a vast number of high-pressure techniques, including hydrostatic, uniaxial, static, dynamic, etc., using a gas, liquid or finely refined solid as the pressure transmitting medium. An up-to-date reference is the text by Eremets.7 I’ll describe below in brief detail the methodology for 2 of the most commonly used types of cell for studies of

bulk properties, the piston-cylinder, and the diamond-anvil cell (DAC). The self-clamped piston-cylinder cell of Fig. 1 has a workable space of about 40 mm3 and it is capable to reach 2.5 GPa reliably. The body is build of Be-Cu, and it has a press-fit core of a hard material, that can be aNiCrAl alloy, WC, or other hardmaterial. For electrical transport measurements, the sample and manometers are mounted on an epoxy sealed feedthrough which is then inserted in a PTFE cup containing a pressure transmitting medium, pushed into the core of the cell, and locked in place. Force is applied at the closed end of the PTFE cup with a fit piston, by means of a hydraulic press, and locked in with a lock nut. In light of the different thermal expansion characteristics of the constituents, the pressure in this type of cell can change noticeably with temperature.8 Pressures near ambient temperature are more conveniently monitored with a manganin manometer, and at low temperatures with the SC Tc of Pb or Sn. A schematic representation of a DAC is shown in Fig. 2. A metal gasket is pressed in between the flat culets of two opposing diamonds. A small hole is drilled into the pre-indented part of the gasket and it becomes the sample space. The sample space volume is typically < 10-2 mm3, and the maximum attainable pressure is inversely proportional to the size of the sample space. This small sample volume obviously imposes many technical challenges. The pressure value can be monitored by the luminescence of ruby. Pressures in excess of 400 GPa have been reported.

In this section we describe recent pressure studies carried out in three materials displaying complex behavior.

UNi0.5Sb2–The UNi0.5Sb2compound displays antiferromagnetic (AFM) order below TN H” 161 K, and corresponding features have been identified in measurements of several bulk properties, including magnetic susceptibility, electrical resistivity, specific heat, thermal expansion, thermopower, and thermal conductivity.11 In addition, two minor features centered near 40 and 85 K have also been identified. Displayed in Fig. 3 is the electrical resistivity vs temperature on a single crystal in pressures up to 2.1 GPa. Hydrostatic pressure drivesthe value of TN up at the rate of

25

Fig. 1. Top: parts of a 2-layer piston-cylinder pressure cell. The main body of the cell is Be-Cu, with a core of NiCrAl alloy or WC; bottom: feedthrough showing the wiring for the sample, Pb, and manganin manometers.

Fig. 2. Schematic representation of a diamond-anvil cell. Left: easy optical access to the sample;9 right: preindentation of the gasket and force distribution.10(From Refs. 9 and 10)

H” 7.6 K/GPa. It also suppresses the features at 40 and 85 K, such that near 2.1 GPa they can no longer be identified.

Hydrostatic pressure studies

LaAg2Sb2– The intermetallic compounds RAg2Sb2 (R = rare earth) have remarkable electronic properties. They crystallize in a simple tetragonal structure such that layers of Sb, Ag, and R-Sb are stacked along the c axis.12 One manifestation of this structural anisotropy is in nesting of the Fermi surface yielding two CDW transitions in LaAg2Sb2, one more pronounced at T1 H” 210 K, and a much more subtle at T2 H” 185 K.12-13The effect of hydrostatic pressure on the behavior of r(T) is shown in Fig. 4. The r(T) data show that pressure lowers the normal state resistivity,

and lowers the onset temperature of the higher temperature CDW state at the approximate rate of -43 K/GPa. The extent to which the CDW gaps the Fermi surface can be gauged by quantifying the increase in r just below TCDW. The right panel of Fig. 4 shows a plot of Dr/rCDWvs T/T CDW, where Dr is the difference between ther(T)data and the extrapolated value from above TCDW, in pressures up to 2 GPa. A simple caliper of how much Fermi surface is gapped by the CDW is to take the maximum value of Dr(T)/r(TCDW) for each pressure.14 AEFe2As2(AE = Ca, Sr, Ba) – The parent iron arsenide compounds CaFe2As2, SrFe2As2, and BaFe2As2 display structural/magnetic transitions in the 80 – 200 K tempera-

26 ture range, and are not SC at ambient pressures. However, SC can be realized upon doping, or by applying pressure.

In light of the many unusual properties, and Tc values as high as 38 K, these materials attracted great attention.

higher temperature. In light of the correlation between the magnetic and electrical transport properties, it is natural to consider that this gap can be due to magnetic correlations, and that it is perhaps the pseudogap reminiscent of the high temperature SC copper oxide based materials. Pressure drives the maximum in rc(T)upwards in temperature as shown in the bottom panel. The pressure induced suppression of the gap correlates well with the onset of superconductivity near 4.0 GPa.

Fig. 3. Normalized electrical resistivity Ď /Ď 300K vs temperature for UNi0.5Sb2 in pressures up to 2.1 GPa for (a) I//ab-plane; and (b) I//c. The curves for P > 0 are offset for clarity. The inset shows the pressure dependence of TN. (From Ref. 11)

Naturally the issue of pairing mechanism is of great interest. Shown in Fig. 5 are plots of ra(T) and rc(T)for BaFe2As2 in pressures up to 2.3 GPa. The anomaly near 138 K is due to a structural/magnetic transformation.16The effect of pressure is to suppress this anomaly. A full suppression of the anomaly and a zero resistance state can only be accomplished near 4.0 GPa.17 The ambient pressure rc(T)data for BaFe2As2display a maximum near 225 K, which is consistent with the formation of an energy gap at 15

Fig. 5. Temperature dependence of the electrical resistivity in BaFe2As2 under pressure across the a (in-plane) and c (interplane) axis, top and bottom panels, respectively. Pressure values (in kbar) shown are at 4.2 and 300 K. The inset of the top panel shows the pressure dependence of the temperature

Fig. 4. (left) r(T)curves for LaAg2Sb2 in pressures P300K = 0.25, 0.70, 1.11, 1.50, 1.94, and 2.12 GPa; (right) normalized resistivity change below TCDW as a function of the effective temperature. (From Ref. 14)

27 of the structural transformationTsinferred from the anomaly in r(T). The bottom inset shows the pressure dependences of Ts as well, and of the temperature of the maximum in r(T). (From Ref. 17)

Conclusions In summary, pressure studies can provided great insight into the physics at play in a large number of phenomena. Pressure techniques are becoming more widespread and they are being incorporated in a variety of analytical techniques.

Acknowledgment MST gratefully acknowledges support from the US National Science Foundation under contract No. DMR0805335.

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Rev. B 79, 224518 (2009).

axali zegamtari da magnituri masalebis Seswavla maRali wnevis pirobebSi m.s. torikaCvili

fizikis departamenti, san diegos saxelmwifo universiteti, san diego, CA 92182, amerikis SeerTebuli Statebi el–fosta: miltont@mail.sdsu.edu hidrostatikuri wneva warmoadgens Zlier eqsperimentul saSualebas kondensirebuli nivTierebebis fizikis rTuli movlenebis Sesaswavlad. kontrolirebad garemoSi mesris SekumSvis Sedegad, wneviT SesaZlebeli xdeba fizikuri Tvisebebis koreqtireba, romelic, Tavis mxriv, fazuri gardaqmnebis detaluri suraTis Seswavlis saSualebas gvaZlevs, rogorc es zogierT SemTxvevaSi gamoiyeneba. es procesi sruldeba mesris struqturis darRvevis gareSe, rac xSirad arTulebs Semcvleli kvlevebis Catarebas. kvlevaSi ganxilulia: 1) wnevis gavlenis kvlevis safuZvlebi; 2) eleqtro, magnituri da Termuli Tvisebebis gazomvebis ZiriTadi meTodebi wnevis qveS; da 3) warmodgenilia ramdenime magaliTi zegamtarebis magniturad mowesrigebuli sistemebis, struqturuli gardaqmnebis muxti-simkvrive-talRa sistemebis SeswavlaSi wnevis mniSvnelobis Sesaxeb.

28

Mechanical relaxation processes in monocrystalline Si-Ge alloys I. Kurashvili, G. Darsavelidze Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli Str., 0186, Tbilisi, Georgia E-mail: sipt@sipt.org Abstract. Regularities of changing dynamic shear modulus and mechanical oscillations energy scattering temperature spectra in monocrystalline Si1-xGex(x≤0,02) alloys have been investigated. Activation characteristics of structural defects motion have been determined. It has been established, that increasing of Ge concentration causes a decrease of relaxation processes activation characteristics of Si-Ge alloys. Contribution of 600 - and screw dislocations in formation of relaxation processes and shear modulus temperature spectra has been analyzed.

Keywords: Si-Ge, internal friction, shear modulus,activation characteristics.

Introduction Silicon-germanium (SixGe1-x or Germanium –silicon Ge1Si , where x indicates the mole fraction of silicon) is a comx x plete solid-solution semiconductor having the diamond cubic structure. SiGe alloys have attracted great interests for both microelectronic and optoelectronic devices and various functional materials because of the potential for band-gap and strain/lattice parameter engineering they offer. That is, alloying leads to various unique effects on fundamental properties, absent in the component materials Si and Ge. It is well known, that growth of bulk single crystals of SiGe alloys is difficult because of a large miscibility gap and the differences in the densities, lattice parameters and melting temperatures of the constituent elements.

We have investigated monocrystalline Si1-xGex (x≤0,02) alloys in which dislocation density varies in the interval of 103-5.104cm-2. Metallographic studies showed, that by raising Ge content, concentration of dislocation origin defects increase. However, this type of material is suited for a basic study of Ge effect on defects mobility in SiGe alloys.

Basic studies [1-3] illustrate complex character of influence of Ge on dislocations velocity and mechanical properties of SiGe alloys.

Immobilization of dislocations due to the dynamic development of a solute atmosphere around them during deformation leads to an extra stress necessary to release the dislocations from the solute atmosphere. It is shown, that the release process of a dislocation from its solute atmosphere is a thermally activated one.

In the last 10-12 years our creative group experimentally investigated energy dissipation processes of elastic oscillations in a wide temperature range and strain amplitudes of mono- and polycrystalline SiGe alloys. Decrease of activation characteristics of different dislocations motion by increasing Ge content has been established. [4-6].

Some characteristics of dislocation braking and microplastic deformation have been determined from measurements of the amplitude dependences of the shear modulus and internal friction [7].

Materials and Methods Internal friction (Q-1) and squared frequency (f 2), proportional to the dynamic shear modulus, were investigated by the laboratory equipment with reverse torsion pendulum, on which axis samples with 0,6-0,8 mm diameter and 40-50 mm length were fixed with refractory clay based onSiO2. Measurements of Q-1 and f2 temperature dependences were carried out in vacuum 10-4Torr. Sample temperature, logarithmic decrement of damping and oscillations frequency were determined semi-automatically. Measurements were conducted in the following intervals : oscillations frequency - 0,5-5,0Hz, strain amplitude - 1.10-5-5.10-3 and temperature- 20-950°C. Heating-cooling process was carried out indirectly by a resistance furnace.

Activation characteristics of relaxation processes have been determined by known Wert-Marx equation [8]: H ≈ R ⋅ Tmax ⋅ ln

Rk ⋅ Tmax . h ⋅ f max

where R-gas constant, h- Planck’s constant, k-Boltzman constant, Tmaxand fmax temperature and frequency of maxima.

Results and Discussions Temperature dependences of internal friction and dynamic shear modulus of p- type Si + 0,25at% Ge, Si + 1,0at% Ge and Si + 2,0at% Ge alloys specimens have been studied.

Samples were oriented in [111] crystallographic direction.

Dislocation density in their real structure has been varied within 103-104cm -2range.

Fig.1 shows internal friction spectra of Si-Ge alloys, at frequencies ~1 Hz in room temperatures area those contain intensive maxima on exponential background in 300, 450, 600 and 710°C temperatures areas. All three temperatures spectra are thermally unsustainable.

It is seen that, maximum near 300oC significantly reduced by increasing Ge concentration. Its shape and intensity practically does not change depending on strain amplitude in interval of 5.10-5-1.10-3. That shows nondislocation origin of the mentioned maximum. Characteristics of

29 other maxima depend on Ge content and strain amplitude.

That according to the theory [9] indicates their dislocation origin.

Fig. 2. Temperature dependence of relative shear modulus of monocrystalline Si-Ge alloys.

1. Si+0,25at%Ge,2.Si+1,0at%Ge, 3. Si+2,0 at%Ge f0 – frequency at room temperature Fig. 1. Internal friction temperature spectra of monocrystalline Si-Ge alloys 1. Si+0,25at%Ge, 2.Si+1,0at%Ge, 3.

Si+2,0at%Ge

During the first measurement intensities of background and all Q-1 maxima significantly decrease under the influence of heating. By increase of oscillations frequency up to 5Hz internal friction maxima shift towards high temperatures by 15-20°C, that confirms their relaxation nature. Activation characteristics of relaxation maxima are presented in table 1.

Table 1. Activation characteristics of Internal friction maxima

Experimental samples Si+0,25at%Ge

Si+1,0 at%Ge

Si+2,0at%Ge

Temperatures of maxima, oC 280-300 450 600 710 280-300 430

Activation energy Characteristics, eV 1,35 1,70 1,90 2,20 1,35 1,65

Frequency factor, sec-1 1.1013 5.1012 2.1012 8.1011 8.1012 4.1012

580 690 280-300 420 570 675

1,80 2,00 1,30 1,60 1,70 1,85

1.1012 6.1011 4.1012 1.1012 8.1011 3.1011

Table 1 shows, that activation characteristics of internal friction maximumnear of 3000C temperature is independent of Ge concentration.

Nonmonotonous changes of shear modulus in a wide temperature interval confirm complicated nature of torsion oscillations energy scattering processes (Fig.2).

At the relaxation processes temperatures shear modulus defect has been revealed. Its value is proportional to the relaxation maxima intensity.

As is established from Fig.2 temperature intervals of shear modulus anomalous increasing have been revealed.

They shift towards low temperatures by increasing Ge content in Si-Ge alloys. At the same time shear modulus anomalies reveal more clearly.

Thermal annealing in vacuum at 800°C temperature for 3 hrs. causes significant decrease of relaxation internal friction maxima intensities and reveals tendency to their shifting towards high temperatures. In above mentioned conditions thermal annealing practically does not influence on nonmonotonous variation of shear modulus. It is supposed, that shear modulus anomalous changes in a wide range of temperature may be connected to the configuration and composition transformation in various defects complexes distributed in the Cottrell atmosphere around dislocations.

Decrease of activation energy of dislocation origin relaxation maxima by increasing Ge concentration is in full compliance with literature data [10], where based on ó-e diagrams analysis, raising different types dislocations mobility has been shown in a wide range of Ge concentration in bulk Si-Ge alloys.

As mentioned above,relaxation internal friction at 280300oC temperatures is not dislocation origin. It might be connected to migration of point defects in the elastic stress field, such as a pair of vacancy-oxygen atom. Similar maximum stipulated by motion of the above mentioned defect is really detected in internal friction spectrum of neutrons irradiated Si [11]. In this case appropriate number of vacancies in experimental Si-Ge samples are generated in crystal superficial layers during mechanical polishing. Decreasing maxima intensity might be connected to decreasing concentration of oxygen atoms in interstitial positions, that is characteristic for Si-Ge alloys [12].

Considering the presence of different from each otherquantitative characteristics of activation energy of various dislocation motion in crystalline lattice of siliconit is supposed, that maxima at 450 and 6000C temperatures are conditioned by lateral motion of single kinks on 60°- and

30 screw dislocations respectively. It is supposed, that relaxation origin maximum in the vicinity of 710oC temperature is connected with generation and migration of double-kinks on 60°-dislocations.

Received results allows to estimate some parameters of dislocation structures in the experimental Si-Ge alloys based on dislocation double-kinks motion theory forbodycentered cubic crystals with high Peierls barriers [13].Peierls stress for the double kinksmotion on the 60°-degree dislocation can be calculated by following equation:

Table 2. Characteristics of IF maximumconnected with doublekinks motion on the edge 600-dislocations

In summary, conducted investigations, due to the high sensitivity and selectivity of IF method, provide sobtaining information about the mechanisms of mechanical energy dissipation, caused by various dislocations motion in Si-Ge alloys.

Conclusion Regularities of changing activation characteristics of energy dissipation relaxation processes in torsion oscillations 0,5-5,0 Hz range of monocrystalline Si1-xGex(x≤0,02) alloys have been studied. It is shown, that increasing of Ge content in Si-Ge alloys reveals activation energies decreasing trend of different types dislocations, participated in relaxation processes.

References: 1. I.Yonenaga, Dislocation dynamics in SiGe alloys, J.of Physics: Conference Series 471 (2013) 012002-1- 012002-10 2. I.Yonenaga . Dislocation Velocities and Mechanical Strength of Bulk GeSi Crystals, Physica status solidi (a), 1999, 171, 1, 41 46.

3. I.Yonenaga. Growth and mechanical properties of GeSi bulk crystals. Journal of Materials Science: Materials in Electronics, 1999, 10, 5-6, 329 333.

4. I.Kurashvili , G.Bokuchava ,T. Mkheidze, I. Baratashvili, G.Darsavelidze. Inelastic Properties of the Monocrystalline Si-Ge Alloys. Bulletin of the Georgian National Academy of Sciences. 2007, V 175, N4, 62-65 5. G.Darsavelidze, T. Mkheidze, I.Kurashvili, R.Esiava, G.Bokuchava,A.Guldamashvili, B.Shirokov. Influence of germanium on physical-mechanical properties of monocrystalline silicon.Proceedings of XVII International conference on “Physics of radiation phenomena and radiation material science”.2006, Alushta, Crimea, p. 100-101.

6. I. Kurashvili, G. Darsavelidze, G. Bokuchava, I. Tabatadze, G. Chubinidze. Influence of germanium and boron doping on structural and physical-mechanical characteristics of monocrystalline silicon. Journal of International Scientific Publications: Materials, Methods and Technologies. Vol. 8, ISSN 1314-7269 (Online). 298-302. http://www.scientificpublications.net 7. [7] I. Kurashvili Ia, E. Sanaia, G. Darsavelidze, G. Bokuchava, A. Sichinava, I. Tabatadze, V. Kuchukhidze. Physical-Mechanical Properties of Germanium Doped Monocrystalline Silicon. J.Materials Science and Engineering A 3 (10) (2013) 698-703 8. M. Blanter, I. Golovin, H. Neuhauser, H. Sining, Internal friction in metallic materials, A handbook Series: Springer Series in Materials Science 90 ( 2007) 539.

9. A. Pushkar. Internal friction in metals and alloys. London (2005) 640.

10. I.Yonenaga, K.Sumino. Mechanical strength of GeSi alloy.

J.Appl.Phys. 80 (6) 1996. P.3244-3247.

11. L. Aleksandrov, M.Zotov, V.Stas, B.Surin. Investigations of radiation defects in Si , irradiated by neutrons. J.Physics and Technics of Semiconductors. 1984, vol.18,¹1. (in Russian).

12. T.Fukuda, A.Ohsawa. Mechanical strength of silicon crystals with oxygen and/or germanium impurities. J.Appl.Phys.Lett.

60 (10)1992.p.1184-1186.

13. S.Antipov, A.Beliavski, V.Drozhzhin. Solid State Physics, Dislocation internal friction in of filamentous crystals Si. 1982, vol.24, ¹11,p.3269-3272.(in Russian)

meqanikuri relaqsaciuri procesebi monokristalur Si-Ge SenadnobebSi i. yuraSvili, g. darsaveliZe

ilia vekuas soxumis fizika–teqnikis instituti, mindelisq. 7, 0186,Tbilisi, saqarTvelo el–fosta: sipt@sipt.org gamokvleulia monokristalur Si1-xGex(x≤0,02) SenadnobebSi meqanikuri rxevebis energiis STanTqmis speqtrebisa da Zvris dinamiuri modulis cvlilebaTa kanonzomierebani. gansazRvrulia relaqsaciur procesebSi monawile struqturuli defeqtebis moZraobis aqtivaciuri maxasiaTeblebi. naCvenebia, rom germaniumis koncentraciis amaRlebiT mcirdeba Si-Ge Senadnobebis relaqsaciuri procesebis aqtivaciuri maxasiaTeblebi. gaanalizebulia 60-gradusiani da xraxnuli dislokaciebis wvlili relaqsaciuri procesebisa da Zvris modulis temperaturuli speqtrebis formirebaSi.

31

Synthesis and Consolidation of Superconductor Magnesium Diboride E.E. Sanaia, G.V. Bokuchava, R.V. Chedia Ilia Vekua Sukhumi Institute of Physics and Technology, Mindeli st.7, 0186, Tbilisi, Georgia E-mail: sipt@sipt.org Abstract. Magnesium diboride bulk superconductor targets with a diameter 50-52 mm has been obtained in an induction furnace, using hot press and spark-plasma synthesis methods by gradual temperature increase 20-10500C. Increased diameter (>50 mm) of the samples reveal a number of problems. Despite the fact that big diameter samples phase content is like small ones, their porosity is increased and 45-50 % of the obtained samples have macro cracks. Optimal samples were obtained in inductive furnace , when temperature ratio increase till 10500C during 80-85 minutes and press 5 tones.

Keywords: Magnesium diboride, hot pressing, superconductors.

Introduction Following the discovery of MgB2 superconductivity [1], many experiments have been conducted to improve the superconducting properties of these materials. The most efficient sintering method for obtaining high-density bulk materials is hot pressing of MgB2 powders or a mixture of the magnesium and boron elemental precursors. Pressure allows suppress volatility of Mg, impeding its oxidation and promoting the formation of a mechanically stable denser structure [2-4]. A denser material usually exhibits higher superconducting properties, is more stable against degradation during exploitation, less reacts with moisture, etc. [5-7].

Even in case of less synthesis or sintering a preliminarily pressure densification, i.e. pressure treatment, plays a great role in attaining high superconducting and mechanical characteristics of the produced materials. Recently the efficiency of high-pressure densification has been proved for wire manufacturing process, in particular [8]. Despite a comparatively simple lattice structure of MgB2, to find correlations between the MgB2-based material’s structural features and its superconducting properties is a very complicated task. It can be explained by a considerable difficulty that arises from the electronic structure, by the necessity to detect the amount and distribution of light element boron to analyze the boron-containing compounds in nanostructural materials, which are often porous and additionally easily react with oxygen and hydrogen. Magnesium diboride has a potential for superconducting applications against other materials because of its low mass density.

This would allow fabrication of specimens of desirable shapes, such as blocks, cylinders, rods and wires with good mechanical strength. For possible applications, the use of bulk boron-based superconductors is constrained by poor mechanical properties caused by weak grain-to-grain contacts and inadequate porosity of the samples.

Most of the known magnesium diboride production methods are based on the treatment of elements at temperatures above the melting point of magnesium. Heating of the elements in an Ar/H2 or Ar atmosphere in Mo or Ta containers at temperatures of 873K to 1223K followed by hot pressing at 1073K (10 GPa) was applied. The direct

reaction between the components (without pressure) in a Ta container was also performed [9-12].

In the present study, we report the results about magnesium diboride superconductor bulk samples (targets) with a diameter >50 mm obtained in an induction furnace and using spark-plasma synthesis methods.

Experiments Magnesium diboride powder was obtained by solid phase reaction 600-1050°C in vacuum and an inert atmosphere of a mixture of magnesium (Aldrich, >99%) and amorphous boron powders (Aldrich, >99%). Synthesis and consolidation of magnesium diboride were been performed by spark-plasma synthesis and hot pressing method. Homogenization and activation of the mixture of magnesium and boron powders (molar ratio Mg:B=1:2) were conducted in a planetary-type nanomill by WC balls (Pulverisette 7 Premium Line, Fritsch) during 30 min. Then the mixture was pressed in a steel die. The obtained samples represent cylinders with a diameter of 25-52 mm, and height of 5-10 mm. Similar processes were carried out in spark-plasma devices to produce samples in graphite dies lined with sigraflex plates from sides, top and bottom of the punches.

Sigraflex plates were covered by a layer (0.2÷0.3 mm). In this case current was not conducted in the Mg+B mixture, but the die was heated. Magnesium diboride bulk cylinders (d=52 mm) were obtained in the induction furnace.

The increase of the sample diameter from 10 mm to 52 mm required the power increase, which was impossible in the spark-plasma type device. Therefore both synthesis and sintering were performed in the induction furnace equipped with a vacuum system and press.

Results and Discussion Rapid consolidation methods enable to reduce the samples’ heating time, which limits an increase in grain sizes and high density of compacted samples. The hot-pressing synthesis method was chosen from the known methods of pressing. During the spark-plasma synthesis method, the pulse current, going through the preliminarily compacted at low pressure powder, generates a high energy plasma

32 discharge on the surfaces of particles. The HP synthesis method is characterized by: 1) accumulating influence of external parameters (pressure and electrical current) on powders’ compacting and phase generating; 2) rapid volume heating enabling to reduce the increasing kinetics of grain sizes. The HP synthesis makes it possible to implement the process by rapid heating and cooling. The powder compacting process through the HP synthesis method can be implemented by choosing different parameters of direct, alternating and pulse current.

The working pressure in the device is formed by a hydraulic system. The maximum load is 25000 kg. The main node of the heating system is a step-down transformer being operated by an electronic block. The heating system makes it possible to induce the alternating or direct current up to 4000 A. In the compacting node KM54-15, graphite is used as a punch, which enable to vary the working pressure up to 100 MPa. The registration of compacting parameters (pressure, current, resistivity, temperature, motion of punches) is conducted by using the computing unit.

For the purpose of easy removal of consolidated MgB2 from the die, a SIGRAFLEX plate (0.5 mm thick) was inserted in the graphite die coated with a BN layer. The BN layer is formed using Boron Nitride Aerozol Lubricoat (Manufacturer ZYP coatings Inc.). A mixture of Mg and B powders, or tablets made from this mixture, preliminarily pressed in the steel die under 200-400 MPa, were put in the graphite die. The graphite die is heated in vacuum. The powders are pressed by using a hydraulic system with a gradual temperature increase up to 900°C and kept at this temperature for ~ 5÷7 min. After taking off pressure, they are cooled in vacuum until 150-200°C. Cooling of the die is conducted in Ar atmosphere. Grinding and polishing of the obtained tablets is conducted by using dry sandpaper (SiC) in inert atmosphere, following which the BN and SIGRAFLEX remains are removed from the sufraces. The polished tablets are kept in a vacuum polyethylene bag and then are placed in a desiccator in N2 or Ar atmosphere. The spark-plasma method allows successful synthesis and sintering of magnesium boride for 10 mm samples.

The density is measured by Archimedes’ principle in normal heptane, acetone and water. Small-size samples are not characterized of porosity, whereas the big-size samples’ porosity is high (d=52 mm) and their density reaches only 1.7 g/cm3. It is established, that by increasing of pressure, density of the samples obtained by HP method raises and open porosity sharply decreases Fig. 2.

They easily crumble, and so the spark-plasma synthesis and hot pressing method was applied only for the obtaining of the MgB2 powders. As a difractogram shows, the phase composition is identical to the standard sample (Fig.2 a, b, c ).

The samples prepared by means of hot pressing are obtained as pellets (diameter 10 mm, thickness 7–10 mm,) without any cracks. The pellets were cut with a diamond saw and ground. The bulk samples were dry-polished to the thin surface layer (< 0.5 mm). After polishing, the samples were analyzed by X-ray powder diffraction.

Fig.1. a) Dependence of dendity on the pressure of consolidated MgB2 sample; b) dependence of density on the open porosity of the sample

Bulk samples were produced only in the induction furnace. The temperature profile of the synthesis and consolidation is showed on the chart. Pressure on the sample in the induction furnace reached 5 tons. The press mold/dies in this case were also covered with a boron nitride layer, the tantalum or niobium plates. Production of large-diameter samples from the magnesium and boron powders by the hot pressing method is accompanied by several peculiarities: samples’ fragility, pyrophorocity, porosity, etc.

Where the ready MgB2 powders consolidation is quickly possible by increasing the temperature up to 950-10500C (sintering time 10 minutes), the samples obtained by the synthesis and consolidation process are prone to cracking both while sintering (pre-briquetted Mg+B mixture) and when removed from the furnace.

It should be mentioned that both high-density (85-92% theoretical density) and low-density samples (50-60 % theoretical density) are being cracked, (Fig. 4 a,b). 52mm-diameter samples were obtained by the optimization of synthesis and consolidation.

The X-ray phase analysis shows that the samples contain a small amount of MgO and MgB4 phases. Under said conditions, the boron-containing phases are formed by MgB2 disproportions to the metallic magnesium and magnesium tetraboride. The carbon contamination from the graphite was not detected. The obtained material is airand moisture-sensitive. The obtained MgB2 contains a low concentration of the MgO phase. In case of using 99% boron, MgO content in the synthesized MgB2 increases, due to the fact that amorphous boron contains H3BO3 and B2O3, which are reduced by metallic magnesium at high temperatures.

B2O3 + 3Mg 2B + 3MgO The microstructure of the samples shows that pores have diameters from 1 to 25 μm. The average grain size is less than 10 μm. (Fig.5 a,b). Measurements of temperature dependence on magnetization was performed in order to analyze the superconducting characteristic of the obtained samples. The vibrating magnetometer is produced by CRYO-

33

a

b

c Fig.2. X-ray pattern of commercial magnesium diboride powder (Aldrich, >99%) (a); obtained consolidated sample (b) and MgB2 powder by spark-plasma synthesis method (c).

34

a

b

Fig.3. Bulk MgB2 samples without cracks (d=52 mm) simultaneously synthesized and consolidated in the induction furnace 500-10500C (a). Samples of MgB2 with cracks , obtained in the same conditions(b).

a

b

Fig.5. a, b- Microphotography of MgB2 samples (x1600).

GENIC Ltd. and operates in temperature range 2 - 300K and magnetic field up to 5 T. The samples were cooled in zero magnetic field (ZFC) down to 2K, then magnetic field B=20G was applied and magnetization was measured on sample heating (ZFC process). The same measurements were performed by cooling the samples from above Tc with the same applied magnetic field (FC). If the sample is superconductor, a negative magnetic moment (of diamagnetic origin) is induced due to the screening effect, which disappearsm at superconducting transition temperature Tc. Tc measurements of our samples resulted the following: the commercial MgB2 powder -Tc=39K, where MgB2 obtained by simultaneous synthesis and consolidation of Mg+B mixture in a spark-plasma device, Tc=38.5K ( Fig.6 a,b). Bulk samples obtained in the induction furnace -Tc=39K (Fig. 7 a,b). Increase of the duration from 15 till 80รท100 minute resulted in low increase of Tc values 0.5K.

Conclusions The hot pressing of a mixture of Mg and amorphous B powders results in the production of magnesium diboride without loss of the volatile magnesium, in a short time. Bulk superconductor samples with a diameter >50 mm are ob-

tained in an induction furnace by using the hot pressing and spark-plasma synthesis methods. These methods enable to obtain small diameter (up to <10 mm) samples without any difficulties by gradual temperature increase up to 20-10500C. The increased diameter (>50 mm) of the samples reveals a number of problems: porosity is increased and 45-50 % of the obtained samples form macro cracks; in some cases the samples are completely destroyed. The superconducting properties are investigated with magnetization versus temperature measurement. The onset of superconductivity is found to be ~38.5- 39K with sharp transition.

Acknowlegment This researchs is supported by STCU (Science and Technology Center in Ukraine) project number P560 (LBNLT@-0235-GE).

References 1. J. Nagamatsu, N. Nakagawa, T. Muranaka, Y. Zenitani, J. Akimitsu, Nature, 2001, 410, 63-64.

2. T.A. Prikhna W.A. Gawalek, Ya.M. Savchuk, V.E. Moshchil, N.V Sergienko,, T. Habisreuther, M. Wendt, R. Hergt, Ch. Schmidt, J. Dellith, V.S. Melnikov, A. Assman, D. Litzkendorf, P.A. Nagorny. Phisica C . 2004, 402, 223-233.

35

a

b

Fig.6. Temperature dependence of magnetization under an applied field of 20G for commercial MgB2 powders (a) and sample obtained by simultaneous synthesis and consolidation of Mg+B mixture in a spark-plasma device (b).

a

b

Fig.7. Tc of MgB2 samples synthesized and consolidated in the induction furnace within 500-1050 C (graphite die layed with BN, a), (graphite die layed tantalium folgs, b).

0

3. US Patent 6953770 (2005). MgB2-Based Superconductor With High Critical Current Density and Method for Manufacturing the Same.

4. US Patent 7763568 (2008). Methood for producing MgB2 superconductor and MgB2 superconductor.

5. C. Buzea, T. Yamashita, Sc. Technol., 2001, 14, R115-R146.

6. Y. Shimiz, K. Matsuda, M. Mizutani, K. Nishimura et al.

Materials Transactions. 2011, 52(3), 272-275.

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9. B. Birajdar, N. Peranio, O. Eibl, Supercond. Sci. Technol.

2008,21, 073001.

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11. M. Monteverde, et al. Science. 2001, 292 , 75.

12. S.L. Budâ&#x20AC;&#x2122;ko, et al. Phys.Rev.Lett. 2001,86,9,1877.

magniumis diboridis sinTezi da konsolidacia e.e. sanaia, g.v. bokuCava, r.v. Wedia,

soxumis i. vekuas fizika-teqnikis instituti Tbilisi 0186, mindelis q. 7 el-fosta: sipt@sipt.org zegamtari magniumis boridis masiuri nimuSebi 50-52 mm diametriT miRebul iqna magniumisa da amorfuli boris fxvnilebis induqciur RumelSi cxeli dawnexvisa da naperwklovani-plazmuri sinTezis meTodiT temperaturis TandaTanobiT momatebiT 10500C-mde. didi diametris nimuSebis miReba dakavSirebulia mTel rig problemebTan: izrdeba forianoba, miRebuli nimuSebis 40-45%-Si warmoiqmneba makrobzarebi da zog SemTxvevaSi imsxvreva. optimaluri nimuSebi miRebul iqna induqciur RumelSi, rodesac sinTezisa da konsolidaciis temperatura 10500C aRwevs (80-85 wT), xolo wneva 5 tonaa. nimuSebis zegamtaruli gadasvlis temperatura (Tc) 38.5-39K aRwevs.

36

Hydrostatic pressure effects on the superconducting gap symmetry in the iron-based superconductor Ba1-xRbxFe2As2 Z. Guguchia1,2, R. Khasanov1, Z. Bukowski3, A. Shengelaya4, H. Keller2, A. Amato1, E. Morenzoni1 1

Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland

Physik-Institut der Universitat Zürich, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland 3 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-422 Wroclaw, Poland 4 Department of Physics, Tbilisi State University, Chavchavadze 3, GE-0128 Tbilisi, Georgia E-mail:zurab.guguchia@psi.ch 2

Abstract. We report high-pressure muon spin rotation experiments on the temperature-dependent magnetic penetration depth λ (T) in the optimally and over-doped Fe-HTS Ba1-xRbxFe2As2. At ambient pressure the optimally doped material Ba0.65Rb0.35Fe2As2 is known to be a nodeless s-wave superconductor. Upon pressure a strong decrease of λ (0) is observed, while the SC transition temperature remains nearly constant. More importantly, the low-temperature behavior of 1/λ2(T) changes from exponential saturation at zero pressure to a power-law with increasing pressure, providing unambiguous evidence that hydrostatic pressure promotes nodal SC gaps [39]. Comparison to microscopic models favors a d-wave over a nodal s+--wave pairing as the origin of the nodes. Remarkably and in contrast to nodeless SC gap observed in the optimally doped sample x = 0.35 at ambient pressure, the over-doped system x = 0.65 exhibits a d-wave SC gap state. The d-wave symmetry is robust against hydrostatic pressures up to p = 2.3 GPa, suggesting that d is the common and dominant pairing symmetry in over-doped Ba1-xRbxFe2As2. Our results provide a new route of understanding the complex topology of the SC gap in Fe-HTS’s.

PACS numbers: 74.20.Mn, 74.25.Ha, 74.70.Xa, 76.75.+i, 62.50.-p Key words: spin, magnetic penetration, node, superconducting gap, d-wave.

Introduction The family of unconventional superconductors has grown considerably over the last couple of decades and now includes cuprates [1], heavy-fermions [2], organic superconductors [3] and most recently also iron pnictides [4,5]. They all share a similar phase diagram [6,7]. Superconductivity emerges through doping or applied pressure when the competing magnetic state is suppressed. Even after more than 20 years of intensive research the superconducting (SC) pairing mechanism is still not understood for the above mentioned compounds [8]. To understand it, it is instructive to study the symmetry and structure of the SC gap. A significant experimental and theoretical effort has concentrated on studies of this issue in Fe-HTS’s.

However, there is no consensus on a universal gap structure and the relevance for the particular gap symmetry for high-temperature superconductivity in iron-based high temperature superconductors (Fe-HTS’s), which are the first non-cuprate materials exhibiting superconductivity at relatively high temperatures. In contrast to cuprates, where the SC gap symmetry is universal the gap symmetry and/or structure of the Fe-HTS’s can be quite different from material to material [9-25].

We note that an important feature of Ba1-xRbxFe2As2 and the related system Ba1-xKxFe2As2 is that the SC phase exists over a wide range of Rb and K-concentration, respectively, namely from x = 0.2 to x = 1. For clarity, the schematic phase diagram for Ba1-xRbxFe2As2, taken from Ref. 26 is shown in Fig. 1. The data points obtained in the present work are also shown. It was found that this phase

Fig. 1: Schematic phase diagram of Ba1-xRbxFe2As2 (after Ref. 26). The open symbols represent the values of the SC transition temperature obtained in this work. The dashed lines mark the doping levels, studied here.

diagram is remarkably similar to the thoroughly studied system Ba1-xKxFe2As2 [26]. The particularly interesting observation in Ba1-xKxFe2As2 is the systematic doping evolution of the nodal structure for heavy hole-doping [27,28].

At around omptimal doping x = 0.4, where Tc has a maximum value of 38 K, many experiments revealed the occurrence of multiple isotropic SC gaps. A sign changing swave state which is mediated by spin fluctuations has been invoked to explain some of the experimental results. How-

37 ever, this state is expected to be very fragile to the presence of non-magnetic impurities, while Fe-HTS’s are experimentally known to be robust against non-magnetic impurities. A no-sign changing s++-wave state mediated by orbital fluctuations and which is robust against non-magnetic impurities is another possible candidate for the pairing in this system. Hence, the SC pairing symmetry in the optimum region is still an open question. However, there is consensus that the SC gap structure itself is fully gapped for optimally doped samples of Ba1-xKxFe2As2. It is remarkable that in this system, the crossover from nodeless to nodal SC state occurs at x = 0.8. These changes were related to a Lifshitz transition, reflecting the disappearance of the electron pockets in the Fermi surface (FS), at similar Kdoping levels [28] (unlike optimally doped Ba0.6K0.4Fe2As2 which has both electron and hole-FSs, only hole-FSs were found in the extremely hole-doped KFe2As2[29]). The nodeless SC gaps were also observed in Ba1-xRbxFe2As2 at op-

materials very exotic physical properties, pressure induced phase transitions as well as changes of the characteristic SC or magnetic quantities [35-37]. In KFe2As2, a change of the SC pairing symmetry by hydrostatic pressure has been proposed, based on the V-shaped pressure dependence of Tc [38]. Recently, we have shown unambiguous evidence for the appearance of SC nodes in optimally-doped Ba1Rb xFe2As2 upon applied pressure, consistent with a x change from a nodeless s+--wave state to either a d-wave or a nodal s+--wave state [39] (see Fig. 2). Interestingly, the theoretical calculations [40-46] as well as Raman experiments [47,48] revealed a sub-dominant d-wave state close in energy to the dominant s+--state. It seems that pressure affects this intricate balance, and tip the balance in favor of the d-wave state. Besides the appearance of nodes with pressure in optimally-doped Ba1-xRbxFe2As2, another interesting observation was a strong decrease of the magnetic penetration depth λ with pressure [39]. In contrast, in

Fig. 2: Schematic representation of the nodal s+- and d-wave states. In both panels, a density plot of the gap function is superimposed to a representative Fermi surface consisting of a hole pocket (h) at the center and an electron pocket (e) at the borders of the Brillouin zone. In the nodal s+- states (left), the nodes are not enforced by symmetry (here they are located at the electron pockets). In the d-wave state (lower panel), the nodes are enforced by symmetry to be on the diagonals of the Brillouin zone, and therefore can only cross the hole pockets [After 39].

timal doping x = 0.3, 0.35, 0.4 from the temperature dependence of the magnetic penetration depth λ by means of muon-spin rotation (μSR) [11]. μSR experiments performed on polycrystalline samples of extremely hole-doped RbFe2As2 also suggested the presence of two isotropic swave gaps [30,31]. However, recent specific heat and thermal conductivity measurements on single crystals of RbFe2As2 and on the related compound CsFe2As2 provided evidence for nodal SC gap in these materials [32-34].

This suggests that the crossover from nodeless to nodal state upon hole doping should also be present in Ba1RbxFe2As2. In this regard it is important to study the SC x gap symmetry in over-doped Ba1-xRbxFe2As2.

Besides doping another important tuning parameter is the hydrostatic pressure which leads to new and in some

the end member compound RbFe2As2 an increase of λ and no change of the gap symmetry was found up to p = 1.1 GPa [31]. Thus, it is important to study the pressure effects on the SC properties of over-doped Ba1-xRbxFe2As2 system in order to have a picture about the pressure effects on different regions of the phase diagram. In the following we report on μSR studies of the temperature dependence of the penetration depth λ in over-doped Ba0.35Rb0.65Fe2As2 at ambient and under hydrostatic pressures up to p = 2.3 GPa. These results provide evidence for d-wave superconductivity in this system, which is distinctly different from the nodeless gap found at optimal doping. The d-wave order parameter symmetry is preserved under pressure. The SC transition temperature Tc, the value of the d-wave gap as well as the zero-temperature value of the magnetic penetra-

38 tion depth λ(0) show only a modest decrease with pressure. We compare the present pressure data with the previous results of optimally doped Ba0.65Rb0.35Fe2As2[39] and the end member RbFe2As2[31] and discuss the combined results in the light of the possible Lifshitz transition in Ba1RbxFe2As2 induced by hole doping. x

Results and discussion Figure 3a shows the ZF-μSR time spectra for p = 0 and 2.3 GPa obtained at T = 2.5 K for Ba0.35Rb0.65Fe2As2. The ZF relaxation rate stays nearly unchanged between p = 0 GPa and 2.3 GPa, implying that there is no sign of pressure induced magnetism in this system. Fig. 3c exhibits the TF time spectra for Ba0.35Rb0.65Fe2As2, measured at ambient p = 0 GPa and maximum applied pressure p = 2.22 GPa, respectively. Spectra above (45 K) and below (1.7 K) the SC transition temperature Tc are shown. The details of the analysis of the μSR data are given in Ref. 39. As indicated by the solid lines in Fig. 3c, the μSR data are very well described.

A large diamagnetic shift of μ0Hint sensed by the muons below Tc is observed at all applied pressures. This is evident in Fig. 4a, where we plot the difference between the internal field μ0Hint,SC measured in SC state and μ0Hint,NS measured in the normal state at T = 45 K for Ba0.35Rb0.65Fe2As2.

The SC transition temperature Tcis determined from the intercept of the linearly extrapolated μ0(Hint,SC- Hint,NS) curve

recorded at p = 0 GPa for the sample measured together with the cell and without the cell. The temperature dependences as well as the relaxation rates are in good agreement with each other. We observed only a tiny pressure induced decrease of the zero-temperature value of the penetration depth λ (0), which is different from the observation for the x = 0.35 sample where a substantial decrease of λ (0) was reported. Note that for all applied pressures the temperature dependence of λ -2 is well described by a d-wave gap symmetry as shown in Fig. 5. This implies that the dwave symmetry in over-doped Ba0.35Rb0.65Fe2As2 is robust against pressure. We note that the nodal SC gaps are promoted in the optimally doped x = 0.35 system under pressure, as shown in our previous work [39]. However, the nodes exist only on the electron pockets, while in the hole pocket gap is nearly constant. But in case of the overdoped x = 0.65 system, the results are consistent with the presence of nodal d-wave gaps on all Fermi surface sheets.

It is important to emphasize that by heavy hole doping as well as hydrostatic pressure, one can induce stable d-wave pairing in Ba1-xRbxFe2As2. The recent theoretical and experimental [48] studies of optimally-doped Ba0.6K0.4Fe2As2 revealed a sub-dominant d-wave state close in energy to an s+--state. It was shown that the coupling strength in this subdominant d channel is as strong as 60 % of that in the dominant s+--channel. According to the results, presented and discussed above, pressure and heavy hole

Fig. 3: (a) ZF-μSR time spectra for Ba0.35Rb0.65Fe2As2 for p = 0 and 2.3 GPa at the base temperature T = 2.5 K. (c) Transverse-field (TF)- μSR time spectra obtained above and below Tc for Ba0.35Rb0.65Fe2As2 (after field cooling the sample from above Tc) at p = 2.3 GPa. The solid lines represent fits to the data [39].

with it’s zero line and it is found to be Tc = 21.6(7) K and 19.2(5) for p = 0 GPa and 2.3 GPa, respectively. The ambient pressure value of Tc is in perfect agreement with the one Tc = 20.9(5) K obtained from magnetization and specific heat experiments. With the highest pressure applied p = 2.3 GPaTc decreases by ~ 2.4 K, corresponding to a stronger pressure effect on Tc as compared to the one observed in the optimally doped sample Ba0.65Rb0.35Fe2As2. The temperature dependence of σsc for Ba0.35Rb0.65Fe2As2 at various pressures is shown in Fig. 4b. The inset shows the data

doping tip the intricate balance between d and s in favor of a d-wave state. This suggests that two different tuning parameters, heavy hole doping and hydrostatic pressure, promote the same SC pairing mechanism in Ba1-xRbxFe2As2.

The results of λ 2(T) for Ba0.35Rb0.65Fe2As2analysis are summarized in Fig. 6(a-d), showing Tc as well as the zerotemperature values of λ(0), the SC d-wave gap, and the gap to Tc ratio 2Δ/kBTc as a function of hydrostatic pressure.

Upon increasing the hydrostatic pressure from p = 0 to 2.3 GPa, λ(0) is increased by less than 5 % and Tc is decreased

39 by 10 %. Both Δ and 2Δ/kBTcshows only a modest decrease with increasing pressure. Our results show that there are no significant changes of the SC properties of Ba0.35Rb0.65Fe2As2under pressure and d represents the most stable pairing symmetry in Ba0.35Rb0.65Fe2As2.

Fig. 4: (a) Temperature dependence of the difference between the internal field μ0HSC measured in the SC state and the one measured in the normal state μ0HNS at T = 45 K for Ba0.35Rb0.65Fe2As2 recorded for various hydrostatic pressures. (b) Temperature dependence of the superconducting muon spin depolarization rate σsc in an applied magnetic field of μ0H = 50 mT for Ba0.35Rb0.65Fe2As2 for selected applied pressures. The inset shows the data recorded at p = 0 GPa for the sample measured together with the cell and without the cell.

In order to reach a more complete view of the pressure effect on σsc(0) and Tc in Ba1-xRbxFe2As2 in Fig. 6 (a,b) we combined the present data with the previous high-pressure μSR results on optimally doped Ba0.65Rb0.35Fe2As2 and on RbFe2As2 which presents the case of a naturally overdoped system. For all samples, the Tc(p) and λ (0)(p) behaviors are linear, so that the pressure dependence of Tc and λ(0) can be well represented by dTc/dp and d λ(0)/dp values, respectively. The pressure derivative, dTc/dp, is negative for all x = 0.35, 0.65, 1 and it’s magnitude increases with increasing x. However, there is at higher pressures fundamental difference of Tc(p) between the x = 0.35, 0.65 and x = 1 samples. Namely, for x = 1 a V-shaped temperature pressure phase diagram is observed [49] as in KFe2As2[38] which is absent for x = 0.35 and 0.65. Regarding λ (0), application of pressure of p = 2.3 GPa causes a decrease of its value by 15 % in optimally doped sample x = 0.35, while only very tiny decrease of λ (0) is observed for the overdoped system x = 0.65. Instead, for the end member compound an increase of λ (0) with pressure is observed.

This means that the dλ(0)/dp is positive and large for x = 0.35. On further increasing the x to 0.65 it’s magnitude becomes negligibly small but is still negative and becomes positive for the end member x = 1. So, the sign change of dλ(0)/dp takes place for some the x values located between x = 0.65 and 1. The above results provide clear evidence that the SC gap symmetry as well as the pressure effects on Tc and on λ(0) strongly depends on doping level x. Note that in the optimally doped ‘122’-system Ba1-xKxFe2As2 several bands cross the Fermi surface (FS) [9,50,51]. They consist of inner (α) and outer (β) hole-like bands, both centered at the zone center Ã, and an electron-like band (γ) centered at the M point. Band structure of Ba1-xKxFe2As2 changes are associated with hole doping. The hole Fermi surfaces expand with increasing x, whereas electron Fermi surfaces shrink gradually and disappear for x> 0.6, giving rise to a Lifshitz transition. Since, the investigated system is very similar to Ba1-xKxFe2As2, one expects similar doping induced changes in the band structure in both materials.

Hence, the x dependence of the SC gap symmetry as well as the pressure effects, reported above for Ba1-xRbxFe2As2, may be related to this putative Lifshitz transition.

Fig. 5: (a-c) The temperature dependence of ë-2measured at various applied hydrostatic pressures for Ba0.35Rb0.65Fe2As2 in an applied field of μ0H = 50 mT. The solid lines correspond to a single-gap d-wave model.

40

Fig. 6: The zero temperture value of the magnetic penetration depth ë(0) (a) and the SC transition temperature Tc (b) for Ba1-xRbxFe2As2 (x = 0.35, 0.65, 1.0), as well as the d-wave gap (c) and the gap to Tc ratio 2Δ/kBTc(d) for the over doped sample x = 0.65, plotted as function of hydrostatic pressure. The measurements were performed in an applied magnetic field of μ0H = 50 mT. The data for x = 0.35 sample are taken from Ref. 39 and the date for x = 1 are taken from Ref. 31 and Ref. 32. The dashed lines represent the guides to the eyes.

Conclusions In summary, the SC properties of optimally and overdoped Ba1-xRbxFe2As2 (x = 0.35 and 0.65) samples at ambient pressure as well as under hydrostatic pressures up to p = 2.3 GPa were studied by means of zero-field and transverse fieldμSR experiments. Remarkably and in contrast to nodeless SC gap observed in the optimally doped sample x = 0.35, the over-doped system x = 0.65 exhibits a d-wave SC gap state as revealed from the temperature dependence of the magnetic penetration depth λ. The d-wave symmetry is preserved under hydrostatic pressures up to p = 2.3 GPa, indicating the robustness of the d-wave symmetry in the over-doped region. The fact that the rather stable dwave symmetry was also observed in the optimally-doped sample x = 0.35 under pressure indicates that both tuning parameters, heavy hole doping and hydrostatic pressure, promote the same pairing mechanism for superconductivity in Fe-HTS Ba1-xRbxFe2As2. The values of the magnetic penetration depth λ, Tc as well as the d-wave gap Δ and the ratio 2Δ/kBTcshow a small and monotonic decrease with increasing the pressure. By combining the present data with those previously obtained for the optimally doped system [39] and for the end member RbFe2As2[31] we conclude that the SC gap symmetry as well as the pressure effects on the quantities characterizing the SC state strongly depends on the hole doping level x. The combined results may be interpreted by assuming a disappearance of the electron pocket from the Fermi surface upon the high hole

doping, resulting in a Lifshitz transition. Note that the absence of the electron pocket has been observed by ARPES in the related system KFe2As2[29]. Finally, we suggest that the Ba1-xRbxFe2As2 and Ba1-xKxFe2As2 superconducting series have a common doping dependence of the SC properties. The present results offer important benchmarks for the elucidation of the complex microscopic mechanism responsible for the observed non-universality of the SC gap structure and of high-temperature superconductivity in the Fe-HTS’s in general.

Acknowledgements The work was performed at the Swiss Muon Source (SμS) Paul Scherrer Insitute, Villigen, Switzerland. Z.G. acknowledge the support by the Swiss National Science Foundation.

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hidrostatikuri wnevis gavlena zegamtaruli RreCos simetriaze rkinis fuZeze arsebul Ba1-xRbxFe2As2 zegamtarSi z. guguCia1,2, r. xasanovi1, z. bukovski3, a. Sengelaia4, g. keleri2, a. amato1, e. morenzoni1 1 miuon spinis speqtroskopiis laboratoria, pol Sereris instituti, Villigen PSI, Sveicaria 2 ciurixis universitetis fizikis instituti, ciurixi, Sveicaria 3 dabali temperaturebisa da struqturis kvleviTi instituti, poloneTis mecnierebaTa akademia, vroclavi, poloneTi 4 fizikis departamenti, Tbilisis saxelmwifo universiteti, Tbilisi, saqarTvelo el-fosta: zurab.guguchia@psi.ch

warmodgenilia maRali wnevis miuon spinis brunvis eqsperimentebi temperaturaze-damokidebuli magnituri SeRwevadobis siRrmeze (位T) optimalur da Zlierad legirebul rkinis fuZian maRaltemperaturul zegamtarSi Ba1-xRbxFe2As2. garemos wnevaze optimalurad legirebuli Ba0,65Rb0.35Fe2As2 masala cnobilia, rogorc kvanZebisagan Tavisufali s-talRovani zegamtari. naCvenebia wnevis gavleniT 位(0) funqciis Zlieri Semcireba, amasTan erTad zegamtaruli gadasvlis temperatura praqtikulad ar icvleba. kidev ufro mniSvnelovania, rom 1/位2(T) kanonzomiereba ganicdis eqsponencialuri najerobidan nulovani wnevis dros funqcionalur damokidebulebamde wnevis zrdis pirobebSi. es garemoeba calsaxad adasturebs, rom hidrostatikuri wneva xels uwyobs kvanZovani zegamtarul RreCoebis warmoqmnas. mikroskopuli modelebis SedarebiTi analizi avlens d-talRebis gawyvilebis upiratesobas s+- - talRebis gawyvilebasTan SedarebiT kvanZebis warmoqmnaSi. TvalsaCinod da kvanZebisagan Tavisufal zegamatrul RreCoebisagan kontrastulad, romelic gamovlenilia optimalurad dopirebul nimuSebSi (x=0,35) garemos wnevis pirobebSi, Zlierad legirebuli sistema (x=0,65) amJRavnebs dtalRebis zegamtaruli RreCos mdgomareobas. dtalRebis simetria SenarCunebulia P=2,3 gpa hidrostatikur wnevebamde. es miuTiTebs, rom d aris saerTo da umTavresi gawyvilebis simetria Zlierad legirebul Ba1-xRbxFe2As2 nimuSebSi. Cveni Sedegebi iZleva rkinis fuZian maRaltemperaturul zegamtarebSi zegamtaruli RreCoebis rTul topologiaSi garkvevis axal gzas.

42

Relative stability of boron quasi-planar clusters L. Chkhartishvili1,2, R. Becker3, R. Avci4 Department of Engineering Physics, Georgian Technical University, 77 Kostava Ave., 0175, Tbilisi, Georgia Laboratory for Boron and Powdered Composite Materials, Ferdinand Tavadze Institute of Metallurgy and Materials Science, 15 Kazbegi Ave., 0160, Tbilisi, Georgia 3 Boron Cluster Metamaterials, Cluster Sciences Research Institute, 39 Topsfield Rd., 01938, Ipswich, MA, USA 4 Department of Physics, Montana State University, Bozeman, MT 59717, USA E-mail: chkharti@yahoo.com, avci@physics.montana.edu 1 2

Abstract.Nanoboron is a class of advanced materials highly prospective for various technological applications, e.g., in neutron-shielding coatings. Quasi-planar clusters Bn, n = 1, 2, 3, K , consisting of 3-membered rings of B-atoms serve for “building blocks” of nanoboron.Here, small quasi-planar clusters are obtained experimentally in boron vapor and their relative stability is studied theoretically by comparing binding energies per atom Eb . Detected mass-spectra of clusters correlate with obtained Eb − n dependence.

Keywords:binding energy, atomic charge, plane cluster, boron.

Introduction Since carbon nanosystems were discovered, it has triggered interest in other materials, including bare boron, which may also exhibit nanostructures. Boron-based nanomaterials are both of great academic and technological interests [1]. Due to its rich chemistry, boron is a natural choice for constructing clusters, nanotubes, fullerenes, nanowires, etc. The detailed review on boron nanostructures will be given elsewhere [2]. It was recently identified a unique behavior of clusters of elemental boron. They react readily with and cover various surfaces with a hard, smooth, corrosion-resistant, boron-enriched nano-layer.

In the boron 3D-structures, atoms usually are members of almost regular atomic triangles. This leads to the possibility of formation of small quasi-planar clusters Bn,

n = 1, 2, 3, K , as fragments of boron sheet with triangular 2D-lattice. To gain insight in such “building blocks” of nanoboron, here these species are obtained by the evaporation of boron and predictedrelative their relative stability by the binding energies calculations.

Materials and Methods

From the reported experimental and theoretical evidences [3–5] that liquid boron mainly consists of quasi-planar clusters,one can conclude that the vapor formed during melting of boron also has to consist of boron clusters.

Here, vapor of boron clusters is obtained by a method developed by us previously. It is way of generating substantially pure clusters by the heating within a suitable temperature range the electrode from a boron-rich material (Figure 1a), which induces its thermal decomposition in a favorable manner – providing boron vapor and all other species not in the vapor state. Evaporation of clusters on a substrate not interacting with boron (e.g. sapphire) forms

the perfect microcrystals of ground-state 3D modification of boron – b-rhombohedral boron (Figure 1b).

Alternatively,boron clusters are deposited on selected substrates strongly interacting with boron.

Using the plasma spray method,boron is deposited onto iron foil (0.127 mm thick from Alpha Aesar Stock), silicon wafer, and quartz-glass-slide. For this purpose, a high electric current (~ 75 A) was drawn between two graphite electrodes connected by an electrically conductive boron-rich boride powder (with thickness up to 2.5 cm) while in vacuum. The powder melts and begins emitting boron vapor. A high coating rate of over 0.003 in. / min at a distance of 2 in. from the source is observed. Adhesion of boron coatings to these materials is particularly strong. It is also reproduced previously conducted by us [6] process of melting and evaporation of a boron-rich material in the chamber with the nitrogen source in form of high-purity pressed boronnitride rods.Alternatively, by the laser vaporizationof boride targets we have produced [7] theBn clusters.

Nanostructures of obtained B-rich layers are studied

by SEM (scanning electron microscope) and AFM (atomic force microscope). The XPS (X-ray photoelectron spectrometry) and EDAX (energy dispersive analysis by Xray)are used to determine theirchemical composition.The 4×4 indentation marks are created using a sharp (with radius specified to be ~20 nm by the manufacturer, but measured to be ~75 nm) diamond tip mounted at the end of an AFM cantilever with a maximum loading force of ~ 200 N. The resilience of nanoboron-coated surfaces is illustrated by trying to erode by means of sputtering generated by a 12 keV focused Ga+ions at ~ 1 nA beam current or an energetic Ar+ion beam at 2.5 keV impact energy and about 0.7 A ion current.Mass-spectra of cluster-ions of both signs are detected.

43

(a)

(b)

Fig. 1. (a) View of thermalfacilities for obtaining vapor of boron [6] clustersand (b)boron vapor solidified in form of pure shiny microcrystal.

44

(a)

(b)

Fig. 4. Results of EDAX of boron-coating onto quartz-glass slide substrate.

(c)

(d)

Fig.2. Nanoscale surface morphology of (a) untreated and (b) B-film deposited Fe foil.Indentation hardness tests conducted on (c) untreated and (d)B-film deposited Fe foil.

Quartz slide. In Figure 4,the peak at the far left is due to boron coating. The other peaks are from the glass substrate. As EDAX is low-sensitive to light elements, boron peak appears relatively reduced if is compared to the elements from the substrate.[23] BN shell. The boron nitride shell structures of chemical composition BNxwith boron excess () contaminated with carbon are formed (Figure 5a).The synthesized material is conductive despite the fact that all the boron nitrides ofstoichiometric chemical composition BN are insulators.

“Metallic” boron nitride can be modeled [20] as a mixture of structural modifications ofsemiconducting boron and also boron carbide heavily doped with nitrogen and demonstrated [21] that created boron clusters can be self-as-

(a)

Binding energy.Calculated binding energy-spectrum of neutral boron clusters together experimental mass-spectra of cation- and ion-clusters are shown in Figure 6.

The Table 1 shows formulas and calculated values of together with ground-state structures of planar clusters.

Conclusions

Theoretically obtained dependence of binding energy per atom on number of atoms Eb - n in a boron quasi-planar clusters correlates with experimental mass-spectra: all of them reveal a maximum. This result seems quite natural because the cluster’s binding energy per atom is a quantity determining its stability and probability of formation. However, theoretical maximum is shifted toward lighter species. These discrepancies can be related to charge-states of clusters and also differences in kinetics of their formation.

We believe that, at the low number of boron atoms n formation of 2D clusters is preferable kinetically, because they are open for further adding of atoms to realize theirability to bound up to 6 atoms in a plane. However, small

(b)

(c)

Fig.3.Si wafer deposited with B-film: (a) nanoscale surface morphology; (b)in target holder before ion-beam sputtering and (c)formed twin beam-spots.

sembled into nanostructures (Figure 5b and c). Chemical composition of obtained BNx differs for outer and inner surfaces – outer shell: B 85.7–88.6, N 0.3–0.7, C 11.1–13.6, O and other traces 0.0–0.0; inner shell: B 55.3–91.0, N 0.0– 40.2, C 4.5–18.2, O and other traces 0.0–0.8 at. %.

boron clusters would be quasi-planar, not ideally planar.

Due to finite sizes of clusters, constituent atoms at the periphery possess lower coordination numbers, than their counterparts placed at the central part. It leads to the formation of bonds with unequal lengths, i.e. distortion of a

45

(a)

(b)

(c)

Fig. 5. (a) Deposits formed on BN rods and crucible during several melting runs.(b)Outer and (c) inner surface microstructures of a shell.

(a)

(b)

Figure 6. Mass / binding energy per atom spectra of (a)cation-, (b) neutral, and (c) anion-clusters of boron.

Table 1. Binding energy per atom of boron quasi-planar clusters.

(c)

46 structure of regular triangles. This is an explanation why small boron clusters are buckled and / or puckered. When number of atoms becomes sufficiently high, the saturation of all the possible bonds can be achieved by the alternative way – by wrapping of the plane into cylinder or sphere, i.e.by the formation of 3D structures, respectively, boronnanotubes or fullerenes.

References 1. R. Becker, L. Chkhartishvili and P. Martin: Boron, the New Graphene? Vacuum Technology & Coating, 16 (2015) 38-44.

2. L. Chkhartishvili: All-boron nanostructures, CRC Concise Encyclopedia of Nanotechnology, 2015, CRC Press – Taylor & Francis Group, Ch. 7 – in press.

3. N. Vast, S. Bernard and G.Zerah: Structural and Electronic Properties of Liquid Boron from a Molecular-Dynamics Simulation, Physical Review B, 52(1995) 4123-4130.

4. Sh. Krishnan, S. Ansell, J. J. Felten, K. J. Volin and D. L. Price:Structure of Liquid Boron,Physical Review Letters, 81(1998) 586-589.

5. D. L. Price, A. Alatas, L. Hennet, N. Jakse, Sh. Krishnan, A. Pasturel,I. Pozdnyakova, M.-L. Saboungi, A. Said, R. Scheunemann, W. Schirmacher andH. Sinn: Liquid Boron: X-ray Measurements and Ab Initio Molecular Dynamics Simulations, Physical Review B, 79 (2009) 134201 (1-5).

6. R. Becker, L. Chkhartishvili, R. Avci, I. Murusidze, O. Tsagareishvili andN. Maisuradze: “Metallic” Boron Nitride,European Chemical Bulletin, 4(2015)8-23.

7. S.-J. Xu, J. M. Nilles, D. Radisic, W.-J. Zheng, S. Stokes, K. H. Bowen, R. C. Becker and I. Boustani: Boron Cluster Anions Containing Multiple B12 Icosahedra, Chemical Physics Letters,379 (2003) 282-286.

8. L. Chkhartishvili, D. Lezhava and O. Tsagareishvili: QuasiClassical Determination of Electronic Energies and Vibration Frequencies in Boron Compounds, Journal of Solid State Chemistry, 154 (2000)148-152.

9. L. Chkhartishvili:Quasi-Classical Theory of Substance Ground State, 2004, Technical University Press.

10. L. Chkhartishvili: On Quasi-Classical Estimations of Boron Nanotubes Ground-State Parameters, Journal of Physics: Conference Series, 176 (2009) 012013 (1-9).

11. L. Chkhartishvili: Geometrical Models for Bare Boron Nanotubes, Physics, Chemistry and Applications of Nanostructures, 2011, World Scientific, 118-121.

12. L. S. Chkhartishvili, D. L. Gabunia and O. A.Tsagareishvili: Estimation of the Isotopic Effect on the Melting Parameters of Boron, Inorganic Materials, 43 (2007) 594-596.

13. L. S. Chkhartishvili, D. L. Gabunia and O. A. Tsagareishvili: Effect of the Isotopic Composition on the Lattice Parameter of Boron. Powder Metallurgy and Metal Ceramics, 47 (2008) 616-621.

14. L. Chkhartishvili, O. Tsagareishvili and D. Gabunia: Isotopic Expansion of Boron. Journal of Metallurgical Engineering, 3 (2014) 97-103.

15. P. W. Deutsch, L. A. Curtiss and J. A. Pople: Boron Dimer: Dissociation Energy and Ionization Potentials,Chemical Physics Letters,174 (1990)33-36.

16. P. J. Bruna and J. S. Wright: Theoretical Study of the Ionization Potentials of Boron Dimer,TheJournal of Physical Chemistry,94 (1990)1774-1781.

17. S. R. Langhoff and Ch. W. Bauschlicher: Theoretical Study of the Spectroscopy of B2,The Journal of. Chemical Physics, 95 (1991) 5882-5888.

18. V. Yu. Gankin and Yu. V. Gankin: Twenty-First Century General Chemistry, 2014, Renome, Ch. 6.

19. G. V. Tsagareishvili, M. E. Antadze and F. N. Tavadze: Producing and Structure of Boron, 1991, Metsniereba, Ch. 6.

20. R. Becker andL. Chkhartishvili: On Possible Nature of Metallic Conductance of Boron–Nitrogen Compounds, 3rd International Conference “Nanotechnologies”, 2014, Technical University Press, 13-14.

21. I. Boustani and R. Becker: Boron Clusters, Single- and MultiWalled Nanotubes: Theoretical Prediction and Experimental Observation, 9th Annual Nanotechnology Conferenceand Trade Show, 2006, Nano Science and Technology Institute, MO 60.802.

bo ris kvazi planaruli bor klasterebis fardobiTi stabiluroba l. CxartiSvili1,2, r. bekeri3, r. avCi4 1

sainJinro fizikis depatamenti, saqarTvelos teqnikuri universiteti, kostavas q. 77, 0175, Tbilisi, saqarTvelo 2 borisa da fxvnilovani kompozituri masalebis laboratoria, ferdinand TavaZis metalurgiisa da masalaTmcodneobis instituti, yazbegis gamz. 15, 0160, Tbilisi, saqarTvelo 3 boris klasteruli metamasalebi, klasterul mecnierebaTa kvleviTi instituti, tofsfildis gza, 39, 01938, ifsviCi, masaCuseti, aSS 4 fizikis departamenti, montanas Statis universiteti, 59717, bouzmeni, montana, aSS el-fosta: chkharti@yahoo.com, rbecker@clustersciences.com nanobori miekuTvneba mowinave masalaTa im klass, romelic Zalze perspeqtiulia sxvadasxva teqnologiuri gamoyenebisaTvis, magaliTad, neitrondamcavi danafarebisaTvis. B-atomebis samwevra rgolebisagan agebuli kvazi planaruli klasterebi Bn, n=1,2,3, ...., nanoborisaTvis „samSeneblo agurebs“ warmoadgenen. aq mcire zomis kvaziplanaruli klasterebi eqsperimentulad miRebulia boris orTqlidan da maTi fardobiTi mdgradoba Teoriuladaa Seswavlili erT atomze mosuli bmis energiis gamoTvliT. masaTa speqtrebi, deteqtirebuli klasteruli ionebisaTvis, korelireben Teoriul damokidebulebasTan.

47

Îðèãèíàëüíàÿ òåõíîëîãèÿ áûñòðîãî ñèíòåçà ñ ïîìîùüþ ôîòîííîãî îáëó÷åíèÿ äëÿ ñîâðåìåííûõ ìàòåðèàëîâ Ç. Äæèáóòè1,2, Ä. Äàðàñåëèÿ1, Ä. Äæàïàðèäçå1, À. Øåíãåëàÿ1 Òáèëèññêûé ãîñóäàðñòâåííûé óíèâåðñèòåò èì. Èâ. Äæàâàõèøâèëè, ïð. È.×àâ÷àâàäçå, 1, Òáèëèñè, Ãðóçèÿ 2 Èíñòèòóò ìèêðî- è íàíîýëåêòðîíèêè, ïð.È.×àâ÷àâàäçå, 13, Táèëèñè, Ãðóçèÿ Ýë-ïî÷òà: z.jibuti@gmail.com 1

Ðåçþìå.Èññëåäîâàí ìåõàíèçì ïðîâåäåíèÿ ïðîöåññà ôîòîñòèìóëèðîâàííîé òâåðäîôàçíîé ðåàêöèé ïðè áûñòðîì è îòíîñèòåëüíî íèçêîòåìïåðàòóðíîì ñèíòåçå âûñîêîòåìïåðàòóðíûõ ñâåðõïðîâîäíèêîâ. Ïîêàçàíî, ÷òî ïîäáîð ãåîìåòðèè, ñïåêòðàëüíîãî ñîñòàâà è èíòåíñèâíîñòè èìïóëüñíîãî ôîòîííîãî îáëó÷åíèÿ ìîæåò çíà÷èòåëüíî ñíèçèòü äëèòåëüíîñòü è òåìïåðàòóðó ïðîâåäåíèÿ ïðîöåññà ñèíòåçà. Äåëàåòñÿ âûâîä, ÷òî ýôôåêòèâíîñòü ïðîöåññà ïðîâåäåíèÿ óñêîðåííîé ôîòîñòèìóëèðîâàííîé òâåðäîôàçíîé ðåàêöèé îïðåäåëÿåòñÿ ôàêòîðîì èçìåíåíèÿ õèìè÷åñêèõ ñâÿçåé ñèíòåçèðóþùèõ ìàòåðèàëîâ çà ñ÷åò ñåëåêòèâíîãî ïîãëîùåíèÿ ôîòîíîâ.

Êëþ÷åâûå ñëîâà: ôîòîñòèìóëèðîâàííàÿ äèôôóçèÿ, ôîòîñòèìóëèðîâàííûé ñèíòåç, âûñîêîòåìïåðàòóðíûé ñâåðõïðîâîäíèê.

Ââåäåíèå Èñòîðèÿ îòêðèòèÿ è äàëüíåéøåãî ðàçâèòèÿ ÿâëåíèÿ èìïóëüñíîãî îòæèãà â îñíîâíîì ñâÿçàíà ñ ïðîöåññàìè ïîëóïðîâîäíèêîâîé ýëåêòðîíèêè. Îñîáåííî óäà÷íûì îêàçàëîñü ñî÷åòàíèå ïðîöåññîâ èîííîé èìïëàíòàöèè ñ ïîñëåäóþùèì èìïóëüñíûì ôîòîííûì îòæèãîì ñ öåëüþ óñòðàíåíèÿ äåôåêòîâ è êðèñòàëëèçàöèé ñëîåâ. Çíà÷èòåëüíûå ðåçóëüòàòû áûëè äîñòèãíóòû òàêæå â èñïîëüçîâàíèé ôîòîñòèìóëèðîâàííûõ äèôôóçèîííûõ ïðîöåññîâ ëåãèðîâàíèÿ è ñèíòåçà èç íåîãðàíè÷åííîãî èñòî÷íèêà. Áûëèïîëó÷åíû âûñîêîêà÷åñòâåííûå îìè÷åñêèå è áàðüåðíûå êîíòàêòè, ð-n ïåðåõîäû, èçîëèðóþùèå ñëîè è äð. [1,4-8]. Íîâûå ïåðñïåêòèâû èñïîëüçîâàíèÿ ôîòîñòèìóëèðîâàííûõ ïðîöåññîâ â ñîâðåìåííûõ òåõíîëîãèÿõ áûëè ïðåäëîæåíû â ðàáîòàõ[2-3].Àâòîðàìè áûëî ïîêàçàíî âîçìîæíîñòü ïîëó÷åíèÿâûñîêîòåìïåðàòóðíûõ ñâåðõïðîâîäíèêîâ (ÂÒÑÏ) è îêñèäîâ, ïðè áûñòðèõ è îòíîñèòåëüíî íèçêîòåìïåðàòóðíèõ òåõíîëîãè÷åñêèõ ðåæèìàõ ñèíòåçà, ìåòîäîì ôîòîñòèìóëèðîâàííîé òâåðäîôàçíîé ðåàêöèé (ÌÔÒÐ). Òðàäèöèîííî ýòè ìàòåðèàëû ñèíòåçèðóþòñÿ â òåðìîïå÷àõ ïðè òåìïåðàòóðàõ 800 - 1350îÑ â òå÷åíèå äåñÿòîê è äàæå ñîòåí ÷àñîâ, ÷òî ñâîäèòñÿ â ñëó÷àå ðåàëèçàöèé ÌÔÒÐ äî íåñêîëüêèõ ñåêóíä èëè ìèíóò ñ îäíîâðåìåííûì ñíèæåíèåì òåìïåðàòóð ñèíòåçà íà 100 - 300îÑ. Ïîíèìàíèå ìåõàíèçìîâ ïðîâåäåíèÿ ýòèõ ïðîöåññîâ, ÷òî è ÿâëÿåòñÿ öåëüþ íàñòîÿùåé ðàáîòû, äàñò âîçìîæíîñòü åùå áîëåå øèðîêîãî ïðèìåíåíèÿÌÔÒÐ äëÿ ñèíòåçà ñîâðåìåííûõ ìíîãîêîìïîíåíòíûõ ìàòåðèàëîâ.

Ìàòåðèàë è ìåòîäèêè èçìåðåíèé Îáúåêòîì èññëåäîâàíèé áûë âûáðàí ÂÒÑÏLa2SrxCuO4(LSCO). Äëÿ ïðèãîòîâëåíèÿ îáðàçöîâ áðàëèñü

x

èñõîäíûå ðåàãåíòè (òàáë.1)â âèäå ïîðîøêîâ ÷èñòîòîé íå ìåíåå 99,99% . Ïîðîøêè ñìåøèâàëèñü â àãàòîâîé ñòóïêå, äåëèëèñü íà ïîðöèé( 0,2-0,4gr), ïîìåùàëèñü â ñïåöèàëüíûå ôîðìû è ïðåñîâàëèñü ïîëó÷àÿ òàáëåòêè òîëùèíîé 0,2 – 0,4 mm è äèàìåòðîì 12 mm.Ïîñëå ïðîâåäåíèÿ ñèíòåçà: La 2O 3 + SrCO 3 + CuO = La 2-x Sr xCuO 4 òàáëåòêè ñòàíîâèëèñü êåðàìèêîé. Òàáëèöà 1

La2O3

Melting point, C 2320

Band gap, eV 4,3

2

CuO

1326

1,2

3

SrCo3

1494

5

#

Material

1

0

Ôîòîñòèìóëèðîâàííûé ñèíòåç (ÔÑÑ) îñóùåñòâëÿëñÿ íà îðèãèíàëüíûõ óñòàíîâêàõ èìïóëüñíîãî ôîòîííîãî îáëó÷åíèÿ (ÓÈÔÎ) (ðèñ.1) ïîçâîëÿþùèõ:îáëó÷àòü îáðàçöû ñ îáåèõ ñòîðîí; ìåíÿòü ñïåêòðàëüíûé ñîñòàâ îáëó÷åíèÿ â øèðîêîì ýíåðãåòè÷åñêîì äèàïàçîíå: 0,3 – 6,2 eV, çà ñ÷åò èñïîëçîâàíèÿ ãàëîãåííûõ ëàìï ñ ðàçëè÷íîé öâåòîâîé òåìïåðàòóðîé (ðèñ.2) è ðòóòíîé ëàìïû ñâåðõâèñîêîãî äàâëåíèÿ(ðèñ.3); ìåíÿòü ïëîòíîñòü ìîùíîñòè èçëó÷åíèÿ (P) äëÿ ãàëîãåííûõ ëàìï äî P =375W.cm-2, äëÿ ðòóòíûõ ëàìï äî P = 93 W.cm-2; ìåíÿòü äëèòåëüíîñòü ñâåòîâîãî èìïóëüñà îò 0,1 äî 1000 sec, øàãîì 0,1 sec;èçìåðÿòü òåìïåðàòóðó (äèíàìèêó íàãðåâà è îõëàæäåíèÿ) îáðàçöîâ ñ ïîìîùüþ íèçêîèíåðöèîííîé òåðìîïàðû K – òèïà (ðèñ.4); ðåãóëèðîâàòü òåìïåðàòóðó íàãðåâà îáðàçöîâ ñ ïîìîùüþ ïîäáîðàäåðæàòåëåé ñ ðàçëè÷íîé òåïëîïðîâîäíîñòüþ, óäàëåíèåì íàãðåòîãî âîçäóõà èëè ïðîäóâîì ïàðàìè æèäêîãî àçîòà;ðàáîòàòü â ñðåäå êèñëîðîäà èëè èíåðòíûõ ãàçîâ.

48

Ðèñ.1 Áëîê èçëó÷åíèÿ ÓÈÔΖ5

Ñâåðõïðîâîäÿùèå ñâîèñòâà ìàòåðèàëîâ èññëåäîâàëèñü íà âûáðàöèîííîì ìàãíèòîìåòðå (ÑRYOGENIC Ltd)ðàáîòàþùåì âòåìïåðàòóðíîì èíòåðâàëå 2 – 300Kè â ìàãíèòíîì ïîëå äî 5T. Îáðàçöû îõëàæäàëèñü â íóëåâîì ìàãíèòíîì ïîëå äî 5K. Çàòåì ïðèêëàäûâàëîñü ìàãíèòíîå ïîëå äî B=20G è íàáëþäàëè çà èçìåíåíèåì íàìàãíè÷èâàíèÿ ñ ðîñòîì òåìïåðàòóðû. Àíàëîãè÷íûå èçìåðåíèÿ ïðîâîäèëèñü ïðè îõëàæäåíèé îáðàçöîâ â B=20G ìàãíèòíîì ïîëå . Åñëè îáðàçåö ñâåðõïðîâîäíèê, ïðè ïðèëîæåíèé ìàãíèòíîãî ïîëÿ â íåì ïîÿâëÿåòñÿ îòðèöàòåëüíûé ìàãíèòíûé ìîìåíò – Ìäèàìàãíèòíîãî õàðàêòåðà, âûçâàííûé ýôôåêòîì Ìåéñíåðà – Îêñåíôåëäà, êîòîðûé óìåíøàåòñÿ ñ ðîñòîì òåìïåðàòóðû è ïîëíîñòüþ èñ÷åçàåò ïðè êðèòè÷åñêîé òåìïåðàòóðå(Tc) ïåðåõîäà âñâåðõïðîâîäèìîñòü. Ñ ïîìîùüþ ãðàôèêà M(T) ìîæíî ñóäèòü î êà÷åñòâå ñâåðõïðîâîäíèêà, òàê êàê âåëè÷èíà ìàãíèòíîãî ìîìåíòà ïðîïîðöèîíàëüíà âåëè÷èíû äîëè ñâåðõïðîâîäíèêîâîé ôàçû âîáðàçöå.Äëÿ êîíòðîëÿ ôîðìèðîâàíèÿ êðèñòàëëè÷åñêîé ôàçû ñíèìàëèñü ðåíòãåíîäèôðàêòîãðàìû. Òðàäèöèîííûé ìåòîä ïîëó÷åíèÿ ÂÒÑÏ La2-xSrxCuO4 ñîñòîèò èç äâóõ ýòàïîâ òåðìîîáðàáîòêè â ïå÷è: êàëüöèíàöèé ïðè 900îÑ â òå÷åíèå 13,5 ÷àñîâ è îòæèãà ïðè 1130îÑ â òå÷åíèå 64 ÷àñîâ.

Ðåçóëüòàòû

Ðèñ.2 Ñïåêòð èçëó÷åíèÿ ãàëîãåííîé ëàìïû

Ðèñ.3 Ñïåêòð èçëó÷åíèÿ ðòóòíîé ëàìïû

Ðèñ.4. Äèíàìèêà íàãðåâà è îõëàæäåíèÿ îáðàçöîâ ïðè äëèòåëüíîñòè ÈÔÎ 5sec

Ïðè èññëåäîâàíèÿõ ìåõàíèçìîâ ïðîâåäåíèÿ ôîòîñòèìóëèðîâàííûõ àêòèâàöèîííî - äèôôóçèîííûõ ïðîöåññîâ, êàêîâûì ÿâëÿåòñÿ ïðîöåñ ñèíòåçà ÂÒÑÏ,îñíîâíîå âíèìàíèå íóæíî îáðàùàòü íà ñëåäóþùèå ôàêòîðè, ýòî: òåìïåðàòóðà (äèíàìèêà íàãðåâà è îõëàæäåíèÿ) îáðàçöîâ; ãåîìåòðèÿ, ñïåêòðàëüíûé ñîñòàâ, äëèòåëüíîñòü(τint.) è èíòåíñèâíîñòüèìïóëüñíîãî ôîòîííîãî îáëó÷åíèÿ (ÈÔÎ)[4-8]. Ïðîâåäåííûå íàìè ýêñïåðèìåíòû ïî ÔÑ LSCOóñëîâíî ìîæíî ðàçäåëèòü íà äâå ÷àñòè,êîãäà èñòî÷íèêîì ÈÔÎ èñïîëüçóþòñÿ, ãàëîãåííûå ëàìïû íàêàëûâàíèÿ è ãàëîãåííûå è ðòóòíûå ëàìïû âìåñòå. Íà ðèñ.5 – 8 ïîêàçàíû ðåçóëüòàòûèññëåäîâàíèé çàâèñèìîñòè ïðîöåíòíîãî ñîäåðæàíèÿ ñèíòåçèðîâàííîé ñâåðõïðîâîäÿùåé ôðàêöèé îò äëèòåëüíîñòè (êîëè÷åñòâîèìïóëüñîâ) ÈÔÎ â ðàçëè÷íûõ ðåæèìàõ (ñïåêòðàëüíûé ñîñòàâ, ïëîòíîñòü ìîùíîñòè, òåìïåðàòóðà)îáðàáîòêè. Íà ðèñ.5 ïîêàçàíû ðåçóëüòàòû ýêñïåðèìåíòîâ ïî ÔÑÑ LSCO êîãäà îáðàçöû îáëó÷àþòñÿ 20secèìïóëüñàìè ãàëîãåííûõ ëàìï ñ P=160W.cm-2. Ïðè ýòîì ìàêñèìàëüíàÿ òåìïåðàòóðà ( T max.) íàãðåâà îáðàçöîâ â èìïóëüñå äîñòèãàëà Tmax.=1200îÑ. Êàê âèäíî, ñ óâåëè÷åíèåì êîëè÷åñòâà èìïóëüñîâ (äëèòåëüíîñòè ÈÔÎ) óâåëè÷èâàåòñÿ è ïðîöåíòíîå ñîäåðæàíèå ñèíòåçèðîâàííîé ñâåðõïðîâîäÿùåé ôðàêöèé â îáðàçöå (ýôôåêò àäèòèâíîñòè). Îäíàêî, êàê âèäíî èç ðèñ.5 â ñëó÷àå ïðîâåäåíèÿ ÔÑÑ ïðè òîé æå ïëîòíîñòè ìîùíîñòè ÈÔÎ, íî ïðè áîëåå íèçêîé òåìïåðàòóðå (T max. =850 î Ñ âìåñòî 1200 î Ñ) äëÿ äîñòèæåíèÿ àíàëîãè÷íîé ýôôåêòèâíîñòè ñèíòåçà íåîáõîäèìî óâåëè÷åíèå äëèòåëüíîñòè (τint= 240 sec âìåñòî 40 sec) ÈÔÎ.

49 äîñòèãàëàTmax=840 îÑ. Êàê âèäíî èç ðèñ.6 ýôôåêò àäèòèâíîñòè íàáëþäàåòñÿ è â ýòèõ ðåæèìàõ ÔÑÑ. Îäíàêî âîæíåèøèì ÿâëÿåòñÿ òîò ôàêò, ÷òîïðè îäèíàêîâîì ñïåêòðàëüíîì ñîñòàâå ÈÔÎ, óâåëè÷åíèå èíòåíñèâíîñòè (Ð= 375W.cm -2 âìåñòî 160W.cm -2 ) ïîçâîëÿåò çíà÷èòåëüíî ñíèçèòü òåìïåðàòóðó (Tmax.=840 î Ñ âìåñòî 1200 îÑ) è äëèòåëüíîñòü (τint= 35 sec âìåñòî 40 sec) ïðîöåññà ÔÑÑ.

Ðèñ.5. Çàâèñèìîñòü ïðîöåíòíîãî ñîäåðæàíèÿ ñâåðõïðîâîäÿùåé ôðàêöèè îò äëèòåëüíîñòè (êîëè÷åñòâî èìïóëüñîâ) ÈÔÎ ãàëîãåííûìè ëàìïàìè: 1) òî÷êè íà êðèâîé - Ð = 160W.cm-2, Tmax.=1200îÑ; 2) òî÷êà - Ð =160W.cm2 , Tmax.=850îÑ. Ðèñ.7. Çàâèñèìîñòü ïðîöåíòíîãî ñîäåðæàíèÿ ñâåðõïðîâîäÿùåé ôðàêöèè îò òåìïåðàòóðû îáðàçöà:òî÷êè îáëó÷åíèå ãàëîãåííûìè ëàìïàìè øåñòüþ 20sec èìïóëüñàìè Ð=160W.cm-2; 2) òðåóãîëüíèêè - îáëó÷åíèå ãàëîãåííûìè ëàìïàìè äâóìÿ 2minèìïóëüñàìè Ð=160W.cm-2, ïðè íåïðåðûâíîì îáëó÷åíûé ðòóòíîé ëàìïîé P=93W.cm-2.

Ðèñ.6. Çàâèñèìîñòü ïðîöåíòíîãî ñîäåðæàíèÿ ñâåðõïðîâîäÿùåé ôðàêöèè îò äëèòåëüíîñòè (êîëè÷åñòâî èìïóëüñîâ) ÈÔÎ ãàëîãåííûìè ëàìïàìè: 1) òî÷êè íà êðèâîé - Ð = 375W.cm-2, Tmax.=840îÑ; 2) òî÷êà - Ð = 160W.cm-2, Tmax.=1200îÑ.

Èç âûøå èçëîæåííîãî äåëàþòñÿ âûâîäû, ÷òî ïðè îäèíàêîâîì ñïåêòðàëüíîì ñîñòàâå è èíòåíñèâíîòè ÈÔÎ ýôôåêòèâíîñòü ïðîöåññà ïðîâåäåíèè ñèíòåçà ÂÒÑÏ îïðåäåëÿåòñÿ òåìïåðàòóðíî – âðåìåííûì ðåæèìîì îáëó÷åíèÿ, ïîçâîëÿþùèì â îïðåäåëåííûõ ïðåäåëàõ ñíèæàòü âåëè÷èíó îäíîãî ôàêòîðà çà ñ÷åò óâåëè÷åíèÿ äðóãîãî. Íà ðèñ.6 ïîêàçàíû ðåçóëüòàòû ýêñïåðèìåíòîâ ïî ÔÑÑ LSCO êîãäà îáðàçöû îáëó÷àþòñÿ áîëåå êîðîòêèìè, ÷åì â ïðåäûäóùåì ýêñïåðèìåíòå, 5s ecèìïóëüñàìè ãàëîãåííûõ ëàìï, íî ñ áîëüøåéïëîòíîñòüþ ìîùíîñòè èçëó÷åíèÿ P=375W.cm -2 . Ïðè ýòîì ìàêñèìàëüíàÿ òåìïåðàòóðà íàãðåâà îáðàçöîâ â èìïóëüñå

Ðèñ.8. Çàâèñèìîñòü ïðîöåíòíîãî ñîäåðæàíèÿ ñâåðõïðîâîäÿùåé ôðàêöèè îò äëèòåëüíîñòè (êîëè÷åñòâî 20sec èìïóëüñîâ) ÈÔÎ ãàëîãåííûìè ëàìïàìè Ð =375W.cm-2 ïðè íåïðåðûâíîì îáëó÷åíèé ðòóòíîé ëàìïîé P=93W.cm-2.

Íà ðèñ.7 ïîêàçàíû ðåçóëüòàòû ýêñïåðèìåíòîâ ïî ÔÑÑ LSCO êîãäà îáðàçöû îáëó÷àþòñÿ øåñòüþ 20secèìïóëüñàìè ãàëîãåííûõ ëàìï ñ P=160W.cm-2. Ïðè ýòîì, ïðè íåèçìåííîì ñïåêòðàëüíîì ñîñòàâå ÈÔÎ,

50 ìàêñèìàëüíàÿ òåìïåðàòóðà íàãðåâà îáðàçöîâ â èìïóëüñå ìåíÿëàñü â äèàïàçîíå Tmax.=850 - 1200îÑ. Êàê âèäíî, óâåëè÷åíèå òåìïåðàòóðû îáðàçöîâ, â ïðîöåññå ñèíòåçà ïðèâîäèò ê çíà÷èòåëüíîìó óâåëè÷åíèþ ýôôåêòèâíîñòè ýòîãî ïðîöåññà. Íà ðèñ.7,8 ïîêàçàíû ðåçóëüòàòû ýêñïåðèìåíòîâ êîãäà èñòî÷íèêàìè ÈÔÎ âìåñòå ñ ãàëîãåííûìè ëàìïàìè ñëóæèëè ðòóòíûå ëàìïû.  ïåðâîì ýêñïåðèìåíòå (ðèñ.7) îáðàçöû îáëó÷àëèñü, ïðè íåïðåðèâíîì îáëó÷åíèè ðòóòíîé ëàìïîé (P=93W.cm-2), äâóìÿ 2minèìïóëüñàìè ãàëîãåííûõ ëàìï (τint= 4min, P=160W.cm-2). Êàê âèäíî èç ðåçóëüòàòîâ ýêñïåðèìåíòîâ, òàêîé ðåæèì îáëó÷åíèÿ ïðèâîäèò ê âûñîêîé ýôôåêòèâíîñòè ÔÑÑ. Íà ðèñ.8 ïðèâåäåíû ðåçóëüòàòû àíàëîãè÷íîãî ýêñïåðèìåíòà ñ òåì îòëè÷èåì, ÷òî ïðè íåïðåðûâíîì îáëó÷åíèè ðòóòíîé ëàìïîé (P=93W.cm-2) îáëó÷åíèå ãàëîãåííûìè ëàìïàìè îñóùåñòâëÿëîñü ïðè áîëüøåé èíòåíñèâíîñòè ÈÔÎ (Ð= 375W.cm-2), áîëåå êîðîòêèìè (5sec) èìïóëüñàìè ïðè îòíîñèòåëüíî íèçêèõ òåìïåðàòóðàõ îáðàçöà (Tmax.=600îÑ). Îïèðàÿñü íà ðåçóëüòàòû ýêñïåðèìåíòîâ (ðèñ.7,8), ìîæíî ñäåëàòü âûâîä, ÷òî ïðè ÈÔÎ, äîáàâëåíèå ìîùíîãî èçëó÷åíèÿ â óëüòðàôèîëåòîâîé è âèäèìîé îáëàñòÿõ ñïåêòðà, çíà÷èòåëüíî ñïîñîáñòâóåò óâåëè÷åíèþ ýôôåêòèâíîñòè ÔÑÑ. Ïðè îäèíàêîâîé èíòåíñèâíîñòè îáëó÷åíèÿ îáðàçöîâ èçëó÷åíèåì ðòóòíûõ ëàìï, óâåëè÷åíèå èíòåíñèâíîñòè èçëó÷åíèÿ ãàëîãåííûõ ëàìï (Ð= 375W.cm-2,âìåñòî 160W.cm-2) äàåò âîçìîæíîñòü äîñòè÷ü àíàëîãè÷íîé ýôôåêòèâíîñòè ÔÑÑ ïðè ìåíüøåé äëèòåëüíîñòè ÈÔÎ (τ int= 160sec, âìåñòî 4min) è òåìïåðàòóðå (Tmax.=600îÑ, âìåñòî 950îÑ) îáðàçöà. Ñëåäóåò îòìåòèòü, ÷òî ïîñëå ÔÑÑ îáðàçöû ñòàíîâèëèñü êåðàìèêîé. Îäíàêî â ýêñïåðèìåíòàõ ïðåäñòàâëåííûõ íà ðèñ.6,8 ÷åðåç êîðîòêîå âðåìÿ îíè ðàññûïàëèñü â âûäå ïîðîøêà ñ ñîîòâåòñòâóþùèì ñîäåðæàíèåì çåðåí ñèíòåçèðîâàííîãî ÂÒÑÏ. Äëÿ ïîíèìàíèÿ ìåõàíèçìîâ ïðîâåäåíèÿ ýòèõ ïðîöåññîâ âûøåîïèñàííûì ìåòîäîì èç CuO áûëè ñïðåñîâàíû òàáëåòû è ïîäâåðãíóòû ÈÔÎ.  ðåæèìàõ ÈÔÎ ðèñ.5,7 íàáëþäàëîñü èõ ÷àñòè÷íîå èëè ïîëíîå ïëàâëåíèå. Òåðìîîòæèã â ïå÷è ïðè àíàëîãè÷íûõ ñ ÈÔÎ òåìïåðàòóðíî – âðåìåííûõ ðåæèìàõ íå ïðèâîäèò ê ôîðìèðîâàíèþ ÂÒÑÏ [3].

Çàêëþ÷åíèå

Îñíîâíûìè ôàêòîðàìè â ôîòîñòèìóëèðîâàííûõ íèçêîòåìïåðàòóðíûõ òåõíîëîãèÿõ ýëåêòðîíèêè, ÿâëÿþòñÿ: ñïåêòðàëüíûé ñîñòàâ, èíòåíñèâíîñòü, äëèòåëüíîñòü è ãåîìåòðèÿ îáëó÷åíèÿ [4- 8]. Êàê ïîêàçàëè ðåçóëüòàòû ýêñïåðèìåíòîâ, è â ñëó÷àå ñèíòåçà ÂÒÑÏ ìåòîäîì ôîòîñòèìóëèðîâàííîé òâåðäîôàçíîé ðåàêöèè, ïðàâèëüíûé ïîäáîð ýòèõ ôàêòîðîâ è îáúåñïå÷èâàåò âîçìîæíîñòü çíà÷èòåëüíîãî ñíèæåíèÿ òåìïåðàòóð îáðàçöîâ ïðè ÈÔÎ. Àíàëèçèðóÿ ïîëó÷åííûå ðåçóëüòàòû ïðèõîäèì ê âûâîäó ÷òî â çàâèñèìîñòè îò óñëîâèé ÈÔÎ ïðîöåññ ñèíòåçà ìîæåò ïðîèñõîäèòü äâóìÿ ðàçíûìè ìåõàíèçìàìè èìåþùèìè îáùóþ îñíîâó -ýôôåêòèâíîñòü ïîãëîùåíèÿ ôîòîíîâ ñèíòåçèðóþùèìè ìàòåðèàëàìè.  ñëó÷àå CuO ýòî ïîãëîùåíèå â èíôðàêðàñíîé ÷àñòè èçëó÷åíèÿ ãàëîãåííûõ ëàìï (ðèñ.2, Òàáë.1), ïðèâîäÿùèé ê èçìåíåíèþ ñèë õèìè÷åñêèõ ñâÿçåé âïëîòü äî áîëåå

íèçêîòåìïåðàòóðíîãî (àòåðìè÷åñêîãî) ÷åì òåðìîäèíàìè÷åñêîãî ïëàâëåíèÿ. Óâåëè÷åíèå èíòåíñèâíîñòè èçëó÷åíèÿ ãàëîãåííûõ ëàìï è îñîáåííî äîáàâëåíèå èçëó÷åíèÿ ðòóòíîé ëàìïû óâåëè÷èâàåò èíòåíñèâíîñòü èçëó÷åíèÿ â âèäèìîé è óëüòðàôèîëåòîâîé îáëàñòÿõ ñïåêòðà ýôôåêòèâíî ïîãëàùàåìîé La2O3 èSrCO3.  ýòèõ ðåæèìàõ ÈÔÎ ñèíòåç èäåò, âèäèìî, â òâåðäîôàçíîì ðåæèìå ïðè çíà÷èòåëüíî íèçêèõ òåìïåðàòóðàõ è êîðîòêèõ âðåìåíàõ. Íàáëþäàåìûé ýôôåêò àäèòèâíîñòè, âèäèìî, ñâÿçàí ñ ïîñòåïåííûì ïåðåõîäîì ñèíòåçèðóþùèõ êîìïîíåíòîâ â ÂÒÑÏ, ÷òî óâåëè÷èâàåò ýôôåêòèâíîñòü ïîãëîùåíèÿ ôîòîíîâ îò ïîâåðõíîñòè â ãëóáü ìàòåðèàëà.  çàêëþ÷åíèè íåîáõîäèìî îòìåòèòü, ÷òî ïðè ñèíòåçå ÂÒÑÏ â òåðìîïå÷àõ ó÷èòèâàëèñ òîëüêî òåìïåðàòóðíî – âðåìåííû ïîêàçàòåëè ïðîöåññà.  íàñòîÿùåé ðàáîòüå áûëî ïîêàçàíî, ÷òî â ñëó÷àå ïðîâåäåíèÿ ñèíòåçà ÌÔÒÐ, âìåñòå ñ âûøå íàçâàííûìè ôàêòîðàìè, íå òîëüêî çíà÷èòåëüíóþ, à îïðåäåëÿþùóþ ðîëü ìîãóò èãðàòü ñïåêòðàëüíûé ñîñòàâ è èíòåíñèâíîñòü ÈÔÎ.Èñõîäÿ èç âñåãî âûøåèçëîæåííîãî ìîæíî ñäåëàòü âûâîä, ÷òî ïðèìåíåíèå ÌÔÒÐ áóäåò îñîáåííî ýôôåêòèâíûì äëÿ ñèíòåçà òîíêèõ ïëåíîê ìíîãîêîìïîíåíòíûõ ìàòåðèàëîâ, íàïðèìåð ÂÒÑÏ âòîðîãî ïîêîëåíèÿ.

Ëèòåðàòóðà: 1. À.Â.Äâóðå÷åíñêèé, Ã.À.Êà÷óðèí, Å.Â.Íèäàåâ, Ë.Ñ.Ñìèðíîâ. Èìïóëüñíûé îòæèã ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ, 1982, Ìîñêâà, èçä. «Íàóêà», 206.

2. D.Daraselia,D.Japaridze,Z.Jibuti,A.Shengelaia:Synthesis of La2xBaxCuO4 High-Temperature Superconductor by Means of Photostimulated Solid State Reaction,Bull. Georg.

Acad.Sci.,5(2011), 116-118.

3. D. Daraselia, D. Japaridze, Z. Jibuti, A. Shengelaia, and K. A. Müller, “Rapid solid-state Synthesis ofOxides by Means of Irradiation with Light”, J Supercond Nov Magn.,26(2013), 29872991.

4. Z.V.Jibuti, N.D.Dolidze and B.E.Tsekvava. The Electronic Mechanism of Melting of Semiconductor Materials, New Developments in Material Science, 2011, New Science publishers, Inc. New York, 43-54.

5. Z.V.Jibuti,N.D.Dolidze,G.Eristavi,Photostimulatedrelaxation of internal mechanical stresses in epitaxial SOS– structures,Technical Physics,53(2008),6,808-810.

6. Z.V.Dzhibuti, N.D.Dolidze, G.Sh.Narsiya, and G.L.Éristavi, Possible method of reducing annealing temperatures of radiation defects in ion-implanted silicon carbide,Technical Physics Letters, 23(1997),10,746-747.

7. Ç.Â.Äæèáóòè, Í.Ä.Äîëèäçå,Íèçêîòåìïåðàòóðíûé ëàçåðíûé îòæèã äåôåêòîâ, îòâåòñòâåííûõ çà èíôðàêðàñíîå ïîãëîùåíèå â àðñåíèäå ãàëëèÿ,Ïèñüìà â ÆÒÔ, 17(1991),5, 41-44.

8. È.Ã.Ãâåðäöèòåëè, À.Ãåðàñèìîâ, Ç.Â.Äæèáóòè, Ì.Ã.Ïõàêàäçå. Ê ìåõàíèçìó ëàçåðíîãî îòæèãà ïîëóïðîâîäíèêîâ, Ïîâåðõíîñòü, 11(1985), 132-133.

51

Original technologyof fast synthesis of modern materials by photon irradiation Z. Jibuti1,2, D. Daraselia1, D. Japaridze1, A. Shengelaya1 Iv. Javakhishvili Tbilisi State University 1,I.Chavcavadze Ave., Tbilisi 0128, Georgia.

2 Institute of micro and nanoelectronics 13, I.Chavcavadze Ave. Tbilisi 0179, Georgia.

E-mail: z.jibuti@gmail.com

1

The mechanism of the process of the photostimulated solid state reaction at low temperature and rapid synthesis of high-Tc superconductors is studied. It is shown that the selection of the geometry, spectral composition and intensity of the pulsed photon irradiation can substantially reduce the duration and temperature of the synthesis process. It is concluded that the efficiency of process of the accelerated photostimulated solid state reaction (PSSR) is determined by the change in chemical bonds of synthesizing materials due to the selective absorption of photons.

fotonuri dasxivebis gziT swrafi sinTezis originaluri teqnologia, Tanamedrove masalebisTvis z. jibuti1,2, d. daraselia1, d. jafariZe1, a. Sengelaia1 1 iv.javaxiSvilis sax.Tbilisis saxelmwifo universiteti, i.WavWavaZis pr. 1, Tbilisi 0128, saqarTvelo 2 mikro da nanoeleqtronikis instituti, i.WavWavaZis pr. 13, Tbilisi 0179, saqarTvelo elâ&#x20AC;&#x201C;fosta: z.jibuti@gmail.com

Seswavlilia fotostimulirebuli myarfazovani reaqciis gziT maRaltemperaturuli zegamtarebis, swrafi da SedarebiT dabaltemperaturuli, sinTezis procesis meqanizmi. naCvenebia, rom impulsuri fotonuri dasxivebis geometriis, speqtruli Semadgenlobisa da intensivobis SerCeviT SesaZlebelia mniSvnelovnad SevamciroT sinTezis procesis temperatura da xangrZlivoba. keTdeba daskvna, rom aCqarebuli, fotostimulirebuli myarfazovani reaqciis procesis efeqturoba ganisazRvreba masinTezirebel masalebSi fotonebis seleqciuri STanTqmis Sedegad qimiuri kavSirebis cvlilebis faqtoriT.

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Efficiency of application of super-pure gallium (≥ ≥7N+) obtained by membrane technology for production of high quality GaAs single crystals E. Kutelia, G. Kvinikadze, E. Sanaia, T. Dzigrashvili Georgian Technical University, 77, Kostava street., 0175, Tbilisi, Georgia E-mail: ekutelia@gtu.edu.ge Abstract. Development of membrane technology of purification of liquid gallium from impurities, ensuring quick production of 7N+÷8N purity gallium from commercial 6N purity gallium, with the negligibly small energy consumption, motivated us to conduct a comparative study of electro-physical parameters of GaAs single crystals grown from the super-pure (≥7N+) gallium produced by the membrane technology and from commercial 6N purity gallium. The GaAs single crystals were grown using serial industrial installations by a Czochralski method from the melts of the following compositions: 1.Commercial 6NAs+commercial 6NGa, 2.Commercial 6NAs+membrane 7N+Ga and 3.Special 7NAs+membrane 7N+Ga. The measurements of Hall carrier mobility, for the above single crystals, showed an efficiency of the super-pure (≥7N+) gallium for production of high-quality GaAs single crystals. Particularly, there is a possibility of increasing the carrier mobility of GaAs single crystal by ~20%.

Keywords: carrier mobility, GaAs, membrane technology, purification, super-pure gallium.

Introduction

It is known that the physical and electronic properties of GaAs as an advanced electronic material and as a device medium, vastly depends on a purity of initial components for their synthesis [1]. The increasing demand on electronic industry in high quality gallium-base compounds (GaAs, GaP, GaN and so on) is making the problem of superpure (≥7N+) gallium production relevant. Therefore the problem of determining the impurity composition of gallium (more than 6N purity) in order to control its purrification and to obtain the certification of superpure gallium, remains urgent [2]. The fact is that the available traditional technologies for production of high purity (>6N) gallium, which are based on the direct impact on metallic gallium (nitration, multiple vacuum distillation, recrystallization, electrolysis, zone melting, etc.), are technologically complicated, energy intensive, characterized by big duration of multistage process and significant (>10%) losses of initial material that makes final product very expensive.

From this point of view, the application of membrane technology for production of super-pure (≥7N+) gallium is most important way for solving above mentioned problem.

Practice showed, that the membrane technology of purification of liquid gallium from impurities, based on the process so-called – “evaporation through the membrane” and realized by using membrane module “melt-membrane-atmosphere”, ensures high quality of one-step separation in a simple technological installation, with insignificant energy consumption and a little (<1%) loss of initial mass [3,4].

It was determined in our previous work that unlike the 7N purity gallium, produced via conventional technologies, the membrane technology of liquid gallium purification (up to 8N), reveals some unique properties of the product: 1.

Bulk samples (10g ÷ 10kg) remain liquid at room (+20oC) and lower temperatures, including negative range, for prac-

tically unlimited period of time; 2. The isotopic ratio is different from that of natural abundance; and 3. The structure of the overcooled melt is different from that of α-Ga melt [57]. The possibility of production of super-pure (≥7N+) gallium from commercially available 6N purity gallium, with negligible small energy consumption, motivated us to conduct a comparative study of electronic parameters of GaAs single crystals synthesized from super-pure (7N+) gallium produced by the membrane technology and those produced from the commercial 6N purity gallium.

Materials and Methods

In order to reveal the influence of initial gallium purity level on GaAs single crystal’s quality in the required composition for its synthesis, gallium produced by MaTeck company and certificated as having 6N purity level was used. On the part of this commercial 6N gallium was conducted refinement for increasing its purity level up to 8N using membrane technology [3,4]. Starting from the peculiarity of the problem, it was important to conduct preliminary investigation of the commercial 6N purity (according to the certificate) gallium and its samples refined by membrane technology up to 8N (expected) purity level for determining the exact values of impurity concentration in them. The fact is that while determining impurity concentration in 6N purity, and especially more high (up to 8N) purity gallium, we were facing a very difficult problem to define the optimum analytical conditions, relating to the impurity segregation on the surface during the necessary solid specimen preparation for the analysis of the assay taken from gallium melt [8-10]. Certification of commercial 6N purity gallium, defined by the method of spark source mass spectrography (SSMS) for 16 impurity elements, was presented by the manufacturer company. Thus, since the gallium standards with certified levels of impurities are not

53 generally available, the results from Ga analysis by SSMS are subject to huge systematic errors. Even though that direct analysis of gallium melt liquid assay is possible by this method, which also excludes remains of impurity elements induced by surface segregation, SSMS cannot be used to certify purer (>7N) gallium, because detection limit of the method is 10-100 ppbw. Therefore super-pure gallium obtained by us from commercially available 6N purity gallium via membrane technology of purification, was investigated using the very powerful glow discharge mass spectrometry (GDMS) method for elemental analysis, detection limit of which is better than 1-10 ppbw. Despite of GDMS has the advantage over SSMS in all analytical figures of merit, its use during gallium analysis has one great difficulty which is related to the solid analytical sample preparation with the surface free from impurity segregation [8-10]. To solve this problem, a relatively simple and effective method of pre-removal of impurity segregation (particularly enriched with Sn, In and other strongly inclined elements toward segregation in gallium) layer from analytical solid sample surface of gallium obtained by standard way was developed by us for GDMS analysis. We conducted GDMS analysis of commercial 6N gallium (in order to verify the certificate data) and from its part obtained super-pure gallium by membrane purification for accurate determination of purity level. All measurements were carried out using the VG-9000 magnetic sector glow discharge mass spectrometer (Fisons, UK) with a cryocooled discharge cell requiring a pin-shaped cylindrical sample. The results of GDMS analysis for commercial gallium according to the 16 elements defined by certificate and for gallium purified by membrane technology, according to 24 elements are given in Table 1.

Table 1. GDMS analysis results of a commercial 6N Ga and super-pure (up to 8N) Ga obtained by membrane refinement

N

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Symbol of impurity element Mg Al Si Fe Cu Ag Hg Cd Zn Ge As Sb In Tl Pb Bi B Na Cr Ni Se Sn Te Pt

Commercial 6N gallium (MaTecK GMBH, Germany) Concentration ppb (mass %) 50 50 100 50 50 50 100 10 10 50 10 10 100 100 50 50 -

*ND – not detectable, below detection limit

After membrane purification Concentration ppb (mass %) <0.2 0.3 3 5 1 ND* 3 ND 0.8 ND ND ND 1.3 0.5 0.6 0.4 0.5 <0.5 1.3 0.7 ND 4 0.5 0.6

As seen from Table 1, commercial gallium of MaTecK GmbH company really fits 6N purity level specified by certificate, and after membrane refinement of commercial 6N gallium we obtained gallium with 7N+ purity level.

The GaAs single crystals of 73,2mm in diameter were grown using serial industrial installation by Chokhralsky method from the melts of the following compositions: 1.

Commercial 6NAs + commercial 6NGa, 2. Commercial 6NAs + membrane 7N+Ga and 3. Special 7NAs + membrane 7N+Ga. After cutting wafers from GaAs single crystal ingots grown from each of the three composition melt so that for each single crystal we were taking three wafers from top“conical”, middle-cylindrical and bottom-“conical” areas of single crystal ingot, and were making measurements of electro-physical parameters (Hall mobility, electrical resistance) by standard methods.

Results The accumulated experience in experimental study of electronic properties of GaAs single crystals of various “quality” (different by number and type of impurities, naturally concomitant or artificially and purposefully entered, and also – by type and density of crystal lattice defects) allows to make general conclusion that, carrier mobility (transport) and resistivity (conductivity) is a complicated function of temperature, doping and doping compensation [1]. Despite of this complicated problem, it is obvious that measured value of hall mobility at one fixed temperature (300K or 77K) will be a reliable indicator for comparison (valuation) of GaAs single crystals’ quality, grown from compositions of initial ingredients having different purity level. Considering the fact that initial ingredients taken for GaAs synthesis were classified as materials of “High-purity” and “Super-purity” rank, it is obvious that all the three GaAs single crystals, grown by us using Czochralski method, were lightly doped N-type GaAs.

Fig.1. Hall mobility at room temperature (300K) for three “high-purity” N-type GaAs single crystals grown from the melts of following compositions: 1 – (Commercial 6NAs + commercial 6NGa), 2 – (Commercial 6NAs + membrane 7N+Ga), 3 – (Special 7NAs + membrane 7N+Ga).

54 Figure 1 shows Hall mobility vs carrier concentration (for wafers cut from different area of single crystal) measured at room temperature (300K) for three “high-purity” N-type GaAs single crystals grown from the melts of the following three different compositions: 1. Commercial 6NAs + commercial 6NGa, 2. Commercial 6NAs + membrane 7N+Ga and 3. Special 7NAs + membrane 7N+Ga. Obtained results show that use of membrane 7N+Ga for synthesized GaAs single crystal, compared with GaAs single crystal synthesized by conventional 6N purity ingredients, increases Hall mobility by ~ 15%; while rising both components’ purity level up to 7N+ in composition (As + Ga) enables to obtain GaAs single crystal with the all-time high value of 8200 cm2/V·s for Hall carrier mobility at room temperature. The obtained result makes it possible to suppose that the 7N+ purity gallium, produced by membrane technology [3,4], especially clean from limiting elements (<10-8 % mass), will be extremely competitive not only because of its high level of purity, but also due to low cost of production of its functional materials such as GaAs, GaP, GaN and other gallium-base compounds necessary for progress in science, technology and industry.

Conclusions In this paper the results of comparative study of Hall carrier mobility of GaAs single crystals grown from the super-pure (7N+) gallium, produced by the membrane technology of purification of liquid gallium and from commercial 6N purity gallium, are presented.

The measurements of Hall carrier mobility at room temperature for the GaAs single crystals synthesized from the following compositions: (Commercial 6NAs + commercial 6NGa), (Commercial 6NAs + membrane 7N+Ga) and (Special 7NAs + membrane 7N+Ga) showed an efficiency of use of super-pure (e”7N+) gallium for production of high-quality GaAs single crystals. Particularly, there is a possibility of increasing such an important parameter of GaAs single crystal as the Hall carrier mobility by ~20%.

References: 1. J.S. Blakemore: Semiconducting and Other Major Properties of Gallium Arsenide, J. Appl. Phys., 53 (1982), 123-181.

2. I. Shelpakova, N. Zaksas, L. Komissarova, S. Kovalevskij: Spectral Methods for Analysis of High-Purity Gallium with Excitation of Spectra in the Two-Jet Arc Plasmatron, J. Anal.

At. Spectrom, 17 (2002), 270-273.

3. E. Kutelia, B. Kutelia, D. Tsivtsivadze: Obtaining of NanoStructured Membrane for the purification of Liquid Gallium from Impurities up to 8N, Proceedings on the International Congress of Nanotechnology, 2005, San-Francisco, USA, November 1-5.

4. E. Kutelia, D. Tsivtsivadze, B. Kutelia, P. Kervalishvili: Method of Refinement Gallium from impurities, Patent GE,¹1363 A1 GE (1996), C22B, 9/00, 58/00.

5. B. Kutelia: Pecularities of Overcooling in Liquefied Ultrapure Gallium, Georgian Engineering News, 4 (1999), 64-68.

6. E. Kutelia, O. Tsurtsumia, T. Markus, Ch. Chatzicharalampous, T. Kukava: The DTA/TG Investigation of None-Crys-

tallizing Superpure (up to 8N) Gallium Melt obtained by the Membrane Technology, AIP Conference Proceeding, 1400 (2011), 555-559.

7. E. Kutelia, G. Kvinikadze, T. Dzigrashvili: Investigation of the Isotopic Abundance Ratio in the Superpure (7N+) Gallium Melt Obtained by the Method of Membrane Purification, Georgian Engineering news, 1 (2014), 45-49.

8. J. Allegre, B. Boudot: Gallium Analysis: Problem of Impurity Distribution in the Analytical Sample, Journal of Crystal Growth, North-Holland, 106 (1990), 139-142.

9. I. Zakourdaev, A. Tolstogouzov, V. Gnido, T. Kitaeva: Secondary Ion Mass Spectrometry Investigation of Liquid Gallium Recovery, Rapid Commun. Mass Spectrom, 12 (1998), 13561358.

10. W. Vieth, C. Huneke: Analysis of High-Purity Gallium by High-Resolution Glow Discharge Mass Spectrometry, Anal.

Chem., 64 (1992), 2958-2964.

membranuli teqnologiiT miRebuli zesufTa galiumis ≥ 7N+) gamoyenebis efeqturoba (≥ maRali xarisxis GaAs monokristalebis warmoebisTvis e. quTelia, g. kvinikaZe, e. sanaia, T. ZigraSvili

saqarTvelos teqnikuri universiteti, kostavas q. 77, 0175, Tbilisi, saqarTvelo el–fosta: ekutelia@gtu.edu.ge Txevadi galiumis minarevebisagan membranuli teqnologiiT gasufTavebis ganviTarebam, romelic uzrunvelyofs swraf warmoebas 7N+÷8N sisufTavis galiumis komerciuli 6N sisufTavis galiumisgan, umniSvnelod mcire energiis danaxarjebiT, mogvca motivacia Cagvetarebina membranuli teqnologiiT miRebuli zesufTa (≥7N+) galiumisa da komerciuli 6N sisufTavis galiumisgan gamozrdili GaAs monokristalebis eleqtrofizikuri parametrebis SedarebiTi Seswavla. GaAs monokristalebi gamoizardnen Coxralskis meTodiT, seriuli industriuli danadgarebis gamoyenebiT Semdegi kompoziciis mdnarebidan: 1. komerciuli 6NAs+komerciuli 6NGa, 2. komerciuli 6NAs+m e m b r a n u l i 7N+Ga d a 3 . s p e c i a l u r i 7NAs+membranuli 7N+Ga. “Hall carrier mobility”-is gazomvebma, zemoT aRniSnul monokristalebze, aCvena zesufTa (≥7N+) galiumis efeqturoba maRali xarisxis GaAs monokristalebis warmoebisTvis. kerZod, aris SesaZlebloba GaAs monokristalis “carrier mobility”-is gazrda ∼20%.

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Investigation of SiO2/Si structure combine implanted by Zn+ and O+ Ion V. Kulikauskas1, V. Zatekin1, V. Privezentsev2, V. Zinenko3, Yu. Agafonov3, V. Egorov3, E. Steinman4, A. Tereshchenko4 Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Leninskie Gory, 11999,1 Moscow, Russia; 2 Institute of Physics & Technology, Russian Academy of Sciences, Nakhimovskiy prosp. 34,117218, Moscow, Russia; 3 Institute of microelectronics Technology, Russian Academy of Sciences, Chernogolovka,141432 Moscow distr., Russia; 4 Institute of Solid-State Physics, Russian Academy of Sciences, Chernogolovka, 141432 Moscow distr., Russia E-mail: vladimir.zatekin@gmail.com, privezentsev@ftian.ru 1

Abstract. In paper the investigation of near-surface layer of SiO2/Si structure combine implanted by Zn+ and O+ ions with isochronally furnace annealing in neutral/inert atmosphere at elevated temperatures during 1h are presented.The Zn profiles and their evolution upon thermal treatment were investigated by Rutherford backscattering spectroscopy (RBS).

They have trend to permanent move to the SiO2 external surface and slightly decrease. Structure of implant layer was studied using X-ray fluorescence spectroscopy in a mode of total external X-ray reflection (TXRF) and at exceeding critical angle for depth analysis of element content in the sample. Addition to Si Kα, Zn Kα and Zn Kβ peaks were detected Ar Kα and Fe Kα peaks, and their variation with depth fluorescence analysis change was studied. Photoluminescence was spent using He-Cd laser with wavelength 325 nm in a spectral range 240-800 nm. The thick luminescence defect band centroid near 430 nm was observed. Also a big characteristic photoluminescence peak at wavelength of 370 nm, corresponded to ZnO phase was revealed after annealing at 700oC. Keywords: SiO2 film, combine Zn/O ion implantation, ZnO, Rutherford back scattering spectroscopy, X-ray fluorescence spectroscopy, photoluminescence.

Introduction

The properties of metal oxide nanoparticles (NPs) are comprehensively investigated because of possible application in future microelectronic devices [1]. ZnO NPs has an important interest, so ZnO has wide direct band gap of 3.37eV, large exiton binding energy of 60meV, room-temperature ferromagnetism, chemical-sensing and memory effects. Among important application in microelectronics one can note such as: UV light-source [2], solar cells [3], electro luminescence displays [4], chemical sensors [5] and memory devices (memristors) [6]. ZnO NPs in SiO2/Si structure can be made by thermal treatment in an oxidizing atmosphere of Si wafer contained Zn NPs. Theirs NPs have realised in Zn doped Si wafers which can be obtained by Zn ion implantation process, because of the last one is considered as one of the most clean and flexible technology technique. There are many attempts to form such NPs with control size and form in silica glass [7-9] by Zn implantation and by thermal annealing in oxygen. So it is very interesting to form high quality ZnO NPs embedded in microelectronic structures type of SiO2/Si for future industrial application. Here we present the investigation of ZnO phase formation in SiO2/Si structure by combine Zn+ and O+ ion implantation with furnace annealing in neutral/ inert.

Materials and Methods

At first on Si substrate was formed the SiO2 layer with width 170 nm by thermal oxidation in dry O2 at temperature of 1100°C. After that a Varian–Extrion 200–1000 implanter was used to implant Zn+ and O+ ions in SiO2/Si samples.

The parameters of implantation were as follows: for Zn+

ion the energy was 70keV and implant dose was 5.0x1016cm; for O+ ion the energy was 20keV and implant dose was 6.1x1016cm-2. In both cases the ion current density was 8μA/cm2. The energies of Zn+ and O+ ions were chosen so that their projective range in SiO2 was the same. By SRIM calculation it was about 50 nm. After implantation the test samples were subsequently isochronally subjected to annealing during 1h in nitrogen at 400 and 600°C, and then in argon at 700, 800, 900 and 1000°C. The evolution of Zn profiles during annealing was investigated by Rutherford backscattering spectroscopy (RBS) of He+ ions with energy of 2MeV with scattering angle of 160o using the channelling technique. X-ray fluorescence analysis was carried out on the Sokol-3 ion analytical complex in a total external X-ray reflection (TXRF) mode. Under these conditions the detector is fixed output secondary fluorescence of the near-surface layer with thickness of up to 5nm. When the exceeding of total external reflection angle the penetration depth of X-rays in the sample increases, thereby increasing the information-gathering depth for the fluorescence. Photoluminescence was spent in a spectral range 250-800 nm at room temperature and at 4.2K using He-Cd laser with wavelength of 325 nm.

2

Results and Discussion

On Fig. 1 there are presented RBS spectra of test samples. From them one can determine the total quantity of the implanted Zn, its concentration depth profiles and their change during annealing steps. The analysis of the curves in Fig.1 show, that in as implanted state the Zn impurity profile is symmetrical and has a Gauss form. After annealing at 400 and 600oC the Zn concentration peak has weak-

61 ly decreased and weakly moved to the higher channel number, namely, to the substrate surface side (not shown).

As well known, Zn is very mobile in SiO2 at high temperatures (700°C and higher). At these temperatures the behaviour of Zn implant atoms is constant moving to the sample surface which is no limited drain for Zn impurity.

Now Zn implant profile is not symmetrical and additionally to maim maximum it has a little tide.

Fig.2, b. TXRF spectra for annealed at 700oC sample; gathering depth: 3nm (1) and 70nm (2). The spectra 2 shift for 5 cps up to clarity.

Fig. 1. RBS spectra

On Fig. 2a there are presented TXRF spectra of as implanted sample.

From this Fig. one can see that addition to matrix element Si Kα, and implant element Zn Kα and Zn Kβ peaks the Ar Kα (annealing gas) and Fe Kα (stray light of metal sample holder) peaks were detected. With increasing of penetration depth the X-ray fluorescence intensity peaks of Si Kα, Zn Kα and Zn Kβ greatly increased, while peak intensity of Fe Kα decreases, and peak intensity of Ar Kα stays just the same. All this is quite obvious.

On Fig.2b there are presented TXRF spectra of test samples for the sample annealed at 900oC (b). In this case on spectra one can see that all of the peaks of fluorescence intensity for both cases, namely, for surfaces (3nm) and for deep layer of silicon oxide film (70nm) are approximately equal. I.e. annealing contributed some leveling distribution of impurities in the silicon oxide film.

Fig.2, a. TXRF spectra for as implanted sample, gathering depth: 3 nm (1) and 70 nm (2).

On Fig.3,a there are presented the set of test samples PL curves carried out at 10K. At these spectra one can see, that in as implanted sample there are no PL intensity.

From the other hand after annealing at 400oC a big and broad defect-band peak centroid at 420 nm arised. This is so called “defect band” luminescence of ZnO bulk material or/and luminescence due radiation induced point defects in SiO2 film. In ZnO matrix these defects specified as Zn interstitials and O vacancies. As furnace annealing going the defect-band peak have made smaller and arise some good visible peak at 370 nm due to formation on ZnO phase after annealing at 700oC. This is ZnO exciton luminescence peak indeed.

On Fig.3,b there are presented the set of test samples PL curves carried out at 4.2K and at two different slit of He-Cd laser source 1 and 2 mm. From these curves follow that PL spectrum at 370 nm has a doublet form. It may be connected with two kinds of NP sizes. Because it is well known that PL light-length depends from the last value: the smaller the NP size the shorter the light-length from NPs.

Fig.3,a. Photoluminescence at 10K.

62 5. S. Chu, M. Olmedo, Zh. Yang, J. Kong, J. Liu. et al. Appl. Phys.

Lett., 93(2008) 181106-18112.

6. G.P. Smestad, M. Gratzel, J. Chem. Educ., 75 (1998) 752-762.

7. H. Amekura, Y. Takeda, and N. Kishimoto, Mater. Lett., 222 (2011) 96-100.

8. Y.Y. Shen, X.D. Zhang, D.C. Zhang, Y.H. Xue, L.H. Zhang, C.L. Liu. Mater. Lett., 65 (2011) 2966 -2974.

9. V. Privezentsev, V. Kulikauskas, E. Steinman, A. Bazhenov. phys. stat. sol. (c), 10 (2013) 48-51.

Zn+ da O+ ionebiT erToblivad implantirebuli SiO2/Si struqturis kvleva Fig.3,b. Photoluminescence at 10 and 4.2K; slit: 1 and 2mm.

Conclusions 1. Zn+ ions with dose of 5.0 x1016cm-2 and O+ ions with dose of 6.1x1016cm-2 ions were combine implanted in SiO2/ Si structure such so their projective range in SiO2 was just the same and consists 50nm.

2. After implantation the test samples were subsequently isochronally subjected to annealing during 1h in nitrogen at 400 and 600°C, and then in argon at 700, 800, 900 and 1000°C. 3. The RBS investigation follows that after low temperature annealing in N2 the Zn concentration peak has weakly decreased and slightly moved to the substrate body. At high temperature annealing (700°C and higher) in Ar the behaviour of Zn implant atoms is constant moving to the sample surface. At this annealing the Zn implant profile becomes not symmetrical and additionally to maim Zn concentration maximum it was a little tide in a nearsurface layer.

4. From TXRF and at exceeding critical angle for depth analysis of element content in the sample show that addition to matrix Si Kα and implant Zn Kα and Zn Kβ peaks the Ar Kα (annealing gas) and Fe Kα (stray light of metal sample holder) peaks were detected.

5. Photoluminescence at room temperature shows the presence of thick PL defect band centroid near 430 nm.

After annealing at 700oC a big characteristic PL peak at wavelength of 370 nm, corresponded to ZnO phase was revealed in PL spectrum. Photoluminescence at 4.2K shows that this PL peak at 370 nm shaped doublet form.

References: 1. M.I. Baraton. Synthesis, Functionalization, and Surface Treatment of Nanoparticles (2002), Am. Sci., Los-Angeles.

2. C. Flytzanis, F. Haqche, M.C. Klein, D. Ricard, Ph. Roussignol, in Prog.Optics, 29 (1999). E.Wolf ed., North Holland, Amsterdam, p. 321.

3. C.Y. Jiang, X.W. Sun, G.Q. Lo, D.L. Kwong, J.X. Wang. Appl.

Phys. Lett., 90 (2007) 263501-2635507.

4. C. Li, Y. Yang, X.W. Sun, W. Lei, X.B. Zhang, B.P. Wang, J.X. Wang, B.K. Tay, J.D. Ye, G.Q. Lo, D.L. Kwong. Nanotechnology, 18, (2007) 135604-135612.

v. kulikauskasi1, v. zatekini1, v. privezencevi2, v. zinenko3, i. agafonovi3, v. egorovi3, e. steinmeni4, a. tereSCenko4 1

skobelcinis birTvuli fizikis instituti, lomonosovis moskovis saxelmwifo universiteti, leninskie gori, 119991 moskovi, ruseTi; 2fizikisa da teqnikis instituti, ruseTis mecnierebaTa akademia, naximovskis gamziri. 34, moskovi 117218, ruseTi; 3 mikroeleqtronuli teqnologiis instituti, ruseTis mecnierebaTa akademia, Cernogolovka, 141432 moskovis olqi., ruseTi; 4 myari sxeulebis fizika, ruseTis mecnierebaTa akademia, Cernogolovka, 141432 moskovis olqi. ruseTi el–fosta: vskulikauskas@gmail.com, vladimir.zatekin@gmail.com naSromSi gamokvleulia Zn+ da O+ ionebiT erToblivad implantirebuli da inertul atmosferoSi maRaltemperaturebze 1 sT-is ganmavlobaSi RumelSi izoqronulad momwvari SiO2/Si kompoziciis struqturis zedapiruli fena. rezerfordis ukugabnevis speqtroskopiis meTodiT Seswavlilia Zn-is ganawilebis profilebi da maTi Semdgomi cvalebadoba Termuli zemoqmedebis gavleniT. maT axasiaTebT SiO2-is gare zedapiris mimarTulebiT uwyveti moZraoba da amave dros umniSvnelod Semcireba. nimuSSi elementis Semcvelobis siRrmeze damokidebulebis analizis Casatareblad gamokvleuli iqna implantirebuli fenis struqtura rentgenis fluorescenciuli speqtroskopiT - rentgenis sruli gare arekvlis reJimSi, kritikulze ufro maRal arekvlis kuTxeebze. Si Kα, Zn Kα da Zn Kβ pikebTan damatebiT deteqtirebulia Ar Kα da Fe Kα pikebi, Sesabamisad Seswavlili iqna fluorescenciuri analiziT maTi cvalebadoba, rogorc siRrmis funqcia. fotoluminescencia ganxorcielda 325 nm talRis sigrZeze moqmedi He-Cd lazeris gamoyenebiT talRis sigrZis 240-800 nm speqtrul diapazonSi. farTo luminescenciuri defeqtebis zoli damzerilia simZimis centriT 430 nm-s maxloblobaSi. aseve 370 nm talRis sigrZeze gamovlinda fotoluminiscenciis didi maxasiaTebeli piki, romelic Seesabameba ZnO fazas da Cndeba 700oCze mowvis Semdeg.

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Âëèÿíèå ñïåêòðàëüíîãî ñîñòàâà ñâåòà íà ôîòîýëåêòðè÷åñêèå ñâîéñòâà èîííîëåãèðîâàííîãî êðåìíèÿ Í. Äîëèäçå1, Ç. Äæèáóòè1, Ì. Òèãèøâèëè2, Í. Õó÷óà2, Ð. Ìåëêàäçå2, Í. Ãàïèøâèëè1 Èíñòèòóò ìèêðî- è íàíîýëåêòðîíèêè, ïð.È.×àâ÷àâàäçå, 13, 0179 Táèëèñè, Ãðóçèÿ, ÍÏÊ «Ýëåêòðîííàÿ òåõíèêà» ÍÈÈ ïðèêëàäíûõ ïîëóïðîâîäíèêîâûõ òåõíîëîãèé Òáèëèññêîãî ãîñóäàðñòâåííîãî óíèâåðñèòåòà èì. Èâ. Äæàâàõèøèâèëè, ïð. È.×àâ÷àâàäçå, 13, 0179 Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà:nugzardolidze@gmail.com 1

2

Ðåçþìå.Öåëü ðàáîòû çàêëþ÷àåòñÿ â êîíòðîëèðóåìîì èçìåíåíèè îïòè÷åñêèõ ñâîéñòâ êðåìíèÿ çà ñ÷åò äåôåêòîîáðàçîâàíèÿ ïðè èîííîì ëåãèðîâàíèè ïîëóïðîâîäíèêà ïðèìåñÿìè (Â). p-n-Si:B ñòðóêòóðû ïîëó÷åíû ïðè ðàçëè÷íûõ äîçàõ (1õ1013 – 1õ1015ñì-2) è ýíåðãèÿõ óñêîðåíèÿ 32 è 50 êý ñ ïîñëåäóþùèì îòæèãîì (900 è 1000îÑ).Íà îðèãèíàëüíîé îïòè÷åñêîé óñòàíîâêå c ñèñòåìîé ôèëüòðîâ èçìåðÿëñÿ ôîòîîòêëèê p-n-Si:B â çàâèñèìîñòè îò ñïåêòðàëüíîãî ñîñòàâà ñâåòîâîãî ïîòîêà â äèàïàçîíå 350 – 4100 íì.Áûëè ïîëó÷åíû íîâûå èíòåðåñíûå äàííûå, äåìîíñòðèðóþùèå âëèÿíèå ñïåêòðàëüíîãî ñîñòàâà ñâåòà íà ôîòî÷óâñòâèòåëüíîñòü.

Êëþ÷åâûå ñëîâà: èîííîëåãèðîâàííûé áîðîì êðåìíèé. ñïåêòðàëüíàÿ çàâèñèìîñòü ôîòî÷óâñòâèòåëüíîñòè

Ââåäåíèå Èññëåäîâàíèÿ îïòè÷åñêèõ ñâîéñòâ ïîëóïðîâîäíèêîâ â áîëüøèíñòâå ñëó÷àåâ ðàâíîöåííû ïî ñâîåé íàó÷íîé è ïðàêòè÷åñêîé çíà÷èìîñòè. Ïåðâîå ñâÿçàíî ñ âîçìîæíîñòüþ áîëåå ïîëíîãî ïîíèìàíèÿ ïðîöåññîâ, ïðîèñõîäÿùèõ â êîíêðåòíîì ìàòåðèàëå ïðè âîçäåéñòâèè ýëåêòðîìàãíèòíîãî èçëó÷åíèÿ (ÝÌÈ). Âòîðîå îáóñëîâëåíî ìíîãîîáðàçèåì îïòè÷åñêèõ ïîëóïðîâîäíèêîâûõ ïðèáîðîâ, èñïîëüçóþùèõñÿ â ðàçëè÷íûõ îáëàñòÿõ òåõíèêè. Íåìàëîâàæíóþ îáëàñòü ïîäîáíûõ èññëåäîâàíèé ñîñòàâëÿþò ìàòåðèàëû, â êîòîðûõ èñõîäíûå ôóíäàìåíòàëüíûå (ñòðóêòóðíûå, ýëåêòðè÷åñêèå, îïòè÷åñêèå) ñâîéñòâà èçìåíåíû çà ñ÷åò öåëåíàïðàâëåííîãî âîçäåéñòâèÿ òåõíîëîãè÷åñêèõ ïðîöåññîâ [1]. Ê òàêèì ïðîöåññàì îòíîñèòñÿ, â ÷àñòíîñòè, èîííàÿ èìïëàíòàöèÿ (ÈÈ) ïðèìåñåéñ ïîñëåäóþùèì îòæèãîì. Èçìåíÿÿ ðåæèìû ÈÈ è îòæèãà, ìîæíî çà ñ÷åò äåôåêòîîáðàçîâàíèÿ ïîëó÷èòü ìàòåðèàë ñî ñâîéñòâàìè, îòëè÷íûìè îò ñâîéñòâ èñõîäíîãî. Îïòè÷åñêèå ñâîéñòâà ìîäèôèöèðîâàííîãî êðåìíèÿ ïðåäñòàâëÿëè è ïðîäîëæàþò ïðåäñòàâëÿòü îáúåêò ïðèñòàëüíîãî âíèìàíèÿ èññëåäîâàòåëåé, ïîñêîëüêó, ñ îäíîé ñòîðîíû, Si ÿâëÿåòñÿ ìîíîàòîìíûì ìàòåðèàëîì ñ õîðîøî ðàçðàáîòàííîé, îòíîñèòåëüíî äåøåâîé òåõíîëîãèåé, à ñ äðóãîé ñòîðîíû, íà åãî îñíîâå èçãîòîâëÿþòñÿ ñîëíå÷íûåýëåìåíòû, ôîòîäåòåêòîðû è äðóãèå ïðèáîðû. Î÷åâèäíî, ÷òî íàó÷íûé è ïðàêòè÷åñêèé èíòåðåñ ê ïîâûøåíèþ ýôôåêòèâíîñòè îïòè÷åñêèõ ïîëóïðîâîäíèêîâûõ ïðèáîðîâ äîëæåí áûòü ñâÿçàí íå òîëüêî ñî ñâîéñòâàìè ìàòåðèàëà, íî è ñ óñëîâèÿìè âîçäåéñòâèÿ ÝÌÈ (ìîùíîñòü è ñïåêòð èçëó÷åíèÿ). Íåñìîòðÿ íà òî, ÷òî áîð ÿâëÿåòñÿ â êðåìíèåâîé òåõíîëîãèè îäíîé èç íàèáîëåå ïðèìåíÿåìûõ ïðèìåñåé,

âñå åùå îñòàåòñÿ ìíîãî íåðåøåííûõ âîïðîñîâ. Òàê, îòíîñèòåëüíî ïðèðîäû äåôåêòîâ â n-Si, èìïëàíòèðîâàííîì áîðîì [2 – 4], ñóùåñòâóåò ðÿä òðàêòîâîê, ÷àñòî íåñîâïàäàþùèõ äðóã ñ äðóãîì. Åùå ìåíüøå èíôîðìàöèè èìååòñÿ î ìåõàíèçìå âëèÿíèÿ òåõ èëè èíûõ íàðóøåíèé íà îïòè÷åñêèå ñâîéñòâà ñòðóêòóð ñ ð-n ïåðåõîäîì.  îñíîâíîì ïðèâîäÿòñÿ ðåçóëüòàòû äëÿ ñïåêòðîâ ëþìèíåñöåíöèè [5], à ñïåêòðû ôîòî÷óâñòâèòåëüíîñòè èññëåäîâàíû ìàëî è, êàê ïðàâèëî, íå ñâÿçûâàþòñÿ ñ êàêèì-ëèáî òèïîì äåôåêòîâ [6]. Ñòðåìÿñü ðàñøèðèòü ïðåäñòàâëåíèÿ î ïðîöåññàõ, ïðîòåêàþùèõ â p-n ñòðóêòóðàõ, ïîëó÷åííûõ èìïëàíòàöèåé áîðà ñ ïîñëåäóþùèì îòæèãîì (â äàëüíåéøåì – p-n-Si:B), ìû äåëàëè àêöåíò íà èçó÷åíèè ñïåêòðîâ ôîòî÷óâñòâèòåëüíîñòè îáðàçöîâ â ÈÊ è ÓÔ îáëàñòÿõ. Äëÿ ëó÷øåãî ïîíèìàíèÿ ýòèõ ñâîéñòâ â íàøèõ ðàáîòàõ èññëåäîâàëèñü òàêæå ÈÊ ñïåêòðû îòðàæåíèÿ è Ðàìàíñïåêòðû îáðàçöîâ [7-10]. Ðåçóëüòàòû äàííûõ èññëåäîâàíèé ïîçâîëèëè ñäåëàòü ìîòèâèðîâàííûå ïðåäïîëîæåíèÿ î âëèÿíèè ïðîöåññîâ äåôåêòîîáðàçîâàíèÿ â èìïëàíòèðîâàííûõ  êðåìíèåâûõ ñòðóêòóðàõ íà èçìåíåíèå ôîòîýëåêòðè÷åñêèõ ñâîéñòâ ìàòåðèàëà.  ðàáîòå [10] áûëî ïðîäåìîíñòðèðîâàíî, ÷òî îïòè÷åñêèå ñâîéñòâà p-n-Si:B ñòðóêòóð çàâèñÿò êàê îò òåõíîëîãèè, òàê è îò óñëîâèé îáëó÷åíèÿ â ðàçëè÷íûõ äèàïàçîíàõ ÝÌÈ. Ýîò ôàêò ñòèìóëèðîâàë íàñ áîëåå ïîäðîáíî èçó÷èòü âëèÿíèå ïàêåòà ÝÌÈ èçëó÷åíèÿ ÷åðåç ðàçëè÷íûå ôèëüòðû íà ôîòî÷óâñòâèòåëüíîñòü p-n-Si:B ñòðóêòóð. Òàêèì îáðàçîì, öåëüþ íàñòîÿùåé ðàáîòû ÿâëÿåòñÿ äåòàëüíîå èññëåäîâàíèå âëèÿíèå ñïåêòðà èçëó÷åíèÿ íà îïòè÷åñêèå ñâîéñòâà n-Si, èìïëàíòèðîâàííîãî áîðîì ñ

64 ðàçëè÷íûìè äîçàìè è îòîææåííîãî ïðè ðàçíûõ òåìïåðàòóðàõ. äîïîëíåíèå ê ïîëó÷åííûì ðàíåå äàííûì áûëè èçãîòîâëåíû è èçó÷åíû îáðàçöû, ëåãèðîâàííûå Â, ïðè áîëåå íèçêèõ ýíåðãèÿõ óñêîðåíèÿ – 32 êýÂ, â òîì ÷èñëå è ñ öåëüþ èçìåíåíèÿ ãëóáèíû çàëåãàíèÿ p-n ïåðåõîäà.

Ìàòåðèàë è ìåòîäèêè èçìåðåíèé

ð-n ñòðóêòóðû ôîðìèðîâàëèñü íà ïðîìûøëåííûõ ïëàñòèíàõ êðåìíèÿ (Universitywafer, ÑØÀ) n-òèïà ñ îðèåíòàöèåé (100) ìåòîäîì ÈÈ áîðà ñ äîçàìè 1x1013ñì2 , 1x1014ñì-2 è 1x1015ñì-2,ýíåðãèÿìè óñêîðåíèÿ 32êý è 50 êý íà èìïëàíòåðå Âåçóâèé-3Ì. Ïðîåöèðîâàííûå ïðîáåãè Rp è ñòðàããëèíãè ΔRp, ðàññ÷èòàííûå ñ ïîìîùüþ ïðîãðàììû SRIM, ñîñòàâëÿëè 0.1204 ìê, 0.0422 ìêì è 0.1746 ìêì, 0.0557 ìêì, ñîîòâåòñòâåííî. Ïëàñòèíû èìåëè óäåëüíîå ñîïðîòèâëåíèå 70 Îì×ñì, à èõ òîëùèíà ñîñòàâëÿëà 250 ìêì. Ïîñëå ÈÈ ïðîâîäèëñÿ îòæèã â àòìîñôåðå àðãîíà ïðè òåìïåðàòóðàõ 900 è 1000îÑ â òå÷åíèå 20 ìèí. Íà ðàáî÷åé ñòîðîíå ïëàñòèíû ôîðìèðîâàëèñü òî÷å÷íûå, à ñ îáðàòíîé - ñïëîøíûå êîíòàêòû Ti/Pt. Èññëåäîâàíèå âëèÿíèÿ ñïåêòðàëüíîãî ñîñòàâà ñâåòîâîãî ïó÷êà íà ôîòîýëåêòðè÷åñêèå õàðàêòåðèñòèêè äèîäíûõ ñòðóêòóð ïðîèçâîäèëîñü íà îðèãèíàëüíîé óñòàíîâêå (ðèñ.1), ãäå èñòî÷íèêîì èçëó÷åíèÿ ñëóæèëà ãàëîãåííàÿ ëàìïà ìîùíîñòüþ 50 Âò è öâåòîâîé òåìïåðàòóðîé 3000 K.Ñïåêòð èçëó÷åíèÿ ëàìïû ïðèâåäåí íà ðèñ.2.

Ðèñ. 1. Îáùèé âèä óñòàíîâêè èçìåðåíèÿ ôîòî÷óñòâèòåëüíîñòè îáðàçöîâ

Ðèñ.2. Ñïåêòð èçëó÷åíèÿ ãàëîãåííîé ëàìïû

Íàáîð îïòè÷åñêèõ ôèëüòðîâ ïîçâîëÿåò îöåíèâàòü ôîòî÷óâñòâèòåëüíîñòü îáðàçöîâ â ðàçëè÷íûõ äèàïàçîíàõ ÝÌÈ (ðèñ. 3) â îáëàñòè 350-4100 íì. Íîðìèðîâàíèå çíà÷åíèé ôîòîîòêëèêà ïðîâîäèëîñü ñ ó÷åòîì õàðàêòåðèñòèê ïðîïóñêàíèÿ îïòè÷åñêèõ ôèëüòðîâ. Ïîãðåøíîñòü èçìåðåíèé íå ïðåâûøàëà 1% Àïïàðàòóðà ïîçâîëÿåò ïðîâîäèòü èçìåðåíèÿ ïðè 300 è 77K. Âî èçáåæàíèå íàãðåâà îïòè÷åñêèå ôèëüòðû è èññëåäóåìûå îáðàçöûîáäóâàëèñü ïîòîêîì âîçäóõà. Òåìïåðàòóðà âî âðåìÿ èçìåðåíèé êîíòðîëèðîâàëàñü âñòðîåííîé òåðìîïàðîé è íå ïðåâûøàëà êîìíàòíóþ. Ñ ïîìîùüþ ìîíîõðîìàòîðà ÌÄÐ-2 ñíèìàëàñü ñïåêòðàëüíàÿ çàâèñèìîñòü ôîòîîòëèêà îáðàçöîâ â äèàïàçîíå 1,0-2,5 ìêì.

Ðåçóëüòàòû Ðåçóëüòàòû èññëåäîâàíèé îïòè÷åñêèõ ñâîéñòâ p-nSi:B ñòðóêòóð ïðåäñòàâëåíû íà ðèñ.4 è 5. Êàê óêàçûâàëîñü âûøå, íàáîð îïòè÷åñêèõ ôèëüòðîâ ïîçâîëÿë ïîñëåäîâàòåëüíî « «óðåçàòü» êîðîòêîâîëíîâóþ ãðàíèöó ïîääèàïàçîíà.  êàæäîì ñëó÷àå òî÷êèíà ãðàôèêå ðèñ.4 ñîîòâåòñòâóþò íèæíåìó êîðîòêîâîëíîâîìó ïðåäåëó òîãî èëè èíîãî ôèëüòðà. Îòäåëüííûìè òî÷êàìè âûäåëåíû äàííûå äëÿ Si ôèëüòðà (1100íì), îáåñïå÷èâàþùåãî îáëó÷åíèå îáðàçöà â îáëàñòè ïðèìåñíîãî ïîãëîùåíèÿ. Çâåçäî÷êàìè îáîçíà÷åíû çíà÷åíèÿ îòíîñèòåëüíîé ìîùíîñòè ãàëîãåííîé ëàìïû. Èç äàííûõ ðèñ. 4 âèäíî, ÷òî ðåæèìû ÈÈ è îòæèãà âëèÿþò íà âåëè÷èíó îòíîñèòåëüíîé ôîòî÷óâñòâèòåëüíîñòè I/IF(IF – ôîòîòîê ïðè ïîëíîì îñâåùåíèè), à ñòåïåíü ýòîãî âëèÿíèÿ ðàñòåò ñ óâåëè÷åíèåì äëèíû âîëíû äî 1000 íì. Ïðè èñïîëüçîâàíèè Siôèëüòðà ôîòîîòêëèê çàìåòíî îñëàáåâàåò. Èç ðèñ.4,à âèäíî, ÷òî äëÿ ýíåðãèè 50êý íàèëó÷øèé ðåçóëüòàò ïî ôîòî÷óâñòâèòåëüíîñòè äàåò äîçà 1õ1014ñì2 (900îÑ), íàèõóäøèé - 1õ1015ñì-2 (1000îÑ). Îñòàëüíûå çíà÷åíèÿ ðàñïîëîæåíû ìåæäó íèìè. Ïðè ýíåðãèè 32 êý (ðèñ.4,á) ñàìûé èíòåíñèâíûé ôîòîîòêëèê ñîîòâåòñòâóåò îïÿòü-òàêè ðåæèìó 1õ1014ñì-2 (900îÑ), à íàèìåíüøàÿ èíòåíñèâíîñòü èìååò ìåñòî ïðè 1õ1014ñì-2 (1000î Ñ). Êðîìå òîãî, ïðè ýòîé ýíåðãèè âëèÿíèå òåõíîëîãè÷åñêèõ ðåæèìîâ ìåíåå âûðàæåíî. Èçìåíåíèå

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Ðèñ.3. Ñïåêòðû ïðîïóñêàíèÿ îïòè÷åñêèõ ôèëüòðîâ: White (ÁÑ8); Yellow(ÆÑ10,11,12,16,17,18); Orange (ÎÑ11,12,13,14); Red(ÊÑ10,11,13,14,15,17,18,19); Infrared (ÈÊÑ5); Si.

Ðèñ.4. Çàâèñèìîñòü îòíîñèòåëüíîé ôîòî÷óâñòâèòåëüíîñòè p-n-Si:B îáðàçöîâ ñ ðàçíûìè ðåæèìàìè ëåãèðîâàíèÿ îò äëèíû âîëíû äëÿ ðàçëè÷íîãî ñïåêòðàëüíîãî ñîñòàâà èñòî÷íèêà èçëó÷åíèÿ: à – 50êýÂ; á – 32êýÂ; * - îòíîñèòåëüíîå çíà÷åíèå ïîòîêà èçëó÷åíèÿ.

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Ðèñ.5. Çàâèñèìîñòü îòíîñèòåëüíîé ôîòî÷óâñòâèòåëüíîñòè p-n-Si:Bîáðàçöîâ îò äëèíû âîëíû ìîíîõîìàòè÷åñêîãî èçëó÷åíèÿ ïðè ýíåðãèè óñêîðåíèÿ 32êý è äëÿ òåìïåðàòóð îòæèãà: à – 900îÑ; á – 1000îÑ.

îòíîñèòåëüíîé ìîùíîñòè ëàìïû ñ äëèíîé âîëíû ïðîèñõîäèò ìåäëåííåå, ÷åì ñîîòâåòñòâóþùåå óìåíüøåíèå ôîòîîòêëèêà.Ýòî ñâèäåòåëüñòâóåò î òîì, ÷òî êðîìå ìîùíîñòè, áîëüøóþ ðîëü èãðàåò ñïåêòðàëüíûé ñîñòàâ èçëó÷åíèÿ (îñîáåííî äëÿ 32 êýÂ). Àíàëîãè÷íîå çàêëþ÷åíèå äåëàåòñÿ â ðàáîòå [11] ïðè èññëåäîâàíèè àìîðôíîãî êðåìíèÿ.  îáëàñòè ýíåðãèé, ïðåâûøàþùèõ øèðèíó çàïðåùåííîé çîíû Si (äî äëèí âîëí ïîðÿäêà 1100íì), ôîòî÷óâñòâèòåëüíîñòü îïðåäåëÿåòñÿ ïîâåäåíèåì íîñèòåëåé, âîçíèêàþùèõ ó ïîâåðõíîñòè îáðàçöà è äîñòèãàþùèõ ð-n ïåðåõîäà. Î÷åâèäíî, ÷òî êîëè÷åñòâî íîñèòåëåé óìåíüøàåòñÿ ñ ðîñòîì äëèíû âîëíû è óìåíüøåíèåì îòíîñèòåëüíîé ìîùíîñòè èçëó÷åíèÿ èñòî÷íèêà, íà÷èíàÿ ïðèìåðíî ñ 620 íì. Ýòî ìîæåò áûòü ñâÿçàíî êàê ñ óìåíüøåíèåì êîýôôèöèåíòà ïîãëîùåíèÿ êðåìíèÿ, òàê è ñ îñîáåííîñòÿìè îáðàçîâàíèÿ ïðîòÿæåííûõ äåôåêòîâ â èìïëàíòèðîâàííîì ðñëîå. Î ïîñëåäíåì ñâèäåòåëüñòâóåò çàâèñèìîñòü ôîòîîòêëèêà îò òåõíîëîãèè. Ïðè äëèíàõ âîëí, ïðåâûøàþùèõ 1100íì, ãäå Si ïðîçðà÷åí äëÿ ÝÌÈ, â ìîäèôèöèðîâàííîì ÈÈ ìàòåðèàëå ïîÿâëÿåòñÿ ÈÊ ôîòî÷óâñòâèòåëüíîñòü [7–10]. Êàê è â ñëó÷àå ýíåðãèè 50 êýÂ, ïðè 32 êý ïðè èçìåðåíèÿõ ñ ïîìîùüþ ìîíîõðîìàòîðà íàáëþäàåòñÿ àíàëîãè÷íàÿ êàðòèíà (ðèñ.5): ìàêñèìàëüíûé ôîòîîòêëèê ñîîòâåòñòâóåò äîçå 1õ1014ñì-2(900îÑ), à ìèíèìàëüíûé-1õ1015ñì-2 (1000îÑ). Ïî àáñîëþòíîìó çíà÷åíèþ ôîòî÷óâñòâèòåëüíîñòü â ñëó÷àå ðèñ.5,à íà 1.52.0 ïîðÿäêà âåëè÷èíû âûøå âûøå, ÷åì â ñëó÷àå ðèñ.5,á. Äëÿ ïîñëåäóþùåé èíòåðïðåòàöèè íàáëþäàåìûõ ýôôåêòîâ ñëåäóåò èìåòü ââèäó, ÷òî íåçàâèñèìî îò óñëîâèé îáëó÷åíèÿ, äëÿ ýíåðãèé óñêîðåíèÿ 32 è 50 êýÂ,íàèëó÷øèå ðåçóëüòàòû ïî ôîòîîòêëèêó ïîëó÷àþòñÿ äëÿ äîçû 1õ1014ñì-2 (900îÑ), à íàèõóäøèå – äëÿ 1õ1015ñì2 (1000 î Ñ). Ïî âñåé âèäèìîñòè, ýòî âìåñòå ñ ðåçóëüòàòàìè Ðàìàí-ñïåêòðîñêîïèè [9,10] îçíà÷àåò ÷òî ïóòåì êîíòðîëèðóåìûõ òåõíîëîãè÷åñêèõ ïðîöåññîâ íåîáõîäèìî ñîçäàâàòü ïðîòÿæåííûå äåôåêòû ñ äîñòàòî÷íî âûñîêîé êîíöåíòðàöèåé, îäíàêî íå ïðèâîäÿùèå ê çíà÷èòåëüíîìó íàðóøåíèþ ñòðóêòóðû ïîëóïðîâîäíèêà.

Çàêëþ÷åíèå

 ðåçóëüòàòå èññëåäîâàíèÿ ôîòîýëåêòðè÷åñêèõ ñâîéñòâ ÈÈ áîðîì è îòîææåííûõ ñòðóêòóð p-n-Si:B ïîêàçàíî, ÷òî èíòåãðàëüíûé ôîòîîòêëèê îáðàçöîâ â ïîääèàïàçîíàõ ÝÌÈ 350 – 4100 ìêì äëÿ äëèí âîëí áîëåå 620íì ïðîÿâëÿåò âîçðàñòàþùóþ çàâèñèìîñòü îò òåõíîëîãè÷åñêèõ ðåæèìîâ. Êðîìå ìîùíîñòè ëàìïû, áîëüøóþ ðîëü â ôîòîîòêëèêå èãðàåò ñïåêòðàëüíûé ñîñòàâ èçëó÷åíèÿ. Îáà ýòè ôàêòîðà ïðåäñòàâëÿþò èíòåðåñ äëÿ ïðàêòè÷åñêîãî ïðèìåíåíèÿ p-n-Si:B â ðàçëè÷íûõ îáëàñòÿõ ÝÌÈ.

Ëèòåðàòóðà: 1. Ì.Ìèëüâèäñêèé, Â.×àëäûøåâ: Íàíîðàçìåðíûå àòîìíûå êëàñòåðû â ïîëóïðîâîäíèêàõ - íîâûé ïîäõîä ê ôîðìèðîâàíèþ ñâîéñòâ ìàòåðèàëîâ, Ôèçèêà è òåõíèêà ïîëóïðîâîäíèêîâ, 32 (1998), 513-522.

2. S.Eichler, J.Gebauer, F.Börner, A.Polity, R.KrauseRehberg:DefectsinSiliconafterB+Implantation,AStudyUsingaPositronBeam Techniques, Rutherford Backscattering, Secondary Neutral Mass Spectroscopy, and Infrared Absorption Spectroscopy,Physical Review B,56 (1997), 1393-1403.

3. S.L.Libertino, A.La Magna. Damage Formation and Evolution in Ion-Implanted Crystalline Si, Materials Science with ion beams, Springer, 2010, 147-204.

4. À.×åëÿäèíñêèé, Ô.Êîìàðîâ: Äåôåêòíî-ïðèìåñíàÿ èíæåíåðèÿ â èìïëàíòèðîâàííîì êðåìíèè, Óñïåõè ôèçè÷åñêèõ íàóê, 173 (2003), 816-843.

5. M.A.Lourenco, M.Milosavljevic, G.Shao, R.M.Gweilliam, K.P.Homewood: Boron Engineered Dislocation Loops for Eff icient Room Temperature Silicon Light Emitting Diodes,Elsevier, Thin Solid Films, 504 (2006),36-40.

6. M.Casalino: Near-Infrared Sub-Bandgap All-Silicon Photodetectors: a review,International Journal of Optics and Applications, 2(2012), 1-16.

7. Ì.Ã.Òèãèøâèëè, Í.Ã.Ãàïèøâèëè, Ð.Ã.Ãóëÿåâ, Ç.Â.Äæèáóòè, Í.Ä.Äîëèäçå, Í.Ï.Õó÷óà, Ð.Ã.Ìåëêàäçå: Èíæåíåðèÿ äåôåêòîâ âòåõíîëîãèè ð-n ïåðåõîäîâêðåìíèÿ, Georgian Engineering News,2013, N 4, ñòð.75-79.

8. N.P.Khuchua, N.D.Dolidze, N.G.Gapishvili, R.G.Gulyaev, Z.V.Jibuti, R.G.Melkadze, M.G.Tigishvili: Technology of Semiconductor Materials Sensitive to Different Regions of Electromagnetic Radiation Spectrum, Nanotechnology Perceptions, 10 (2014), 91-99.

67 9. Ì.Òèãèøâèëè, Í.Õó÷óà, Ð.Ìåëêàäçå, Í.Äîëèäçå, Í.Ãàïèøâèëè, Ç.Äæèáóòè, Ã.Äîâáåøêî, Â.Ðîìàíþê: Ïîëóïðîâîäíèêîâûé ìàòåðèàë ñ íîâûìè îïòè÷åñêèìè ñâîéñòâàìè äëÿ ôîòîäåòåêòîðîâ èíôðàêðàñíîé è óëüòðàôèîëåòîâîé îáëàñòåé ñïåêòðà, Ñáîðíèê äîêëàäîâ II Ìåæäóíàðîäíîé êîíôåðåíöèè «Ñîâðåìåííûå òåõíîëîãèè è ìåòîäû íåîðãàíè÷åñêîãî ìàòåðèàëîâåäåíèÿ»,Òáèëèñè 2015, 288-295.

10. N. Khuchua, M.Tigishvili, R.Melkadze, N.Dolidze, N.Gapishvili, Z. Jibuti, G.Dovbeshko, and V. Romanyuk: Defect Formation in Ion-Implanted Si - Approach to Controlled Semiconductor Optical Properties, Solid State Phenomena, 242 (2016), in press.

11. Ñ.Òèì÷åíêî,Î.Äåìåíòüåâà, Í.Çàäîðîæíûé: Âëèÿíèå ñïåêòðà èçëó÷åíèÿ íà õàðàêòåðèñòè÷åñêèå êðèâûå ñîëíå÷íîé áàòàðåè, Ôèçè÷åñêîå îáðàçîâàíèå â âóçàõ, 21 (2015), 3.

sinaTlis speqtruli Sedgenilobis gavlena ionolegirebuli siliciumis fotoeleqtrul Tvisebebze

Effect of Light Spectral Composition on Photoelectric PropertiesofIon Doped Silicon

naSromis mizania siliciumis optikuri Tvisebebis kontrolirebuli Secvla defeqtwarmoqmnis xarjze naxevargamtaris boris ionebiT legirebisas. p-n-Si:B struqturebi miRebulia ionebis sxvadasxva dozebis (1x1013– 1x10 15cm-2) da energiebis 32 da 50 keV saSualebiT. legirebis Semdgomi gamowva tardeboda or temperaturaze – 900 da 1000oC. optikuri filtrebis sistemiT aRWurvil originalur optikur danadgarze izomeboda p-nSi:B–is fotomgrZnobiarobis sinaTlis speqtrul Sedgenilobaze damokidebuleba 350–4100 nm diapazonSi. miRebulia axali saintereso monacemebi fotomgrZnobiarobaze speqtruli Sedgenilobis gavlenis Sesaxeb.

N. Dolidze1, Z. Jibuti1, N. Tigishvili2, N. Khuchua2, R. Melkadze2, N. Gapishvili1 Institute of Micro- and Nanoelectronics, 13, Chavchavadze ave., Tbilisi, Georgia 2 RPC “Electron Technology”, Research Institute of Applied Semiconductor Technologies of Iv. Javakhishvili Tbilisi State University, 13, Chavchavadze ave., Tbilisi, Georgia E-mail: z.jibuti@jmail.com

1

The aim of the work is a controlled change of the optical properties of silicon due to defect formation during ion implantation of impurities (B) into a semiconductor. p-n-Si:B structures were obtained at different doses (1x1013– 1x10 15cm-2) and the acceleration energies of 32 and 50 keV, followed by annealing (900 and 1000oC). The dependence of p-n-Si:B photoresponse on spectral composition of the luminous flux in the range of 350 – 4100 nm was measured using the original optical setup with filter system. New interesting data demonstrating the effect of the spectral composition on the photosensitivity of the samples were obtained.

n. doliZe1, z. jibuti1, m. tigiSvili2, n. xuWua2, r. melqaZe2, n. gafiSvili1 1 mikro da nanoeleqtronikis instituti, i. WavWavaZis prosp. 13, 0179, Tbilisi, saqarTvelo 2 iv.javaxiSvilis sax. Tbilisis sax. universitetis naxevargamtaruli gamoyenebiTi teqnologiebis ski, ssk „eleqtronuli teqnika“ 0179, Tbilisi, saqarTvelo el–fosta: nugzardolidze@gmail.com

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Òåõíîëîãèÿ ñîçäàíèÿ ðàäèàöèîííî-ñòîéêèõ ìàòåðèàëîâ Í. Êåêåëèäçå1,2,3, Ä. Êåêåëèäçå2, Å. Õóöèøâèëè1, Á. Êâèðêâåëèÿ1,2,3, Ë. Íàäèðàäçå3, È.Àìáîêàäçå2, Ã. Êåêåëèäçå4 Èíñòèòóò ìåòàëëóðãèè è ìàòåðèàëîâåäåíèÿ èì. Ôåðäèíàíäà Òàâàäçå. 0160, Òáèëèñè, Ãðóçèÿ Òáèëèññêèé Ãîñóäàðñòâåííûé Óíèâåðñèòåò èì. Èâàíý Äæàâàõèøâèëè. 0179, Òáèëèñè, Ãðóçèÿ 3 Ãðóçèíñêèé Òåõíè÷åñêèé Óíèâåðñèòåò, 0175, Òáèëèñè, Ãðóçèÿ 4 BOTEUROSOLARe.V.Bonn53113,Bonn,Germany Ýë–ïî÷òà:lali6565@gmail.com 1 2

Ðåçþìå. Íà îñíîâå îòêðûòîãî íàìè ÿâëåíèÿ âçàèìíîé êîìïåíñàöèè ðàäèàöèîííûõ äîíîðîâ è àêöåðòîðîâ áûëà ðàçðàáîòàíà òåõíîëîãèÿ ñîçäàíèÿ ðàäèàöèîííî- ñòîéêèõ ìàòåðèàëîâ ïîëóïðîâîäíèêîâ òèïà III-V. Áûëè ñîçäàíû ðàäèàöèîííî- ñòîéêèå ýëåêòðè÷åñêèå è îïòè÷åñêèå ìàòåðèàëû, âèäåðæèâàþùèå áîëüøèå ïîòîêè æåñòêîãî îáëó÷åíèÿ.

Êëþ÷åâûå ñëîâà: Ðàäèàöèîííî-ñòîéêèå ìàòåðèàëû, îïòè÷åñêèå ìàòåðèàëû, òåõíîëîãèÿ, âçàèìíàÿ êîìïåíñàöèÿ

Ââåäåíèå Ïîëóïðîâîäíèêîâûå ïðèáîðû ÿâëÿþòñÿ íåçàìåíèìûìè ýëåìåíòàìè äëÿ ïðîâåäåíèÿ êîñìè÷åñêèõ èññëåäîâàíèé, èç-çà ñâîèõ ìàëûõ ìàññ è ãàáàðèòîâ, èç-çà âûñîêîé ÷óâñòâèòåëüíîñòè è ýôôåêòèâíîñòè. Ïîëóïðîâîäíèêîâûå óñòðîéñòâà èãðàþò âàæíóþ ðîëü â ÿäåðíûõ ðåàêòîðàõ, â àòîìíûõ ýëåêòðîñòàíöèÿõ, â òîì ÷èñëå íà Áîëüøîì Àäðîííîì Êîëëàéäåðå (Öåðí). Èñïîëüçîâàíèå ïîëóïðîâîäíèêîâûõ ïðèáîðîâ ýôôåêòèâíî è íåîáõîäèìî íà ðàäèàöèîííî-çàãðÿçíåííûõ òåððèòîðèÿõ, òàêèõ êàê ×åðíîáûëü è Ôóêóñèìà. Îäíàêî, ïîëóïðîâîäíèêîâûå ïðèáîðû, òàêæå ÷óâñòâèòåëüíû ê ðàäèàöèè. Ïðè âûñîêèõ äîçàõ ðàäèàöèè ïàðàìåòðû ïîëóïðîâîäíèêîâûõ ïðèáîðîâ ðåçêî óõóäøàþòñÿ è îíè ïðåêðàùàþò ôóíêöèîíèðîâàòü. Ïîýòîìó î÷åâèäíî, ÷òî ñîçäàíèå ïîëóïðîâîäíèêîâûõ ðàäèàöèîííî-ñòîéêèõ ìàòåðèàëîâè ìèêðî- è îïòîýëåêòðîííûõïðèáîðîâ íà èõ îñíîâå,ÿâëÿåòñÿ âåñüìà àêòóàëüíûì.

êðèñòàëëè÷åñêîé ðåøåòêè òâåðäûõ ðàñòâîðîâ InP-InAs [1], êîòîðîå óêàçûâàåò íà ñîõðàíåíèå èíäèâèäóàëüíûõ ñâîéñòâ ïîäðåøåòîê InP è InAs â òâåðäûõ ðàñòâîðàõ. Íàøè ðåçóëüòàòû ïîëó÷èëè øèðîêîå ìåæäóíàðîäíîå ïðèçíàíèå. Îíè áûëè êîëè÷åñòâåííî ïîäòâåðæäåíû â Îêñôîðäå â Êëàðåíäîíñêîé ëàáîðàòîðèè[2], è âî Ôðàíöèè â ÿäåðíîì öåíòðå Ñaêëå [3], à òàêæå â îáøèðíîé íîâîé ðàáîòå [4] è äðóãèõ ïóáëèêàöèÿõ.  ïîëóïðîâîäíèêîâûõ ñîåäèíåíèÿõ, â ÷àñòíîñòè â òâåðäûõ ðàñòâîðàõ InPõAs1-õ íàìè áûëî îòêðûòî ÿâëåíèå âçàèìíîé êîìïåíñàöèè ðàäèàöèîííûõ äîíîðîâ è àêöåïòîðîâ íà îñíîâå êîòîðîãî áûëà ðàçðàáîòàíà òåõíîëîãèÿ ñîçäàíèÿ ðàäèàöèîííî- ñòîéêèõ ìàòåðèàëîâ [5, 6]. Ñóùíîñòü ÿâëåíèÿ îïèñàíà íèæå. Íàìè ïîêàçàíî, ÷òî â ðåçóëüòàòå îáëó÷åíèÿ áûñòðûìè íåéòðîíàìè, êîíöåíòðàöèÿ ýëåêòðîíîââ êðèñòàëëàõáëèñêèõ ïî ñîñòàâó ê InP(ðàâíî êàê è â êðèñëëàõ ôîñôèäà èíäèÿ) ðåçêî ïàäàåò. Îòìå÷åííîå äåìîíñòðèðóåòñÿ íà ðèñ.1.

Ìàòåðèàëû è ìåòîäû III-V ìàòåðèàëû InP, InAs è èõ òâ ðäûå ðàñòâîðû InPõAs1-õ ïðàêòè÷åñêè âñåõ íåîáõîäèìûõ ñîñòàâîâ, áûëè âûðàùåíû ñ ïîìîùüþ ìîäèôèöèðîâàííîãî ìåòîäà çîííîé ïëàâêè. Êðèñòàëëû ëåãèðîâàëèñü äîíîðíûìè è àêöåïòîðíûìè ïðèìåñÿìè â øèðîêîì êîíöåíòðàöèîííîì èíòåðâàëå. Èçìåðÿëèñü òåìïåðàòóðíûå è äîçîâûå çàâèñèìîñòè êîíöåíòðàöèè íîñèòåëåé çàðÿäà è óäåëüíîãî ñîïðîòèâëåíèÿ. Êðèñòàëëû îáëó÷àëèñü áûñòðûìè íåéòðîíàìè è ýëåêòðîíàìè äî ïîòîêîâ Ô=2·1018í/cì2 è Ô=5·1017ý/cì2 ñîîòâåòñòâåííî.

Ðåçóëüòàòû è îáñóæäåíèå Ê ðàçðàáîòêå òåõíîëîãèè è ñîçäàíèþ ðàäèàöèîííîñòîéêèõ ìàòåðèàëîâ íàñ ïðèâåëî âûÿâëåííîå ðàííåå íàìè â òâåðäûõ ðàñòâîðàõ ò.í. äâóõìîäîâîå êîëåáàíèå Ðèñ.1. Òåìïåðàòóðíûå çàâèñèìîñòè êîíöåíòðàöèè

69 íîñèòåëåé çàðÿäà äëÿ ñïëàâà

InP0,8As0.2 ñ èñõîäíîé êîíöåíòðàöèåé ýëåêòðîíîâ n0=3.6·1016 ñì-3. 1-äî îáëó÷åíèÿ, 2-ïîñëå îáëó÷åíèÿ ïîòîêîì áûñòðûõíåéòðîíîâ Ô=2·1018n/cm2, 3-ïîñëå îòæèãà T=3000C, 4- ïîñëå îòæèãà T=4000C. Ïîêàçàíî, ÷òî íàáëþäàåìîå ÿâëåíèå âûçâàíî äåéñòâèåì ãëóáîêèõ ðàäèàöèîííûõ äåôåêòîâ àêöåïòîðíîãî òèïà, èãðàþùèõ ðîëü öåíòðîâ çàõâàòà îñíîâíûõ íîñèòåëåé çàðÿäà, êàê ýëåêòðîíîâ, òàê è äûðîê. Ïðèìå÷àòåëüíî, ÷òî ïîäîáíûì ñâîéñòâîì õàðàêòåðèçóþòñÿ ïðàêòè÷åñêè âñå îñíîâíûå ïîëóïðîâîäíèêîâûå ìàòåðèàëû. Íà ðèñ. 2 è 3 ïðåäñòàâëåíû ñîîòâåòñòâóþùèå êðèâûå äëÿ êðåìíèÿ è àðñåíèäà ãàëèÿ.

(ðàâíî, êàê è â InP) êîíöåíòðàöèÿ íîñèòåëåé êàòàñòðîôè÷åñêè óìåíüøàåòñÿ â ðåçóëüòàòå îáëó÷åíèÿ. Ñîîòâåòñòâåííî, ðåçêî óâåëè÷èâàåòñÿ âåëè÷èíà óäåëüíîãî ñîïðîòèâëåíèÿ è ìàòåðèàë ïðàêòè÷åñêè ïðåâðàùàåòñÿ â èçîëÿòîð, à ýëåêòðîííûå ïðèáîðû, ñêîíñòðóèðîâàííûå íà èõ îñíîâå, ïðåêðàùàþò ôóíêöèîíèðîâàòü. Ñîâåðøåííî îòëè÷íûì ðàäèàöèîííûì ñâîéñòâîì õàðàêòåðèçóåòñÿ àðñåíèä èíäèÿ.  InAs, êàê ïîêàçàë Îêåðìàí [9], îáëó÷åíèå áûñòðûìè íåéòðîíàìè âûçûâàåò ðîñò êîíöåíòðàöèè ýëåêòðîíîâ. Íàìè äåòàëüíî èçó÷åíû îáëó÷ ííûå êðèñòàëëû InAs è ïîêàçàíî, ÷òî îíè îáëàäàþò óíèêàëüíûì ðàäèàöèîííûì ñâîéñòâîì.  íèõ, â îòëè÷èå îò ïðàêòè÷åñêè âñåõ ýôôåêòèâíûõ äëÿ ýëåêòðîíèêè ìàòåðèàëîâ, îáëó÷åíèå âñåãäà âûçûâàåò ðîñò êîíöåíòðàöèè ýëåêòðîíîâ. Ýêñïåðèìåíòû ïðîâîäèëèñü â ñîâåðøåííî ðàçíûõ óñëîâèÿõ, ìåíÿëñÿ òèï îáëó÷åíèÿ (áûñòðûå íåéòðîíû, ýëåêòðîíû ñ ýíåðãèåé E=50Mev, E=7,5Mev, E=3Mev è èîíû), òåìïåðàòóðà, óñëîâèÿ îáëó÷åíèÿ. Íåêîòîðûå èçìåðåíèÿ ïðîâîäèëèñü íåïîñðåäñòâåííî â õîëîäíîì êàíàëå ðåàêòîðà. Èññëåäîâàëèñü îáðàçöû êàê ýëåêòðîííîé, òàê è äûðî÷íîé ïðîâîäèìîñòè, â êîòîðûõ êîíöåíòðàöèèëåãèðóþøèõ ïðèìåñåé ìåíÿëèñü â øèðîêèõ ïðåäåëàõ. Âî âñåõ ñëó÷àÿõ íåèçìåííî íàáëþäàëñÿ äîíîðíûé ýôôåêò. Íàøè ðåçóëüòàòû ïîäòâåðæäåíû â ðàáîòàõ[10,11]. Êàê îòìå÷àëîñü âûøå, â òâåðäûõ ðàñòâîðàõ InAsInP, ïîäðåøåòêè InAs è InP ñîõðàíÿþò ñâîè èíäèâèäóàëüíûå ñâîéñòâà. Îòìå÷åííîå ïîäòâåðæäàåòñÿ íàøèìè ðåçóëüòàòàìè, ïðåäñòàâëåííûìè íà ðèñ.4.

Ðèñ.2. Çàâèñèìîñòü ïðîâîäèìîñòè êðåìíèÿ ï-òèïà îò ïîòîêà áûñòðûõ íåéòðîíîâ[7].

Ðèñ.4. Òåìïåðàòóðíûå çàâèñèìîñòè êîíöåíòðàöèè íîñèòåëåé òîêà â ñïëàâå InP0.1As0.9 (n0=3.5·1016 ñì-3). 1-äî îáëó÷åíèÿ, 2-ïîñëå îáëó÷åíèÿ ïîòîêîì áûñòðûõ íåéòðîíîâ Ô=2·1018n/cm2

Ðèñ.3. Çàâèñèìîñòü êîíöåíòðàöèè ýëåêòðîíîâ îò ïîòîêà áûñòðûõ íåéòðîíîâ äëÿ îáðàçöîâ GaAs ñ ðàçëè÷íîé íà÷àëüíîé êîíöåíòðàöèåé íîñèòåëåé çàðÿäà[8].

Èç êðèâûõ ÷åòêî âèäíî, ÷òî â êðèñòàëëàõ Si è GaAs

Èç ðèñ.4 âèäíî, ÷òî è â òâåðäîì ðàñòâîðå InP0-1As0-9, êàê è â àðñåíèäå èíäèÿ, èìååò ìåñòî ïðåèìóùåñòâåííîå ðîæäåíèå ðàäèàöèîííûõ äîíîðîâ, õîòÿ ðîñò êîíöåíòðàöèè ýëåêòðîíîâ çàìåäëÿåòñÿ ïî ñðàâíåíèþ ñ InAs.Êàê áûëî îòìå÷åíî, â òâåðäûõ ðàñòâîðàõ, áëèçêèõ ïî ñîñòàâó ê InP, íàáëþäàåòñÿ îáðàòíûé ýôôåêò. Òàêèì îáðàçîì, ïîêàçàíî, ÷òî â òâåðäûõ ðàñòâîðàõ InPõAs 1-õ, âî âðåìÿ îáëó÷åíèÿ â ïîäðåøåòêå InP ïðåèìóùåñòâåííî ðîæäàþòñÿ ðàäèàöèîííûå àêöåïòîðû, ÷òî âûçûâàåò ðåçêîå óìåíüøåíèå êîíöåíòðàöèè ýëåêòðîíîâ (â ìàòåðèàëå n-òèïà), à â ïîäðåøåòêå InAs ðàçâèâàåòñÿ îáðàòíûé ýôôåêò – îáëó÷åíèå ñîçäàåò ïðåèìóùåñòâåííî ðàäèàöèîííûå äîíîðû, è êîíöåíòðàöèÿ ýëåêòðîíîâ ðàñòåò.

70 Ñóòü ðàçðàáîòàííîé òåõíîëîãèè çàêëþ÷àåòñÿ â ïîäáîðå ñîñòàâà òâåðäûõ ðàñòâîðîâ, êîãäà îñóùåñòâëÿåòñÿ âçàèìíàÿ êîìïåíñàöèÿ ðàäèàöèîííûõ äîíîðîâ è àêöåïòîðîâ, ÷òî ïðèâîäèò ê ñîçäàíèþ ðàäèàöèîííî-ñòîéêîãî ìàòåðèàëà. Íàì óäàëîñü ðåøèòü óêàçàííóþ ïðîáëåìó ïóò ì ïîäáîðà ñîñòàâà òâ ðäîãî ðàñòâîðà InPõAs1-õ, êîãäà õ=0,3÷0,35. Ðåçóëüòàòû ïðåäñòàâëåíû íà ðèñ.5

8. Â.Ô.Ñòåëüìàõ, Â.Ä.Òêà÷åâ. Èçâåñòèÿ ÂÓÇîâ ÑÑÑÐ, Ôèçèêà, Ø, 71, (1973) 9. L. W. Aukerman. Phys. Rev.115(5), 1133–1135, (1959) 10. W. Walukiewicz, J. Vac.Sci. & Technol. 5 (4) 1062-1067, (1987) 11. Í. Gerstenberg, PhysicaStaus Solidi (A) 128 (2) 483-490, (1991)

Technology for creation of radiation hard materials N. Kekelidze1,2,3, D. Kekelidze2, E. Khutsishvili1, B. Kvirkvelia1,2,3, L. Nadiradze3, I. Ambokadze2, G. Kekelidze4

F.Tavadze Institute of Metallurgy and Material Science, 0160, Tbilisi, Georgia 2 Ivane Javakhishvili Tbilisi State University, 0179, Tbilisi, Georgia 3 Georgian Technical University, 0175, Tbilisi, Georgia 4 BOTEUROSOLARe.V.Bonn53113,Bonn,Germany E-mail:lali6565@gmail.com 1

Ðèñ. 5. Çàâèñèìîñòü óäåëüíîãî ñîïðîòèâëåíèÿ InP0,3As0,7îò ïîòîêà áûñòðûõ íåéòðîíîâ (Ô·1017)äëÿ îáðàçöà ñ n0=1.5·1017ñì–3.

Ñðàâíèâàÿ óêàçàííóþ çàâèñèìîñòü ñ êðèâûìè ïðåäñòàâëåííûìè íà ðèñ. 2 è ðèñ.3 ìîæíî çàêëþ÷èòü, ÷òî íàìè ðàçðàáîòàíà òåõíîëîãèÿ è ñîçäàíû ðàäèàöèîííî-ñòîéêèå ìàòåðèàëû â êîòîðûõ êîíöåíòðàöèÿ ýëåêòðîíîâ è ñîîòâåòñåâåííî ýëåêòðîïðîâîäíîñòü ïðàêòè÷åñêè íå ìåíÿåòñÿ äàæå ïîñëå îáëó÷åíèÿ áîëüøèì ïîòîêîì áûñòðûõ íåèòðîíîâ. Ïîëó÷åííûé ðåçóëüòàò ïîçâîëÿåò íà îñíîâå óêàçàííîãî ìàòåðèàëà ñîçäàòü ðÿä ðàäèàöèîííî-ñòîéêèõ ýëåêòðîííûõ ìàòåðèàëîâ. Íàìè áûë ïðèãîòîâëåí ëàáîðàòîðíûé îáðàçåö ðàäèàöèîííî-ñòîéêîãî ñåíñîðà Õîëëà. Íà îñíîâå ðàçðàáîòàííîé òåõíîëîãèè íàìè áûëè ñîçäàíû òàêæå ðàäèàöèîííî-ñòîéêèå îïòè÷åñêèå ìàòåðèàëû, â ÷àñòíîñòè êðèñòàëëû, â êîòîðûõ êîýôôèöèåíò îïòè÷åñêîãî ïîãëîùåíèÿ âáëèçè ôóíäàìåíòàëüíîãî êðàÿ íå ìåíÿåòñÿ â ðåçóëüòàòå îáëó÷åíèÿ.

References 1. N.P., Kekelidze, G.P. Kekelidze, Z.D.Makharadze.

J.Phys.Chem. Sol. 34, 117-126, (1973) 2. R.J.Nicholas et.al. J.Phys.C: 13, 899-910 (1980) 3. N.Talwar et al. J.Phys.C,13, 3775-3793 (1980) 4. D.J. Lockwood at al. J. Appl. Phys. 102, 033512-033512-11 (2007) 5. N. Kekelidze, G. Kekelidze, D. Kekelidze, V. Aliyev, American Institute of Physics (AIP), Conference Proceedings 1566, (2013) 6. Kekelidze N., Kvirkvelia B., Kekelidze D., Aliyev V., Khutsishvili E.and Kekelidze G. Journal of Electrical Engineering, David Publishing Company. V. 2, ¹4, pp.187-192, (2014) 7. Â.Ñ.Âàâèëîâ, Í.À.Óõèí. Àòîìèçäàò, Ì., (1969)

Technology for creation of radiation hard III-V type crystals was developed on the basis of our earlier discovery of the phenomenon of mutual compensation of radiation donors and acceptors.

The radiation resistant electrical and optical materials, with standing high fluence of hard radiation have been created.

radiaciulad mdgradi masalebis Seqmnis teqnologia n. kekeliZe1,2,3, d. kekeliZe2, e. xuciSvili1, b. kvirkvelia1,2,3, l. nadiraZe3, i. ambokaZe2, g.k ekeliZe4 1 ferdinand TavaZis metalurgiisa da masalaTmcodneobis instituti. 0160, Tbilisi, saqarTvelo 2 ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti, 0160, Tbilisi, saqarTvelo 3 saqarTvelos teqnikuri universiteti, 0175, Tbilisi, saqarTvelo 4 BoT EUROSOLAR e.V.Bonn 53113, boni, germania el–fosta: lali6565@gmail.com

radiaciuli donorebisa da aqceptorebis urTierTkompensaciis Cvens mier aRmoCenili movlenis safuZvelze damuSavebul iqna III-V ti pis radiaciulad mdgradi masalebis miRebis teqnologia. Seqmnil iqna radiaciulad mdgradi eleqtruli da optikuri masalebi, romlebic uZleben maRali dozis xist dasxivebas.

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Âëèÿíèå îáëó÷åíèÿ èîíàìè àðãîíà íà ýëåêòðîôèçè÷åñêèå õàðàêòåðèñòèêè ïîäëîæåê Si-Ge È. Òàáàòàäçå1, Ì. Êàäàðèÿ1, Ã. ×óáèíèäçå1, Ë. Ãàïèøâèëè2, Ò. Ìåëàøâèëè1, Ê. Êîìàõèäçå1 Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà,óë. Ìèíäåëè 7,0186,Òáèëèñè, Ãðóçèÿ Èíñòèòóò ìèêðî è íàíîýëåêòðîíèêè, óë. Ìíàòîáè 73, 0186, Òáèëèñè, Ãðóçèÿ. Ýë–ïî÷òà:sipt@sipt.org 1 2

Ðåçþìå: Ïðèâåäåíû ðåçóëüòàòû èññëåäîâàíèÿ ìèêðîñòðóêòóðû è ýëåêòðîôèçè÷åñêèõ õàðàêòåðèñòèê ïîëèêðèñòàëëè÷åñêèõ ïîäëîæåê Si-Ge â èñõîäíîì, îáëó÷åííîì èîíàìè àðãîíà è îòîææåííîì ñîñòîÿíèÿõ. Ïîêàçàíî íåìîíîòîííîå èçìåíåíèå ýëåêòðè÷åñêèõ õàðàêòåðèñòèê ïðè ïîâûøåííûõ ôëþåíñàõ èîíîâ Ar è òåìïåðàòóðû èìïóëüñíîãî ôîòîííîãî îòæèãà. Íàáëþäàåìûå ñïåöèôè÷åñêèå èçìåíåíèÿ ïðîàíàëèçèðîâàíû ñ òî÷êè çðåíèÿ ðåàëèçàöèè ïðåâðàùåíèé â äåôåêòàõ, îáðàçîâàííûõ â ñïëàâàõ Si-Ge ïðè êðèñòàëëèçàöèè è ðàäèàöèîííîì âîçäåéñòâèè.

Êëþ÷åâûå ñëîâà: ôëþåíñ,ìèêðîñòðóêòóðà, ñïëàâû Si-Ge, èîííàÿ èìïëàíòàöèÿ, ðàäèàöèîííûå äåôåêòû, äèñëîêàöèè

Ââåäåíèå

Ìàòåðèàëû è ìåòîäû

 ñîâðåìåííîì îïòî- è ìèêðîýëåêòðîííîì ïðèáîðîñòðîåíèè øèðîêî ïðèìåíÿþòñÿ ñïëàâû Si1-xGex. Ïðèáîðû íà èõ îñíîâå îòëè÷àþòñÿ âûñîêîé ðàäèàöèîííîé ñòîéêîñòüþ, ñðàâíèòåëüíî íèçêîé ñåáåñòîéìîñòüþ, íèçêèì óðîâíåì øóìà. Äëÿ óñïåøíîãî èñïîëüçîâàíèÿ ñïëàâîâ ñèñòåìû Si-Ge â êà÷åñòâå ïîäëîæåê ïîëóïðîâîäíèêîâûõ ñòðóêòóð ñ p-n ïåðåõîäàìè âàæíîå çíà÷åíèå èìååò èçó÷åíèå äåôåêòîâ ïðè ïîâåðõíîñòíîé ñòðóêòóðû, îáðàçîâàííûõ â ïðîöåññàõ ðåçêè íà àëìàçíîì äèñêå, ïîëèðîâàíèÿ, à òàêæå ðàäèàöèîííîãî îáëó÷åíèÿ ðàçëè÷íîãî ïðîèñõîæäåíèÿ. Èññëåäîâàíèåï ðîöåññîâ âçàèìîäåéñòâèÿ èîíîâ èíåðòíûõ ãàçîâ ñ êðèñòàëëàìè ïðåäñòàâëÿåòñÿ âàæíûì äëÿ ñîçäàíèÿ ïðèáîðíûõ ñòðóêòóð ñ ïîâûøåííîé ðàäèàöèîííîé ñòîéêîñòüþ [1,2]. Îñîáî âàæíûìè ÿâëÿþòñÿ èññëåäîâàíèÿ ïîâåðõíîñòíîé ñòðóêòóðû ïîäëîæåê Si-Ge, â êîòîðûõ ïðèñóòñòâèå Ge çíà÷èòåëüíî èçìåíÿåò ýëåêòðîôèçè÷åñêèå õàðàêòåðèñòèêè ñòðóêòóðíûõ äåôåêòîâ, îáðàçîâàííûõ ïîä âëèÿíèåì äåôîðìàöèè, òåðìè÷åñêîé îáðàáîòêè è îáëó÷åíèÿ âûñîêîýíåðãåòè÷åñêèìè ÷àñòèöàìè, â ÷àñòíîñòè èîíàìè Ar[3-5]. Êîìïëåêñíîå èññëåäîâàíèå ïîâåðõíîñòíîé ñòðóêòóðû ïîäëîæåê SiGe ìîæåò äàòü öåííóþ èíôîðìàöèþ î íàðóøåíèÿõ êðèñòàëëè÷åñêîé ñòðóêòóðû. íàñòîÿùåå âðåìÿ äëÿ îáðàçîâàíèÿ ðàäèàöèîííûõ äåôåêòîâ è ñîçäàíèÿ ýôôåêòíûõ öåíòðîâ ðåêîìáèíàöèè óñïåøíî ïðèìåíÿåòñÿ ìåòîä îáëó÷åíèÿ ìàòåðèàëîâ ïîòîêàìè ðàçíîãî âèäà.  äàííîé ðàáîòå ïðèâîäÿòñÿ ðåçóëüòàòû êîìïëåêñíîãî èññëåäîâàíèÿ ìèêðîñòðóêòóðû è ýëåêòðîôèçè÷åñêèõ õàðàêòåðèñòèê ñïëàâîâ Si-Geâ èñõîäíîì ñîñòîÿíèè è ïîñëå èìïëàíòàöèè èîíàìè àðãîíà ñ ïîñëåäóþùèì èìïóëüñíûì ôîòîííûì îòæèãîì.

Ìîíî- è ïîëèêðèñòàëëè÷åñêèå ñïëàâû Si-Ge ïîëó÷åíû ìåòîäîì ×îõðàëüñêîãî â èíäóêöèîííîé ïå÷è ñèñòåìû EQSKJ-50CZ.Ïëàâëåíèå ïðîâîäèëîñü â êâàðöåâîì òèãëå. Äëÿ ïîëó÷åíèÿ ëåãèðîâàííûõ êðèñòàëëîâ ãîòîâèëàñü ñìåñü ïóòåì ìåõàíè÷åñêîãî ñìåøèâàíèÿ èç êîìïîíåíòîâ ñ îïðåäåëåííîé êîíöåíòðàöèåé. Çàòðàâêîé ñëóæèë ìîíîêðèñòëëè÷åñêèé ñòåðæåíü êðåìíèÿ êðèñòàëëîãðàôè÷åñêîé îðèåíòàöèè [111]. Ðåçêà ïîëó÷åííûõ êðèñòàëëîâ ïðîâîäèëàñü íà óñòàíîâêå ñ àëìàçíûì äèñêîì âíóòðåííeé ðåçêîé. Èññëåäîâàíèå ìèêðîñòðóêòóðû ïðîâåäåíî íà îïòè÷åñêîì ìèêðîñêîïå HMM-800RF/TRF. Èìïëàíòàöèÿ èîíàìè àðãîíà â èíòåðâàëå ôëþýíñîâ 1011 -1014 ñì-2 ïðîâåäåíà íà ìîäåðíèçîâàííîé óñòàíîâêå èîííîé èìïëàíòàöèè “Âåçóâèé-3Ì“. Óñêîðÿþùåå íàïðÿæåíèå èîíîâ ñîñòàâëÿëî 100 êÂ, ïëîòíîñòü èîííîãî òîêà - 2ìêÀ/ñì -2. Íà èìïëàíòèðîâàííûõ îáðàçöàõ ïðîâåäåí èìïóëüñíûé ôîòîííûé îòæèã ïðè òåìïåðàòóðàõ 715 è 920 0 Ñ â òå÷åíèå 5 ñåê. Ýëåêòðîôèçè÷åñêèå õàðàêòåðèñòèêè ïîäëîæåê Si-Ge áûëè îïðåäåëåíû ìåòîäîì Âàí Äåð Ïàó íà óñòàíîâêå “EcopiaHMS-3000” ïðè êîìíàòíîé òåìïåðàòóðå.

Ýêñïåðèìåíòàëüíûå ðåçóëüòàòû

Èññëåäîâàíèå ìèêðîñòðóêòóðû ìíîãèõ îáðàçöîâ ïîêàçàëî, ÷òî ðàçâèòàÿ äèñëîêàöèîííàÿ ñòðóêòóðà îáðàçóåòñÿ â ïðîöåññå êðèñòàëëèçàöèè ñ âûñîêîé ñêîðîñòüþ (5ìì/÷), âìåñòå ñ ýòèì ïëîòíîñòü äèñëîêàöèé ïîâûøàåòñÿ ëåãèðîâàíèåì ãåðìàíèåì è áîðîì. Ïðè îòæèãå â îáëàñòè ñðåäíèõ òåìïåðàòóð çíà÷èòåëüíûõ èçìåíåíèé â äèñëîêàöèîííîé ñòðóêòóðå êðèñòàëëîâ SiGe íå íàáëþäàåòñÿ. Íà ðèñ.1. ïîêàçàíà êðóïíîçåðíèñòàÿ ñòðóêòóðà êðåìíèÿ, ëåãèðîâàííîãî ãåðìàíèåì. Âèäíî, ÷òî ãðàíèöû ðàçäåëà ïðåèìóùåñòâåííîëèíåéíûå, ðàçìåðû çåðåí ìåíÿþòñÿ â ïðåäåëàõ 0,05-1,0 ìì.

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Ðèñ.1. Ìèêðîñòðóêòóðà êðóïíîçåðíèñòîãî ñïëàâà Si+1àò%.Ge. à) –èíäèâèäóàëüíûå è ñãïóïïèðîâàííûå äâîéíèêè; á)áåñïîðÿäî÷íîå ðàñïðåäåëåíèå äèñëîêàöèé â)-ðàñïðåäåëåíèå äèñëîêàöèé â îáúåìå è â îáëàñòè ðàñòÿíóòûõ äåôåêòîâ; ã)-íåðàâíîìåðíîå ðàñïðåäåëåíèå äèñëîêàöèé âíóòðè ñòðóêòóðû çåðåí.

Âî âíóòðåííåé ñòðóêòóðå îòäåëüíûõ çåðåí íàáëþäàþòñÿ èíäèâèäóàëüíûå äâîéíèêè è èõ ñêîïëåíèÿ (ðèñ.1.à).  îáëàñòè ãðàíèö çåðåí ñêîïëåíû ÿìêè òðàâëåíèÿ.Âî ìíîãèõ ñëó÷àÿõ, â ñòðóêòóðå îòíîñèòåëüíî áîëüøèõ áëîêîâ âûÿâëÿþòñÿ äèñëîêàöèîííûå ôèãóðû òðàâëåíèÿ âûñîêîé êîíöåíòðàöèè, êîòîðûå ðàñïðåäåëåíû âåñüìà íåðàâíîìåðíî. Îíè ñãðóïïèðîâàíû â äåôåêòàõ óïàêîâêè è ïàêåòàõ äâîéíèêîâ (ðèñ.1.á). Âäîëü ñëåäîâ ïëàñòè÷åñêîé äåôîðìàöè è íàáëþäàþòñÿ ìíîæåñòâî äèñëîêàöèé (ðèñ.1.â). ×àñòî äèñëîêàöèîííûå ÿìêè òðàâëåíèÿ îòëè÷àþòñÿ äðóã îò äðóãà ïî ôîðìå è ðàçìåðó (ðèñ.1.ã). Èçìåíåíèå ôîðìû ÿìîê òðàâëåíèÿ â ëîêàëüíûõ ó÷àñòêàõ âûçâàíî êðèñòàëëîãðàôè÷åñêîé äåçîðèåíòàöèåé, à èçìåíåíèå ðàçìåðîâ ÿìîê òðàâëåíèÿ îïðåäåëÿþòñÿ ìíîæåñòâîì ôàêòîðîâ. Ñðåäè íèõ ñëåäóåò îòìåòèòü íàëè÷èå ñèëüíî ëîêàëèçîâàííûõ äåôîðìàöèé, ñðàâíèòåëüíî âûñîêàÿ êîíöåíòðàöèÿ ïðèìåñåé.  äàííîì êîíêðåòíîì ñëó÷àå ýòè óñëîâèÿ ìîãëè ïðèâåñòè ê ïîâûøåíèþ êîëè÷åñòâà äèñëîêàöèîííûõ ôèãóð òðàâëåíèÿ. Ñëåäóåò îòìåòèòü, ÷òî ôîðìèðîâàíèå ñðàâíèòåëüíî íåáîëüøèõ ðàçìåðîâ äèñëîêàöèîííûõ ôèãóð òðàâëåíèÿ õàðàêòåðíî äëÿ ìèêðîñòðóêòóðû ìàññèâíîãî êðèñòàëëà êðåìíèÿ â îáëàñòÿõ ñâîáîäíîé îò ïðèìåñåé[1,6].

 òàáëèöå ïðåäñòàâëåíû ðåçóëüòàòû èçìåðåíèé ýëåêòðîôèçè÷åñêèõ õàðàêòåðèñòèê îáðàçöîâ ñïëàâà Si+1,5% Ge:B (1015 ñì-3) íåîáëó÷åííûõ, îáëó÷åííûõ ðàçíûìè ôëþåíñàìè èîíîâ àðãîíà è ïðîøåäøèõ èìïóëüñíûéôîòîííûé îòæèã â òå÷åíèå 5 ñåê ïðè ðàçíûõ òåìïåðàòóðàõ. Òàáëèöà 1. Ýëåêòðîôèçè÷åñêèå õàðàêòåðèñòèêè ïîäëîæåê Si+1,5%Ge:B(1015 ñì-3), îáëó÷åííûõ èîíàìè àðãîíà ñ ýíåðãèåé 100 êýÂ. Электрич еские характери стики NS,см-2

Необлуч енное состоян ие 1·1012

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865

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Флюенс 2·1013см-2

7150С 920 0С 715 0С 920 0С 715 0С 920 0С 5,6·1011 2,8·1013 2,5·1011 6,3·1011 4,4·1011 2,1·1012 130

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ãäå- N S ïîâåðõíîñòíàÿ êîíöåíòðàöèÿ, ìïîäâèæíîñòü íîñèòåëåé òîêà. Èç òàáëèöû âèäíî,÷òî èñõîäíûå è îáëó÷åííûå èîíàìè Ar îáðàçöû äî òåðìè÷åñêîé îáðàáîòêè îòëè÷àþòñÿ äðóã îò äðóãà çíà÷åíèÿìè êîíöåíòðàöèé íîñèòåëåé òîêà è èõ ïîäâèæíîñòè.  îáðàçöàõ, îáëó÷åííûõ àðãîíîì, çíà÷èòåëüíî âûøå êîíöåíòðàöèÿ äûðîê è ñíèæåíà èõ ïîäâèæíîñòü. Íàáëþäàåìîå ðàçëè÷èå âîçìîæíî ñâÿçàíî ñ ïîÿâëåíèåì â ñòðóêòóðå îáðàçöîâ Si-Ge,áîëüøîãî êîëè÷åñòâà ýëåêòðè÷åñêè

85 àêòèâíûõ ðàäèàöèîííûõ äåôåêòîâ, ïðè èìïëàíòàöèè èîíàìè àðãîíà. Êðàòêîâðåìåííûé èìïóëüñíûé ôîòîííûé îòæèã ïðè òåìïåðàòóðå 715 0Ñ ñòèìóëèðóåò àííèãèëÿöèþ ñìåùåííûõ â ïîçèöèè âíåäðåííûõ àòîìîâ Si è Ge ñ âàêàíñèÿìè, â ýòî âðåìÿ ïðàêòè÷åñêè íå ìåíÿþòñÿ ïëîòíîñòü è õàðàêòåð ðàñïðåäåëåíèÿ äåôåêòîâ äèñëîêàöèîííîãî ïðîèñõîæäåíèÿ. Ïîâèäèìîìó ðàññåÿíèå íîñèòåëåé òîêà íà äèñëîêàöèîííûõ è ïëàíàðíûõ äåôåêòàõ îïðåäåëÿþò ïîíèæåíèå ïîäâèæíîñòè íîñèòåëåé òîêà. Ñðàâíåíèå ïîêàçûâàåò, ÷òî êîíöåíòðàöèÿ íîñèòåëåé òîêà è èõ ïîäâèæíîñòü ìåíÿþòñÿ íåìîíîòîííî ñ óâåëè÷åíèåì ôëþåíñà èîíîâ àðãîíà è òåìïåðàòóðû ôîòîííîãî îòæèãà. Óêàçàííûå ñïåöèôè÷åñêèå èçìåíåíèÿ ýëåêòðè÷åñêèõ õàðàêòåðèñòèê âèäèìî îáóñëîâëåíû ýëåêòðè÷åñêîé àêòèâíîñòüþ ðàçíîîáðàçíûõ òî÷å÷íûõ, ëèíåéíûõ è ïëàíàðíûõ äåôåêòîâ â ñòðóêòóðå ïîäëîæåê Si-Ge, ñôîðìèðîâàííûõ â ïðîöåññå êðèñòàëëèçàöèè. Ïðè âîçäåéñòâèè îáëó÷åíèÿ âûñîêîýíåðãåòè÷åñêèìè èîíàìè àðãîíà ìåëêîìàñøòàáíûå ïëàíàðíûå è ëèíåéíûå äåôåêòû ýëåêòðè÷åñêè àêòèâèðóþòñÿ. Âîçìîæíî òàêæå ïðåîáðàçîâàíèå ýëåêòðè÷åñêè àêòèâíûõ êîìïëåêñîâ è îáðàçîâàíèå íîâûõ ýëåêòðè÷åñêè íåéòðàëüíûõ êîìïëåêñîâ. Ñëåäóåò ó÷åñòü òàêæå, ÷òî èîíû àðãîíà ïðîíèêàþò íà íåáîëüøèå ãëóáèíû, ãäå âûñîêà ïîäâèæíîñòü äèñëîêàöèîííûõ äåôåêòîâ. Èññëåäîâàíèå ïîêàçàëî, ÷òî îáëó÷åíèå èîíàìè àðãîíà ðàçíûõ ôëþåíñîâ è ïîñëåäóþùèé èìïóëüñíûé ôîòîíûé îòæèã, ñîçäàþò óñëîâèÿ èçìåíåíèÿ ýëåêòðîôèçè÷åñêèõè÷åñêèõ õàðàêòåðèñòèê ïîëèêðèñòàëëè÷åñêèõ îáðàçöîâ ñïëàâîâ Si-Ge. Ýòî âåñüìà âàæíî äëÿ öåëåíàïðàâëåííîãî ìîäèôèöèðîâàíèÿ ïîäñèñòåìû äåôåêòîâ è ýëåêòðè÷åñêèõ õàðàêòåðèñòèê ñòðóêòóð ñ p-n ïåðåõîäàìè íà îñíîâå Si-Ge.

Çàêëþ÷åíèå  îáðàçöàõ, îáëó÷åííûõ áîëüøèìè ôëþåíñàìè èîíîâ Ar âûÿâëåíî îòêëîíåíèå îò îæèäàåìûõ èçìåíåíèé êîíöåíòðàöèè íîñèòåëåé òîêà è èõ ïîäâèæíîñòè. Ïðåäïîëàãàåòñÿ ïðîÿâëåíèå èçìåíåíèÿ ýëåêòðè÷åñêîé àêòèâíîñòè äåôåêòîâ â ïðîöåññå èõ ñòðóêòóðíûõ ïðåâðàùåíèé.

Ëèòåðàòóðà:

1. Ê. Ðåéâè. Äåôåêòû è ïðèìåñè â ïîëóïðîâîäíèêîâîì Si. Ì.: Ìèð, 1984, 320.

2. È.À. Çåëüöåð, Å.Í. Ìîîñ. Ñòðóêòóðà êðèñòàëëîâ Si ïîñëå èìïëàíòàöèè èîíàìè B, As, He, P, Ar è N. Ýëåêòðîííàÿ ïðîìûøëåííîñòü, 1982, âûï. 10-11, ñ. 63-68.

3. J. Vanhellemont, M. Suezawa, J. Yonenaga. On the Impact of Ge Doping on the Vacancy Formation Energy in Czochralskigrown Si. J. Applied Physics, 108, 016105-1-3(2010).

4. Ë. Ô. Ìàêàðåíêî, Ô. Ï. Êîðøóíîâ, Ñ. Á. Ëàñòîâñêèé, Í. Â. Àáðîñèìîâ. Òåðìè÷åñêàÿ óñòîé÷èâîñòü äåôåêòîâ ìåæäîóçåëüíîãî òèïà â êðåìíèè è êðåìíèé-ãåðìàíèåâûõ ñïëàâàõ, ëåãèðîâàííûõ áîðîì.  ñá. «Ìàòåðèàëû è ñòðóêòóðû ñîâðåìåííîé ýëåêòðîíèêè», Ìèíñê, Áåëàðóñü, 2012, ñ. 138-141.

5. Ë. Ô. Ìàêàðåíêî, Í.Ì. Êàçþ÷èö, Í.Ô. Ãîëóáåâ. Èçó÷åíèå äåôåêòîîáðàçîâàíèÿ â êðèñòàëëàõ Si, îáëó÷åííûõ òÿæåëûìè èîíàìè.  ñá. «Âçàèìîäåéñòâèå èçëó÷åíèé ñ òâåðäûì òåëîì». Ìèíñê, Áåëàðóñü, 2009, ñ. 98-100.

6. À.Ë. Àñååâ, Ë.È. Ôåäèíà, Ä. Õeëü, Õ. Áàð÷. Ñêîïëåíèÿ ìåæäîóçåëüíûõ àòîìîâ â Si è Ge. Íîâîñèáèðñê, «Íàóêà»,1991, 148 ñ.

Influence of Argon Ion Irradiation on the Electrical Characteristics of Si-Ge Substrates I. Tabatadze 1,M. Kadaria1, G. Chubinidze1, L. Gapishvili2, T. Melashvili1, K. Komakhidze1 Ilia Vekua Sukhumi Institute of Physics and Technology,7Mindeli str.0186, Tbilisi, Georgia, 2 Institute of Micro and Nano Electronics,73Mnatobi str., 0186, Tbilisi, Georgia.

E-mail:sipt@sipt.org

1

The results of the study of the microstructure and the electrical characteristics of polycrystalline Si-Ge substrates in the initial, irradiated by argon ions and annealed condition are presented.

Displaying nonmonotonic variation of electrical characteristics at high fluences of Ar ions and high temperatures of pulse photon annealing are shown. The observed specific changes are analyzed from the point of view of implementation transformations in the defects produced during crystal grow and radiation exposure.

argonis ionebiT dasxivebis gavlena Si-Ge fuZeSreebis eleqtrofizikur maxasiaTeblebze i. tabataZe1, m. qadaria1, g. CubiniZe1, l. gafiSvili2, t. melaSvili1, k. komaxiZe1 1 ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo 2 mikro da nanoeleqtronikis instituti, mnaTobis q. 73, 0186, Tbilisi, saqarTvelo. el–fosta: sipt@sipt.org

warmodgenilia sawyis, Ar -is ionebiT dasxivebul da impulsurad momwvar mdgomareobaSi polikristaluri Si-Ge fuZeSreebis mikrostruqturisa da eleqtrofizikuri maxasiaTeblebis kvlevis Sedegebi. naCvenebia eleqtrofizikuri maxasiaTeblebis aramonotonuri cvlilebebi Aris ionebis dasxivebis fluensisa da impulsuri mowvis temperaturis amaRlebis pirobebSi. gamovlenili specifikuri cvlilebebi gaanalizebulia kristalizaciisa da radiaciuli zemoqmedebis procesebSi warmoqmnil defeqtebSi ganxorcielebuli gardaqmnebis safuZvelze.

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Removal of impurities from metallurgical silicon E. Khutsishvili1, N.Khutsishvili2, L. Gabrichidze1, N. Kobulashvili1, N. Kekelidze1,2 Ferdinand Tavadze Institute of Metallurgy and Materials Science, 0160, Tbilisi, Georgia Georgian Technical University, 77 Kostava str., 0175, Tbilisi,Georgia E-mail:nunuki55@mail.ru 1 2

Abstract. The process of purification of metallurgical–grade silicon with 98 Si wt % is considered. Because of small values of impurities segregation coefficient (10-4-10-6) in Si for purifying of metallurgical–grade silicon a method based on segregation of impurities at solidification has been applied.

Keywords: detrimental impurities, purification, metallurgical –grade silicon.

Introduction Silicon is still the basic active component of modern high-performance semiconductor devices, especially for photovoltaic application [1]. They are advantageous because of Si abundance on earth, satisfaction of certain criterion and quite number properties comparatively with other semiconductor materials [2, 3].So today and in the near future Si is just one practically applied material in photo cells[4, 5]. However further development of Si producing is held back by high cost price because of laborious and quite complicated existent technologies and application of dangerous materials. In this connection the search of other environmentally clean technologies of Si producing is very actual[4-8].

The first stage of Si producing is obtaining of technical purity Si called metallurgical Si (MG-Si). This process is generally carried out by restoration of silicon from quartzite with reaction to carbon. The carbothermal process of Si producing is in principle slagless process that means that except elements, generating at melting gaseous components, all elements in batch load will be the components of producible Si. In this way restored Si contains ample quantity of impurities and it is ordinarily ~98-99%Si purity in mass. Minimization of impurities content in Si,intended for its application as semiconductor material, is realized by using such known refinement methods astraditional purification based on the Siemens process, electrolytic, vacuum,chemical,oxidation, chemicaltransport reaction, crystallization at alias. Because impurities in Si are inherently different, the full and deep purification of Si presents complex problem. Control of metal impurities is essential for developing modern Si-based photovoltaics. The properties of high-performance photovoltaic devices are defined by removal and passivation of detrimental impurities [5-8]. Much effort has been focused on the improvement of Si technology.

However, recent evidence suggests these techniques can only achieve partial success [5-10]. Crystallization from melts is widely used for purification of semiconductor materials. As a rule it is applied on the final stage of techno-

logical process of purification of substances. However in given work directional crystallization is used for purificationdirectly metallurgical Si without intermediate stages.

The results of purification of metallurgical grade silicon bydirectional crystallization are presented in this paper.

Materials and Methods Initial metallurgical grade Si was 98%Si purity in mass with 2% of collection of unwanted following impurities: Fe, Al, P, Na, Cu, Mg, Mn, Ni, Ti.Among them Al, Mg, Fe, Mn, Ni, Ca, Cu impurities are middle melt able, Ti– high-melting metals.

It is remarkable that phase diagrams of many dissolved impurity elements in silicon have identical characteristic species and are eutectic type [11]. The impurity-silicon micro phase diagrams demonstrate that solubility of impurities in Si is small and different in solid and liquid phases.

So it is possible to consider impurity-silicon systems as dilute. Thereby the values of segregation coefficient of main impuritiesin Si are small (10-4-10-6) (Table 1).

Table 1. Segregation coefficient of impurities in Si

Therefore for intermediate purifying of metallurgical– grade siliconit was applied comparatively ecologicaly pure technology based on segregation of impurities at directional solidification. One variety of this method-normal directionalcrystallization with multiple remelting and exposure in liquid state has been used.

The content of contaminating impurities in Si before and after purification have been establishedby X-ray diffraction method by modernized DRON-4-07 the equipment at Mo radiation in 0.5 degree/min,emissive spectral analysis with electric arcactuation and electrical properies measurements.Investigations of the substitutional impurities oxygen and carbon vibration modes has been carried out by measurements of infrared spectra on the UR-20 spec-

87 trometer (absolute method measurements).Microstructure has been observed on the Neophont microscope. The samples of Si crystals with various purity has been mechanically grinded, polished, washed in the distilled water and etched for 1-5 minutes in the alkaline etchant solution of 30%KOH at 50-1000C.

Results The main impurities in initialexperimental samples of MG-Si are Fe, Al, Ca and Ti. The mentioned elementsand other impurities, including transition metals fall one after the other in liquid Si in time of restoration of Si from quartz sand. Applied restorative materials and technology equipment also contaminate MG Si at obtaining. Carbon and oxygen are present at MG Si too because of technology process.

At initial step of melting at low temperatures Si is purified from mixture of those impurities which are more volatile than basic component.The melt has sufficiently large surface. So volatile impurities activelyevaporate from the surface of Si melt at low temperatures and 10-3Hg pressure.

Their content is defined by pressure and composition of atmosphere in a processing chamber. At temperatures lower than Si melting temperature (14500C) impurities with less fusion temperature evaporatetoo. On the next step of process temperature is increased by 50-700C higher than 14500C and Si melt stays in liquid state certain time for removal (evaporation) of uneasily meltableimpurities like Fe,Ti etc.

Under the conditions of low pressure and high temperatures those impurities which vapor tension is higher than one of Si (P, Al etc) evaporate too.

At the purification of substance fromimpurities by evaporation it is known[12], that quantity of impurity , which vaporizes from open unit area of melt (refllection of molecules from cruicible walls is take into account) is defined by:

(1),

where P –equilibrium pressure of impurity steam, Mmolecular weight of impurity, R- gas constant, T-melting temperature, (2), where a-condensing coefficient, d- crucible diameter, lheight of walls of cruicible abovethe melt.

Purification by evaporation is effective for those impurities, which equilibrium pressure of steam exceeds one for Si. Those impurities which equilibrium pressure of steam is higher than for the rest of theimpurities vaporize easier at the identical conditions. The ratio of equilibrium pressure of steam for impurity and silicon defines the degree of their partition.From (1) expression it follows, that the vaporizability or ability to be removed of easy vaporable impurities from Si melt reduces in the row of Mg>Ca>Mn>Al>Cu> Fe>Ni>Òi.

Among a great number of foreign unforeseen electrically neutral impurities carbon and oxygen in Si attract attention, getting into semiconductors during the meltingprocess. Gaseous products of the reaction are removed by gas-extracting arrangement. At the same time in the mutual reaction refractory products are precipitated in the end of crystal. Finally they are removed with cutoff part of Si crystal.Maximum amount of residual oxygen and carbon make upcoincide with maximal solubility in Si 1.8×1018and 6×1018cm-3.

Experimental resultsof Si purification processes investigation are shown in Table2 and Fig.1.Table 2 and Fig.1 show, that after first remelting of MG-Si (2 hours of exposure in liquid state)silicon has been significantly purified from majority of impurities. Si purification process of unwanted impurities has continued by further remelting.

Therewith Si conductivity type has already changed from n- to p-type after the second remelting (5 hours of exposure in liquid state).

Table 2. Electrical properties of Si experimental samples and conditions of experiments at normal directional crystallization

The most effect of purification is achived after third remelting of Si (6 hours of exposure in liquid state). The measurements on the cut off upper and lower parts of silicon crystals has confirmed the focusing of hazardous impurities in this extreme parts. It is remarkable, that metallurgical Si has been purified practically from majority of impurities.Particularly, middle meltable Al, Mg, Fe, Mn, Ni, Ca, Cu impurities removal has been realized efficiently.

Hereof the quantity of Ca, Cu, Ni,Mn impurities reduces as a result of remelting thus much that their presense in Si goes out of detection limit of impurities determination methods. Ti and Fe present the exception because of their high melting temperature and low aporability from Si melt surface.

The removal of impurities has an effect on the electrical and microstructural properties of Si. After remelting, besides the change of conductivity type, the current carriers concentration falls by 100 times relatively to data for initial metallurgical Si (Table 2).Typical microstructures of Si experimental samples after the different steps of purification process are shown in Fig 2.

The tracks of different phase inclusions are observed in initial microstructure of MG Si. Phase inclusions are created byunmanageable impurities, concentration of which exceed the limit of their solubility in Si and does not create solid solution with Si. During the purification process phase

88 inclusions reduce in size little by little and finally almost disappear.

After first remelting microstructure ofSi have already became more consistent and is characterized by bigger size of grains with straight boundaries. Microstructure of Si have much improved after second remelting.

Conclusions It has been worked out comparatively inexpensive ecologicaly pure technology of intermediate purifying of metallurgical –grade silicon. Multiple remelting and soaking in liquid state of metallurgical –grade silicon were applied for intermediate purifying process. The method gives an opportunity to receivepreliminarily refined silicon forsubsequent growth of ”solar-grade”silicon by Czochralski pulling. The developing technology is based on the difference of solubility, volatility and segragation coefficient for silicon and impurties.

References:

Fig.1. Dependence of hazardous impurities content in silicon experimental samples on exposure time in liquid state at normal directional crystallization process with multiple remelting at T~1430-1500°C.

1. W. Koch, A.L.Endros,D.Franke,C.Haßler,J. P. Kalejs and H. J. Moller.Handbook of Photovoltaic Science and Engineering,2003,Edited by A. Luque and S. Hegedus. John Wiley & Sons, ,Ltd ISBN: 0-471-49196-9.

2. William B. Shockley, 79, Creator of Transistor and Theory on Race. 14 August 1989, New York Times..

3. A. De Vos, Journal of Physics D: Applied Physics ,13(1980), 839-846,.

a)

b)

c)

d)

Fig. 2. Microstructure of Si experimental samples of various purity, obtained at different remelting steps at normal directionalcrystallization process. x100. a)-metallurgical MG Si;remelting steps: b)- first; c)-second; d)third.

89 4. M. Powell,M. T. Winkler, H. J. Choi, C. B. Simmons, D. Berney Needleman and T. Buonassisi. Energy Environ. Sci., 5(2012), 5874–5883.

5. S. Hudelson , B. K. Newman , S. Bernardis , D. P. Fenning , M. I. Bertoni , M. A. Marcus , S. C. Fakra , B.Lai T. Buonassisi.

Adv. Mater.,22(2010),3948–3953.

6. K. Tang , G. M. Tranell , E. J. Øvrelid , M. Tangstad , Crystal Growth of Silicon for Solar Cells (Eds: K. Nakajima , N. Usami ), 2010,Springer , Berlin.

7. D. P. Fenning, J. Hofstetter, M. I. Bertoni, S. Hudelson, M. Rinio et al. Appl. Phys. Lett. 98(2011),162103; doi: 10.1063/ 1.3575583 8. Fritz Kirscht, Matthias Heuer, Martin Kaes, TilBartel, Terry Jester, Clemens Hofbauer, Alain Turenne, Metallurgically refined silicon for photovoltaics,Third International Symposium NES-2013, August 6-8, Almaty, Kazakhstan.

9. Jing-wei Li,Zhan-cheng Guo, Hui-qing Tang, Jun-cheng Li, High Temperature Materials and Processes. 0(2013), 1–8, ISSN (Online) 2191-0324, ISSN (Print) 0334-6455, DOI: 10.1515/htmp-2012-0157.

10. J.C.S. Pires, et al. Solar Energy Materials & Solar Cells, 79 (2003),347–355.

11. F.A.Trumbore .Bell Syst Tech J ,39(1960), 205-33.

12. K. S. W. Sing, D. H. Everett ,R. A. W. Haul , l. Moscou ,R. A. Pierotti , J. Rouquerol, T. Siemieniewska,Pure Appl. Chem, 57 (1985), 603-619.

narCeni minarevebisagan metalurgiuli siliciumis gawmenda e. xuciSvili1, n. xuciSvili2, l. gabriWiZe1, n. qobulaSvili1, n. kekeliZe1,2 1 ferdinand TavaZis metalurgiisa da masalaTmcodneobis instituti, 0160, Tbilisi, saqarTvelo 2 saqarTvelos teqnikuri universiteti, 0175, Tbilisi, saqarTvelo el-fosta: nunuki55@mail.ru

ganxilulia 98% (mas)sisufTavis metalurgiuli siliciumis gawmendis procesi. siliciumSi minarevebis segregaciis koeficientis dabal sidideebTan dakavSirebiT metalurgiuli siliciumis gasawmendad gamoyenebulia meTodi, romelic dafuZnebulia gamyarebis procesSi minarevebis segregaciaze.

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Âëèÿíèå êîíöåíòðàöèè áîðà íà âðåìÿ æèçíè íîñèòåëåé çàðÿäà â íåéòðîííîëåãèðîâàííîì êðåìíèè Ø. Ìàõìóäîâ, Ø. Ìàõêàìîâ, À. Ñóëàéìàíîâ, À. Ðàôèêîâ, Ê. Áåêìàòîâ, Õ. Ýðãàøåâ Èíñòèòóò ßäåðíîé ôèçèêè ÀÍÐÓç, ï.Óëóãáåê, 100214, ã. Òàøêåíò, Óçáåêèñòàí, Ýë–ïî÷òà: rafikov@inp.uz Ðåçþìå.  ðàáîòå èçìåðåíèåì ýëåêòðîôèçè÷åñêèõ ïàðàìåòðîâ è ìåòîäîì çàòóõàíèÿ ôîòîïðîâîäèìîñòè èçó÷àëîñü âëèÿíèå âûñîêîòåìïåðàòóðíîé îáðàáîòêè íà ðåêîìáèíàöèîííûå ñâîéñòâà íåéòðîííî-ëåãèðîâàííîãî êðåìíèÿ (ÍËÊ) â çàâèñèìîñòè îò êîíöåíòðàöèè áîðà. Ïîêàçàíî, ÷òî ñ ðîñòîì èñõîäíîé êîíöåíòðàöèè íîñèòåëåé çàðÿäà (â äàííîì ñëó÷àå áîðà-Â) â êîìïåíñèðîâàííîì êðåìíèè íàáëþäàåòñÿ âîçðàñòàíèå t, êîòîðîå îáóñëîâëåíî ôîðìèðîâàíèåì â îáúåìå ÍËÊ ìèêðîíåîäíîðîäíîñòåé, ðàçëè÷àþùèõñÿ ïî ïðîâîäèìîñòè è ñòåïåíè êîìïåíñàöèè. Óñòàíîâëåíî, ÷òî òåðìîñòàáèëüíîñòü âðåìåíè æèçíè íîñèòåëåé çàðÿäà â ÍËÊ çàâèñèò îò èñõîäíîé êîíöåíòðàöèè áîðà. Óâåëè÷åíèå èñõîäíîé êîíöåíòðàöèè áîðà ïðèâîäèò ê ñìåùåíèþ äëèòåëüíîñòè òåðìî-îòæèãà â îáëàñòü áîëüøèõ âðåìåí. Ïîëó÷åííûå ðåçóëüòàòû ïîêàçàëè øèðîêèå òåõíè÷åñêèå âîçìîæíîñòè ïîëó÷åíèÿ áîëåå îäíîðîäíîãî òåðìîñòàáèëüíîãî âûñîêîîìíîãî ìîíîêðèñòàëëè÷åñêîãî ÍËÊ.

Êëþ÷åâûå ñëîâà: ýëåêòðîôèçè÷åñêèå ñâîéñòâà, êðåìíèé ð-òèïà, ëåãèðîâàíèå, îáëó÷åíèå íåéòðîíàìè, ñòðóêòóðíûå äåôåêòû, ïîäâèæíîñòü íîñèòåëåé çàðÿäà, êîíöåíòðàöèÿ è âðåìÿ æèçíè íîñèòåëåé çàðÿäà, ðåëàêñàöèÿ.

Ââåäåíèå Îäíèì èç òåõíîëîãè÷åñêèõ îïåðàöèé ïðè ïîëó÷åíèè íåéòðîííî-ëåãèðîâàííîãî ìîíîêðèñòàëëè÷åñêîãî êðåìíèÿ (ÍËÊ) ÿâëÿåòñÿ òåðìè÷åñêèé îòæèã ïðè âûñîêèõ òåìïåðàòóð. Ðåçóëüòàòû, ïîëó÷åííûå ðàçëè÷íûìè àâòîðàìè ïî èçìåíåíèþ ýëåêòðîôèçè÷åñêèõ ïàðàìåòðîâ ïðè òåðìîîáðàáîòêå ÍËÊ, îñîáåííî âðåìåíè æèçíè íîñèòåëåé òîêà íå âñåãäà ñîãëàñóåòñÿ [1-3]. Ïðè÷èí ýòîãî, íà íàø âçãëÿä, ÿâëÿåòñÿ ðàçëè÷íûå óñëîâèÿ è ðåæèì òåðìîîáðàáîòêè êðåìíèÿ (òåìïåðàòóðà, âðåìÿ îòæèãà, ãåòòåðèðóþùàÿ ñðåäà, óäåëüíîå ñîïðîòèâëåíèå êðèñòàëëà è äð.) ïîñëå íåéòðîííîãî ëåãèðîâàíèÿ.  äàííîé ðàáîòå èçìåðåíèåì ýëåêòðîôèçè÷åñêèõ ïàðàìåòðîâ è ìåòîäîì çàòóõàíèÿ ôîòîïðîâîäèìîñòè èçó÷àëîñü âëèÿíèå âûñêîòåìïåðàòóðíîé îáðàáîòêè íà ðåêîìáèíàöèîííûå ñâîéñòâà ÍËÊ â çàâèñèìîñòè îò êîíöåíòðàöèè áîðà.

Ïîäãîòîâêà îáðàçöîâ è ìåòîäèêà ýêñïåðèìåíòà Äëÿ ðåøåíèÿ ïîñòàâëåííîé çàäà÷è â êà÷åñòâå èñõîäíîãî ìàòåðèàëà èñïîëüçîâàëñÿ êðåìíèé ð - òèïà c óäåëüíûì ñîïðîòèâëåíèåì 1 ÷ 100 Îì×ñì. Ëåãèðîâàíèå êðåìíèÿ ïðèìåñÿìè ôîñôîðà - Ð ïðîâîäèëîñü ïóòåì ÿäåðíîé ðåàêöèè (ÍËÊ): 30Si (ν,γ) 31Si → 31P +β− ïðè îáëó÷åíèå â àòîìíîì ðåàêòîðå òèïà ÂÂÐ-ÑÌ, èíòåíñèâíîñòè òåïëîâûõ íåéòðîíîâ ñîñòàâëÿÿ I ∼1⋅1014 ñì-3 . Ïðè ýòîì êîíöåíòðàöèþ ââåäåííîãî ôîñôîðà ìîæíî ðàññ÷èòàòü ïî ôîðìóëå: NP =1,7⋅10-4 Ô, ãäå Ô = It – èíòåãðàëüíûé ïîòîê ìåäëåííûõ íåéòðîíîâ, ñì-2, I-

ïëîòíîñòü ïîòîêà ìåäëåííûõ íåéòðîíîâ, ñì-2ñ-1, t – âðåìÿ îáëó÷åíèÿ, ñ. Îòæèã ðàäèàöèîííûõ äåôåêòîâ (ÐÄ) ïðîâîäèëîñü ïðè òåìïåðàòóðå ∼1270 Ê íà âîçäóõå, â òå÷åíèå ∼30 ìèí. ñ ïîñëåäóþùåì ìåäëåííûì îõëàæäåíèåì (5÷10) ãðàä/ ìèí. Äëÿ âûÿñíåíèÿ íîìèíàëüíîãî çíà÷åíèÿ ïîäâèæíîñòè îñíîâíûõ íîñèòåëåé çàðÿäà, ïðîâîäèëñÿ èçîòåðìè÷åñêèé îòæèã, ïðè òåìïåðàòóðå ∼1270 Ê. Îìè÷åñêèå êîíòàêòû íà p-Si<B,P> è p-Si<B> ïîëó÷àëè ïóòåì ïðèïàèâàíèÿ ñïëàâà Sn+In (50% + 50%) ïðè òåìïåðàòóðå ∼400 Ê. Äî è ïîñëå îòæèãà èçìåðÿëèñü êîíöåíòðàöèÿ è âðåìÿ æèçíè íîñèòåëåé çàðÿäà ìåòîäàìè ýôôåêòà Õîëëà è ñòàöèî-íàðíîé ôîòîïðîâî-äèìîñòè [4], ñîîòâåòñòâåííî. Ýëåêòðîôèçè÷åñêèå è ðåêîìáèíàöèîííûå ïàðàìåòðû ëåãèðîâàííîãî êðåìíèÿ ïðèâåäåíû â òàáëèöå.

Ýêñïåðèìåíòàëüíûå ðåçóëüòàòû è èõ îáñóæäåíèå Êàê âèäíî èç òàáë. ïîäâèæíîñòè îñíîâíûõ íîñèòåëåé çàðÿäà â íåéòðîííî-êîìïåíñèðîâàííîì êðåìíèè ð-òèïà (ïðè èäåíòè÷íîñòè ρ) èçìåíÿåòñÿ â çàâèñèìîñòè îò èñõîäíîé êîíöåíòðàöèè áîðà, ò.å. ïðè âûøåóêàçàííîé òåìïåðàòóðå îòæèãà ðàäèàöèîííûå äåôåêòû îòæèãàþòñÿ íå ïîëíîñòüþ. Âðåìÿ æèçíè íîñèòåëåé çàðÿäà â ÍËÊ ïðàêòè÷åñêè íå çàâèñèò îò êîíöåíòðàöèè áîðà è ñîñòàâëÿåò îêîëî ìêñåê. Êàê âèäíî èç ðèñóíêà 1 ïîäâèæíîñòü íîñèòåëåé çàðÿäà (μ) óâåëè÷èâàåòñÿ ñ ðîñòîì âðåìåíè èçîòåðìè÷åñêîãî îòæèãà è, ÷åì áîëüøå êîíöåíòðàöèè êîìïåíñèðóþùèõ äîíîðíûõ öåíòðîâ (â äàííîì ñëó÷àå,

91 ôîñôîðà), òåì áîëüøå íîìèíàëüíîå çíà÷åíèå μ ñäâèãàåòñÿ â ñòîðîíó áîëüøåãî âðåìåíè îòæèãà (ïðè ýòîì êîíöåíòðàöèÿ îñíîâíûõ íîñèòåëåé çàðÿäà â èññëåäîâàííûõ îáðàçöàõ îñòà òñÿ ïðàêòè÷åñêè íåèçìåííîé). Ñëåäîâàòåëüíî, ìîæíî ñêàçàòü, ÷òî äëÿ äîñòèæåíèÿ íîìèíàëüíîãî çíà÷åíèÿ êîíöåíòðàöèè íîñèòåëåé çàðÿäà äîñòàòî÷íî òåìïåðàòóðû 1270 Ê è âðåìåíè îòæèãà t =30 ìèí., à äëÿ óìåíüøåíèÿ âëèÿíèÿ ñòðóêòóðíûõ äåôåêòîâ (íàïðèìåð, îáëàñòåé ðàçóïîðÿäî÷åíèÿ) íåîáõîäèìî óâåëè÷èòü âðåìÿ îòæèãà. Êèíåòèêà ðåëàêñàöèè íåðàâíîâåñíûõ íîñèòåëåé çàðÿäà. â êîìïåíñèðîâàííîì ìàòåðèàëå ïðîèñõîäèò ðàçëè÷íûì îáðàçîì: t2 ≈ 98 ñ äëÿ ð-Si<B,P>, à t2 ≈ 5 ñ äëÿ ð-Si<B>. Îòëè÷èå ðåëàêñàöèîííûõ ïðîöåññîâ â êîìïåíñèðîâàííîì è êîíòðîëüíîì êðåìíèè îáúÿñíÿåòñÿ ðàçëè÷íîé ñòåïåíüþ ìèêðîíåîäíîðîäíîñòè ïî ïðîâîäèìîñòè.

Èçìåíåíèå âðåìåíè æèçíè íîñèòåëåé çàðÿäà îò äëèòåëüíîñòè òåð-ìîîáðàáîòêè ïîêàçàíî íà ðèñ. 2. Êàê âèäíî èç ðèñ.2. ñ óâåëè÷åíèåì âðåìåíè îòæèãà çíà÷åíèÿ t âíà÷àëå âîçðàñòàåò, à çàòåì ñòàáèëèçèðóåòñÿ. Ýòîò ýôôåêò, íà íàø âçãëÿä, ñâÿçàí ñ íåêîíòðîëèðóåìûìè ïðèìåñÿìè â îáúåìå ìàòåðèàëà, ñîçäàþùèìè ãëóáîêèå ýíåðãåòè÷åñêèå óðîâíè. Íåçíà÷èòåëüíîå óâåëè÷åíèå çíà÷åíèé t ñ óìåíüøåíèåì êîíöåíòðàöèè àòîìîâ áîðà (ïðèâåäåííûå â òàáë.), òàêæå ïîäòâåðæäàåò, ÷òî çíà÷åíèå t ñâÿçàíî íåêîíòðîëèðóåìûìè ïðèìåñÿìè.

№ Исходн ый образец

Нейтронно-легированный кремний (НЛК) р (или τ, с ρ, μ, n), см-3 см2/В.с Ом.см

1 2 3 4

КДБ-1

2,8. 103 2,6. 103 2,9. 103 4.103

1,3.1013 1.2.1013 1,95.1013 2,2.1012

170 200 180 700

6.10-7 8.10-7 6.10-7 9.10-7

5 6 7 8

КДБ-10

3,7.103 3,6.103 3,6.103 5.104

6,1.1012 6,34.1012 6,94.1012 1,25.1011

282 274 250 1000

3.10-6 2.10-6 1,5.10-6 1.10-6

105

9 9 1 0

КДБ100

2,4. 103 2. 103 2,2.103

7,9.1012 9,7.1012 8,74.1012

330 320 325

6.10-6 7.10-6 5.10-6

104

μ, см2/В⋅с

Òàáëèöà 1. Ýëåêòðîôèçè÷åñêèå ïàðàìåòðû íåéòðîííî – ëåãèðîâàííîãî êðåìíèÿ â çàâèñèìîñòè îò èñõîäíîãî ìàòåðèàëà (Òîòæ =1270 Ê, tîòæ =30 ìèí)

350

Время облучения тепловым нейтронами, t , с 106

3

300

2

250 1

200 0

1

2

3

4

5

6

7

t, c

Ðèñ.1. Çàâèñèìîñòü ïîäâèæíîñòè íîñèòåëåé çàðÿäà îò òåìïåðàòóðû èçîòåðìè÷åñêîãî îòæèãà â ÍËÊ (ïîñëå òåìïåðàòóðû îòæèãà Òîòæ. = 1270 Ê, t = 30 ìèí) ïðè ðàçëè÷íîì ôëþåíñå òåïëîâûõ íåéòðîíîâ (ñì-2): 1- 1019; 2- 1018; 3- 1017.

Ðèñ.2. Çàâèñèìîñòü âðåìåíè æèçíè íîñèòåëåé çàðÿäà â ÍËÊ (èñõîäíûé ÊÄÁ-1) îò äëèòåëüíîñòè îòæèãà, ïðè òåìïåðàòóðå ∼1270 Ê.

Íà îñíîâå ïîëó÷åííûõ ðåçóëüòàòîâ (òàá.) ïîêàçàíà âîçìîæíîñòü ïîëó÷åíèÿ òåðìîñòàáèëüíîãî âûñîêîîìíîãî ìàòåðèàëà ÍËÊ, êîòîðûé ìîæåò èñïîëüçîâàòüñÿ äëÿ ñîçäàíèÿ ïîëóïðîâîäíèêîâûõ ïðèáîðîâ ðàáîòàþùèõ äî ÷àñòîòû ∼1 ÌÃö. Çàêëþ÷åíèå Íà îñíîâå ïîëó÷åííûõ ýêñïåðèìåíòàëüíûõ ðåçóëüòàòîâ ìîæíî ñäåëàòü ñëåäóþùèå âûâîäû: Ñ ðîñòîì âðåìåíè èçîòåðìè÷åñêîãî îòæèãà ïîäâèæíîñòü íîñèòåëåé çàðÿäà (μ) ðàñòåò è, ÷åì áîëüøå êîíöåíòðàöèÿ ôîñôîðà, òåì áîëüøå ñìåøàåòñÿ íîìèíàëüíîå çíà÷åíèå m â ñòîðîíó áîëüøåãî âðåìåíè îòæèãà, ÷òî ñâÿçàíî ñ íåïîëíûì îòæèãîì ñòðóêòóðíûõ äåôåêòîâ (â äàííîì ñëó÷àå, îáëàñòü ðàçóïîðÿäî÷åíèÿ).  êîìïåíñèðîâàííîì p-Si<B,P> è êîíòðîëüíîì pSi<B> ðåëàêñàöèîííûé ïðîöåññ ïðîèñõîäèò ðàçëè÷íûì îáðàçîì: τ ≈ 98 ñ äëÿ ð-Si<B,P>, è τ ≈ 5 ñ äëÿ ð-Si<B>. Ïðè ýòîì ñ ðîñòîì èñõîäíîé êîíöåíòðàöèè íîñèòåëåé çàðÿäà (â äàííîì ñëó÷àå áîðà-Â) â êîìïåíñèðîâàííîì êðåìíèè íàáëþäàåòñÿ âîçðàñòàíèå t (ïðè ðàâíûõ çíà÷åíèÿõ ρ), êîòîðîå îáóñëîâëåíî ðàçëè÷íîé ñòåïåíüþ ìèêðîíåîäíîðîäíîñòè ïî ïðîâîäèìîñòè â èññëåäîâàííûõ îáðàçöàõ. Òåðìîñòàáèëèçàöèÿ âðåìåíè æèçíè íîñèòåëåé çàðÿäà â ÍËÊ çàâèñèò îò èñõîäíîé êîíöåíòðàöèè áîðà, ò.å. ÷åì áîëüøå èñõîäíàÿ êîíöåíòðàöèÿ áîðà, òåì áîëüøå äëèòåëüíîñòü òåðìî-îòæèãà.

92 Ëèòåðàòþðà: 1. Â.Â. Áîëîòîâ, À.Â.Âàñèëüåâ, À.Â.Äâóðå÷åíñêèé è äð. Îïðîñû ðàäèàöèîííîé òåõíîëîãèè ïîëóïðîâîäíèêîâ, Íîâîñèáèðñê: Íàóêà, 1980, 296 ñ.

2. Ïàãàâà Ò.À.: ÔÒÏ,. ò. 38, N 6 (2004), 665-669.

3. Êàðèìîâ Ì., Çàéíàáèäèíîâ Ñ., Êóðáàíîâ À.Î., Êàðàõîäæàåâ À.Ê.: Èçâåñòèÿ âóçîâ, Ôèçèêà, N 2 (2006), 57-61 4. Ôèñòóëü Â.È. Ââåäåíèå â ôèçèêó ïîëóïðîâîäíèêîâ. - Ì.: Âûñøàÿ øêîëà, 1984, 352 ñ.

Ðàáîòà âûïîëíåíà â ðàìêàõ ãðàíòà Ô2-ÔÀ-Ô121 Êîìèòåòà ïî êîîðäèíàöèè è ðàçâèòèÿ íàóêè è òåõíîëîãèé ïðè Êàáèíåòå Ìèíèñòðîâ ÐÓç. Èíñòèòóò ÿäåðíîé ôèçèêè ÀÍ Ðåñïóáëèêè Óçáåêèñòàí, ã. Òàøêåíò E-mail: natur@inp.uz Ìàõìóäîâ Øåðçîä Àõìàäîâè÷, ê.ô.-ì.í.,, çàâ. ëàá. ðàäèàöèîííîé ôèçèêè ïîëóïðîâîäíèêîâ ÈßÔ ÀÍ ÐÓç; Ìàõêàìîâ Øåðìàõìàò, ê.ô.-ì.í., çàâ. ëàá. ôèçèêè è òåõíèêè ïîëóïðîâîäíèêîâîé ýëåêòðîíèêè ÈßÔ ÀÍ ÐÓç; Áåãìàòîâ Êîáèë Àäèëîâè÷, ìë.íàó÷.ñîòð. ëàá. ôèç. è òåõ. ïîëóïðîâîäíèêîâîé ýëåêòðîíèêè ÈßÔ ÀÍ ÐÓç; Ñóëàéìàíîâ Àáäóðàõìîí Àáäóðàøèäîâè÷, âåä. èíæåíåð ëàá. ðàäèàöèîííîé ôèçèêè ïîëóïðîâîäíèêîâ ÈßÔ ÀÍ ÐÓç; Ðàôèêîâ Àâàç Êàðèìæîíîâè÷, âåä. èíæåíåð ëàá. ðàäèàöèîííîé ôèçèêè ïîëóïðîâîäíèêîâ ÈßÔ ÀÍ ÐÓç; Ýðãàøåâ Õàìèä Àáäóëëàåâè÷, ìë.íàó÷.ñîòð. ëàá. ðàäèàöèîííîé ôèçèêè ïîëóïðîâîäíèêîâ ÈßÔ ÀÍ ÐÓç.

Influence of Boron concentration on charge carriers lifetime in neutrondoped Silicon Sh. Makhmudov, Sh. Makhkamov, A. Sulaimanov, R. Rafikov, K. Bakmatov, Kh. Ergashev Institute of Nuclear Physics of Uzbekistan Academy of Science , settl.Ulugbek, 100214, Tashkent, Uzbekistan E-mail: rafikov@inp.uz In the presented work by the measurements of the electro physical parameters and by the method of the damping of photoconductivity influence of the high temperature treatment on the recombination properties of the neutron – doped silicon (NDS) in the dependence of the boron concentrations was studied.

It was shown, that at the increase of initial concentration of the charge carriers (in the given case boron -B) in the compencate silicon increase of the τ was observed, which is induced by the formation of micro in homogeneities in the NDS volume, differenced by the conductivity and degree of compensation.

It was established, that thermal stability of life time of the charge carriers in NDS depends from the initial concentration of boron.

Increase of initial concentration of boron leads to the displacement of the thermo anneal duration into the field of larger time.

Obtained results showed more wide technical abilities at the obtaining more uniform thermo stable high ohm monocrystals NDS.

boris koncentraciis gavlena muxtis matareblebis sicocxlis xangrZlivobaze neitronulad - legir ebul legirebul siliciumSi S. maxmudovi, S. maxkamovi, a. sulaimanovi, r. rafikovi, k. bakmatovi, x. ergaSevi

uzbekeTis mecnierebaTa akademiis birTvuli fizikis instituti, ulugbekis das., 100214, taSkenti, uzbekeTi el–fosta: rafikov@inp.uz naSromSi eleqtrofizikuri parametrebis gazomvisa da fotogamtarobis milevis meTodebiT gamokvleulia boris sxvadasxva Semcvelobis neitronebiT legirebuli siliciumis rekombinaciul Tvisebebze maRaltemperaturuli Termuli damuSavebis gavlena. naCvenebia τ-s amaRleba kompensirebul siliciumSi muxtis matareblebis sawyisi koncentraciis (B) amaRlebis pirobebSi, romelic ganpirobebulia araerTgvarovani mikro areebis formirebiT nimuSis moculobaSi, isini erTmaneTisgan gansxvavebulia gamtarobiTa da kompensaciis xarisxiT. dadgenilia, rom muxtis matareblebis sicocxlis xangrZlivobis Termuli stabiluroba neitronebiT legirebul siliciumSi damokidebulia boris sawyis koncentraciaze. boris sawyisi koncentraciis gazrda iwvevs Termuli mowvis xangrZlivobis amaRlebas. kvlevis Sedegebma gamoavlines Termulad mdgradi maRalomiani neitronebiT legirebuli monokristaluri siliciumis miRebis farTo teqnikuri SesaZleblobebi.

93

Îñàæäåíèå ïîðèñòûõ ïëåíîê äèîêñèäà êðåìíèÿ çîëü-ãåëü ìåòîäîì Ò. Ïàâëèàøâèëè1, À. Òóòóíäæÿí1, Ã. Öåðöâàäçå2 Èíñòèòóò ìèêðî-è íàíîýëåêòðîíèêè. Ïðîñïåêò È. ×àâ÷àâàäçå 13, 0179 Òáèëèñè, Ãðóçèÿ Ãðóçèíñêèé òåõíè÷åñêèé óíèâåðñèòåò. Ïðîñïåêò Ì. Êîñòàâà 77, 0175 Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà: pavliashvilitamaz@yahoo.com

1 2

Ðåçþìå. Èññëåäóåòñÿ ïîëó÷åíèå ïîðèñòûõ ïëåíîê äèîêñèäà êðåìíèÿ ïî çîëü-ãåëü òåõíîëîãèè. Èñõîäíûìè ðåàãåíòàìè ÿâëÿþòñÿ: òåòðàýòîêñèñèëàí, ýòèëîâûé è áóòèëîâûé ñïèðòû.  êà÷åñòâå êàòàëèçàòîðà ïðîöåññà ãèäðîëèçà áûëà âûáðàíà ñîëÿíàÿ êèñëîòà. Èçó÷åíèå ïîðèñòîñòè ïîëó÷åííûõ ïëåíîê ïðîâîäèëîñü ìåòîäàìè ýëåêòðîíîãðàôèè, îïòè÷åñêîé è òðàíñìèññèîííîé ýëåêòðîííîé ìèêðîñêîïèè.

Êëþ÷åâûå ñëîâà:ýòèëîâûå è áóòèëîâûå ñïèðòû, ïîðèñòûå äèýëåêòðè÷åñêèå ïëåíêè, çîëü-ãåëü òåõíîëîãèÿ, òåòðàýòîêñèñèëàí.

Ââåäåíèå

 ïîñëåäíèå ãîäû çíà÷èòåëüíî âîçðàñëà ðîëü ìåòîäîâ çîëü-ãåëü òåõíîëîãèè äëÿ ðàçðàáîòêè íîâûõ ìàòåðèàëîâ è ñîçäàíèÿ óñòðîéñòâ íîâîãî ïîêîëåíèÿ. Çîëü-ãåëü òåõíîëîãèÿ íàíîêîìïîçèòîâ îáëàäàåò áîëüøèìè ïîòåíöèàëüíûìè âîçìîæíîñòÿìè äëÿ ñîçäàíèÿ ìàòåðèàëîâåä÷åñêîé áàçû íîâûõ íàó÷íî-òåõíè÷åñêèõ íàïðàâëåíèé: âîäîðîäíîé ýíåðãåòèêè, ôîòîíèêè, íàíîýëåêòðîíèêè, ìèêðî è íàíîñèñòåìíîé òåõíèêè [1]. Ýòîò ìåòîä ïîçâîëÿåò ïðîâîäèòü ñèíòåç ãèáðèäíûõ îðãàíî-íåîðãàíè÷åñêèõ ïëåíîê, ìàãíèòíûõ íàíîêîìïîçèòîâ è íîâûõ íàíîñòðóêòóðèðîâàííûõ ìàòåðèàëîâ ñ óíèêàëüíèìè ñâîéñòâàìè. Ïîðèñòûå ìàòåðèàëû õàðàêòåðèçóþòñÿ òâåðäîé îñíîâîé ñ íåïðåðûâíîé ñèñòåìîé ïîð. Ñóøåñòâóåò ìíîãî òèïîâ ïîðèñòûõ ñèñòåì.  íàñòîÿùåå âðåìÿ ìåæäóíàðîäíûì ñîþçîì ïî òåîðåòè÷åñêîé è ïðèêëàäíîé õèìèè (IUPAC) îôèöèàëüíî ïðèíÿòà êëàññèôèêàöèÿ ïîð ïî ðàçìåðàì. Ñîãëàñíî ñ ýòîé êëàññèôèêàöèåé ïîðû äåëÿòñÿ íà ìèêðîïîðû (<2íì), ìåçîïîðû (2-50íì) è ìàêðîïîðû (>50íì)[2]. Ïîðà, êàê ëîêàëüíàÿ îáúåìíàÿ íåñïëîøíîñòü èëè ôàçà ïóñòîòû â îáúåìå òâåðäîãî òåëà è, â ÷àñòíîñòè, ïëåíêàõ, õàðàêòåðèçóåòñÿ îïðåäåëåííîé ôîðìîé è ðàçìåðàìè.  ðåàëüíûõ îñàæäåííûõ ïëåíêàõ ñîäåðæèòñÿ ñîâîêóïíîñòü íåèäåíòè÷íûõ ïî ôîðìå è ðàçìåðàì ïîð. Ñëåäóåò îòìåòèòü ÷òî ïîðû ðàçëè÷íîé äèñïåðñíîñòè ïîðàçíîìó âëèÿþò íà ñâîéñòâà ìàòåðèàëîâ, à òàêæå íà ïðîòåêàíèå òåõ èëè èíûõ ôèçèêî-õèìè÷åñêèõ ïðîöåññîâ. Åñòåñòâåííî, ÷òî â êà÷åñòâå íàíîðåàêòîðîâ áîëüøå ïîäõîäÿò ìèêðî è ìåçîïîðèñòûå ìàòåðèàëû. Ìåçîïîðèñòûå ìàòåðèàëû èëè, íàçûâàåìûå èíà÷å, ìåëåêóëÿðíûå ñèòà ïðîÿâèëè ñåáÿ êàê ýôôåêòèâíûå àäñîðáåíòû è êàòàëèçàòîðû. Ìîëåêóëÿðíûå ñèòà õàðàêòåðèçóþòñÿ ðàçìåðîì ïîð îò 1,5 äî 40íì, è îíè ÿâëÿþòñÿ èäåàëüíûìè ìàòðèöàìè äëÿ ïîëó÷åíèÿ íàíîìàòåðèàëîâ. Îñíîâîé ìîëåêóëÿðíûõ ñèò ÿâëÿåòñÿ äèîêñèä êðåìíèÿ[3].

Ìàòåðèàëû è ìåòîäû

 íàñòîÿùåå âðåìÿ äëÿ ïîëó÷åíèÿ ïëåíîê èç ðàñòâîðîâ äëÿ ìèêðî– è íàíîýëåêòðîíèêè îñíîâíûì èñõîäíûì

ðåàãåíòîì ÿâëÿåòñÿ òåòðàýòîêñèñèëàí (TÝÎÑ) Si(ÎÑ2Í5)4.Ýòîò ðåàãåíò ìàëîòîêñè÷åíè ãèäðîëèçóåòñÿ ñ ìåíüøåé ñêîðîñòüþ, ÷òî ïîçâîëÿåò ïîëó÷àòü óñòîé÷èâûå âî âðåìåíè ïëåíêîîáðàçóþùèå çîëè.  âîäå ÒÝÎÑ íå ðàñòâîðÿåòñÿ, íî ìåäëåííî ãèäðîëèçóåòñÿ. Ïðèñóòñòâèå îðãàíè÷åñêîãî ðàñòâîðèòåëÿ îáëåã÷àåò ñìåøèâàíèå ÒÝÎÑ ñ âîäîé è ñîçäàåò ãîìîãåííóþ ñðåäó. Ãèäðîëèç ÒÝÎÑ ïðîòåêàåò î÷åíü ìåäëåííî, ïîýòîìó ââîäÿò êàòàëèçàòîðû. Îáû÷íî â êà÷åñòâå êàòàëèçàòîðà èñïîëüçóþò ñîëÿíóþ, àçîòíóþ êèñëîòû èëè ðàñòâîð àììèàêà. Ïðè îñàæäåíèè ïëåíîê èç çîëåé ðåàêöèè ãèäðîëèçà è ïîëèêîíäåíñàöèè ÿâëÿþòñÿ îñíîâíûìè. Ýòè ðåàêöèè ïðîèñõîäÿò îäíîâðåìåííî, à õàðàêòåð èõ ïðîòåêàíèÿ çàâèñèò îò ðÿäà õèìè÷åñêèõ è òåõíîëîãè÷åñêèõ ôàêòîðîâ:- ïðèðîäû è êîëè÷åñòâà èñõîäíîãî ñîåäèíåíèÿ, -êîëè÷åñòâà âîäû, -êîëè÷åñòà ðàñòâîðèòåëÿ, -êèñëîòíîñòè ñðåäû, -òåìïåðàòóðû ñèíòåçà, -ïðèåìîâ ãîìîãåíèçàöèè ïëåíêîîáðàçóþùåãî ðàñòâîðà. «Ñîçðåâàíèå» ðàñòâîðà ÒÝÎÑ (òî åñòü, êîãäà îí ïðèîáðåòàåò ïëåíêîîáðàçóþùèå ñâîéñòâà) ïðîòåêàåò â òðè ñòàäèè: -ñîëüâîëèç èëè îáðàçîâàíèå ïðîìåæóòî÷íûõ ïðîäóêòîâ âçàèìîäåèñòâèÿ ñ ìîëåêóëàìè ðàñòâîðèòåëÿ èêàòàëèçàòîðà; -÷àñòè÷íûé ãèäðîëèç; -êîíäåíñàöèÿ ïðîäóêòîâ ãèäðîëèçà. Èç èçâåñòíûõ ìåòîäîâ íàíåñåíèÿ ïîêðûòèé èç ðàñòâîðîâ â ìèêðîýëåêòðîííîé òåõíîëîãèè íàèáîëüøóþ ðàñïðàñòðàíåííîñòü ïîëó÷èë ìåòîä öåíãðèôóãèðîâàíèÿ. Íà òîëùèíó è ðàâíîìåðíîñòü îñàæäåííûõ ñëîåâ âëèÿþò òàêèå ôàêòîðû êàê ñêîðîñòü âðàùåíèÿ öåíòðèôóãè, òåìïåðàòóðà è âëàæíîñòü îêðóæàþùåé ñðåäû, âÿçêîñòü è äð. Çàêëþ÷èòåëüíîé òåõíîëîãè÷åñîé îïåðàöèåé ÿâëÿåòñÿ òåðìîîòæèã ïëåíîê. Îñíîâíûìè ôàêòîðàìè, îïðåäåëÿþùèìè ðåæèì òåðìîîòæèãà ÿâëÿþòñÿ òåìïåðàòóðà, äëèòåëüíîñòü òåðìîîáðàáîòêè è ãàçîâàÿ ñðåäà. Òåðìîîòæèã ïðèâîäèò ê çàâåðøåíèþ ðåàêöèè ðàçëîæåíèÿ ïðîìåæóòî÷íûõ ïðîäóêòîâ ãèäðîëèçà è ê ïîëíîìó óäàëåíèþ ðàñòâîðèòåëÿ è ïðîìåæóòî÷íûõ ïðîäóêòîâ ãèäðîëèçà. Îñàæäåííûå ïëåíêè áûëè ðàâíîìåðíûå ïî òîëùèíå. Ïîðèñòîñòü ïëåíîê îöåíèâàëàñü òðåìÿ ìåòîäàìè:

94 ýëåêòðîãðàôè÷åñêèì, îïòè÷åñêîé òåìíîïîëíîé ìèêðîñêîïèåé è ïðîñâå÷èâàþùèì ýëåêòðîííîé ìèêðîñêîïèåé. Ñóòü ýëåêòðîãðàôè÷åñêîãî ìåòîäà ñîñòîèò â òîì, ÷òî, ýëåêòðè÷åñêèé òîê ïðîõîäÿ ÷åðåç ïîìåùåííóþ â âîäíóþ ñðåäó ôîòîáóìàãó, âîçäåéñòâóåò íà ýìóëüñèþ è âûçûâàåò åå ïî÷åðíåíèå â ìåñòàõ ìàêðîïîð. Âîññòàíîâëåíèå èîíîâ ñåðåáðà íà ãðàíèöå ðàçäåëà ýìóëüñèÿ-êàòîä âáëèçè ìàêðîïîðû ïëåíêè çàâèñèò îò ïëîøàäè êàòîäà, êîëè÷åñòâà ðàñòâîðåííîãî ñåðåáðà, ïîäâèæíîñòè èîíîâ è ïîòåíöèàëà ýëåêòðîäà. Ñòåïåíü ëîêàëüíîãî ïî÷åðíåíèÿ ýìóëüñèè ôîòîáóìàãè ïðîïîðöèîíàëüíàÿ êîëè÷åñòâó âîññòàíîâëåííîãî ñåðåáðà, õàðàêòåðèçóåòñÿ ïàðàìåòðàìè ýëåêòðîëèòè÷åñêîãî ïðîöåññà: ïëîòíîñòè òîêà è âðåìåíè åãî ïðîïóñêàíèÿ. Ïëîòíîñòü òîêà ìîæåò áûòü ñêîìïåíñèðîâàíà óâåëè÷åíèåì âðåìåíè ýêñïîçèöèè. Ñëåäîâàòåëüíî, èçîáðàæåíèå ìàêðîïîðû íà ôîòîáóìàãå ìîæåò çíà÷èòåëüíî ïðåâûøàòü åãî ðåàëüíûå ðàçìåðû. Ïîýòîìó, ìåòîäîì ýëåêòðîãðàôèè ìîæíî îïðåäåëèòü ñðåäíóþ ïëîòíîñòü ìàêðîïîð è èõ ðàñïðåäåëåíèå ïî ïîäëîæêå, îäíàêî îí íå ïîçâîëÿåò îïðåäåëÿòü àáñîëþòíûå ðàçìåðû ìàêðîïîð. Ïðè èçìåðåíèè ïëîòíîñòè ìàêðîïîð áûëà èñïîëüçîâàíà êîíòðàñòíàÿ ãëÿíöåâàÿ ôîòîáóìàãà, êîòîðàÿ ñìà÷èâàëàñü â äèñòèëèðîâàííîé â âîäå.  çàâèñèìîñòè îò òîëùèíû ïëåíêè äèîêñèäà êðåìíèÿ, ìåæäó ýëåêòðîäàìè ïðèêëàäèâàëîñü íàïðÿæåíèå 25-70Â. Âðåìÿ ýêñïîçèöèè îïðåäåëÿëîñü îïûòíûì ïóòåì è ñîñòàâëÿëà 30-60 ñåê.Äîñòîèíñòâîì ýòîãî ìåòîäà ÿâëÿåòñÿ åãî íåèíâàçèâíîñòü, íåäîðîãîñòîÿùèå ìàòåðèàëû è îáîðóäîâàíèå è ñðàâíèòåëüíàÿ ïðîñòîòà ýêñïåðèìåíòà. Ìèíèìàëüíûé ðàçìåð âûÿâëÿåìûõ ìàêðîïîð ýòèì ìåòîäîì, ñîñòîâëÿåò -0,1ìêì. Ìèêðîñêîïèÿ â òåìíîì ïîëå îñíîâàíà íà òîì, ÷òî ÷àñòèöû ëåæàùèå çà ïðåäåëàìè ðàçðåøàþùåé ñïîñîáíîñòè ìèêðîñêîïà, ñòàíîâÿòñÿ âèäèìûìè â ëó÷àõ, èäóùèõ ïîä òàêèì áîëüøèì óãëîì, ÷òî â îáúåêòèâ íå ïîïàäàþò.  îáúåêòèâ ïîïàäàåò òîëüêî ñâåò, îòðàæåííûé îò ýòèõ ÷àñòèö. Îñîáåííîñòüþ òåìíîïîëüíîé ìèêðîñêîïèè ÿâëÿåòñÿ ñïîñîá îñâåùåíèÿ îáðàçöà, êîòîðûé îñóùåñòâëÿåòñÿ «ñáîêó». Ìåòîä òåìíîïîëüíîé ìèêðîñêîïèè ñ óñïåõîì ïðèìåíÿåòñÿ äëÿ àíàëèçà áèîëîãè÷åñêèõ îáúåêòîâ, à òàêæå øèðîêî èñïîëüçóåòñÿ ïðè èçó÷åíèè äåôåêòíîñòè ïëåíîê. Îñíîâíûì îãðàíè÷èâàþùèì ôàêòîðîì ýòîãî ìåòîäà ÿâëÿåòñÿ òî, ÷òî òîëüêî ìàëàÿ ÷àñòü ïàäàþùåãî ñâåòà ôîðìèðóåò èçîáðàæåíèå, ïîýòîìó íåîáõîäèìî ïðèìåíÿòü äîñòàòî÷íî ìîùíûå èñòî÷íèêè ñâåòà, ÷òî èíîãäà ïðèâîäèò ê ïîâðåæäåíèþ îáðàçöà. Ñëåäóåò òàêæå îòìåòèòü , ÷òî èíòåðïðåòàöèþ òåìíîïîëüíûõ èçîáðàæåíèè ñëåäóåò ïðîâîäèòü êîððåêòíî è îñòîðîæíî, òàê êàê íåêîòîðûå äåòàëè , íå âèäíûå ìåòîäîì ñâåòëîãî ïîëÿ, âèäíû òåìíîïîëüíîé ìèêðîñêîïèåé è íàîáîðîò. Äëÿ îöåíêè ïîðèñòîñòè ïëåíîê äèîêñèäà êðåìíèÿ òåìíîïîëüíûì ìåòîäîì èñïîëüçîâàëñÿ ìèêðîñêîï LeitzERGOLUX c óâåëè÷åíèåì äî õ1250. Ìåòîä ïðîñâå÷èâàþùåé ýëåêòðîííîé ìèêðîñêîïèè (ÏÝÌ) ïðèìåíÿåòñÿ äëÿ èçó÷åíèè ñòðóêòóðû ìàòåðèàëà, êàê â îáúåìå îáðàçöà, òàê è â åãî ïðèïîâåðõíîñòíîé îáëàñòè. ÏÝÌ – îäèí èç íàèáîëåå âûñîêîèíôîðìàòèâíûõ

ìåòîäîâ èññëåäîâàíèÿ, èñïîëüçóåìûõ â ìàòåðèàëîâåäåíèè, ìèêðî- è íàíîòåõíîëîãèè è â äðóãèõ îáëàñòÿõ. ÏÝÌ ðàáîòàåò ïî ñõåìå ïðîõîäÿùèõ ýëåêòðîííûõ ëó÷åé. Èçîáðàæåíèå ôîðìèðóåòñÿ çà ñ÷åò ïðîõîæäåíèÿ ïó÷êà áûñòðûõ ýëåêòðîíîâ ÷åðåç àíàëèçèðóåìûé îáðàçåö. Ñèñòåìà ýëåêòðîìàãíèòíûõ ëèíç ðàçìåùåíà â êîëîííå ìèêðîñêîïà, â êîòîðîé â ïðîöåññå ðàáîòû ìèêðîñêîïà ïîääåðæèâàåòñÿ âàêóóì 10-2 -10-3 Ïà[4]. Äëÿ èçó÷åíèÿ ñòðóêòóðû ïëåíîê äèîêñèäà êðåìíèÿ áûë èñïîëüçîâàí ìèêðîñêîï Jem 100-Sx. Ïðèãîòîâëåíèå îáðàçöîâ äëÿ ÏÝÌ ïðîâîäèëîñü ñëåäóþùèì îáðàçîì: îäíà êàïëÿ «ñîçðåâøåãî» çîëÿ íàíîñèëàñü íà ñïåöèàëüíóþ ìåäíóþ ñåòêó è ñóøèëàñü â òåðìîñòàòå ïðè òàêèõ æå òåìïåðàòóðíî-âðåìåííûõ ðåæèìàõ, â êàêèõ ïðîâîäèëñÿ òåðìîîòæèã ïëåíîê äèîêñèäà êðåìíèÿ.

Ðåçóëüòàòû

 ïðåäñòàâëåííîé ðàáîòå äëÿ ïîëó÷åíèÿ ïîðèñòûõ ïëåíîê äèîêñèäà êðåìíèÿ èñïîëüçîâàëñÿ ðàñòâîð ñëåäóþùåãî ñîñòàâà: òåòðàýòîêñèñèëàí-8ìë, ýòèëîâûé ñïèðò -16-20ìë, ñîëÿíàÿ êèñëîòà- 0,04 ìîëÿ HCl íà 1 ìîëü ÒÝÎÑ (îäíà êàïëÿ). Ñêîðîñòü âðàùåíèÿ öåíòðèôóãè áûëà 3000 îá/ìèí. Ïëåíêè îñàæäàëèñü íà êðåìíèåâûå ïîäëîæêè äûðî÷íîé ïðîâîäèìîñòè ìàðêè ÊÄÁ-10 äèàìåòðîì 60ìì, à òàêæå íà êðåìíèåâûõ ïëàñòèí äèàìåòðîì 40ìì è100ìì. Ïåðåä îñàæäåíèåì ïëåíîê ïîäëîæêè êðåìíèÿ ïîäâåðãàëèñü õèìè÷åñêîé îáðàáîòêå êèïÿ÷åíèåì â àöåòîíå è èçîïðîïèëîâîì ñïèðòå â òå÷åíèå 20 ìèíóò. Ïîñëå íàíåñåíèÿ ïëåíîê ïðîèçâîäèëàñü ñòóïåí÷àòàÿ òåðìè÷åñêàÿ îáðàáîòêà â òåðìîñòàòå ïðè 1300Ñ â òå÷åíèå 20 ìèíóò, ïðè 1900Ñ -30ìèíóò è 2900C20ìèíóò. Îêîí÷àòåëüíûé òåðìîîòæèã ïðîâîäèëñÿ â äèôôóçèîííîé ïå÷è ïðè òåìïåðàòóðå 4500Ñ,â àðãîííîé àòìîñôåðå â òå÷åíèè 1 ÷àñà. Îñàæäåííûå ïëåíêè áûëè ðàâíîìåðíûå ïî òîëùèíå. Îïûòíûì ïóòåì íàéäåíà îïòèìàëüíàÿ ñêîðîñòü âðàùåíèÿ öåíòðèôóãè (3000îá/ìèí) à òàêæå óñòàíîâëåíû ðåæèìû òåðìîîòæèãà ïîëó÷åííûõ ñëîåâ. Ïëîõàÿ ñìà÷èâàåìîñòü ïðè îñàæäåíèè ïëåíîê èç ðàñòâîðà ÒÝÎÑ ñ ýòàíîëîì áûëà óñòðàíåíà äîáàâëåíèåì â ðàñòâîð ìàëîãî êîëè÷åñòâà áóòèëîâîãî ñïèðòà. Ïîëó÷åíûå ïëåíêè äèîêñèäà êðåìíèÿ îáëàäàëè âîñïðîèçâîäèìîé ïîðèñòîé ñòðóêòóðîé.  ñèñòåìå ïîð ïðåîáëàäàëè ìåçà è ìèêðîïîðû, à äîëÿ ìàêðîïîð áûëà âåñüìà ìàëà(ðèñ.1)

Ðèñ.1. Òåìíîïîëüíàÿ ìèêðîôîòîãðàôèÿ ïëåíêè äèîêñèäà êðåìíèÿ (ìàñøòàá: 1äåë. = 1ìêì).

95 Ïðîñòîòà è äîñòóïíîñòü ìåòîäà, âîçìîæíîñòü åãî äàëüíåéøåãî óñîâåðøåíñòâîâàíèÿ äåëàåò åãî âåñüìà ïåðñïåêòèâíûì äëÿ ìèêðî–è íàíîýëåêòðîíèêè.

Ëèòåðàòóðà:

Ðèñ.2. Ìèêðîôîòîãðaôèÿ ïëåíêè äèîêñèäà êðåìíèÿ ñ ñèñòåìîé ìåçàïîð

Ñèñòåìà ïîð íå áûëà ðåãóëÿðíîé , îäíàêî ïîðû áûëè ðàñïðåäåëåíû ðàâíîìåðíî ïî âñåìó îáúåìó ïëåíêè (ðèñ2).

1. Ìàêñèìîâ À.È., ìîøíèêîâ Â.À., Òàèðîâ Þ.Ì., Øèëîâà Î.À. Îñíîâû çîëü-ãåëü òåõíîëîãèè íàíîêîìïîçèòîâ ÑàíêòÏåòåðáóðã Èçäàòåëüñòâî ÑÏÁÃÝÒÓ «ËÝÒÈ» 2007. 156ñ 2. Ïàëàòíèê Ë.Ñ., ×åðåìñêîé Ï.Ã., Ôóêñ Ì.ß. Ïîðû â ïëåíêàõ.Ì., Ýíåðãîèçäàò 1982. 216ñ 3. Ìèõàèëîâ Ì.Ä. Õèìè÷åñêèå ìåòîäû ïîëó÷åíèÿ íàíî÷àñòèö è íàíîìàòåðèàëîâ Ñàíêò –Ïåòåðáóðã Èçäàòåëüñòâî ïîëèòåõíè÷åñêîãî Óíèâåðñèòåòà 2012. 259ñ.

4. Ãàâðèëîâà Í.Í., Íàçàðîâ Â.Â., ßðîâàÿ Î.Â. Ìèêðîñêîïè÷åñêèå ìåòîäû îïðåäåëåíèÿ ðàçìåðîâ ÷àñòèö äèñïåðñíûõ ìàòåðèàëîâ Ìîñêâà., ÐÕÒÓ èì. Ìåíäåëååâà, 2012.52ñ.

Deposition of Porous Silicon Dioxide Films by Sol-Gel Method T. Pavliashvili1, A. Tutunjyan1, G. Tsertsvadze2 Institute of Micro- and Nanoelectronics, 13, Chavchavadze ave., 0179 Tbilisi, Georgia 2 Georian Technical University, 77, M.kostava ave.,0175 Tbilisi, Georgia E-mail:pavliashvilitamaz@yahoo.com

1

Formation of porous silicon dioxide films by sol- gel technologys using the centrifuging method is investigated. Initial reagents are tetraethoxysilane, ethyl alcohol, butyl alcohol and distilled water. The catalyst of the hydrolysis process is hydrochloric acid. The formed films are studied using electronography, optical and transmission electron microscopy.

Ðèñ.3. Ìèêðîôîòîãðàôèÿ öèëèíäðè÷åñêèõ ïîð âûÿâëåííûõ ñ ïîìîùüþ ÏÝÌ. ( x105000)

Èññëåäîâàíèÿ ñ ïîìîùúþ ïðîñâå÷èâàþùåãî ýëåêòðîííîãî ìèêðîñêîïà ïîêàçàëè, ÷òî ïîðû â îñíîâíîì èìåëè öèëèíäðè÷åñêóþ ôîðìó(ðèñ.3). Ðàçìåðû ïîð áûëè îò 5íì äî 70íì.

Çàêëþ÷åíèå  íàñòîÿùåå âðåìÿ çîëü-ãåëü òåõíîëîãèÿ ÿâëÿåòñÿ èíòåíñèâíî ðàçâåâàåìûì íàó÷íûì íàïðàâëåíèåì. Çîëüãåëü òåõíîëîãèÿ îáëàäàåò áîëüøèìè ïðèêëàäíûìè âîçìîæíîñòÿìè è èìååò øèðîêèé ñïåêòð ïðèìåíåíèé.  ðåçóëüòàòå ïðîâåäåííûõ èññëåäîâàíèé èç ðàñòâîðà íà îñíîâå òåòðàýòîêñèñèëàíà ïîëó÷åíû ìåçàïîðèñòûå ïëåíêè äèîêñèäà êðåìíèÿ ñ öèëèíäðè÷åñêèìè ïîðàìè. Ñôîðìèðîâàííûå ïëåíêè ìîæíî èñïîëüçîâàòü â êà÷åñòâå ìàòðèöû ïðè ñîçäàíèè ãàçîâûõ ñåíñîðîâ , ãèáðèäíûõ îðãàíî-íåîðãàíè÷åñêèõ ìàòåðèàëîâ è íîâûõ íàíîñòðóêòóðèðîâàííûõ ïëåíîê.

siliciumis dioqsidis forovani firebis dafena zol-gel– meTodiT T. pavliaSvili1, a. tutunjiani1, g. cercvaZe2 1

mikro da nano eleqtronikis instituti, i.

WavWavaZis gam. 13, 0179 Tbilisi, saqarTvelo 2 saqarTvelos teqnikuri universiteti, m. kostavas gam. 77, 0175 Tbilisi,saqarTvelo el-fosta: pavliashvilitamaz@yahoo.com siliciumis dioqsidis forovani afskebi formirebuli iyo zol–gel-meTodis gamoyenebiT, centrifugirebis saSualebiT. sawyis reagentebad gamoyenebuli iyo tetraetoqsisilani, eTilis spirti, buTilis spirti da agreTve distilirebuli wyali. hidrolizis procesis katalizatorad gamoiyeneboda marilmJava. miRebuli firebis kvlevisas gamoyenebuli iyo eleqtronografiuli, optikuri da transmisiuli eleqtronuli mikroskopia.

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Development of technology receiving thin dielectric layers for micro and nanoelectronics A. Bibilashvili, S. Sikharulidze, Z. Kushitashvili, L. Jangidze, L. Jibuti LEPL Micro and Nanoelectronics, Chavchavadze ave.13, 0179 Tbilisi, Georgia E-mail:amiran.bibilashvili@tsu.ge, zurab_kush@yahoo.com, ladojibuti@gmail.com Abstract. In this report is considered the low temperature technology - Catholytic Plasma Anodizing for receiving thin dielectric layers such as SiO2, Al2O3 and TiO2 oxides.. Given kinetic of formation dielectrics, main electro-physical parameters and the mechanism of catalytic plasma anodizing. Received parameters is used to suggest the rout of two gate field effect transistor technology and in this transistor as a gate dielectric is used the silicon dioxide dielectric layer received

by Catholytic plasma anodizing. There measured C-V characteristics oxides and some static parameters.

Key words: anodization, ion, catalytic, plasma

Introduction Progress in microelectronics and nanoelectronics has stimulated the design of fundamentally new methods for producing oxide films, as well as the further development of conventional methods. High-temperature treatment leads to the spread of diffusion regions, the diffusion of unwanted impurities, the generation of defects (dislocations, voids, cracks), the violation of the ratio between the components in binary semiconductor compounds, and so on. All these factors have a detrimental effect on the parameters if integrated circuits and the yield of devices. Taking into account the factors above, we have reason to believe that low-temperature methods are very promising. Despite this circumstance, the low-temperature process of plasma anodizing of metals and semiconductors has not found wide use for the formation of insulator layers owning to its low efficiency and the low growth rate the oxide [1].

In this paper, we report the results of studying the promotion of the plasma anodization of metals and semiconductors and suggest mechanisms for the methods of lowtemperature plasma anodization that increase the oxidation efficiency and the growth rate of the oxide. Stimulation is attended using a catalyst (a rare earth element) deposited on the surface of the material to be anodized [2-5].

We used the oxides of rare elements (REEs) as catalysts on the surface of Al, Ti and Si.

Experiment

.

In the experiment were used (100), 10 Ί cm, 2 inch, ntype and p-type silicon wafers as a substrate. Thin films of pure titanium (99.999%) and Al (99.999%) were deposited

by DC magnetron sputtering using 100 mm diameter and 6 mm thickness sputtering targets. High purity argon was used as the sputtering gas. Rotary and turbo pump combination was used to get the desired vacuum. The base pressure of the system was less than 10-6 torr. After attaining the base pressure the argon partial pressure was set using a needle valve. Before each run the target was pre sputtered for 5-10 min in order to remove the surface oxide layer

from the target. All the depositions were carried out at a total pressure of 1,3x10-3torr. The distance between the target and silicon substrates was kept at 45 mm and the substrate temperature was 473K. After deposition of metals, at a base pressure 10-6torr were deposited by e-beam technic 30nm thin layer of rare earth element â&#x20AC;&#x201C; Yttrium (Y), which has a catalytic properties in the metal oxidation processes [6]. The deposition was carried out at the same temperature 473K. After finishing all deposition processes the structure Si-Al-Y and Si-Ti-Y (Fig.1) was placed in plasma anodizing vacuum chamber to proceed the anodization.

Fig.1. Structures of Si â&#x20AC;&#x201C;Y, Si-Al-Y and Si-Ti-Y

After receiving high vacuum (10-6torr) by diffusion pump, in the chamber were entered Ar and O2 gases with ratio 2:8 respectively. Prior to the technological processes, the surface of the substrate was treated chemically using conventional methods.

The process of plasma anodizing of structures consisting of an REE and the material to be anodized were carried out in a DC source of oxygen-containing plasma. The plasma anodization was performed under galvanostatic conditions, i.e., at a constant current density of oxide forming.

The catalyst was removed chemically without damaging the Al2O3, TiO2 and SiO2 surfaces after completion of the catalytic plasma anodizing.

Metal-insulator-semiconductor structures were formed by deposition aluminum contacts. We studied electrical and other parameters by optical methods, Auger spectroscopy, high-frequency capacitor-voltage characteristics and roughness.

Results and Discussion Catalytic plasma anodizing was carried out in the galvanostatic mode. In this case anodization current density

97 was kept constant (I=const). During anodization increases oxide layer thickness, simultaneously increases the resistivity of oxide layer and applied voltage drops, it is necessary to increase applied voltage to keep anodization current constant. Growing oxide thickness is in linear dependence on applied voltage. Voltage drop shows increasing oxide thickness and during all experiment we can record the kinetic of voltage drop dependence on time V(t), which means dependence on oxide thickness (Fig.2).

For electrical parameters was measured capacitancevoltage characterization. Fig.3 and Fig.4 shows capacitance dependence on the applied voltage for SiO2, Al2O3 and TiO2 oxides.

Fig.3. On n-type silicon substrate SiO2-Al and Al2O3-Al structures normal capacitance-voltage characterization; (1) theoretical curve

Fig.4. On p-type silicon substrate TiO2-Al structures capacitance-voltage characterization; (2) theoretical curve

For surface analysis was measured surface roughness.

Fig.5 shows roughness of SiO2, Al2O3 and TiO2 oxides.

Table 1. Oxides electrophysical parameters # 1 2 3 4 5

Fig.2. Kinetic of growing oxide thicknesses of SiO2, Al2O3 and TiO2, (1) with catalyst, (2) without catalist

Parameter Thickness d (nm) Oxide charge, 1011Qss, cm-2 Roughness, Ra(Å) Dielectric constant ε Electrical breakdown, 106, v/cm

SiO2 39-43

Al2O3 42-55

TiO2 35-40

3 12 4,5 4

2 19 6.0 6

2 9 73,0 5

In table 1 is shown main electro-physical parameters of oxides received by catalytic plasma anodization SiO2 received by catalytic plasma anodization was used as a gate dielectric in the two gates field transistors. Fig.6 shows the rout of two gate field effect transistor technology.

98

Fig.5. Surface roughness of SiO2, Al2O3 and TiO2 oxides.

99

Fig.6. The rout of two gate field effect transistor technology; 1- substrate, 2- source, 3 and 4 â&#x20AC;&#x201C;gates, 5 - drain

They are governed by low voltage (~5v), in the open mode they have low resistance (~0,001ohm) and very low (ns) switching time. Two gates field transistor simplified high frequency amplifier circuits. Applied voltage on the gates can independency each to other change the transistor channel width and can regulate current passed in the transistor. It gives opportunity to expand functional abilities of transistors and their new design gave them preference comparing to other type transistors.

In developing a mechanism of catalytic plasma anodizing of metals and semiconductors, we should take into account the specific features that distinguish this process form other methods for obtaining oxides. These features are as follows: (I) the catalytic effect is not observed if anodization is performed in an electrolyte; (II) the catalytic effect is observed in the course of repeat anodization in plasma of structures that consist of a catalyst, the oxide, and the material to be anodized and were preliminary grown in an electrolyte or plasma; (III) the region of the negative space charge in plasma at the sample surface is not observed experimentally in catalytic plasma anodization; (IV) a metal whose oxide is the catalyst has unoccupied d or f orbitals; (V) the catalyst has superionic conduction of oxygen and a low electron conductivity (i.e., the catalyst is a solid electrolyte); (VI) the self-diffusion coefficient of oxygen is larger than that of the metal [7]; (VII) the electronegativity of the material to be anodized is higher than that of the metal whose oxide serves as the catalyst; and (VIII) an unusually high oxidation rate for a metal whose oxide is used as the catalyst.

We used the facts above to suggest a mechanism of catalytic plasma anodizing. We used an Y (Yttrium) catalyst in the anodization of silicon as an example. In the initial stage of the process, the primary Y oxide film is obtained owing to chemisorption of oxygen, since Y has a high adsorptivity and the process has a very high rate [8]. A farther increase in the thickness of the Y oxide occurs owing to the diffusion and drift of oxygen atoms through the oxide film. This process also has a high rate since the diffusion coefficient of oxygen in Y2O3 is very large [9].

Since the electronegativity of oxygen is higher than that of Y [10], oxygen carries a negative effective charge and its motion is accelerated by an applied external electric field. In addition, the presence of the catalyst oxide above the silicon surface increases the surface density of oxygen by many orders of magnitude. As the electronegativity of Si is higher than that of Y, silicon atoms attract oxygen atoms from Y2O3 and react with them to form the SiO2 oxide.

The applied film is conductive to the formation of a new molecule that consists of an O atom and a Si atom, which ensures the growth of oxides. The oxygen vacancies at the catalyst surface are easily filled with oxygen atoms form the plasma.

When a voltage that is positive relative to the plasma is applied to the sample, the mutual migration of cations of the anodized material and oxygen anions from the plasma occurs, and the oxide of the anodized material is formed as a result of a chemical reaction. Electrons also enter Y2O3 if an external field is applied. These injected electrons are antibonding quasiparticles and they weaken the chemical bond between O and Y. However, it is well known that Y atoms have unoccupied d orbitals; as a result, electrons in the conduction band (an antibonding band) have a very large effective mass [11] and do not play a significant role in the electrical conductivity. Therefore, the forming current for SiO2 under the catalyst consists predominantly of the ionic component. Cations do not migrate to the Y2O3 â&#x20AC;&#x201C; plasma interface since their coefficient of self-diffusion in Y2O3 is much smaller than that for oxygen [9]. This means that the ionic-transport number a=1 in the case under consideration; i.e., the catalyst is a solid electrolyte and its oxide exhibits anionic mobility.

Thus, the Y layer oxidizes very rapidly, holds electrons within its volume, transfers oxygen to Si, and easily takes oxygen again from the plasma.Yttrium is an effective source of oxygen ions for Si; i.e., it acts as the catalyst for the SiO2 compound.

It is well known that the presence of a catalyst stimulates the appearance of intermediate complexes with an activation energy that is lower than that of complexes formed without a catalyst. Some of the ions whose energy is insufficient for overcoming the barrier are accumulated in the plasma near the sample [12]. These ions are inactive in the absence of a catalyst and become active if there is a catalyst. In the case, the space charge in the plasma is not observed, and, consequently, the reaction rate increase.

Catalytic plasma anodizing develops owing to a reduction in the activation energy for oxidation of the material.

In general, this reduction is caused by the formation of new intermediate complexes (Y-O complexes in the case under consideration), which changes the shape and lowers the height of the potential barrier (Fig.7).

As a result, the reaction can proceed via a new channel that involves a barrier with a lower height.

Thus, unlike the widely accepted concepts that electrons hinder plasma anodization, in the catalytic plasma anodization electrons play a decisive role by weakening

100 the chemical bonding of the metal to oxygen. Further more, electrons are held in the catalyst, are hardly involved in the forming current, and thus increase the ionic component of this current. This circumstance can be explained by the fact that there is no catalytic effect in an electrolyte where are no electrons.

5. A.P. Bibilashvili, Fiz. Khim. Obrab. Meter., No. 5, 40 (2001) 6. S. Gourrier, A Mircca, and M. Bacal, thin solid Films 65, 315 (1980) 7. V.N. Chebotin ,,Phys.Chim. Solids’’ M., ,,Khim’’, 1982, 320pp 8. K.N.R. taylor and M.I. Darby, Physics of Rare Earth Solids (Chapman and Hall, London, 1972; Mir. Moscow, 1978) 9. V.I. Fistul’, Physics and chemistry of Solids (Metalurgiya, Moscow, 1995), Vol.2 10. L. Pauling and P. Pauling, Chemistry (Freeman, San Francisco, 1975; Mir, Moscow, 1978) 11. A.N. Kocharian and D.I. Khomskii, Zh. Vses. Khim.)=v aim.

D.I. mendeleeva 26. 39 (1981) 12. J.F. O’Hanlon and W.B. Pennebakei, Appl. Phys. Let 18, 554 (1971)

Txeli dieleqtrikuli firebis damzadebis teqnologiis damuSaveba mikro- da nanoeleqtronikisaTvis Fig.7 .Potential barrier of oxygen atoms in the anodization process with catalyst (II) and without catalyst

Conclusion We have studied catalytic plasma anodization to receive thin oxide layers SiO2, Al2O3 and TiO2. Was calculated main electro-physical parameters and was shown that we can use oxides received by this technology in the two gates field transistors.

In order to carry out the process of catalytic plasma anodization, the following conditions are necessary: electrons should be injected into the material to be anodized (electrons are antibonding particles and, as such, weaken the chemical bonds and facilitate the motion of atoms), the material used as the catalyst must have unoccupied d and f orbitals, and the electronegativity of the material to be anodized must exceed that of the material used as the catalyst.

Acknowledgment The authors would like to thank Shota Rustaveli National Science Foundation, Tbilisi, Georgia for founding the project (¹ AR/64/3-250/13/48), this research and for supporting all measurement which is given in this article.

References 1. V.P. Parthutik and V.A.Labunov, Plasma Anodization: Physics, Technology and Application in Microelectronics (Naika I Tekhnika, Minsk,1990), p.276 2. A.P. Bibilashvili, A.B. Gerasimov, and G.B. chakhunashvili, Invemtor’s Certificate No. 551, 972 (1976) 3. S.V. Baras’ev, A.P. Bibilashvili, and A.B. Gerasimov, Invemtor’s Certificate No. 1017124 (1983) 4. A.P. Bibilashvili, M.T. Vepkhvadze, A.B. Gerasimov, et al, Pis’ma Zh. Tekh. Fiz.25 (15), 5 (1999) [tech. Phys. Lett.25, 593 (1999)

a. bibilaSvili, s. sixaruliZe, z. yuSitaSvili, l. jangiZe, l. jibuti

mikro da nanoeleqtronikis instituti, WavWavaZis gamz., 13, 0179, Tbilisi, saqarTvelo el–fosta: amiran.bibilashvili@tsu.ge, zurab_kush@yahoo.com, ladojibuti@gmail.com mocemul naSromSi ganxilulia dabaltemperaturuli teqnologia – katalizuri plazmuri anodireba. es teqnologia saSualebas gvaZlevs miviRoT Txeli oqsiduri firebi, rogorebicaa SiO2, Al2O3 da TiO2. mocemulia am oqsidebis zrdis kinetika, ZiriTadi eleqtro–fizikuri parametrebi da katalizuri plazmuri anodirebis meqanizmi. miRebuli parametrebi gamoyenebulia orCamketiani velis tranzistoris teqnologiuri marSutis SemuSavebisTvis. aseT tranzistorSi CamketqveSa dieleqtrikad gamoyenebulia swored plazmuri anodirebiT miRebuli siliciumis dioqsidi. miRebul oqsidebze gazomili iqna volt–faraduli maxasiaTebeli da sxva statikuri parametrebi.

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Èññëåäîâàíèå ìåõàíè÷åñêèõ ñâîéñòâ ìîíîêðèñòàëëè÷åñêèõ ñïëàâîâ ≤0,02) Si1-õGeõ(õ≤ À. Â. Ñè÷èíàâà, Þ. È. Íàðäàÿ, Í. Ã. Ãàïèøâèëè, Ã. Àð÷óàäçå, Ö. Ì. Íåáèåðèäçå, Î.Â. Êàøèÿ Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà, óë.Ìèíäåëè 7, 0186, Òáèëèñè, Ãðóçèÿ. Ýë–ïî÷òà: sipt@sipt.org Ðåçþìå. Èññëåäîâàíî âëèÿíèå ïðîöåíòíîãî ñîäåðæàíèÿ Ge è èìïëàíòàöèè èîíàìè Ar íà ìèêðîòâåðäîñòü è ìîäóëü óïðóãîñòè ñïëàâîâ Si-Ge. Íà çàâèñèìîñòÿõ ìåõàíè÷åñêèõ õàðàêòåðèñòèê îò ãëóáèíû èíäåíòèðîâàíèÿ âûÿâëåí ò.í. îáðàòíûé «Ðàçìåðíûé ýôôåêò». Ïîêàçàíî óìåíüøåíèå ìèêðîòâåðäîñòè è ìîäóëÿ óïðóãîñòè ñ óâåëè÷åíèåì êîíöåíòðàöèè ãåðìàíèÿ â èññëåäîâàííûõ ñïëàâàõ Si-Ge. Âûÿâëåíî ïîíèæåíèå ìåõàíè÷åñêèõ õàðàêòåðèñòèê ïðè âîçðàñòàíèè ôëþåíñîâ èîíîâ Ar îò 6X1011 ñì-2 äî 5X1012 ñì-2. Äàëüíåéøåå óâåëè÷åíèå ôëþåíñà èîíîâ Ar äî 2,5X1014 ñì-2 âåäåò ê ðîñòó ìåõàíè÷åñêèõ õàðàêòåðèñòèê îáðàçöîâ. Íåçàâèñèìî îò ôëþåíñà èîíîâ Ar, èìïóëüñíûé ôîòîííûé îòæèã â îáëàñòè âûñîêèõ òåìïåðàòóð òàêæå âûçûâàåò óïðî÷íåíèå îáðàçöîâ, âñëåäñòâèå îòæèãà ðàäèàöèîííûõ äåôåêòîâ è óñèëåíèÿ òîðìîæåíèÿ äèñëîêàöèé.

Êëþ÷åâûå ñëîâà: ðàçìåðíûé ýôôåêò èíäåíòèðîâàíèÿ, ìèêðîòâåðäîñòü, èîííàÿ èìïëàíòàöèÿ, ðàäèàöèîííûå äåôåêòû, ñïëàâû Si-Ge.

Ââåäåíèå Èçâåñòíî, ÷òî ïðè èîííîé áîìáàðäèðîâêå ïîëóïðîâîäíèêîâ[1] ìîãóò îáðàçîâûâàòüñÿ òåðìè÷åñêè ñòîéêèå ðàäèàöèîííûå äåôåêòû è èõ êîìïëåêñû. Îïðåäåëåííûå òèïû ðàäèàöèîííûõ äåôåêòîâ â çàïðåùåííîé çîíå îáðàçóþò ãëóáîêèå ýíåðãåòè÷åñêèå óðîâíè, ÷òî âåñüìà ñóùåñòâåííî äëÿ òåõíîëîãèè äåòåêòîðîâ ÈÊ èçëó÷åíèÿ. Èñõîäÿ èç ýòîãî êîìïëåêñíîå èçó÷åíèå ôèçèêî-ìåõàíè÷åñêèõ ñâîéñòâ ñïëàâîâ Si-Ge ïðè âîçäåéñòâèè ðàçëè÷íûõ òèïîâ èçëó÷åíèÿ ïðåäñòàâëÿåò çíà÷èòåëüíûé íàó÷íûé è ïðàêòè÷åñêèé èíòåðåñ.  íàñòîÿùåé ðàáîòå èññëåäîâàíî âëèÿíèå ïðîöåíòíîãî ñîäåðæàíèÿ ãåðìàíèÿ, èìïëàíòàöèè èîíàìè àðãîíà è èìïóëüñíîãî ôîòîííîãî îòæèãà íà ìèêðîòâåðäîñòü è ìîäóëü èíäåíòèðîâàíèÿ ñïëàâîâ SiGe.

Ìàòåðèàëû è ìåòîäû Ìîíîêðèñòàëëè÷åñêèå îáðàçöû ñïëàâîâ Si-Ge ïîëó÷åíû ìåòîäîì ×îõðàëüñêîãî âûòÿãèâàíèåì èç ðàñïëàâà ïî íàïðàâëåíèþ [111]. Èçó÷åíèå êèíåòè÷åñêîé ìèêðîòâåðäîñòè è ìîäóëÿ èíäåíòèðîâàíèÿ ïðîâåäåíî íà óëüòðà ìèêðî òâåðäîìåðå DUH-211S â ðåæèìå íàãðóçêè-ðàçãðóçêè â äèàïàçîíå íàãðóçîê 1-1500 ìÍ èíäåíòîðàìè Áåðêîâè÷à è Âèêêåðñà. Âðåìÿ çàäåðæêè íà ìàêñèìóìå íàãðóçêè ñîñòàâëÿëî 10 ñåê., à â êîíöå ðàçãðóçêè-5 ñåê. Èìïëàíòàöèÿ èîíàìè àðãîíà ìîíîêðèñòàëëè÷åñêèõ îáðàçöîâ Si-Ge ïðîâåäåíà íà ìîäåðíèçîâàííîé óñòàíîâêå «Âåçóâèé-3Ì» ïðè óñêîðÿþùåì íàïðÿæåíèè 100±1 êÂ, ïëîòíîñòè èîííîãî òîêà 3±0,2ìêÀ/ñì-2 è ôëþýíñîâ 1011-1015ñì-2. Èìïóëüñíûé ôîòîííûé îòæèã îáðàçöîâ ïðîâåäåí íà ëàáîðàòîðíîé óñòàíîâêå,

èñòî÷íèêîì èçëó÷åíèÿ èñïîëüçîâàíà ñèñòåìà èç 19 ãàëîãåííûõ ëàìï Êà 1000-220, áåëîãî èçëó÷åíèÿ, äëèòåëüíîñòü èìïóëüñà ñîñòàâëÿëà 5 ñåê. Äëÿ âûÿâëåíèÿ çàêîíîìåðíîñòåé èçìåíåíèÿ ìèêðîòâåðäîñòè îáðàçöîâ îáóñëîâëåííûõ âîçäåéñòâèåì èîíîâ àðãîíà, ïðîâåäåí ðàñ÷åò ïàðàìåòðîâ ðàñïðåäåëåíèÿ èîíîâ àðãîíà è îáðàçîâàííûõ â ìàòðèöå Si+1.5àò.%Ge ðàäèàöèîííûõ äåôåêòîâ. Ðàñ÷åò ïðîâåäåí ïðîãðàììîé TRIM-2012 [2] â áèíàðíîé ìîäåëè èîíàòîìíîãî âçàèìîäåéñòâèÿ äëÿ ïîëíîãî êàñêàäà ñòîëêíîâåíèé. Íèæå ïðèâîäÿòñÿ íåêîòîðûå çíà÷åíèÿ ðàñ÷åòíûõ ïàðàìåòðîâ: R p=112,3 íì, ÄR p=39,8 íì, ãäå - R p, ñðåäíèé ïðîåêòèâíûé ïðîáåã èîíîâ àðãîíà â ìàòðèöå Si+1.5àò.%Ge, ÄRp-ñòðàããëèíã, ï.â.à. – ïåðâè÷íî âûáèòûå àòîìû. Îáùåå ÷èñëî âàêàíñèé -1710 âàêàíñèÿ/èîí, äëÿ Si – 1682 âàêàíñèÿ/èîí, äëÿ Ge -28 âàêàíñèÿ/èîí.

а) погери энергии %: ò ионы п.в.а ионизация 30,97 27,77 вакансия 0,17 3,23 фононы 0,52 37,36 б) коэффициент распыления атом/ион эВ/атом общее 1,209 Si 1,19 148,3 Ge 0,09 913,3

102

Ðèñ.1. Çàâèñèìîñòü êèíåòè÷åñêîé ìèêðîòâåðäîñòè îáðàçöîâ Si-Ge êðèñòàëëîãðàôè÷åñêîé îðèåíòàöèè [111] îò ãëóáèíû èíäåíòèðîâàíèÿ

Ðèñ.2. Çàâèñèìîñòü ìîäóëÿ èíäåíòèðîâàíèÿ îáðàçöîâ Si-Ge êðèñòàëëîãðàôè÷åñêîé îðèåíòàöèè [111] îò ãëóáèíû èíäåíòèðîâàíèÿ

Íà ðèñ.1 è 2 ïðèâåäåíû çàâèñèìîñòè êèíåòè÷åñêîé ìèêðîòâåðäîñòè è ìîäóëÿ èíäåíòèðîâàíèÿ îò ãëóáèíû ïðîíèêíîâåíèÿ èíäåíòîðà Áåðêîâè÷à äëÿ îáðàçöîâ ñ ðàçëè÷íûì ïðîöåíòíûì ñîäåðæàíèåì Ge. Èçìåíåíèå îáîèõ ìåõàíè÷åñêèõ âåëè÷èí íîñÿò äîâîëüíî ñëîæíûé õàðàêòåð. Âûÿâëåí ò.í. îáðàòíûé «ðàçìåðíûé ýôôåêò»: íà ìàëûõ ãëóáèíàõ ïðîíèêíîâåíèÿ(ìàëûå íàãðóçêè) èõ âåëè÷èíà âîçðàñòàåò äîñòèãàÿ îïðåäåëåííîãî ìàêñèìóìà, ïîñëå ÷åãî ìåäëåííî ñïàäàåò ê ñòàöèîíàðíîìó çíà÷åíèþ. Äëÿ ñðàâíåíèÿ â òàáëèöå 1. ïðèâåäåíû çíà÷åíèÿ èõ

ìàêñèìóìîâ è ñîîòâåòñòâóþùèõ ãëóáèí èíäåíòèðîâàíèÿ îáðàçöîâ Si è Si-Ge. Òàáëèöà 1. Çíà÷åíèÿ ìàêñèìóìîâ ìèêðîòâåðäîñòè è ìîäóëÿ èíäåíòèðîâàíèÿ Si-Ge ñïëàâîâ Образец Si(111):B(2·1013см-3)

Si+0.5ат.%Ge:B Si+1.2 ат.%Ge:B Si+2 ат.%Ge:B

Модуль Глубина, Кинетическая микротвердость индентирования мкм Eit, ГПа H, ГПа 0.1309 7.068 164.3 0.1757 6.331 141.2 0.2296 5.55 125.7 0.232 4.361 85.17

103 Êàê âèäíî èç òàáëèöû 1. íàáëþäàåòñÿ òåíäåíöèÿ óâåëè÷åíèÿ ãëóáèíû èíäåíòèðîâàíèÿ ïðè ýêñòðåìóìàõ H è Eit è óìåíüøåíèå èõ çíà÷åíèé ñ óâåëè÷åíèåì êîíöåíòðàöèè ãåðìàíèÿ. Îäíîé èç ïðè÷èí óìåíüøåíèÿ ìèêðîòâåðäîñòè ñ óâåëè÷åíèåì êîíöåíòðàöèè ãåðìàíèÿ ìîæíî ïðåäïîëîæèòü, ÷òî â îáëàñòè àòîìîâ Ge ìåíåå èíòåíñèâíî ïðîõîäÿò ïðîöåññû âçàèìíîé áëîêèðîâêè äåôåêòîâ äèñëîêàöèîííîãî ïðîèñõîæäåíèÿ ñóùåñòâóþùèõ â ïðèïîâåðõíîñòíûõ ñëîÿõ îáðàçöà. Èçâåñòíî, ÷òî ïîä âëèÿíèì ãåðìàíèÿ óìåíüøàåòñÿ ïðî÷íîñòü êðåìíèÿ[3]. Ëåãèðîâàíèå ãåðìàíèåì óâåëè÷èâàåò êîâàëåíòíóþ äëèíó ñâÿçè èç-çà óâåëè÷åíèÿ ïàðàìåòðà ðåøåòêè, ÷òî â èòîãå ïðèâîäèò ê óìåíüøåíèþ ýíåðãèè ìåæàòîìíîãî âçàèìîäåéñòâèÿ è ñîîòâåòñòâåííî ìèêðîòâåðäîñòè è ìîäóëÿ èíäåíòèðîâàíèÿ Íà ðèñ.3. ïîêàçàíà çàâèñèìîñòü ìèêðîòâåðäîñòè èìïëàíòèðîâàííûõ èîíàìè àðãîíà ñ ýíåðãèåé 100 êý (ôëþýíñû 10 11 -10 15ñì -2) îáðàçöîâ Si+1,5àò.%Ge:B (2×1013ñì-3) îò ãëóáèíû ïðîíèêíîâåíèÿ èíäåíòîðà Âèêêåðñà. Ìèêðîòâåðäîñòü è ìîäóëü èíäåíòèðîâàíèÿ â çàâèñèìîñòè îò ôëþýíñà èçìåíÿþòñÿ íåìîíîòîííî. Îíè óìåíüøàþòñÿ ïðè ôëþýíñàõ îò 6X1011 äî 5X1012 ñì-2, äàëüíåéøåå óâåëè÷åíèå ôëþýíñà âûçûâàåò óâåëè÷åíèå ìèêðîòâåðäîñòè è ìîäóëÿ óïðóãîñòè è ïðè ôëþýíñå 2,5X1014 ñì-2 èõ çíà÷åíèÿ ïðåâîñõîäÿò àíàëîãè÷íûå õàðàêòåðèñòèêè èñõîäíîãî, íåîáëó÷åííîãî îáðàçöà. Ýòè èçìåíåíèÿ ÿñíî ïîêàçàíû â òàáëèöå 2. Òàáëèöà 2. Çàâèñèìîñòü ìåõàíè÷åñêèõ õàðàêòåðèñòèê îáðàçöîâ Si+1,5àò.%Ge:B(2X1013ñì-3) îò ôëþýíñà èìïëàíòèðîâàííûõ èîíîâ àðãîíà ñ ýíåðãèåé 100 êýÂ

Ñ ïîâûøåíèåì òåìïåðàòóðû îòæèãà íàáëþäàåòñÿ òåíäåíöèÿ âîçðàñòàíèÿ ìåõàíè÷åñêèõ õàðàêòåðèñòèê. Îäíàêî, ïîñëå îòæèãà ïðè 1050°C îáíàðóæèâàåòñÿ èõ íåçíà÷èòåëüíîå óìåíüøåíèå. Ýòî, âèäèìî ñâÿçàíî ñ èñïàðåíèåì àòîìîâ êèñëîðîäà èç àòìîñôåðû Êîòðåëëà è èõ ïåðåðàñïðåäåëåíèåì â îáúåìå êðèñòàëëà. Ïðåäïîëàãàåòñÿ, ÷òî èìïóëüñíûé ôîòîííûé îòæèã ïðàêòè÷åñêè íå âëèÿåò íà äèñëîêàöèîííóþ ñòðóêòóðó èññëåäóåìûõ îáðàçöîâ Si-Ge . Ïðè ýòîì îæèäàåòñÿ òîëüêî àííèãèëÿöèÿ âàêàíñèé è ïðèìåñíûõ àòîìîâ è èõ äèôôóçèÿ âäîëü äèñëîêàöèé íåïîñðåäñòâåííî â îáëó÷åííûõ ñëîÿõ êðèñòàëëà. Âëèÿíèå èìïóëüñíîãî ôîòîííîãî îòæèãà íà ìåõàíè÷åñêèå ñâîéñòâà íåçíà÷èòåëüíî â îáëàñòè áîëüøèõ ãëóáèí ïðîíèêíîâåíèÿ èíäåíòîðà. Óâåëè÷åíèå ìèêðîòâåðäîñòè (è ìîäóëÿ èíäåíòèðîâàíèÿ) ñ ïîâûøåíèåì òåìïåðàòóðû îòæèãà îáúÿñíÿåòñÿ óñòðàíåíèåì ìåòàñòàáèëüíûõ ðàäèàöèîííûõ äåôåêòîâ è óñèëåíèåì áëîêèðîâàíèÿ äèñëîêàöèé òî÷å÷íûìè äåôåêòàìè, ïðîäóêòàìè ðàñïàäà ìåòàñòàáèëüíûõ äåôåêòîâ.

Çàêëþ÷åííèå Ïðîâåäåíî èññëåäîâàíèå äèíàìè÷åñêèõ ìåõàíè÷åñêèõ ñâîéñòâ (ìèêðîòâåðäîñòü è ìîäóëü èíäåíòèðîâàíèÿ) â øèðîêîé îáëàñòè íàãðóçîê íà èíäåíòîðàõ Áåðêîâè÷à è Âèêêåðñà íà óëüòðà ìèêðîòâåðäîìåðå DUH-211S ìîíîêðèñòàëëè÷åñêèõ îáðàçöîâ Si1-xGex(x≤0.02). Âûÿñíåíû çàêîíîìåðíîñòè èçìåíåíèÿ ìåõàíè÷åñêèõ õàðàêòåðèñòèê â çàâèñèìîñòè îò êîíöåíòðàöèè ãåðìàíèÿ, ôëþýíñîâ èîíîâ àðãîíà è óñëîâèé èìïóëüñíûõ ôîòîííûõ îòæèãîâ, ÷òî èìååò âàæíîå çíà÷åíèå äëÿ ðàçðàáîòêè íîâûõ ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ íà îñíîâå Si-Ge ñ çàäàííûìè ñâîéñòâàìè.

Ëèòåðàòóðà Ãäå –DHV êèíåòè÷åñêàÿ ìèêðîòâåðäîñòü ïî Âèêêåðñó, Eit- ìîäóëü èíäåíòèðîâàíèÿ, hmax ãëóáèíà ïðè ìàêñèìóìàõ DHV è Eit. Êàê âèäíî èç ðèñ.3. è òàáëèöû 2. ìèêðîòâåðäîñòü è ìîäóëü èíäåíòèðîâàíèÿ âñåõ îáðàçöîâ õàðàêòåðèçóþòñÿ îáðàòíûì «ðàçìåðíûì ýôôåêòîì». Êàê ñëåäóåò èç ðàáîòû [4], îáðàòíûé ðàçìåðíûé ýôôåêò íàáëþäàåòñÿ äëÿ õðóïêèõ ìàòåðèàëîâ (êåðàìèêà, ïîëóïðîâîäíèêè) è ñâÿçàí ñ âîçíèêíîâåíèåì ìèêðîòðåùèí âîêðóã îòïå÷àòêîâ èíäåíòèðîâàíèÿ. Èçó÷åíî âëèÿíèÿ èìïóëüñíîãî ôîòîííîãî îòæèãà îáðàçöîâ Si+1,5àò.%Ge: B(2 X10 13ñì -3), îáëó÷åííûõ èîíàìè àðãîíà ñ ýíåðãèåé 100 êý è ôëþýíñîì 2X1013ñì2 íà ìèêðîòâåðäîñòü è ìîäóëü èíäåíòèðîâàíèÿ ïðè òåìïåðàòóðàõ 715, 920 è 1050°C â òå÷åíèå 5 ñåê. Âî âñåõ ñëó÷àÿõ îòæèãà çàâèñèìîñòü ìèêðîòâåðäîñòè îò ãëóáèíû èíäåíòèðîâàíèÿ õàðàêòåðèçóåòñÿ îáðàòíûì «ðàçìåðíûì ýôôåêòîì»(Ðèñ.4.).

1. Í. Í. Ãåðàñèìåíêî Íàíîðàçìåðíûå ñòðóêòóðû â èìïëàíòèðîâàííûõ ïîëóïðîâîäíèêàõ. Ðîññèéñêèé õèìè÷åñêèé æóðíàë. 2002. Ò. 46. N 5.,C. 30–41.

2. J. F. Ziegler, J. P. Biersack, M. D. Ziegler. SRIM The Stopping and Range of Ions in Matter. IIT Co. 2015, 15th Edition, 398 p. www.srim.org.

3. B. Roos, H. Richter, J. Wollweber. Composition dependence of hardness and elastic modulus in Si-Ge measured by nanoindentation-possible consequences for elasto-plastic relaxation and diffusion. Solid State Phenomena. 47-48, 1996, pp.509516.

4. H. Li and R. C. Bradt, The effect of indentation-induced cracking on the apparent microhardness. J. Mater. Sci. 31, 1065 (1996).

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Ðèñ.3. Çàâèñèìîñòü êèíåòè÷åñêîé ìèêðîòâåðäîñòè îáðàçöîâ Si+1,5àò.%Ge:B(2x1013ñì-3) èìïëàíòèðîâàííûõ èîíàìè àðãîíà ðàçíûõ ôëþýíñîâ è ýíåðãèåé 100 êý îò ãëóáèíû ïðîíèêíîâåíèÿ èíäåíòîðà.

Ðèñ.4. Çàâèñèìîñòü êèíåòè÷åñêîé ìèêðîòâåðäîñòè îáðàçöîâ Si+1,5àò.%Ge:B (2x1013ñì-3) èìïëàíòèðîâàííûõ èîíàìè àðãîíà ñ ýíåðãèåé 100 êý è ôëþýíñîì 2x1013ñì-2 îò ãëóáèíû ïðîíèêíîâåíèÿ èíäåíòîðà Âèêêåðñà, ïðè ðàçíûõ òåìïåðàòóðàõ èìïóëüñíîãî ôîòîííîãî îòæèãà.

105

Influence of Argon Ion Irradiation on Mechanical Properties of Monocrystalline Si-Ge Alloys A. Sichinava, I. Nardaia, N. Gapishvili, G. Archuadze, Ts. Nebieridze, O. Kashia Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli, 0186, Tbilisi, Georgia.

E-mail sipt@sipt.org The influence of Argon ion implantation and Ge content on the microhardness and elastic modulus of Si-Ge alloys are investigated. Reverse “Indentation Size Effect” revealed. Reducing of microhardness and elasticity modulus with increasing of Ge concentration is revealed. The dependence of the mechanical properties on the argon ion fluence is complicated. Pulse photon thermal annealing of Si-Ge samples has a tendency hardening of mechanical characteristics. This is due to annealing of metastable radiation defects and increased blocking of dislocations by point defects.

argonis ionebis dasxivebis gavlena monokristaluri Si-Ge Senadnobebis meqanikur Tvisebebze a. siWinava, i. nardaia, n. gafiSvili, g. arCuaZe, c. nebieriZe, o. kaSia

soxumis ilia vekuas fizika-teqnikis instituti, mindelis q.7, 0186, Tbilisi, saqarTvelo. el–fosta: sipt@sipt.org Seswavlilia sxvadasxva faqtorebis gavlena Si-Ge Senadnobebis mikrosisalesa da drekadobis modulze. gamovlenilia e.w. Sebrunebuli “zomiTi efeqti“ indentoris SeRwevis siRrmis mimarT. naCvenebia mikrosisalisa da drekadobis modulis Semcireba Ge-s koncentraciis gazrdiT. maRal temperaturaze impulsuri fotonuri mowva iwvevs nimuSebis ganmtkicebas radiaciuli defeqtebis mowvisa da dislokaciebis damuxruWebis gaZlierebis Sedegad.

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Ðàçðàáîòêà òåðìîýëåêòðè÷åñêèõ ñïëàâîâ Si0,95Ge0,05 n- è p-òèïà è ñîçäàíèå íà èõ îñíîâå òåðìîýëåêòðè÷åñêîé áàòàðåé, ðàáîòàþùåé íà âîçäóõå äî òåìïåðàòóðû 10000C Ê. Áàðáàêàäçå, Ì. Áèëèñåèøâèëè, Ç. Èñàêàäçå, ß.Òàáàòàäçå, Â. Ãàáóíèÿ, À. Êóöèÿ, Ì. Áàðáàêàäçå, Ì. Ðåõâèàøâèëè. Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà, óë. Ìèíäåëè 7,0186,Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà:sipt@sipt.org Ðåçþìå.  ðàáîòå ïðåäñòàâëåíû ðåçóëüòàòû èññëåäîâàíèÿ òåðìîýëåêòðè÷åñêèõ n- è p-òèïà ñïëàâîâ íà áàçå Si0,95Ge0,05. Îáðàçöû ïîëó÷åíû ìåòîäàìè ñîâìåñòíîãî ïëàâëåíèÿ êîìïîíåíòîâ è ãîðÿ÷èì ïðåññîâàíèåì ïîðîøêîâ ñîâìåñòíî èçìåëü÷åííûõ êîìïîíåíòîâ. Èçó÷åíû òåðìîýëåêòðè÷åñêèå õàðàêòåðèñòèêè ëèòûõ è ïðåññîâàííûõ îáðàçöîâ. Âûáðàíû êîììóòàöèîííûå ìàòåðèàëû ãîðÿ÷èõ è õîëîäíûõ êîíöîâ òåðìîýëåêòðè÷åñêîé áàòàðåé. Ñîçäàíû òåðìîýëåêòðè÷åñêèå áàòàðåè íà îñíîâå n- è p-òèïà ñïëàâîâ Si0,95Ge0,05, ñèíòåçèðîâàííûõ ãîðÿ÷èì ïðåññîâàíèåì,. Èçó÷åíû èõ ýëåêòðè÷åñêèå õàðàêòåðèñòèêè è òåðìè÷åñêàÿ ñòîéêîñòü â ãðàäèåíòå òåìïåðàòóðû 600-130°C.

Êëþ÷åâûå ñëîâà: òåðìîýëåêòðè÷åñêèå ìàòåðèàëû, òåðìîýëåêòðè÷åñêèé ãåíåðàòîð, òåðìîýëåêòðè÷åñêàÿ áàòàðåÿ, òåðìîýëåìåíò, êîììóòàöèîííûå ïåðåõîäû, ýôôåêòèâíîñòü.

Ââåäåíèå Ñîçäàíèå íåòðàäèöèîííûõ èñòî÷íèêîâ ýëåêòðîýíåðãèè äëÿ îáñëóæèâàíèÿ êîììóíèêàöèîííûõ è èíôîðìàöèîííûõ ñðåäñòâ, îñâåùåíèÿ è äðóãèõ íåîáõîäèìûõ îáîðóäîâàíèé æèòåëåé íåýëåêòðîôèöèðîâàííûõ ðåãèîíîâ è ñïåöèàëèñòîâ, ðàáîòàþùèõ â ïîëåâûõ óñëîâèÿõ, àêòóàëüíàÿ çàäà÷à. Ñ ýòîé öåëþ èíòåðåñíû òåðìîýëåêòðè÷åñêèå ïðåîáðàçîâàòåëè, êîòîðûå ïðÿìî ïðåîáðàçóþò òåïëî â ýëåêòðè÷åñòâî. Èõ ôóíêöèîíèðîâàíèå íå çàâèñèò îò âðåìåíè è ïîãîäû. Îñíîâíûì ðàáî÷èì óçëîì òåðìîýëåêòðè÷åñêîãî ïðåîáðàçîâàòåëÿ ÿâëÿþòñÿ âåòâè òåðìîýëåêòðè÷åñêèõ ìàòåðèàëîâ n- è p-òèïà ïðîâîäèìîñòè, êîòîðûå ïðåîáðàçóþò ÷àñòü ïðîõîäÿùãî ÷åðåç íèõ òåïëà â ýëåêòðè÷åñòâî. ÊÏÄ èõ ïðåîáðàçîâàíèÿ–ç âûðàæàåòñÿ ôîðìóëîé

η=

Тh − Тc Тh

Тh + Тc −1 2 Т + Тc Тc 1+ Ζ h + 2 Тh 1+ Ζ

ãäå Th è Tc òåìïåðàòóðû ãîðÿ÷åãî è õîëîäíîãî êîíöîâ ñòîëáèêà òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà ñîîòâåòñòâåííî, à Z–ýôôåêòèâíîñòü òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà. Ïåðâûé ÷ëåí ýòîé ôîðìóëûTh-Tc/ T hïðåäñòàâëÿåò òåðìîäèíàìè÷åñêóþ ÷àñòü ÊÏÄ, êîòîðûé ñ óâåëè÷åíèåì òåìïåðàòóðû ãîðÿ÷åãî êîíöà óâåëè÷èâàåòñÿ, âòîðîé ÷ëåí ïðåäñòàâëÿåò ìàòåðèàëüíóþ ÷àñòü ÊÏÄ, êîòîðûé ñ óâåëè÷åíèåì ýôôåêòèâíîñòè òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà óâåëè÷èâàåòñÿ. Ñ ýíåðãåòè÷åñêîé òî÷êè çðåíèÿ öåëåñîîáðàçíî ñîçäàíèå

âûñîêîòåìïåðàòóðíîãî òåðìîýëåêòðè÷åñêîãî ïðåîáðàçîâàòåëÿ íà îñíîâå âûñîêîýôôåêòèâíûõ òåðìîýëåêòðè÷åñêèõ ìàòåðèàëîâ. Ýôôåêòèâíîñòü òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà Z (K-1) âûðàæàåòñÿ ôîðìóëîé Z=α2σ/λ Ãäå α–êîåôôèöèåíò Çååáåêà (âò.K -1 ), σ – ýëåêòðîïðîâîäíîñòü (îì-1.ñì-1), à λ – òåïëîïðîâîäíîñòü (âò. ñì-1.K-1). Îñíîâíîå âíèìàíèå ó÷eíûõ, ðàáîòàþùèõ â îáëàñòè òåðìîýëåêòðè÷åñòâà, íàïðàâëåíî íà ñîçäàíèå âûñîêîýôôåêòèâíûõ òåðìîýëåêòðè÷åñêèõ ìàòåðèàëîâ ïóòåì ïîâûøåíèÿ ýíåðãåòè÷åñêîãî ôàêòîðà α2σ è ïîíèæåíèÿ òåïëîïðîâîäíîñòè λ. Ðåàëüíûé òåðìîýëåêòðè÷åñêèé ãåíåðàòîð (ÒÝÃ) ñîñòîèò èç íåñêîëüêèõ òåðìîýëåêòðè÷åñêèõ áàòàðåé (ÒÝÁ), êîòîðûå ïîñëåäîâàòåëüíî, ïàðàëëåëüíî èëè ñìåøàííî ñîåäèíåíû ìåæäó ñîáîé. Àíàëîãè÷íî, ÒÝÁ ñîñòîèò èç íåñêîëüêèõ òåðìîýëåìåíòîâ (ÒÝ)òàêæå ïîñëåäîâàòåëüíî, ïàðàëëåëüíî èëè ñìåøàííî ñîåäèíeííûõ ìåæäó ñîáîé. Ñàì ÒÝ, ÿâëÿþùèéñÿ ïðîñòåéøèì ÒÝÃ-îì, ñîñòîèòèç äâóõ ïîñëåäîâàòåëüíî ñîåäèíeííûõ ñòîëáèêîâ òåðìîýëåêòðè÷åñêèõ ìàòåðèàëîâ n- è p-òèïà ïðîâîäèìîñòè. Âàæíåéøèìè óçëàìè ÒÝÃà ÿâëÿþòñÿ êîììóòàöèîííûå ïåðåõîäû, îáåñïå÷èâàþùèå ìèíèìàëüíûå ïîòåðè òåïëà è ýëåêòðè÷åñòâà. Ýôôåêòèâíîñòü Z′ âåòâè ÒÝ âûðàæàåòñÿ ôîðìóëîé[1]

Z′=Z(1/1-

2ρ h ) ρl

ãäå Z–ýôôåêòèâíîñòü òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà(K -1), ρ k –óäåëüíîå ýëåêòðè÷åñêîå

l

111 ñîïðîòèâëåíèå êîíòàêòà(îì\ñì 2 ), ρ– óäåëüíîå ýëåêòðè÷åñêîå ñîïðîòèâëåíèå òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà (îì.ñì) èρl–äëèíà âåòâè ÒÝ (ñì). Èç ýòîé ôîðìóëû ñëåäóåò, ÷òî ïîòåðè ýôôåêòèâíîñòè âåòâè ÒÝñ óâåëè÷åíèåì ρk óâåëè÷èâàþòñÿ, à ñ óâåëè÷åíèåì ρ è – , óìåíüøàþòñÿ. Íàïðèìåð, ïðè ρk=10-5 îì ñì2, ρ=10-3 îì ñì è =1 ñì, ïîòåðè ýôôåêòèâíîñòè âåòâè ÒÝ ñîñòàâëÿåò 2%. Äîñòèæåíèå òàêîãî íèçêîãî êîíòàêòíîãî ýëåêòðîñîïðîòèâëåíèÿ òðåáóåò ãëóáîêîãî èññëåäîâàíèÿ ïî òåðìîìåõàíè÷åñêîé, ýëåêòðîôèçè÷åñêîé è õèìè÷åñêîé ñîâìåñòèìîñòè ìàòåðèàëîâ êîììóòàöèîííîãî ïåðåõîäà. Ñðåäè èçâåñòíûõ òåðìîýëåêòðè÷åñêèõ ìàòåðèàëîâ òîëüêî ñïëàâû Si-Ge íàøëè ïðàêòè÷åñêîå ïðèìåíåíèå äëÿ ñîçäàíèÿ âûñîêîòåìïåðàòóðíûõ ÒÝÃ-îâ[2-4].Îíè äî òåìïåðàòóðû 1000°C õàðàêòåðèçóþòñÿ âûñîêîé ìåõàíè÷åñêîé ïðî÷íîñòüþ, âûñîêîé ïëîòíîñòüþ âûðàáîòàííîé ýëåêòðè÷åñêîé ìîùíîñòè (áîëüøå 4 âò/ ñì 2 ) è ñòàáèëüíîé ðàáîòîé íà âîçäóõå. Ýòè õàðàêòåðèñòèêè âàæíû äëÿ ñîçäàíèÿ êîìïàêòíîóïàêîâàííûõ ÒÝÃ-îâ,ñðàâíèòåëüíî ïðîñòûì îáñëóæèâàíèåì.  ýòîì íàïðàâëåíèè ïðîâåäåíû ôóíäàìåíòàëüíûå èññëåäîâàíèÿ è ðàçðàáîòàíû âûñîêîòåìïåðàòóðíûå æàðîñòîéêèå êîììóòàöèîííûå ïåðåõîäû ê ñïëàâàì SiGe è ñïîñîá èçãîòîâëåíèÿ ìîíîëèòíîé æàðîñòîéêîé ÒÝÁ [5-8]. Èñòî÷íèêàìè òåïëà æàðîñòîéêèõ ÒÝÃ-îâ ìîãóò áûòü èñïîëüçîâàíû äðîâÿíûå, êàìåííîóãîëüíûå, êåðîñèíîâûå èëè ãàçîâûå ïå÷è, èñïîëüçóåìûå äëÿ óäîâëåòâîðåíèÿ íåîáõîäèìûõ áûòîâûõ íóæä íàñåëåíèÿ. Âûñîêàÿ ðûíî÷íàÿ ñòîéìîñòü ãåðìàíèÿ (~2000$ çà 1êã) ìåøàåò øèðîêîìó ïðàêòè÷åñêîìó ïðèìåíåíèþ ýôôåêòèâíûõ ñïëàâîâ Si-Ge, ñîäåðæàùèõ 20-30 àò%Ge. Ñ ó÷eòîì ýòîãî ìû ðåøèëè ñîçäàòü ÒÝÁ íà îñíîâå ñïëàâà Si0,95Ge 0,05,ñîäåðæàùåãî 5 àò%Ge. Ýíåðãåòè÷åñêèå õàðàêòåðèñòèêè ýòîãî ñïëàâà ðàññìîòðåííû â ðàáîòàõ [9,10]. Ñèíòåç n- è p-òèïà ñïëàâîâ Si0,95Ge0,05áûë ïðîâåäåí êàê ñîâìåñòíûì ñïëàâëåíèåì èñõîäíûõ êîìïîíåíòîâ, òàê è ãîðÿ÷èì ïðåññîâàíèåì ñìåñåé èõ ïîðîøêîâ.  êà÷åñòâå îñíîâíûõ êîìïîíåíòîâ ñïëàâîâ èñïîëüçîâàíû ïîëèêðèñòàëëè÷åñêèå êðåìíèé è ãåðìàíèé, à â êà÷åñòâå ëåãèðóþùèõ ýëåìåíòîâ äëÿ ñïëàâà p-òèïà –àìîðôíûé B, à äëÿ ñïëàâà n-òèïà –àìîðôíûé P è êðèñòàëëè÷åñêèé GaP. Ñïëàâû,èçãîòîâëåííûå ïëàâëåíèåì, äîñòàòî÷íî ãîìîãåííû. Ïàðàìåòð èõ ðåøeòêè áëèçîê ê ïàðàìåòðó ðåøeòêè êðåìíèÿ, ÷òî ìîæíî îáúÿñíèòü óìåíüøåíèåì ïàðàìåòðà ðåøeòêè ñïëàâà Si0,95 Ge 0,05â ðåçóëüòàòå ðàñòâîðåíèÿ â íåì ëåãèðóþùèõ ýëåìåíòîâ áîðà èëè ôîñôîðà. Èõ ìèêðîñòðóêòóðû ñîäåðæàò ìèêðîòðåùèíû (ðèñ.1à), êîòîðûå ïðîÿâëÿþòñÿ ïîñëå òðàâëåíèÿ èõ ìåòàëëîãðàôè÷åñêîãî øëèôà. Íà øëèôàõ îáðàçöîân-òèïà,ñîäåðæàùèõ3-5ìàñ.%GaP, ÷åðåç íåñêîëüêî äíåé èõ èçãîòîâëåíèÿ ïîÿâëÿþòñÿ âûäåëåíèÿ Gaâ âèäå ÿðêèõ êðóãëûõ êðàòåðîâ (ðèñ.1á). Ãîìîãåííîñòü ñïëàâîâ, ñèíòåçèðîâàííûõ ãîðÿ÷èì ïðåññîâàíèåì, íèçêà. Èõ ìèêðîñòðóêòóðà íåîäíîðî-

äíà. íèõ èìåþòñÿ ìåëêèå ïîðû è îòäåëüíûå ó÷àñòêè îïëàâëåíèÿ (ðèñ.2à), â êîòîðûõ ðàññïîëîæåíû ñðàâíèòåëüíî êðóïíûå ïîðû.  ðåçóëüòàòå îòæèãà ïðè òåìïåðàòóðå 1350°C, â òå÷åíèè 25 ÷àñîâ, ñïëàâ ñòàë áîëåå ãîìîãåííûì è åãî ìåëêèå ïîðû ñîåäèíèëèñü è îáðàçîâàëè êðóïíûå ïîðû (ðèñ.2á). Òåðìîýëåêòðè÷åñêèå õàðàêòåðèñòèêè ðàññìàòðèâàåìûõ ñïëàâîâ ïðèâåäåíû â òàáëèöå 1. Ñïëàâû, ñèíòåçèðîâàííûå ïëàâëåíèåì, áîëåå ïåðñïåêòèâíû, êàê ñ òî÷êè çðåíèÿ òåõíîëîãèè èçãîòîâëåíèÿ, òàê è ñ òî÷êè çðåíèÿ òåðìîýëåêòðè÷åñêèõ õàðàêòåðèñòèê. Ïîñëå îòæèãà ïðè òåìïåðàòóðå 1350°C, â òå÷åíèè 25 ÷àñîâ, ýôôåêòèâíîñòü ñïëàâà Si0,95Ge0,05+1ìàñ.%P óâåëè÷èâàåòñÿ äî 0,22 10-3 K-1, à ñïëàâà Si0,95Ge0,05+ 0,2ìàñ.%B äî 0,23 10-3 K-1. Óâåëè÷åíèå ýôôåêòèâíîñòè ïðîèçîøëî, â îñíîâíîì, çà ñ÷åò ñíèæåíèÿ òåïëîïðîâîäíîñòè.

à

á Ðèñ.1.Ìèêðîñòðóêòóðû ñïëàâîâ:à–Si0,95Ge0,05 + B 0,2ìàñ.%; á– Si0,95Ge0,05+GaP5ìàñ.%.

112

à

á Ðèñ.2. Ìèêðîñòðóêòóðà ñïëàâà Si0,95Ge0\05+5ìàñ.% GaP, ñèíòåçèðîâàííîãî ãîðÿ÷èì ïðåññîâàíèåì ïðè òåìïåðàòóðå 1290°C :à–äî îòæèãà; á–ïîñëå îòæèãà ïðè òåìïåðàòóðå1350°C, â òå÷åíèè 25 ÷àñîâ. Òàáëèöà 1. Òåðìîýëåêòðè÷åñêèå õàðàêòåðèñòèêè ñïëàâîâ ïðè êîìíàòíîé òåìïåðàòóðå

Ìèêðîñòðóêòóðû êîììóòàöèîííûõ ïåðåõîäîâ ê ñïëàâàì Si0,95Ge0,05+5ìàñ.% GaP è Si0,95Ge0,05+0,2ìàñ.% B, ñèíòåçèðîâàííûõ ãîðÿ÷èì ïðåññîâàíèåì, ïîêàçàíû íà ðèñ.3. Èõ êîììóòèðîâàíèå ïðîâîäèëîñü ïàéêîé, ñ ïðèìåíåíèåì ïðèïîÿ Fe-Ni, â âàêóóìå, ïðè òåìïåðàòóðàõ 1150-1200 0C.  îáëàñòè êîíòàêòîâ èìåþòñÿ âêëþ÷åíèÿ èç ïðîäóêòîâ ðåàêöèè òåðìîýëåêòðè÷åñêîãî ìàòåðèàëà ñ ïðèïîåì. Êîíòàêòíîå ýëåêòðîñîïðîòèâëåíèå íå ïðåâûøàåò 3.10-6îì\ñì2. Êîììóòàöèîííûå ïåðåõîäû òåðìîñòîéêè è ìîãóò ñòàáèëüíî ðàáîòàòü äî òåìïåðàòóðû 1000°C â òå÷åíèè äëèòåëüíîãî âðåìåíè.

à

á Ðèñ.3.Ìèêðîñòðóêòóðû êîììóòàöèîííûõ ïåðåõîäîâ ê ñïëàâó Si0,95Ge0\05+5ìàñ.% GaP ñèíòåçèðîâàííîãî ãîðÿ÷èì ïðåññîâàíèåì: à–êîììóòàöèîííûé ìàòåðèàë ãðàôèò (ñëåâà); á–êîììóòàöèîííûé ìàòåðèàë ñïëàâ Si-Mo ëåãèðîâàííûé áîðîì (ñëåâà).

Ñ öåëüþ ýôôåêòèâíîãî èñïîëüçîâàíèÿ ðàáî÷åé ïëîùàäè ÒÝÃ-à áûëî ðåøåíî ñîçäàòü ìîíîëèòíûé ÒÝÁ, ñ ïëîòíîóïàêîâàííûìè âåòâÿìè òåðìîýëåìåíòîâ. Òàêîé ÒÝÁ ìîæåò âûðàáîòàòü ñðàâíèòåëüíî áîëüøóþ ýëåêòðè÷åñêóþ ìîùíîñòü ñ åäèíèöû ðàáî÷åé ïëîùàäè è íàäåæåí â ýêñïëóàòàöèè. Ñáîðêà ìîíîëèòíîãî ÒÝÁ-à íà îñíîâå òåðìîýëåêòðè÷åñêèõ ñïëàâîâ Si0,95Ge0,05+P5ìàñ.% Ga n-òèïà è Si0,95Ge0,05+0,2ìàñ% B pòèïà, ñèíòåçèðîâàííûõ ãîðÿ÷èì ïðåññîâàíèåì, ïðîâîäèëàñü ñëåäóþùèì îáðàçîì. Ñïðåññîâàííûå áðèêåòû óêàçàííûõ ñïëàâîâ áûëè ðàçðåçàíû âíóòðåííèì àëìàçíûì äèñêîì íà ïëàñòèíû ñ ðàçìåðàìè 20x28x3 ìì. Èç ýòèõ ïëàñòèí,ðàçëîæåííûõ â n-p-n-p-n-p ïîñëåäîâàòåëüíîñòè, ñ ïîìîùüþ òîíêèõ (~0,3ìì) ýëåêòðîèçîëÿöèîííûõ ñëîeâ èç ñòåêëî-êåðàìè÷åñêîé êîìïîçèöèè,áûë ñâÿçàí ìîíîëèòíûé ïàêåò (ðèñ.4à). Íà âåðõíèé è íèæíèé òîðöû ýòîãî ïàêåòà áûëè ïðèïàÿííû ñ ïîìîùþ Fe-Ni êîììóòàöèîííûå ïëàñòèíû ñ ðàçìåðàìè 21x28x3 ìì, èçãîòîâëåííûå èç ãðàôèòà è ñïëàâà Si-

113 Mo, ëåãèðîâàííîãî áîðîì. Ñêîììóòèðîâàííûé ïàêåò áûë ðàçðåçàí âíóòðåííèì àëìàçíûì äèñêîì íà ìîíîëèòíûå ðÿäû ïàðàëëåëüíî ñîåäèíeííûõ âåòâåé òåðìîýëåìåíòîâ (ðèñ. 4á).

à

á

â Ðèñ.4. à– Ìîíîëèòíûé ïàêåò, ñîñòîÿùèé èç 6 ïëàñòèí (3 n-òèïà è 3 p-òèïà) òåðìîýëåêòðè÷åñêèõ ñïëàâîâ Si0,95Ge0,05; á–ìîíîëèòíûé ðÿä èç ïàðàëëåëüíî ñîåäèíeííûõ âåòâåé òåðìîýëåìåíòîâ; â–ìîíîëèòíàÿ òåðìîýëåêòðè÷åñêàÿ áàòàðåÿ, ñîñòîÿùàÿ èç 36 âåòâåé (18 n-òèïà è 18 p-òèïà), ñîåäèíåííûõ ïîñëåäîâàòåëüíî.

Èç ýòèõ ðÿäîâ áûëà ñâÿçàíà, ñ ïîìîùüþ ñòåêëîêåðàìè÷åñêîé êîìïîçèöèè, ìîíîëèòíàÿ çàãîòîâêà ÒÝÁ.  íåé ãîðÿ÷èå è õîëîäíûå êîììóòàöèîííûå ïåðåõîäû ðàññïîëîæåíû â ðàçíûõ ïëîñêîñòÿõ, à ñîñåäíèå êðàéíèå âåòâè - â n-p-n-p-n-p ïîñëåäîâàòåëüíîñòè. Ãîðÿ÷èå è õîëîäíûå êîììóòàöèîííûå ïëàñòèíû ïîëó÷åííîé

çàãîòîâêè áûëè ðàçðåçàíû íàðóæíûìè àëìàçíûìè äèñêàìè òàêèì îáðàçîì, ÷òî ðÿäû ïàðàëëåëüíî ñîåäèíeííûõ âåòâåé ïðåâðàòèëèñü â ðÿäû ïîñëåäîâàòåëüíî ñîåäèíeííûõ âåòâåé. Íà òîðöû ãðàôèòîâûõ êîììóòàöèîííûõ ïëàñòèí êðàéíèõ âåòâåé çàãîòîâêè ÒÝÁ áûëè ãàëüâàíè÷åñêè íàíåñåíû ñëîè íèêåëÿ è ÷åðåç ýòè ñëîè ìåäíûìè ïëàñòèíàìè è îëîâÿííûì ïðèïîåì áûëè ñîåäèíåíû ïîñëåäîâàòåëüíî ðÿäû âåòâåé ÒÝ è ïðèïàÿíû òîêîâûå âûâîäû. Ïîëó÷åííàÿ òåðìîýëåêòðè÷åñêàÿ áàòàðåÿ ïîêàçàíà íà ðèñ. 4ã. Åe ýëåêðè÷åñêîå ñîïðîòèâëåíèå íà 5% áîëüøå ñóììàðíîãî ýëåêòðîñîïðîòèâëåíèÿ âåòâåé òåðìîýëåìåíòîâ. Ïîñëå 100 êðàòíîãî òåðìîöèêëà â ãðàäèåíòå òåìïåðàòóð 700-150°C ýëåêòðîñîïðîòèâëåíèå áàòàðåé ïðàêòè÷åñêè íå èçìåíèëîñü.

Ëèòåðàòóðà 1. Ë. Ñ. Ñòèëüáàíñ. Î êîììóòàöèè ïîëóïðîâîäíèêîâûõ òåðìîýëåìåíòîâ. ÆÒÔ, XXVII, 1, 212, 1967.

2. È.Ã.Ãâåðäöèòåëè, Þ.Ä.Ãóáàíîâ, Ã.È.Êàëàíäàäçå, Ñ.Ï.Ëàëûêèí, À.È. Ìàòèòàøâèëè.Èññëåäîâàíèå ïî ñîçäàíèþ âûñîêîòåìïåðàòóðíûõ ïîëóïðîâîäíèêîâûõ ïðåîáðàçîâàòåëåé. Îò÷eò Ï/ß À-7797, èíâ.N64, 1960 ã.

3. Ê.Ã. Áàðáàêàäçå, Ì.Ì. Áîíäàðþê, È. Ì. Âèøíåïîëüñêèé, È.Ã. Ãâåðäöèòåëè, Þ.Ä.Ãóáàíîâ,Â. Ê. Êîâûðçèí, Ñ. Ï. Ëàëûêèí. Êîñìè÷åñêàÿ ÿäåðíî-ýíåðãåòè÷åñêàÿ óñòàíîâêà ÁÝÑ-5. Àñ N33798 (ÑÑÑÐ), 1966.

4. J. F. Braun. Application of Silicon Germanium thermoelectric devices for electrical power production in Space. In: Proc. of XIV International Conference of the Energy Conversion. S.Petersburg, 1995, pp.394-400.

5. Ê. Ã. Áàðáàêàäçå, Ò. Ñ. Âåêóà, À. À. Ãâåëåñèàíè,È.Ã. Ãâåðäöèòåëè,Î. È. Ìèêàäçå. Æàðîñòîèêèé êîììóòàöèîííûé ïåðåõîä ê òåðìîýëåêòðè÷åñêèì ñïëàâàì Si-Ge. À.ñ. N 52165 (ÑÑÑÐ), 1968.

6. Ê. Ã. Áàðáàêàäçå, È.Ä. Íåêëþäîâ. Ýëåêòðîèçîëÿöèîííîå ñâÿçûâàíèå êðåìíå-ãåðìàíèåâûõ âåòâåé òåðìîýëåìåíòîâ. Àñ. N322979 (ÑÑÑÐ), 1991ã.

7. Ê. Ã. Áàðáàêàäçå, Ò. Ñ. Âåêóà.Ôîðìèðîâàíèå êðåìíåãåðìàíèåâûõ âåòâåé òåðìîýëåìåíòîâ ñ ãðàôèòîâûìè ýëåêòðîäàìè. ÏÏÒÝÝèÒÝ, 1987, N1-2, ñ223-227.

8. Ê. Áàðáàêàäçå, Ì. Áàðáàêàäçå, Ì. Áèëèñåèøâèëè, Ã. Áîêó÷àâà, Ç. Èñàêàäçå, À. Êóöèÿ, Â. Êó÷óõèäçå, Ì. Ðåõâèàøâèëè. Òåðìîýëåêòðè÷åñêàÿ áàòàðåÿ íà îñíîâå ñïëàâà Si0,68Ge0,32n- è p-òèïà. Õèìè÷åñêèé æóðíàë Ãðóçèè, ò.14, N1, 2014ã.

9. J. P. Dismukes, l. Ekstrom, E. F. Steigmeier, I. Kudman, D. S. Beers. Thermal and Electrical Properties of Heavily Doped Ge-Si Alloys up to 1300K. J. of Appl. Phys. 35 (1964), pp.

2899-2907.

10. G.H. Zhu, H. Lee, Y.C. Lan, X.W. Wang, G. Joshi, D.Z. Wang, J. Yang, D. Vashace, H. Guilbert, A. Pillitteri, M.S. Dresselhaus, G. Chen, and Z.E. Ren. Increased Phonon Scattering by Nanograins and Point Defects in Nanostructured Silicon with a Low Concentration of Germanium. PRL, 102, 196803 (2009).

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Development of thermoelectric n- and ptype Si0,95Ge0,05 alloys and creation on their base thermoelectric batteries, working in air till temperature 1000°C K. Barbakadze, M. Biliseishvili, Z. Isakadze, I. Tabatadze, V. Gabunia, A. Kutsia, M. Barbakadze, M. Rekhviashvili

ti pis Si0,95Ge0,05 n- da p-ti Senadnobebis damuSaveba da maTfuZeze haerze 1000°C temperaturamde momuSave Termoeleqtruli batareis Seqmna

Ilia Vekua Sukhumi Institute of Physics and Technology,7Mindeli str.0186, Tbilisi, Georgia E-mail:sipt@sipt.org

k. barbaqaZe, m. biliseiSvili, z. isakaZe, i. tabataZe, v. gabunia, a. kucia, m. barbaqaZe, m. rexviaSvili

The paper presents investigation results of the thermoelectric n- and p-type Si0,95Ge0,05alloys. The samples have been obtained with the methods of components joint melting and powders hotpressing, obtained by jointly grinding of the components. The samples’ thermoelectric characteristics of cast and hot pressing has, been studied. The materials for the contact of hot and cold ends of the thermoelectric battery, has been selected. The thermoelectric battery based on Si0,95Ge0,05n- and p-type alloys, synthesized by hot pressing has been created. The electric properties and thermal stability the batteries in the temperature range of 600-130°C gradient has been studied.

soxumis ilia vekuas fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo el–fosta: sipt@sipt.org naSromSi warmodgenilia n- da p-ti pis Termoeleqtruli Si0,95Ge0,05Senadnobebis kvlevis Sedegebi. nimuSebi damzadebulia komponentebis erToblivi dnobiTa da komponentebis erToblivi dafqviT miRebuli fxvnilis cxeli wnexviT. Seswavlilia nadnobi da dawnexili nimuSebis Termoeleqtruli maxasiaTeblebi. SerCeulia Termoeleqtruli batareis civi da cxeli boloebis sakomutacio masalebi. Seqmnilia Termoeleqtruli batareebi cxeli wnexvis meTodiT sinTezirebuli n- da p-ti pis Si0,95Ge0,05 Senadnobebis fuZeze.

Seswavlilia maTi eleqtruli maxasiaTeblebi da Termuli mdgradoba 600-130°C temperaturul gradientSi.

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Ãàçîôàçíûå ìåòîäû â ðàçðàáîòêàõ òåðìîýëåêòðè÷åñêèõ ïðåîáðàçîâàòåëåé è ãåòåðîýïèòàêñèàëüíûõ ñòðóêòóð À. Æóðàâëåâ1, Á. Øèðîêîâ1, À. Øèÿí1, Ã. Áîêó÷àâà2, Ã. Äàðñàâåëèäçå2 Íàöèîíàëüíûé íàó÷íûé öåíòð «Õàðüêîâñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò»,óë. Àêàäåìè÷åñêàÿ 1, 61108,Õàðüêîâ, Óêðàèíà.

2 Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì.àêàä. È.Í. Âåêóà, óë. Ìèíäåëè 7,0186, Òáèëèñè, Ãðóçèÿ. Ýë–ïî÷òà:sipt@sipt.orgshirokov@kipt.kharkov.ua 1

Ðåçþìå. Âûïîëíåíû èññëåäîâàíèÿ ïî ïîëó÷åíèþ êàðáèäà áîðà è êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ ãàçîôàçíûì ìåòîäîì. Îïðåäåëåíà äîáðîòíîñòü ð- è n- âåòâåé òåðìîýëåìåíòîâ êàðáèäà áîðà è êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ. Ðàññ÷èòàííûé êîýôôèöèåíò ïîëåçíîãî äåéñòâèÿ òåðìîïðåîáðàçîâàòåëÿ èç âåòâåé B6,5C – ïëàçìîõèìè÷åñêèé è (Si0,7Ge0,3 + 0,3%Ð) – ãàçîôàçíûé, ñîñòàâëÿåò 5% Ïîëó÷åíû ãåòåðîýïèòàêñèàëüíûå ñòðóêòóðû ãàçîôàçíûì, ïëàçìîõè-ìè÷åñêèì è ñóáëèìàöèîííûì îñàæäåíèåì ýïèòàêñèàëüíûõ ïëåíîê íà ìîíîêðèñòàëëè÷åñêèå ïîäëîæêè êðåìíèÿ è êðåìíèé-ãåðìàíèÿ. Îñàæäåííûå ãåòåðîýïèòàêñèàëüíûå ñòðóêòóðû îáåñïå÷èâàþò ïðèåì ñèãíàëà â áëèæíåé èíôðàêðàñíîé îáëàñòè ñïåêòðàëüíîãî äèàïàçîíà

Ââåäåíèå  íàñòîÿùåå âðåìÿ áîëüøîå âíèìàíèå óäåëÿåòñÿ ñîçäàíèþ ýôôåêòèâíûõ óñòðîéñòâ äëÿ ïðÿìîãî ïðåîáðàçîâàíèÿ òåïëîâîé ýíåðãèè â ýëåêòðè÷åñêóþ. Îñíîâîé ïðåîáðàçóþùèõ óñòðîéñòâ ÿâëÿþòñÿ òåðìîýëåìåíòû èç ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ. Ìàòåðèàëîì äëÿ âûñîêîòåìïåðàòóðíûõ òåðìîýëåìåíòîâ ÿâëÿþòñÿ êðåìíèé-ãåðìàíèåâûå ñïëàâû ñ ïðèìåñÿìè áîðà (ð-òèï) èëè ôîñôîðà (n-òèï). Ìåòîäîì ïîëó÷åíèÿ êðåìíèéãåðìàíèåâûõ ñïëàâîâ ÿâëÿåòñÿ ãîðÿ÷åå ïðåññîâàíèå ïîðîøêîâ â âàêóóìå. Ïîëó÷åííûå òàêèì ìåòîäîì ñïëàâû íå îáëàäàþò íåîáõîäèìîé ãîìîãåííîñòüþ. Êðîìå òîãî, íåäîñòàòî÷íîé ÿâëÿåòñÿ ðàäèàöèîííàÿ ñòîéêîñòü êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ, îñîáåííî ðòèïà. Íåîáõîäèìîñòü â ðàäèàöèîííîñòîéêèõ òåðìîïðåîáðàçîâàòåëÿõ îáóñëîâëåíà òåì, ÷òî äëÿ òåðìîýëåêòðè÷åñêèõ ãåíåðàòîðîâ ÷àñòî èñïîëüçóþòñÿ ÿäåðíûå ýíåðãåòè÷åñêèå óñòàíîâêè.  ïîñëåäíèå âðåìÿ áîëüøîé èíòåðåñ âûçûâàþò ãåòåðîñòðóêòóðû íà îñíîâå ëåãèðîâàííûõ òâåðäûõ ðàñòâîðîâ Si-Ge.  ñïëàâàõ ñèñòåìû Si-Ge èìååòñÿ âîçìîæíîñòü ïëàâíîãî ðåãóëèðîâàíèÿ ïàðàìåòðà ðåøåòêè è øèðèíû çàïðåùåííîé çîíû, ÷òî ìîæåò áûòü óñïåøíî èñïîëüçîâàíî â îïòîýëåêòðîííûõ ïðèáîðàõ äëÿ èçìåíåíèÿ ÷àñòîòû ãåíåðèðóåìîãî èëè ïðèíèìàåìîãî ýëåêòðîìàãíèòíîãî èçëó÷åíèÿ[1].

Ìàòåðèàëû è ìåòîäû èññëåäîâàíèÿ Ïîëó÷åíèå êàðáèäà êðåìíèÿ è ðàçíîîáðàçíûõ ñòðóêòóð ñïëàâîâ Si-Ge ïðîâîäèëîñü íà óñòàíîâêå ãàçîôàçíîãî îñàæäåíèÿ [2]. Íà ðèñ. 1 ïðèâåäåíà ñõåìà óñòàíîâêè äëÿ ïîëó÷åíèÿ êîíäåíñàòîâ êàðáèäà áîðà è êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ. Íà ýòîé æå óñòàíîâêå ïðîèçâîäèëîñü ïëàçìîõèìè÷åñêîå âîññòàíîâëåíèå SiCl4 è GeCl4.

Ðèñ. 1. Ñõåìà óñòàíîâêè ãàçîôàçíîãî îñàæäåíèÿ.

1 – ðåàêöèîííàÿ êàìåðà, 2 – ôîðêàìåðû, 3 – ãåíåðàòîð, 4 – ïîäëîæêà, 5 – èíäóêòîð, 6 – àçîòíûå ëîâóøêè, 7 – ôîðíàñîñ, 8 – èñòî÷íèê ïèòàíèÿ íàãðåâàòåëÿ, 9 – ñìîòðîâîå îêíî.

Äëÿ ôîðìèðîâàíèÿ ýïèòàêöèàëüíûõ ñòðóêòóð ñóáëèìàöèîííûì ìåòîäîì ïðåäâàðèòåëüíî ãàçîôàçíûì ìåòîäîì ñîçäàâàëèñü ñóáëèìàöèîííûå èñòî÷íèêè.

Ýêñïåðèìåíòàëüíûå ðåçóëüòàòû Îñàæäåíèå êàðáèäà áîðà îñóùåñòâëÿëè ïóòåì âîäîðîäíîãî âîñ-ñòàíîâëåíèÿ òðåõõëîðèñòîãî áîðà â ïàðàõ òîëóîëà â ðåàêòîðå ïðîòî÷íîãî òèïà íà ïîäëîæêàõ èç ãðàôèòà, ïðîïèòàííîãî ïèðîóãëåðîäîì. Äëÿ îáåñïå÷åíèÿ ðàâíîìåðíîñòè è ñîñòàâà ïîêðûòèé ïî äëèíå îáðàçöà ðàñõîäû èñõîäíûõ ðåàãåíòîâ, ñêîðîñòü îòêà÷êè è ïàðöèàëüíûå äàâëåíèÿ âûáèðàëèñü òàê, ÷òîáû ïàðîãàçîâûé ïîòîê áûë âÿçêîñòíûì, ëàìèíàðíûì, áåç êîíâåêòèâíûõ òîêîâ. Âûïîëíåííûå ðàñ÷åòû êðèòåðèåâ òåîðèè ïîäîáèÿ ïîçâîëèëè îïðåäåëèòü äèàïàçîí ïàðàìåòðîâ, â êîòîðûõ âûïîëíÿþòñÿ ýòè óñëîâèÿ.

116 Èññëåäîâàíû êèíåòè÷åñêèå îñîáåííîñòè îñàæäåíèÿ êàðáèäà áîðà èç ïàðîãàçîâîé ñìåñè ÂÑl3 - Ñ7 Í 8 - Í2. Îñàæäåíèå êàðáèäà áîðà ïðîâîäèëè â äèàïàçîíå äàâëåíèé 13,3 – 13,3·10 3 Ïà. Ðàñõîä âîäîðîäà ïîääåðæèâàëè íà óðîâíå 60 ë/÷àñ. Îòíîøåíèå ïàðöèàëüíûõ äàâëåíèé ÂÑl3 ê Ñ7 Í 8 íàõîäèëîñü â ïðåäåëàõ (2 ∑ 8): (0,75 ∑ 3). Òåìïåðàòóðíûé äèàïàçîí - 1000 ∑ 1700 °Ñ. Óñòàíîâëåíî, ÷òî ïîâûøåíèå òåìïåðàòóðû îñàæäåíèÿ îò 1000°Ñ äî 1700°Ñ óâåëè÷èâàåò ñêîðîñòü îñàæäåíèÿ êîíäåíñàòîâ, äîñòèãàÿ ìàêñèìóìà ïðè òåìïåðàòóðàõ 1600 – 1650 °Ñ. Èçìåíåíèå îòíîøåíèÿ òîëóîëà ê òðåõõëîðèñòîìó áîðó îò 0,75 äî 3 ïðè òåìïåðàòóðå îñàæäåíèÿ 1350 °Ñ ïðèâîäèò ê óâåëè÷åíèþ ñêîðîñòè îñàæäåíèÿ Â4Ñ â äâà ðàçà. Ïðè òåìïåðàòóðàõ íèæå 1400 °Ñ îñàæäàþòñÿ êîíäåíñàòû ñ îòêëîíåíèåì ñîñòàâà â ñòîðîíó óâåëè÷åíèÿ ñîäåðæàíèÿ áîðà. Ñ ïîâûøåíèåì òåìïåðàòóðû êîíöåíòðàöèÿ áîðà â êîíäåíñàòàõ ïàäàåò è ïðè òåìïåðàòóðå âûøå 1400 °Ñ â êîíäåíñàòàõ óâåëè÷èâàåòñÿ êîíöåíòðàöèÿ óãëåðîäà.  äèàïàçîíå äàâëåíèé 1,33 – 13,3 Ïà. îò Â×ãåíåðàòîðà â ðåàêöèîííîé êàìåðå âîçáóæäàëè âûñîêî÷àñòîòíûé ðàçðÿä íà ïàðîãàçîâîé ñìåñè. Äëÿ ýôôåêòèâíîãî óïðàâëåíèÿ ïëàçìîõèìè÷åñêèì ïðîöåññîì èññëåäîâàëèñü ýíåðãåòè÷åñêèå õàðàêòåðèñòèêè çàðÿæåííûõ ÷àñòèö íèçêîòåìïåðàòóðíîé ïëàçìû. Ïàðàìåòðû ýëåêòðîííîé êîìïîíåíòû ïëàçìû îïðåäåëÿëè èç âîëüòàìïåðíûõ õàðàêòåðèñòèê (ÂÀÕ) îäèíî÷íîãî è äâîéíîãî çîíäîâ.Èññëåäîâàëàñü ôóíêöèÿ ðàñïðåäåëåíèÿ ýëåêòðîíîâ ïî ýíåðãèÿì (ÔÐÝÝ), è ôóíêöèÿ ðàñïðåäåëåíèÿ àòîìîâ âîäîðîäà ïî ýíåðãèÿì (ÔÐÀÝ).  ÔÐÝÝ íàáëþäàåòñÿ óâåëè÷åíèå êîíöåíòðàöèè âûñîêîýíåðãåòè÷íûõ ýëåêòðîíîâ â ñðàâíåíèè ñ ðàñïðåäåëåíèåì Ìàêñâåëëà. Âûñîêîýíåðãåòè÷íûå ýëåêòðîíû îñóùåñòâëÿþò äèññîöèàöèþ ìîëåêóëÿðíîãî âîäîðîäà. Íàëè÷èå àòîìàðíîãî âîäîðîäà ñóùåñòâåííî âëèÿåò íà êèíåòèêó ïëàçìîõèìè÷åñêèõ ïðåâðàùåíèé. Âîçáóæäåíèå âûñîêî÷àñòîòíîãî èíäóêöèîííîãî ðàçðÿäà â ïàðîãàçîâîé ñìåñè ñïîñîáñòâóåò ñíèæåíèþ íà 200 – 2500Ñ òåìïåðàòóðû îñàæäåíèÿ êàðáèäà áîðà. Ñòåõèîìåòðè÷åñêèé ñîñòàâ â êîíäåíñàòàõ ïðè ïëàçìîõèìè÷åñêîì îñàæäåíèè äîñòèãàåòñÿ ïðè áîëåå íèçêèõ òåìïåðàòóðàõ îñàæäåíèÿ, ÷åì â ãàçîôàçíîì âàðèàíòå. Ïðè ïëàçìîõèìè÷åñêîì îñàæäåíèè ýíåðãèÿ àêòèâàöèè ïðîöåññà íà 7 - 8 êÄæ/ìîëü íèæå ýíåðãèè àêòèâàöèè ïðîöåññà ãàçîôàçíîãî îñàæäåíèÿ. Îñàæäåíèå êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ âîäîðîäíûì âîññòàíîâ-ëåíèåì õëîðèäîâ êðåìíèÿ è ãåðìàíèÿ. Ãàçîôàçíîå îñàæäåíèå êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ îñóùåñòâëÿëîñü ñîâìåñòíûì âîäîðîäíûì âîññòàíîâëåíèåì õëîðèäîâ êðåìíèÿ è ãåðìàíèÿ íà óñòàíîâêå, ñõåìà êîòîðîé ïðèâåäåíà íà ðèñ.1. Ñ èñïîëüçîâàíèåì êðèòåðèåâ òåîðèè ïîäîáèÿ ðàññìîòðåíû ãàçîäèíàìè÷åñêèå ïàðàìåòðû ïàðîãàçîâîãî ïîòîêà ïðè îáòåêàíèè ïîêðûâàåìîé ïîâåðõíîñòè â ðåàêòîðå ïðîòî÷íîãî òèïà. Ðàñ÷åòû âûïîëíåíû äëÿ äèàïàçîíà

òåìïåðàòóð 700 – 12000Ñ, ðàñõîäîâ ïàðîãàçîâîé ñìåñè äî 400 ë/÷àñ, äèàïàçîíà äàâëåíèé 13,3 – 13,3·103 Ïà, äèàìåòðà ðåàêöèîííîé êàìåðû 150 ìì, äëèíîé 600 ìì.  óêàçàííûõ óñëîâèÿõ ïàðîãàçîâûé ïîòîê ÿâëÿåòñÿ âÿçêîñòíûì, ëàìèíàðíûì, áåç êîíâåêòèâíûõ òîêîâ. Âûïîëíåí òåðìîäèíàìè÷åñêèé àíàëèç èçîáàðíîèçîòåðìè÷åñêîãî ïîòåíöèàëà ðåàêöèé âîäîðîäíîãî âîññòàíîâëåíèÿ õëîðèäîâ êðåìíèÿ è ãåðìàíèÿ. Èçîáàðíî-èçîòåðìè÷åñêèé ïîòåíöèàë ðåàêöèè âîäîðîäíîãî âîññòàíîâëåíèÿ õëîðèäà êðåìíèÿ ñòàíîâèòñÿ îòðèöàòåëüíûì ïðè òåìïåðàòóðàõ âûøå 9000Ñ, õëîðèäà ãåðìàíèÿ ïðè òåìïåðàòóðàõ âûøå 6000Ñ. Ñíèæåíèå äàâëåíèÿ ïðèâîäèò ê ñìåùåíèþ êðèâûõ â ñòîðîíó áîëåå íèçêèõ òåìïåðàòóð. Èññëåäîâàíà êèíåòèêà âîäîðîäíîãî âîññòàíîâëåíèÿ õëîðèäîâ êðåìíèÿ, ãåðìàíèÿ, êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ. Ïîêàçàíî, ÷òî ïðèñóòñòâèå â ïàðîãàçîâîé ñìåñè õëîðèäà ãåðìàíèÿ èíòåíñèôèöèðóåò îñàæäåíèå êðåìíèÿ â ñïëàâå. Àíàëèç êèíåòè÷åñêèõ çàâèñèìîñòåé ñêîðîñòè îñàæäåíèÿ ñïëàâîâ îò òåìïåðàòóðû è ñîîòíîøåíèé èñõîäíûõ ðåàãåíòîâ ïîêàçàë, ÷òî ïðîöåññ îñàæäåíèÿ ñïëàâîâ ïðè òåìïåðàòóðå 1100 – 12000Ñ îñóùåñòâëÿåòñÿ â äèôôóçèîííîé îáëàñòè.  ñòàäèè äèôôóçèîííîãî êîíòðîëÿ ïîëó÷åíû îáðàçöû êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ ñ ðàçëè÷íûì ñîäåðæàíèåì ãåðìàíèÿ. Îïðåäåëåíèå êîíöåíòðàöèè ãåðìàíèÿ â îáðàçöàõ ïðîâîäèëîñü ÿäåðíî-ôèçè÷åñêèì ìåòîäîì ïî ðåãèñòðàöèè õàðàêòåðèñòè÷åñêîãî ðåíòãåíîâñêîãî èçëó÷åíèÿ, âîçáóæäàåìîãî óñêîðåííûìè ïðîòîíàìè. Îïðåäåëåíèå äîáðîòíîñòè (Z) è êîýôôèöèåíòà ïîëåçíîãî äåéñòâèÿ (ç) Äîáðîòíîñòü è êîôôèöèåíò ïîëåçíîãî äåéñòâèÿ òåðìîïðåîáðàçîâàòåëÿ îïðåäåëÿëèñü èç âûðàæåíèé:

ãäå T = (TH +TC)/2, TH è TC – àáñîëþòíûå òåìïåðàòóðû ãîðÿ÷åãî è õîëîäíîãî êîíöîâ òåðìîýëåìåíòà. Ïðè ðàñ÷åòàõ ïðèíèìàëîñü, ÷òî TC = 300 Ê, à TH= 1200 Ê. Äëÿ îáðàçöîâ Â4Ñ è Â6,5Ñ, ïîëó÷åííûõ ãàçîôàçíûì ìåòîäîì, âåëè÷èíà äîáðîòíîñòè èìååò çíà÷åíèå 0,31·103 è 1·10-31/ãðàä, ñîîòâåòñòâåííî, à ïëàçìîõèìè÷åñêèì ìåòîäîì – 1,3·10-3 1/ãðàä. Äîáðîòíîñòü n-âåòâè îáðàçöîâ èç ãàçîôàçíîãî ñïëàâà Si0,7Ge0,3 + 0,3% Ð ðàâíà 0,39·103 1/ãðàä.

117

Ðèñ.2. Èçìåðåííûå çàâèñèìîñòè ýëåêòðîïðîâîäíîñòè, òåïëîïðîâîäíîñòè è òåðìî-ÝÄÑ äëÿ îáðàçöîâ êàðáèäà áîðà (Â6,5Ñ), ïîëó÷åííûõ ãàçîôàçíûì è ïëàçìîõèìè÷åñêèì ìåòîäàìè

Äîáðîòíîñòü òåðìîïðåîáðàçîâàòåëÿ èç âåòâåé (Si0,7Ge0,3 + 0,3%Ð)ãàç – (Â6,5Ñ)ãàç ñîñòàâëÿåò 2,2.10-4 1/ ãðàä, à ÊÏÄ – 4,4%. Åùå ëó÷øå ïîêàçàòåëè òåðìîïðåîáðàçîâàòåëÿ èç n-âåòâè (Si0,7Ge0,3 + 0,3%Ð)ãàç è ð-âåòâè èç ïëàçìîõèìè÷åñêîãî Â6,5Ñ. Äîáðîòíîñòü òàêîé ïàðû ñîñòàâëÿåò 2,5.10-4 1/ãðàä, à ÊÏÄ – 5,0%. Ãåòåðîýïèòàêñèàëüíûå ñòðóêòóðû Èññëåäîâàíèÿ ïî îñàæäåíèþSiGe ñïëàâîâ ïðîâîäèëèñü íà óñòàíîâêå, ðèñ.1  êà÷åñòâå ïîäëîæåê èñïîëüçîâàëèñü ïëàñòèíêè ìîíîêðèñòàëëè÷åñêîãî êðåìíèÿ è êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ ñ îðèåíòàöèåé (111). Ïåðåä óñòàíîâêîé â êàìåðó ïîäëîæêè ïîäâåðãàëàñü õèìè÷åñêîé îáðàáîòêå â ñìåñè àçîòíîé, ïëàâèêîâîé è óêñóñíîé êèñëîò â ñîîòíîøåíèè 9:2:4. Äëÿ óäàëåíèÿ îñòàòî÷íîé îêèñíîé ïëåíêè íåïîñðåäñòâåííî ïåðåä íàíåñåíèåì ýïèòàêñèàëüíîãî ñëîÿ ïîäëîæêó îòæèãàëè â î÷èùåííîì âîäîðîäå ïðè 1100 °Ñ â òå÷åíèå 30 ìèíóò. Íàíåñåíèå ýïèòàêñèàëüíûõ ñëîåâ SiGe ñ ðàçíûì ñîäåðæàíèåì ãåðìàíèÿ íà ïîäëîæêè èç Si ïðîâîäèëè èç îäíîãî êîíòåéíåðà ñî ñìåñüþ òåòðàõëîðèäîâ êðåìíèÿ è ãåðìàíèÿ. ðåçóëüòàòå ýêñïåðèìåíòîâ áûëè îïðåäåëåíû äèàïàçîíû ïàðàìåòðîâ îñàæäåíèÿ: òåìïåðàòóðà 980 - 1130 °Ñ, ðàñõîä SiCl4 – 2-4 ë/÷àñ, ðàñõîä Í2 – 50 - 90 ë/÷àñ, äàâëåíèå â ðåàêöèîííîì îáúåìå 0,4 – 4,0 êÏà.Òîëùèíà ïëåíîê îïðåäåëÿëàñü èíòåðôåðåíöèîííûì ìåòîäîì Ïëàçìîõèìè÷åñêîå âîññòàíîâëåíèå SiCl4 è GeCl4 (PCVD-ìåòîä) Èññëåäîâàíèÿ ïî ïîëó÷åíèþ êðåìíèé-ãåðìàíèåâûõ ñïëàâîâ âîññòàíîâëåíèåì õëîðèäîâ êðåìíèÿ è ãåðìàíèÿ â âîäîðîäíîé íèçêîòåìïåðàòóðíîé íåðàâíîâåñíîé ïëàçìå Â×-ðàçðÿäà ïðîâîäèëèñü íà óñòàíîâêå, ðèñ.1. Âîçáóæäåíèå ðàçðÿäà â ñìåñè èç òåòðàõëîðèäîâ êðåìíèÿ

è ãåðìàíèÿ ñ âîäîðîäîì îñóùåñòâëÿëîñü èíäóêòîðîì âûñîêî÷àñòîòíîãî ãåíåðàòîðà Â×È-63/044 ñ ÷àñòîòîé 440 êÃö, ðàñïîëîæåííûì ñíàðóæè ðåàêòîðà. Ðàçðÿä çàæèãàëè ïðè óñòàíîâëåíèè äàâëåíèÿ ïàðîãàçîâîé ñìåñè â ðåàêöèîííîì îáúåìå 30 Ïà. Òåìïåðàòóðà îñàæäåíèÿ ñîñòàâëÿëà 700 – 800 °Ñ. Ñîîòíîøåíèå GeCl4/SiCl4 íå ïðåâûøàëî 0,05. Ïðè ýòèõ óñëîâèÿõ ñêîðîñòü îñàæäåíèÿ áûëà ~ 100 Å /ìèí. Ýêñïåðèìåíòàëüíî óñòàíîâëåíî, ÷òî âîçáóæäåíèå âûñîêî÷àñòîòíîãî èíäóêöèîííîãî ðàçðÿäà â ïàðîãàçîâîé ñìåñè ñïîñîáñòâóåò ñíèæåíèþ òåìïåðàòóðû îñàæäåíèÿ íà 200-250 0Ñ, ÷òî ìîæíî îáúÿñíèòü àêòèâàöèåé ïðîöåññà îñàæäåíèÿ âîçáóæäåííûìè ÷àñòèöàìè ïëàçìû. Ðåàêöèè â ðàçðÿäå ïðîòåêàþò ïîä âîçäåéñòâèåì âûñîêîýíåðãåòè÷íûõ ýëåêòðîíîâ. Òàêèå ýëåêòðîíû â ìåíüøåé ñòåïåíè ïîäâåðæåíû àêòàì çàõâàòà ìîëåêóëàìè ãàëîãåíèäîâ. Ïîëó÷åííûå, â ðåçóëüòàòå âîçäåéñòâèÿ âûñîêîýíåðãåòè÷íûõ ýëåêòðîíîâ íà ìîëåêóëÿðíûé âîäîðîä, àòîìû âîäîðîäà çàìåòíî óñêîðÿþò õèìè÷åñêèå ïðîöåññû â ðåàêöèÿõ âîññòàíîâëåíèÿ ãàëîãåíèäîâ [3]. Ïîëó÷åíèå ýïèòàêñèàëüíûõ ïëåíîê èç ñóáëèìàöèîííûõ èñòî÷íèêîâ Ïîëó÷åíèåýïèòàêñèàëüíûõ ñòðóêòóð ñ ðåçêèìè ãðàíèöû ðàçäåëà âîçìîæíî ìåòîäîì ñóáëèìàöèîííîãî îñàæäåíèÿ èç ñèëèöèäîâ òóãîïëàâêèõ ìåòàëëîâ [4]. Ñèëèöèäíûå ïîêðûòèÿ îáëàäàþò ñïîñîáíîñòüþ ïðè íàãðåâå íà âîçäóõå ôîðìèðîâàòü íà ïîâåðõíîñòè ñàìîçàëå÷èâàþùóþñÿ îêñèäíóþ ïëåíêó SiO2 , êîòîðàÿ ïðåäîòâðàùàåò ïðîíèêíîâåíèå êèñëîðîäà ê ïîâåðõíîñòè ìåòàëëîâ [5] Ïðè íàãðåâå ñèëèöèäíûõ ïîêðûòèé â âàêóóìå, èç-çà îòñóòñòâèÿ êèñëîðîäà, ïðîèñõîäèò èñïàðåíèå êðåìíèÿ.

118 Êàê âèäíî èç ðèñ. 3 ìàêñèìàëüíîå äàâëåíèå ïàðà Si, ïðè òåìïåðàòóðå áëèçêîé ê ïëàâëåíèþ 1620 K ñîñòàâëÿåò ~ 5Ïà. [6].

 òàáëèöå ïðèâåäåíà ãåòåðîýïèòàêñèàëüíàÿ ñòðóêòóðà îáåñïå÷èâàþùàÿ ïðèåì ñèãíàëà â áëèæíåì èíôðàêðàñíîì äèàïàçîíå.

Çàêëþ÷åíèå

Ðèñ.3. Çàâèñèìîñòü äàâëåíèÿ ïàðà ðàáî÷èõ âåùåñòâ îò òåìïåðàòóðû. 1 – êðèñòàëëè÷åñêèé êðåìíèé, Si; 2 – äèñèëèöèä âîëüôðàìà, WSi2

Ñóáëèìàöèîííûé èñòî÷íèê èçãîòàâëèâàëñÿ ãàçîôàçíûì ìåòîäîì. Íà òóãîïëàâêèé ìåòàëë (W, Mo) îñàæäàëè ïîêðûòèå èç ïàðîãàçîâîé ñìåñè SiCl4 + GeCl4 + BCl3 (PCl3) +H2â îïðåäåëåííûõ ñîîòíîøåíèÿõ..Íà ðèñ.

4 ïðèâåäåíà ñõåìà ýêñïåðèìåíòàëüíîé óñòàíîâêè äëÿ îñàæäåíèÿ ýïèòàêñèàëüíûõ ïëåíîê ñóáëèìàöèîííûì ìåòîäîì

Ðèñ. 4. Ñõåìà óñòàíîâêè äëÿ íàíåñåíèÿ ñòðóêòóð:1 – çàùèòíûé êîëïàê; 2 –âàêóóìíàÿ êàìåðà; 3 – òåïëîâûå ýêðàíû; 4 –ñóáëèìàöèîííûé èñòî÷íèê; 5 – ïîäëîæêà; 6 – èñòî÷íèê ïèòàíèÿ; 7 – ñèñòåìà îòêà÷êè; 8 – çàñëîíêà; 9 – äîïîëíèòåëüíûå ýêðàíû; 10 – íàãðåâàòåëü; 11 – èçîëÿòîð; 12 – òîêîââîäû.

Ïðîâåäåíû èññëåäîâàíèÿ ïî ðàçðàáîòêå âûñîêîòåìïåðàòóðíîé, ñòîéêîé ê âîçäåéñòâèþ ðàäèàöèîííîãî èçëó÷åíèÿ ð-âåòâè èç êàðáèäà áîðà.  êà÷åñòâå n-âåòâè èñïîëüçîâàëñÿ êðåìíèé-ãåðìàíèåâûé ñïëàâ, ëåãèðîâàííûé ôîñôîðîì Îñàæäåíèå ìíîãîñëîéíûõ ãåòåðîýïèòàêñèàëüíûõ ñòðóêòóð îñóùåñòâëåíî âîäîðîäíûì âîññòàíîâëåíèåì õëîðèäîâ êðåìíèÿ è ãåðìàíèÿ è ñóáëèìàöèåé íà ìîíîêðèñòàëëè÷åñêèõ ïîäëîæêàõ êðåìíèÿ è êðåìíèéãåðìàíèåâûõ ñïëàâîâ Ëèòåðàòóðà 1. Þ. Á. Áîëõîâèòÿíîâ, Î. Ï. Ï÷åëÿêîâ, Ñ. È. ×èêè÷åâ.// Êðåìíèé-ãåðìàíèåâûå ýïèòàêñèàëüíûå ïëåíêè: ôèçè÷åñêèå îñíîâû ïîëó÷åíèÿ íàïðÿæåííûõ è ïîëíîñòüþ ðåëàêñèðîâàííûõ ñòðóêòóð.// ÓÔÍ, òîì171, 7, ñ.

689 – 715.

2. Lonin Yu.F., Pilipets Yu.O., Khovansky N.A., Sheremet V.I., Shirokov B.M//Installation for gas-phase deposition of materials // Is published in a magazine Problems of an atomic science and engineering. A series «Nuclear Physics Investigations» v.

1(42), 2004 ã., page 221-222 3. ÁîáûëüÀ. Â., ÊàðìàíåíêîÑ. Ô. //Ôèçèêîõèìè÷åñêèåîñíîâûòåõíîëîãèèïîëóïðîâîäíèêîâ. Ïó÷êîâûå è ïëàçìåííûå ïðîöåññû â ïëàíàðíîé òåõíîëîãèè // Ó÷åá. ïîñîáèå. ÑÏá. Èçä-âî Ïîëèòåõí. óíòà, 2005. 113 ñ.

4. À . à . Äåíèñîâ è äð. // Ìîëåêóëÿðíûå èñòî÷íèêè óñòàíîâîê äëÿ ìîëåêóëÿðíî-ëó÷åâîé ýïèòàêñèè//Îáçîðû ïî ýë. òåõíèêå, ñåð. 7, âûï. 12, 1986.

5. Äçÿäûêåâè÷ Þ.Â. // Æàðîñòîéêèå ïîêðûòèÿ äëÿ ìîëèáäåíà è ñïëàâîâ íà åãî îñíîâå // Ïîðîøêîâàÿ ìåòàëëóðãèÿ.- 1988. – 2 – ñ. 41 - 48.

6. Â.Ï. Êóçíåöîâ, À.Þ. Àíäðååâ, Î.À. Êóçíåöîâ, Ë.Å. Íèêîëàåâà, Ò.Ì. Çîòîâà, Í.Â. Ãóäêîâà.// Íåîðã. ìàòåð., 27, 1337 (1991).

119

The gas-phase deposition methods in the development of thermoelectric converters and heteroepitaxial structures A. Juravlev1, B. Shirokov1, A. Shiyan1, G. Bokuchava2, G. Darsavelidze2.

1 National Science Center „Kharkov Institute of Physics and Technology“, 1 Academicheskaya St., Kharkov, 61108, Ukraine 2 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli str.0186, Tbilisi, Georgia E-mail:shirokov@kipt.kharkov.ua , sipt@sipt.org

Studies on development of high-temperature and resistant to radiation impact of boron carbide p-branches are conducted. Phosphorus doped silicon-germanium alloy used as an n-branch. The deposition of multilayer heteroepitaxial structures accomplished by methods hydrogen reduction of silicon and germanium chloride and by sublimation of Si-Ge alloys on monocristalline Si and Si-Ge substrates.

gazfazuri meTodebi Termoeleqtruli gardamqnelebisa da heteropitaqsiuri struqturebis damuSavebaSi a. Juravliovi1, b . Sirokovi1, a.Siiani1, g. bokuCava2, g. darsaveliZe2 1 erovnuli samecniero centri, xarkovis fizika–teqnikis instituti, akademiCeskaias q. 1, 61108, xarkovi, ukraina 2 soxumis ilia vekuas fizika–teqnikis instituti, mindelisq. 7, 0186, Tbilisi, saqarTvelo el–fosta: shirokov@kipt.kharkov.uasipt@sipt.org

Sesrulebulia boris karbidis da silicium– germaniumis kondensantebis gazfazuri miRebis kvleviTi samuSaoebi. gansazRvrulia Termo elementis Semadgeneli boris karbidisa da silicium–germaniumis Senadnobebis p– da n–ti pis Stoebis efeqturoba. gaTvlebiT dadgenilia, rom plazmoqimiuri B6.25C da gazfazuri Si0.7Ge0.3+3% p StoebiT Sedgenili Termoeleqtruli gardamqnelis m.q.k. Seadgens 5%. monokristalur Si da Si–Ge fuZeSreebze gazfazuri, plazmaqimiuri da sublimaciuri dafarvis meTodebiT Seqmnilia heteropitaqsiuri struqturebi. maTi saSualebiT SesaZlebelia signalebis miReba speqtruli diapazonis axlo infrawiTel areSi.

120

Metrology of thermoelectric materials V. Lysko Institute of Thermoelectricity NAS of Ukraine 1, Nauky Str., Chernivtsi, 58029, Ukraine, E-mail: anatych@gmail.com Abstract. The report provides the analysis of the impact of the accuracy of measurements of thermoelectric properties of materials on the progress in improving their figure of merit.

The reasons for the lack of accuracy of measurements of parameters of materials is given and ways to improve the metrological quality of the measurements is considered. The results of computer simulation of various measurement techniques are provided. They confirm the advantage of the absolute method. The methods of minimizing the errors in the measurement of the properties of materials absolute method are also presented.

The high-precision equipment to measure the parameters of materials for the temperature range of 30 - 900 ° C was developed. The conductivity measurement errors were minimized to 1.5%, thermoelectric power to 1.5%, the thermal conductivity to 5%. To create a fully automated equipment for measuring thermoelectric material parameters, the accuracy of which is superior to the known analogues was developed.

Keywords: errors, measurements, thermoelectric parameters, automatic equipment.

Introduction It is known that recent decades have seen no considerable improvement of thermoelectric materials quality [1, 2].

As before, the best materials used in thermoelectric power converters for generation and refrigeration equipment are Bi – Te, Pb – Te, and Ge – Si compounds and, sometimes, others.

Various methods are used to devise new materials and improve the existing ones. Chemical composition is changed, various impurities are introduced and various material structures are used - inhomogeneous, nanostructures, powders and others. The influence of these effects on material is determined experimentally by measurement of electric conductivity σ, thermopower α, thermal conductivity ê and figure of merit Z. Analysis of known methods and equipment for measurement of thermoelectric material properties has shown that the errors in determination of thermoelectric figure of merit Z achieve 10-15% [3-5]. The largest values of errors in the determination of figure of merit occur when measuring the electric conductivity, thermopower and thermal conductivity on different samples. Thus, thermal conductivity errors are 3 to 7% (guarded hot plate method, heat flux measurement method, laser flash method), electric conductivity errors – 2 to 3% (two-probe method, four-probe method, Van der Paw method), the Seebeck coefficient errors – 2 to 5% (steady-state method, hot probe method) [413]. Thus, total error in the determination of figure of merit can reach 20%. Besides, as long as material is practically always slightly inhomogeneous, this leads to additional error, which is on the average 3 to 5%. Total error in the determination of Z in this case can reach 23 to 25%.

Such errors become an obstacle to solving the tasks of material figure of merit improvement, as long as measurement accuracy can prove to be lower than improvement of material properties with a change of affecting factors.

If the absolute method and the Harman methods are implemented, the results obtained can be considered more reliable.

A series of research [14-15] performed in the Institute of Thermoelectricity has shown that the errors during the figure of merit determination by the Harman method can be about 5-6% in some cases only, namely when a considerable number of additional parameters, such as the sample and the thermostat radiating properties, thermal conductivity of current leads and thermocouples etc., is known.

The absolute method seems to be more efficient as it allows instrumental minimizing of the majority of error sources.

It is widely used for creation of references and offers important advantages, namely σ,α,κ, and Z are simultaneously measured on the same sample, which reduces the errors; small-size samples can be used for measurement; thermoelectric parameters are found from classical formulae without corrections.

The purpose of this work is research aimed at minimization of errors in the measurement by the absolute method and creation of high-precision measurement equipment for complex determination of thermoelectric material properties over a wide temperature range.

Physical, mathematical and computer models of the absolute method A physical model of the method is given in Fig. 1. It comprises a sample which is in thermal and electrical contact with the thermostated base and a reference heat source on the upper surface of the sample. Under the ideal conditions the lateral and upper surfaces of the heat source are adiabatically isolated. Distortions in the determination of thermoelectric parameters are due to two main reasons.

121 The first reason results from instrumental errors in the determination of sample cross-section values, the distances between thermocouples and measuring probes, the values of current and potential difference between the probes, temperature difference, heat flow through the sample. With the use of up-to-date measurement equipment the total effect of these errors will be less than 0.2%.

The second component is method errors. They are due to a deviation from ideal physical model conditions, namely conditions of adiabaticity and uniformity of heat and current flows through the sample, as well as deviation from point-by-point measurements of measuring probes and thermocouples. The largest distortions take place in thermal conductivity measurement.

Heat Q which is released by the reference heater passes not only through the sample, but also through the electrodes connected to the sample. Moreover, there is heat rejection due to radiation and convection to the environment. The number of such heat losses depicted in Fig. 1 is 18. The situation is somewhat better when performing measurements in vacuum. In that case the values of distorting thermal flows are somewhat reduced, and the number of heat losses is decreased to 16. Electric conductivity measurement also involves problems. The presence of the Peltier and Joule heat creates sample nonisothermality which can cause gross errors.

Such problems are difficult to be solved analytically due to complexity of geometry, the presence of anisotropy and nonuniformity, the temperature dependences of sample material properties and structural members of measurement equipment. To calculate the temperature and electrical fields, as well as the effect of various factors on them, computer models of object-oriented simulation of real physical modes were used.

Such methods yield a solution of a system of secondorder differential equations in partial derivatives written as follows

(

)

⎧⎪−∇ ( κi + αi 2σiT + αi ϕσi ) ∇T − ∇ ( ( αi σiT + ϕσi ) ∇ϕ ) = 0, ⎨ −∇ ( σi ∇ϕ ) − ∇ ( σi αi∇T ) = 0. ⎪⎩

(i = 1..20)

(1) and derived from the laws of conservation of electrical charge and energy. In formula (1): αι,σι,κι are the Seebeck coefficient, the electrical and thermal conductivities of physical model elements, T is temperature, ϕ is electrical potential.

Computer model was built with the use of COMSOL Multiphysics application program package [16], which allows by means of finite element method to find a solution of system (1) with the respective boundary conditions.

Methods for reduction of errors

Fig. 2. Use of gradient radiation shield Fig. 1. Real physical model of the absolute method 1 –sample, 2, 3 – thermocouples, 4 – reference heater, 5 – pressure, 6 – electrodes

To determine the effect of these factors on measurement accuracy, it is necessary to solve a problem of finding the distributions of electrical potential and thermal flows in the presence of heat losses and the Joule and Peltier effect.

The elaborated computer model was used to obtain the distributions of heat and current flows in the sample and structural components of measurement installation and to study possible measurement errors.

They can be divided into two main groups. The first one is due to thermal radiation from the surface of sample and reference heater. According to investigations, these errors are the largest and can reach 75%. They were reduced with the use of additional heat source and radiation

122 shield (Fig. 2). The same temperature gradient is created on the shield as on the sample. However, due to re-radiation a radiation component along the sample is created. For this reason radiation from the sample surface remains large and results in thermal conductivity measurement errors up to 15-20%. It was proposed to use radiation rings on the shield and a shiny reflector on the base. In so doing, heat losses and, accordingly, the errors are reduced to 1.5%.

Fig. 3. Thermal switch

The second group of errors is due to losses of heat along the electrodes of sample and reference heater. For their minimization it was proposed to use the so-called thermal switches. They are components made of heat-conducting insulators, such as beryllium oxide, whose thermal conductivity is close to that of copper (Fig. 3). Mounted in them are electrodes that are brought in thermal contact with ceramics. The latter, in turn, is in thermal contact with the radiation shield. In this case the difference in temperatures on the electrodes is considerable, heat flow through the electrodes is minimized and the error values are minimized accordingly. Computer simulation showed that total error due to these losses will be ~ 0.5%.

Optimization calculations and computer simulation have shown that equalization of electric current and heat flow density requires metallization of sample ends. An optimal set of metal coatings was determined (Fig. 4.) Layer thicknesses: Ni – 10 μm, Cu – 100 μm, Ni – 10 μm, W – up to 200 μm.

Computer simulations were also made of electrical and thermal field distortions at places of sample contact to measurement probes. It was established that even at contact diameters 0.1-0.5 mm the probes average the temperature, yielding a reasonably precise temperature value, like at point contact. The error in this case does not exceed 0.05%.

The issue of equipment rapidity improvement was studied. As long as to perform the experiment it is necessary to achieve steady-state conditions, time required to measure the temperature dependences of one sample properties is 15 hours, with the measurement of 12 temperature points.

Measurement rate can be increased by passing of alternating current through the sample (Fig. 5). This accelerates heating of sample central part due to the Joule heat release. This method allows achievement of steady-state temperature mode in the sample 3 times as fast. Measurement rate can be further improved by heating of the hot sample side with a reference heater. Due to combination of these two methods, measurement rapidity can be increased up to 8 to 10 times.

Fig. 5. Methods for increasing the rate of the attainment of a steady state

Description of measurement equipment Fig. 4. Contact structures improving the quality of thermal and electrical contacts of sample to heat exchangers 1 – sample; 2 – reference heater; 3- thermostat

Another important factor causing the errors is the influence of current and thermal contacts of the sample.

With the use of pressure contacts, the heater touches the sample at least at three points, which can distort the uniformity of heat and current flows. The latter will affect the distribution of temperatures and electrical potential in the sample.

A design of experimental measurement unit is given in Fig. 6. It employs all methods for minimization of the errors described above.

For convenience and minimization of the influence of human errors, the setup is automated to the maximum. It comprises power unit and measurement control unit based on high-precision multi-channel microcontroller analog-todigital converter. On entering the measured temperature data, all measurement processes are performed unattended. Processed measurement results in the form of plots or tables are displayed in computer.

123

Fig. 6. Design of measurement unit

Fig. 7. External view of automated setup for measurement of thermoelectric material properties in the temperature range of 30-900oC

High-temperature modification of measurement unit was created that allows measurements to be made in the temperature range from 30 to 900oC. Its key feature was using of insulation fills to eliminate radiation losses increasing at such temperatures. As well as the above contact structures with nickel, copper and tungsten layers.

External view of this automated setup is given in Fig. 7.The use of the above described methods for minimization of errors allowed reducing the errors in the measurement of electric conductivity to 1.5%, thermopower – to 1.5%, thermal conductivity – to 5%.

Conclusions The influence of various factors on the accuracy of measurement of thermoelectric properties of materials by the absolute method has been studied. New methods for minimization of errors have been developed – gradient radiation shields with ring-shaped notches, thermostat reflector, thermal switches, metal contact structures for a re-

liable connection of sample end surfaces to current and thermal contacts.

Error reduction methods were used to fabricate an automated measurement setup for determination of thermoelectric material parameters in the temperature range of 30 to 900 °Ñ. A totality of measures taken allows reducing the figure of merit errors by a factor of 3 to 5.

Methods for essential, up to 10-fold, increase of the rate of attainment of a steady-state in the measured samples have been developed.

References: 1. A.O.Yepremyan, V.M. Arutiunyan, and A.I.Vaganyan, Figureof Meritof Novel Thermoelectric Materials,Alternative Energetics and Ecology 5, 7-18 (2005).

2. L.I.Anatychuk,Thermoelementsand Thermoelectric Devices(Kyiv: NaukovaDumka, 1978).

3. www.qdusa.com.

4. www.ipm.fraunhofer.de.

5. www.ulvac.com.

124 6. L.I. Anatychuk, S.V. Pervozvansky, and V.V. Razinkov,Precise Measurement of Cooling Thermoelectric Material Parameters: Methods, Arrangements and Procedures, Proc. of the 12thIntern. Conf. Thermoelectrics (Japan, Yokohama, 1993).

7. H. Czichos, T. Saito, and L. Smith, Springer Handbook of Metrology and Testing (Springer, 2011).

8. T.Tritt, Electrical and ThermalTransportMeasurementTechniquesforEvaluationoftheFigure-of-MeritofBulkThermoelectricMaterials, Thermoelectric Handbook, ed.by D.M. Rowe (CRC Press, 2006)).

9. A.S.Okhotin, A.S.Pushkarsky, R.P.Borovikova, and V.A.Simonov, Method of Measuring Thermoelectric Materials and Converters Characteristics (Moscow: Nauka, 1974).

10. www.linseis.com.

11. www.dlr.de.

12. www.netzsch-thermal-analysis.com.

13. D.M.Freik, M.O.Haluschak, V.G. Ralchenko, and A.I.Tkachuk, Methodsof Measuring Thermal Conductivityin Massive Solidsand Thin Films (Review), Physicsand Chemistryof the Solid State14(2), 317-344 (2013).

14. V.V.Lysko, ModifiedHarman’sMethod, J.Thermoelectricity 4,84-92 (2011).

15. L.I. Anatychuk, V.V. Lysko, ModifiedHarman’sMethod,AIP Conf. Proc,1449 (2012), 373-376 (2012).

16. M. Jaegle, SimulatingThermoelectricEffectswithFiniteElementAnalysis UsingComsol, Proc. of the European COMSOL Conference(Hannover, 2008).

Termoeleqtruli metrologia

masalebis

v. lisko

Termoeleqtrobis instituti ukranis mecnierebaTa erovnuli akademia 58000 naukis quCa, 1, Cernovci, ukraina, el–fosta: anatych@gmail.com naSromSi warmodgenilia masalebis Termoeleqtruli Tvisebebis zusti gazomvebis gavlena maTi efeqturobis gaumjobesebis mimdinareobaze. warmodgenilia masalebis parametrebis zusti gazomvebis simwiris mizezebi da ganxilulia metrologiuri gazomvebis xarisxis gaumjobesebis gzebi. warmodgenilia gazomvebis sxvadasxva meTodis kompiuteruli modelirebis Sedegebi, romlebic adastureben absoluturi meTodis upiratesobas. masalebis Tvisebebis gazomvebSi cdomilebebis minimizaciis meTodebTan erToblivad ganxilulia aseve absoluturi meTodi. damuSavebulia 30 - 900oC intervalSi masalebis parametrebis maRali sizustiT gamzomi mowyobiloba. minimizebulia gamtarobis gazomvebis cdomilebebi 1.5%-mde, Termoeleqtruli energiis 1.5%mde, siTbogamtarobis ki 5%-mde. damuSavebulia Termoeleqtruli masalebis parametrebis srulad avtomatizebuli gamzomi danadgari, romelic sizustiT bevrad aRemateba arsebul analogebs.

125

Study on the Possibilities for Changing the Absorption Spectra of Photocatalytic TiO2 Nanopowders with the Aim of Improving Their Efficiency M. Nadareishvili, T. Gegechkori, G. Mamniashvili, T. Zedginidze, T. Petriashvili.

Tbilisi State University, E.Andronikashvili Institute of Physics. 6 Tamarashvili str., 0177, Tbilisi, Georgia E-mail: tinikozedginidze@yahoo.com, mnadarei@gmail.com 1

Abstract. The possibilities for changing the absorption spectra of photocatalytic TiO2 nanopowders were studied with the aim of using more efficiently the solar energy by increasing the absorption of UV light and involving the visible light into the catalytic process. At E. Andronikashvili Institute of Physics, Iv. Javakhishvili Tbilisi State University, a unique low â&#x20AC;&#x201C; temperature (50-600C) nanotechnology of deposition of Ni-B and Co-B nanoclusters on the surfaces of TiO2 nanopowders was developed. The use of this nanotechnology improves significantly the light absorption in the UV region.

It was also revealed that, by further treatment of cluster-coated TiO2 nanopowders, we can increase the light absorption by these nanopowders in long-wavelength regions. Particularly, under heat treatment of cluster-coated TiO2 nanopowders in vacuum, there was observed a detectable shift of absorption spectra of the powders under study towards the longwavelength region, while the spectra of uncoated nanopowders did not change.

Keywords: nanopowders, absorption spectra, clusters, nanotechnology.

Introduction It is well known that gas and fuel resources on the Earth will soon be exhausted. Hence the search for alternative energy sources is essential.

One of the most promising trends on this way is the dissociation of water into hydrogen and oxygen using the solar energy and the utilization of produced hydrogen as fuel, the final product of which under burning is again water.

Water does not dissociate immediately under the action of solar light rays. For dissociation of water by solar energy, special stimulators of this process, so-called photocatalysts must be used.

The reaction of water dissociation into hydrogen and oxygen with solar radiation energy by using catalysts is called photocatalysis. Currently it is believed that the most promising substance for the photocatalysis is titanium dioxide TiO2 [1]. The essence of the photocatalysis is as follows: photocatalysis over a semiconductor oxide is initiated by the absorption of a photon with energy equal to or greater than the band gap of the semiconductor (3.2 eV for TiO2) producing the electron - hole (e-/h+) pairs [2] TiO2

eâ&#x20AC;&#x201C;cb (TiO2) + hvb+ (TiO2)

(1)

Consequently, after irradiation, the TiO2 particle can act as either an electron donor or an acceptor for molecules in the surrounding media and hence it can dissociate water and organic compounds dissolved in it (Fig.1) The current actual problem hindering the wide application of the above-described method in practice is the low efficiency of the photocatalytic reaction. Considering the importance of the problem, it attracts the attention of many researchers around the world [3-5].

As it was mentioned, the band-gap width for TiO2 is 3.2 eV, hence only ultraviolet rays participate in the catalytic reaction.

The first problem in regard the improvement of the efficiency of the photocatalytic reaction is an increase in the use of UV radiation in the photocatalytic process. For this purpose, it is necessary to increase the absorption of UV radiation by photocatalytic powders.

Fig.1. Irradiation of TiO2 nanoparticles

The second problem consists in involving the visible light into the photocatalytic process, because its share in the solar radiation is by an order of magnitude higher than that of the UV radiation. Theoretically it is possible, because the energy necessary for water dissociation is 1.23 eV, and the photons of corresponding energy are located in the visible part of the solar spectrum. Therefore, for solving this problem, it is necessary to impart the property of absorption of the visible light to the photocatalytic powders.

Materials and Methods Two crystallographic modifications of the TiO2 nanopowder (anatase and rutile) were used in investigations. The size of powder particles was ~200nm. The experiments were conducted by the following procedure: the optical absorp-

126 tion spectra of the distilled water suspensions of the photocatalyst powders were studied. The light absorption of distilled water over the entire working spectral range was preliminarily studied. It appeared to be rather low. However, in order to exclude the distortion of the absorption spectra of the powders under study as a result of the distilled water effect, we recorded the absorption spectra of the powders dissolved in the distilled water in reference to pure distilled water instead of the air. For this purpose a cell with the solution of the powder under study was placed in one compartment of the 4-compartment spectrophotometer ô-46 and an identical cell with pure distilled water – in other compartment. To check the validity of the used procedure, we prepared several similar reference aqueous suspensions of the same powder. Then their absorption curves were taken. The obtained spectra coincided very closely with the maximum difference of ± 5%.

Results In this paper we investigated the optical absorbtion spectra of the TiO2 nanopowders in order to study the possibility of the improvement of their photocatalytic properties by increasing the UV light absorption and the visible light share in the photocatalytic process and hence for the improvement of the efficiency of the photocatalysis reaction. We performed some investigations and some methods making it possible to change the optical properties of TiO2 powders as desired were found. First of all, at Andronikashvili Institute of Physics, a unique nanotechnology of coating surfaces of TiO2 nanoparticles with clusters of different sizes from different materials (for example, NiB) was developed [6].

These nanostructures were fabricated using electroless deposition of metals and alloys. The peculiarity of the method consists in maintaining of low temperature during the coating reaction (58-60oC), which preserves the physical-technical properties of the substance to be coated. This nanotechnology is also simple, low-cost and hence competitive for production process purposes.

For investigation, we took two modifications of the TiO2 powder, anatase and rutile, with the grains ~ 200nm in size.

We prepared their identical suspensions in distillate and recorded their absorption spectra over the wavelength range from 300 to 800 nm. Then we deposited Ni-B clusters on the powders under study. In Fig.2 are shown the results of these experiments: curve 1 corresponds to the absorption spectrum of rutile modification of the TiO2 powder before deposition of clusters, after deposition of clusters the spectrum hardly changed and it is omitted. Curve 2 corresponds to the absorption spectrum of the anatase modification of the TiO2 powder before deposition of clusCurves 1 and 2 showed that the absorption spectra of the rutile and anatase modifications before deposition of Ni-B clusters were very much alike, without any particular absorption at any wavelength. After deposition of clusters, the absorption spectrum of the rutile modification did not change, as it was mentioned above, but the spectrum of the anatase modification changed dramatically, as curve 3 showed. ters, and curve 3 to that after deposition of clusters.

Fig.2. The absorption spectra of nanopowders TiO2 before and after coating with clusters 1- absorption spectrum of the TiO2 nanopowders (rutile) before coating with clusters 2-absorption spectrum of the TiO2 nanopowders (anatase) before coating with clusters 3- absorption spectum of the TiO2 nanopowders (anatase) after coating with clusters

The observed phenomenon is caused by the fact that, before deposition of clusters, the electron-hole pairs recombine on the nanoparticle surfaces, but, after deposition of clusters, the latter capture the electrons and hinder the recombination (Fig.3) [2]. In the result, the number of splitted water molecules increases, i.e. improves the efficiency of the photocatalytic reaction.

Fig.3. Capture of electrons and holes by the clusters deposited on the surface of the nanoparticles

After the vacuum heat treatment effect on the absorption spectra of photocatalytic TiO2 nanopowders was studied. The size of powder particles was again 200 nm.

For heat treatment in vacuum, we used high-temperature high-vacuum furnace ÑÍÂÝ-1.31/16ÈÇ-ÓÕË41, which provides heat treatment over the range from room temperature to 16000C in 10-5mm Hg high vacuum.

In the beginning the heat treatment effect on the optical absorption spectra of pure TiO2 (both anatase and rutile ) nanopowders was studied. The absorption spectra of these powders practically remained unchanged. After the heat vacuum treatment, the absorption spectrum of TiO2 (rutile) coated with Ni-B clusters remained unchanged too.

127 In Fig. 4 are shown the absorption spectra before the heat vacuum treatment and after it for TiO2 (anatase) coated with Ni-B clusters. Curve 1 corresponds to the optical absorption spectrum of Ni-B/TiO2 (anatase) powder without heat treatment and curve 2 â&#x20AC;&#x201C; to that of the same powder heat treated in vacuum at 6000C for 5 hours. As it is seen from the figure, as a result of heat - treatment, one could observe a significant change in the optical absorption spectrum of Ni-B/TiO2 powder, namely, the absorption of solar energy increased significantly over the range of 400-500 nm. This fact is particularly important for enhancing the photocatalyst efficiency in the visual range of solar radiation.

References: 1. J.Schneider, M.Matsuoka, M.Takeuchi, J.Zhang, Y.Horiuchi, M.Anpo, and D.W.Bahneman, Understanding TiO2 Photocatalysis: Mechanisms and Materials, Chem. Rev. 2014, 114(19), pp 9919-9986 2. A. Linsebigler, G.Lu, and J. Yates. Photocatalysis on TiO2 surfaces: Principles, mechanisms, and selected results.

J.Chem.Phys.1995. 95,735-758.

3. M. Kaneko. I. Okuna. Photocatalysis Science and Techology.

Kodansha Springer. Tokyo 202. Ch.1 4. J.J.Ramsden. Nanotechnology, Copenhagen: Ventus (2009).

5. A. Kudo. H. Kato and I.Tsuji. Strategies for development of visible-light-driven Photocatalysts for water splitting. Chemistry Letters 2004, v. 33.N 12. pp. 1534.

6. Teimuraz Khoperia, Grigor Mamniashvili, Malkhaz Nadareishvili and Tinatin Zedginidze, Competitive nanotechnology for deposition of films and fabrication of povder-like particles, ECS Trans. vol.35, Iss.10, 17 (2011)

TiO2 fotokatalizatorebis STanTqmis speqtrebis cvlilebis SesaZlebloba maTi efeqturobis gazrdis mizniT

Fig.4. Vacuum heat treatment effect on the TiO2 nanopowders (anatase) 1- absorption spectrum of the TiO2 nanopowders (anatase) before vacuum heat treatment 2-absorption spectrum of the TiO2 (anatase) nanopowders after vacuum heat treatment

Conclusions From our experiments it follows: 1. The absorption of light energy by the TiO2 nanopowders both anatase and rutile without deposition of the Ni-B clusters is very low without any particular absorption at any wavelength.

2. After deposition of the Ni-B clusters on the surface of the TiO2 nanoparticles, the absorption spectrum of rutile nanopovder changed only slightly, while that of anatase altered dramatically: there appeared a clear and wide maximum at the wavelength 360nm. This implies a sharp increase in the absorption of light energy and would enhance the efficiency of the photocatalytic reaction.

3. The vacuum heat treatment of the pure TiO2 nanopowders did not change their electron excitation spectrum.

However after coating of TiO2 nanoparticles with the Ni-B clusters, the vacuum heat treatment resulted in the change of the electron excitation spectrum of these particles followed by the increase in the absorption in the visible part of the spectrum, which in turn would also enhance the efficiency of th photocatalytic reaction.

The work was supported by Rustaveli Foundation grant #AR/126/3-250/14

m. nadareiSvili, t. gegeWkori, g. mamniaSvili, T. zedginiZe, T. petriaSvili Tbilisis saxelmwifo universiteti, e. andronikaSvilis fizikis instituti, TamaraSvilis q.

6, 0177, Tbilisi. saqarTvelo el-fosta: tinikozedginidze@yahoo.com, mnadarei@gmail.com Seswavlilia TiO2 nanofxvniluri fotokatalizatorebis STanTqmis speqtrebis cvlilebis SesaZlebloba mzis energiis ufro efeqturad gamoyenebis mizniT, am fxvnilebis mier ultraiisferi sinaTlis STanTqmis gaumjobesebisa da aseve katalizis procesSi xiluli sinaTlis CarTvis meSveobiT. e. andronikaSvilis sax. fizikis institutSi damuSavda TiO2-is nanonawilakebis zadapirebis Ni-B-isa da Co-B-is kidev ufro mcire zomis klasterebiT dafarvis originaluri, dabaltemperaturuli, (500-600)C, nanoteqnologia, romlis gamoyenebac mniSvnelovnad aumjobesebs sinaTlis STanTqmas ultraiisfer regionSi. SemCneulia agreTve, rom klasterebiT dafaruli TiO2 -is nanonawilakebis Semdgomi damuSavebiT SesaZlebelia am fxvnilebis mier sinaTlis STanTqmis gazrda speqtrebis grZeltalRovan areebSi. konkretulad nanoklasterebiT dafaruli TiO2-is fxvnilebis vakuumSi Termuli damuSavebis Sedegad daimzireboda am fxvnilebis STanTqmis speqtrebis mniSvnelovani zrda grZeltalRovan ubnebSi, maSin, rodesac klasterebiT daufaravi fxvnilebis speqtri rCeboda ucvleli.

128

Ïîëó÷åíèå è èññëåäîâàíèå ìàòåðèàëîâ àíòèñóáëèìàöèîííîé çàùèòû ñðåäíåòåìïåðàòóðíûõ âåòâåé òåðìîýëåìåíòîâ è òåðìîáàòàðåé íà îñíîâå ñïëàâîâ PbTe è GeTe Ô. Áàñàðèÿ, È. Òàáàòàäçå, Ì. Ðåõâèàøâèëè Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà, óë. Ìèíäåëè 7,0186,Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà:sipt@sipt.org Ðåçþìå. Ïîëó÷åíû ìàòåðèàëû ýëåòêðîèçîëÿöèîííîãî è àíòèñóáëèìàöèîííîãî ïîêðûòèÿ âåòâåé òåðìîýëåìåíòîâ íà îñíîâå ñïëàâîâ ð- GeTe è n- PbTe èç íåîðãàíè÷åñêèõ ñòåêëîýìàëåé è ñîçäàíà òåõíîëîãèÿ èõ ôîðìèðîâàíèÿ. Èçó÷åíû ôèçèêî-õèìè÷åñêèå è àíòèñóáëèìàöèîííûå ñâîéñòâà ïîëó÷åííûõ ïîêðûòèé â èíòåðâàëå òåìïåðàòóð 350500 0Ñ. Ïîêàçàíî, ÷òî ìàòåðèàëû ïîêðûòèÿ è òåõíîëîãèÿ åãî ôîðìèðîâàíèÿ íå âëèÿþò íà òåðìîýëåêòðè÷åñêèå õàðàê-òåðèñòèêè âåòâåé òåðìîýëåìåíòîâ, à ñòåêëîýìàëü çàìåòíî ïðåâîñõîäèò ïî àíòèñóáëèìàöèîííûì ñâîéñòâàì òåðìîöåìåíò è ãàçîôàçíûé SiN. Óêàçàííûå âåòâè òåðìîýëåìåíòîâ, çàùèùåííûå ñòåêëîýìàëüþ, ïðè òåìïåðàòóðå 500-520 0Ñ ìîãóò ðàáîòàòü áîëåå, ÷åì 4500 ÷.

Êëþ÷åâûå ñëîâà:ìàòåðèàëû, òåðìîýëåìåíòû, òåðìîáàòàðåÿ, ñóáëèìàöèÿ.

Ââåäåíèå Äëÿ ñîçäàíèÿ àâòîíîìíûõ èñòî÷íèêîâ ýëåêòðîýíåðãèè íàçåìíîãî è êîñìè÷åñêîãî íàçíà÷åíèÿ ñ 60-õ ãîäîâ ïðîøëîãî âåêà íà÷àëè øèðîêî èñïîëüçîâàòü òåðìîýëåêòðè÷åñêèå ïðåîáðàçîâàòåëè òåïëîâîé ýíåðãèè â ýëåêòðè÷åñêóþ.  äàííîé ðàáîòå ðàññìîòðåíî ïîëó÷åíèå è èññëåäîâàíèå ñðåäíåòåìïåðàòóðíûõ âåòâåé òåðìîýëåìåíòîâ (ÒÝ) è òåðìîáàòàðåé (ÒÁ) íà îñíîâå òåðìîýëåêòðè÷åñêèõ ìàòåðèàëîâ ð-òèïàGeTe è n-òèïà PbTe. Çíà÷èòåëüíàÿ ñóáëèìàöèÿ òåëëóðà ñ ïîâåðõíîñòè è èç îáúåìà âåòâåé ÒÝ íà îñíîâå ýòèõ ñïëàâîâ ïðè òåìïåðàòóðå âûøå 350 0Ñ âûçûâàþò íåîáõîäèìîñòü ïðåäâàðèòåëüíîãî ôîðìèðîâàíèÿ íà ïîâåðõíîñòè âåòâåé àíòèñóáëèìàöèîííîãî ïîêðûòèÿ). Äëÿ çàùèòû îò èñïàðåíèÿ âåòâåé ÒÝ íà îñíîâå ñïëàâîâ PbTe è GeTe â ðàáî÷åì èíòåðâàëå òåìïåðàòóð 300-500 0Ñ ïðèìåíÿþò ïîêðûòèÿ: - èç íèòðèäà êðåìíèÿ èëè áîðà, ïîëó÷åííûå ïóòåì ãàçî-ôàçíîãî èëè èîííî-ïëàçìåííîãî íàïûëåíèÿ; - èç òåðìîöåìåíòà íà îñíîâå ýëåòêðîêîðóíäà, ñ ãèäðîëèçèðîâàííûì ýòèëîâûìýôèðîì îðòîêðåìíåâîé êèñëîòû â êà÷åñòâå ñâÿçêè [1, 2], - èç îðãàíî-ñèëèêàòíîãî è êðåìíå-îðãàíè÷åñêîãî ìàòåðèàëîâ [3, 4]. Èñïîëüçîâàíèå ýòèõ ìàòåðèàëîâ áûëî îáóñëîâëåíî èõ ôèçèêî-õèìè÷åñêèìè ñâîéñòâàìè, õîðîøåé àäãåçèåé ê ïîäëîæêå è òåõíîëîãè÷íîñòüþ [5]. Îñíîâíûìè íåäîñòàòêàìè ýòèõ ìàòåðèàëîâ ÿâëÿåòñÿ òî, ÷òî îíè õàðàêòåðèçóþòñÿ âûñîêîé õðóïêîñòüþ èëè ñòàíîâÿòñÿ õðóïêèìè â ïðîöåññå ðàáîòû òåðìîýëåêòðè÷åñêîãî ïðåîáðàçîâàòåëÿ. Ýòîò ïðîöåññ ïðèâîäèò ê ñóùåñòâåííîìó ñíèæåíèþ àíòèñóáëèìàöèîííûõ ñâîéñòâ ïîñëåäíåãî.  ñëó÷àå æå ïîêðûòèÿ èç îðãàíî-ñèëèêàòíûõ è êðåìíå-îðãàíè÷åñêèõ ìàòåðèàëîâ äîïîëíèòåëüíûì

íåäîñòàòêîì ÿâëÿåòñÿ è òî, ÷òî ïðè ðàáî÷èõ òåìïåðàòóðàõ âåòâåé ÒÝ èç íèõ âûäåëÿþòñÿ óãëåâîäîðîäû â âèäå ìåòàíà (ÑÍ4), áåíçîëà (Ñ6Í6) è äðóãèõ îðãàíè÷åñêèõ ñîåäèíåíèé [6], êîòîðûå ïðîíèêàÿ â óçëû èçîëÿöèè, óõóäøàþò èçîëÿöèþ ÒÝÃ, âïëîòü äî êîðîòêîãî çàìûêàíèÿ.

Ìàòåðèàëû è ìåòîäû èññëåäîâàíèÿ Ñ ó÷åòîì èçâåñòíûõ òðåáîâàíèé ê àíòèñóáëèìàöèîííûì è ýëåêòðîèçîëÿöèîííûì ïîêðûòèÿì âåòâåé ÒÝ ïîñòàâëåíà çàäà÷à ïîëó÷åíèÿ çàùèòíîãî ïîêðûòèÿ äëÿ óêàçàííûõ âåòâåé ÒÝ ñ èññëåäîâàíèåì íåîðãàíè÷åñêèõ ñòåêëîýìàëåé. Áûëè âûáðàíû ñëåäóþùèå ñèñòåìû ñòåêîë: à) Äëÿ GeTep-òèïà SiO 2 -B 2 O 3 -PbO-Na 2 O (èññëåäîâàëîñü 5 êîíêðåòíûõ ñîñòàâîâ p1-p5); á) Äëÿ PbTen-òèïà SiO 2 -TiO 2 -B 2 O 3 - PbO-Na 2 O (èññëåäîâàëîñü 5 êîíêðåòíûõ ñîñòàâîâ n1-n5). Ðàñ÷åò êîëè÷åñòâåííîãî ñîäåðæàíèÿ êîìïîíåíòîâ â ñîñòàâàõ p1-p5 è n1-n5, ñîñòàâëåíèå øèõòû, ïðèãîòîâëåíèå øëèêåðîâ è ôîðìèðîâàíèå çàùèòíîãî ñòåêëîýìàëåâîãî ïîêðûòèÿ íà ïîäãîòîâëåííîé ïîâåðõíîñòè âåòâåé ÒÝ îñóùåñòâëÿëèñü ïî îáùåïðèíÿòîé íà ïðàêòèêå òåõíîëîãèè ýìàëèðîâàíèÿ ìåòàëëè÷åñêèõ èçäåëèé [7, 8].

Ðåçóëüòàòû è îáñóæäåíèå

Äîïóñòèìîñòü èñïîëüçîâàíèÿ íåîðãàíè÷åñêèõ ñòåêëîýìàëåé â êà÷åñòâå àíòèñóáëèìàöèîííîãî ïîêðûòèÿ äëÿ òåëëóðèäíûõ âåòâåé ÒÝ ïîäòâåðæäàåòñÿ äàííûìè, ïðèâåäåííûìè â òàáëèöå 1. Äëÿ ñðàâíåíèÿ òàì æå ïðèâåäåíû àíàëîãè÷íûå õàðàêòåðèñòèêè âåòâåé ÒÝ íà îñíîâå ñïëàâîâ GeTe è PbTe áåç çàùèòíûõ ïîêðûòèé. Âî âñåõ ñëó÷àÿõ ïðèâåäåííûå íèæå ðåçóëüòàòû ñîîòâåòñòâóþò ñðåäíåìó èç 10 èñïûòàíèé âåòâåé ÒÝ.

129

130 «ìÿãêîå» ñòåêëîýìàëåâûå ïîêðûòèÿ íå ìîãóò îáåñïå÷èòü ñîõðàíåíèå öåëîñòíîñòè àíòèñóáëèìàöèîííîé çàùèòû. Íà ðèñ. 3 ïðåäñòàâëåíà ìèêðîôîòîãðàôèÿ øëèôà ÒÝ ð-òèïà (GeTe), ïðîøåäøåãî â ñîñòàâå ÒÁ ðåñóðñíîå èñïûòàíèå ïðè òåìïåðàòóðå ãîðÿ÷åãî ñïàÿ 520 0Ñ â òå÷åíèå 4500 ÷ (ðèñ. 3. à, â). Ðåçóëüòàòû èññëåäîâàíèÿ ïîêàçàëè ñëåäóþùåå:

âîçíèêíîâåíèÿ êàêèõ-ëèáî íàðóøåíèé, òðåùèí, ïîð è äðóãèõ âèäîâ äåôåêòîâ. Ïðè îáåñïå÷åíèè òàêèõ óñëîâèé ñî ñòîðîíû ïîäëîæêè, ò.å. ÒÝ, ñòåêëîýìàëåâîå ïîêðûòèå ìîæåò åùå î÷åíü äîëãî è íàäåæíî çàùèùàòü òåðìîýëåêòðè÷åñêèé ìàòåðèàë îò èñïàðåíèÿ. Ñîâåðøåííî ïðîòèâîïîëîæíîå ÿâëåíèå èìååò ìåñòî íà ãîðÿ÷åì ñïàå (ó÷àñòêå) ÒÝ, ãäå ðàçâèâàþòñÿ òâåðäîôàçíûå ðåàêöèè âçàèìîäåéñòâèÿ òåðìîýëåòêðè÷åñêîãî ñïëàâà ñ ìàòåðèàëîì êîììóòàöèè [9]. Ýòîò ïðîöåññ ïðèâîäèò ê îáðàçîâàíèþ è âûäåëåíèþ áîëüøîãî îáúåìà ãàçîâ. Ñëåäñòâèåì ðåàêöèîííîé äèôôóçèè ÿâëÿåòñÿ îáðàçîâàíèå íîâûõ ôàç è ïóñòîò. Ïîñëåäíèå âíà÷àëå ìåëêèå, ïîñòåïåííî ñëèâàþòñÿ â êðóïíûå ïîðû, êîòîðûå, ðàçðàñòàÿñü ìåæäó ñïëàâîì 1 è êîììóòàöèåé 3, äîñòèãàþò âíóòðåííåé ïîâåðõíîñòè «ìÿãêîãî» ñòåêëîýìàëåâîãî ñëîÿ (Ðèñ. 3, ïîðà 4, ñòåêëîýìàëü 2 è îáðàçóåòñÿ ïåðâàÿ îòêðûòàÿ ïóñòîòà - ïîðà) 5. Âñëåäñòâèå ïðîòåêàíèÿ ýòèõ ïðîöåññîâ ïðîèñõîäèò èñïàðåíèå òåðìîýëåòêðè÷åñêîãî ìàòåðèàëà è îáðàçîâàíèå ïîëîñòè6 ìåæäó êîììóòàöèåé 3 è ñïëàâîì 1 (Ðèñ.

3, â). Âñå âûøå óêàçàííûå ïðîöåññû ïðèâîäÿò ê êîíäåíñèðîâàíûåòåðìîýëåêòðè-÷åñêîãî ìàòåðèàëà íà íàðóæíîé ïîâåðõíîñòè ÒÝ (çåðíà 7, ðèñ. 3, à). Èñõîäÿ èç ýòèõ äàííûõ ñëåäóåò, ÷òî ðåñóðñ ÒÝ è ÒÝà â öåëîì îïðåäåëÿåòñÿ èñêëþ÷èòåëüíî ðàçâèòèåì òâåðäîôàçíîãî ïðîöåññà âçàèìîäåéñòâèÿ ïîëóïðîâîäíèêà ñ êîììóòàöèåé, êîòîðûé ïðèâîäèò ê äåôîðìàöèè ïîâåðõíîñòè è, êàê ñëåäñòâèå, ðàçðóøåíèþ ñòåêëîýìàëåâîãî òîíêîãî àíòèñóáëèìàöèîííîãî ñëîÿ.  öåëÿõ óìåíüøåíèÿ âëèÿíèÿ ýòèõ ïðîöåññîâ è ïðîäëåíèÿ ðåñóðñà ÒÝ áûëî ðåøåíî îñóùåñòâèòü óâåëè÷åíèå òîëùèíû ñòåëîýìàëåâîãî ñëîÿ íà 2-3 ìì âûñîòû ñî ñòîðîíû ãîðÿ÷åãî ñïàÿ ÒÝ. Íåîáõîäèìî ïîä÷åðêíóòü äîìèíèðóþùóþ ðîëü ïîð â ïðîöåññå óìåíüøåíèÿ ðåñóðñà âåòâåé ÒÝ, ò.ê. îáðàçîâàíèå ìèêðîè ìàêðîòðåùèí íà ïîâåðõíîñòè è â îáúåìå ïîñëåäíèõ íå ïðèâîäÿò ê íàðóøåíèþ öåëîñòíîñòè ñòåêëîýìàëåâîãî ïîêðûòèÿ è óõóäøåíèþ åãî àíòèñóáëèìàöèîííûõ ñâîéñòâ. Èñõîäÿ èç âûøåèçëîæåííîãî öåëåñîîáðàçíî ïðèìåíÿòü â êà÷åñòâå ýëåêòðîèçîëÿöèîííîãî è àíòèñóáëèìàöèîííîãî ïîêðûòèÿ íåîðãàíè÷åñêóþ ñòåêëîýìàëü äëÿ íèçêîòåìïåðàòóðíîãî Bi2(TeSe)3, (BiSb)2Te3 âåòâåé ÒÝ è äëÿ âûñîêîòåìïåðàòóðíîãî SiGe - âåòâè ÒÝ ïðè èçãîòîâëåíèè ìíîãîêàñêàäíûõ ÒÝÃ.

Çàêëþ÷åíèå Ðèñ. 3.Ìèêðîôîòîãðàôèè ÒÝ ïîñëå ðåñóðñíûõ èñïûòàíèé, õ265: à – 4500 ÷, íà ðàññòîÿíèè 1 ìì îò êîììóíèêàöèè; á – 1440 ÷, ãîðÿ÷èé êîíåö ÒÝ; â – 4500 ÷. ãîðÿ÷èé êîíåö ÒÝ. 1-7 ó÷àñòêè

Íà ó÷àñòêå ð- è n-òèïà âåòâåé ÒÝ íà íåáîëüøîì ðàññòîÿíèè (~1 ìì) îò ãîðÿ÷åãî ñïàÿ ÒÝ, â ñïëàâå 1 è, ñîîòâåòñòâåííî, â ñëîå ñòåêëîýìàëè 2 íå çàìåòíû

Ïîêàçàíî, ÷òî ïðåäëîæåííûå ñòåêëîýìàëè ïî àíòèñóáëèìàöèîííûì ñâîéñòâà çàìåòíî ïðåâîñõîäÿò òåðìîöåìåíò è ãàçîôàçíûé SiN. Óñòàíîâëåíî, ÷òî ïðè èñêëþ÷åíèè òâåðäîôàçíîãî âçàèìîäåéñòâèÿ ìåæäó ïîëóïðîâîäíèêîì è êîììóòàöèåé ñòåêëîýìàëåâîå ïîêðûòèå ìîæåò î÷åíü äîëãî è íàäåæíî çàùèøàòü òåðìîýëåêòðè÷åêèé ìàòåðèàë îò èñïàðåíèÿ. Ïîýòîìó ïðè èçãîòîâëåíèè

131 êàñêàäíûõ ÒÝà öåëåñîîáðàçíî â êà÷åñòâå àíòèñóáëèìàöèîííîãî ïîêðûòèÿ äëÿ âñåõ âåòâåé òåðìîýëåìåíòîâ ïðèìåíÿòü ñòåêëî åìàëü.

Ëèòåðàòóðà: 1. Â. Ò. Ñòåïàíîâà è äð. Êëåé è òåõíîëîãèÿ ñêëåèâàíèÿ, 1960, 164 ñ.

2. Ð. Ñ. Àìáàðöóìÿí è äð. Ãåëèîòåõíèêà. 1968, 3. N 2, 3 ñ.

3. 3.Ï. À. Âåñåëîâ è äð.  ñá. «Õèìèÿ è ïðàêòè÷åñêîå ïðèìåíåíèå êðåìíåîðãàíè÷åñêèõ ñîåäèíåíèé». 1968, 218 ñ.

4. Ï. À. Âåñåëîâ è äð.  ñá. «Êðåìíåîðãàíè÷åñêèå ìàòåðèàëû».

1971, 242 ñ.

5. Í. Ï. Õàðèòîíîâ è äð. Âàêóóìíîïëîòíûå êîìïîçèöèîííûå ìàòåðèàëû íà îñíîâå ïîëèîðãàíîñèëèêàòîâ. 1975, 165 ñ.

6. Ê. Í. Ñòåïàíîâ è äð. Æàðîñòîéêèå îðãàíîñèëèêàòíûå ïîêðûòèÿ. 1979, 249 ñ. Ýìàëèðîâàíèå ìåòàëëè÷åñêèõ èçäåëèé. 1972. 326 ñ.

7. À. Ïåòöîëüö è äð. Ýìàëü è ýìàëèðîâàíèå. 1990. 400 ñ.

8. Ë. Ä. Äóäêèí è äð. Èññëåäîâàíèå è ðàñ÷åò ðåñóðñíîé ñòàáèëüíîñòè íèçêîòåìïåðàòóðíûõ òåðìîýëåêòðè÷åñêèõ èñòî÷íèêîâ òîêà – «Ýëåêòðîòåõíè÷åñêàÿ ïðîìûøëåííîñòü, õèìè÷åñêèå è ôèçè÷åñêèå èñòî÷íèêè òîêà». 1976, N 5(50), 6.

Obtaining and investigating materials for anti-sublimation of medium temperature branches of thermoelements and thetmobatteries based on PbTe and GeTe F. Basaria, I. Tabatadze, M. Rekhviashvili Ilia Vekua Sukhumi Institute of Physics and Technology,7Mindeli str.0186, Tbilisi, Georgia, .

E-mail:sipt@sipt.org

Materials for insulating and antisublimation coating of thermoelements based on p-type GeTe and n-type PbTe were received from inorganic vitreous enamel and technologyof their formation were developed. Physical-chemical and antisublimation properties of obtained coatings were studied in 350-500oC temperature interval. It has been shown, that materials for coating and technology of their formation do not influence on thermoelectric characteristics of thermoelement branches. But antisublimation properties of vitreous enamel noticeably exceeds thermal cement and gaseous SiN. Abovementioned thermoelement branches protected with vitreous enamel at 500-5200C temperatures allow operation over 4500hrs.

GeTe da PbTe Senadnobebis fuZeze Seqmnili saSualotemperaturuli Termoelementebisa da Termobatareebis Stoebis antisublimaciuri dacvis masalebis miReba da kvleva f. basaria, i. tabataZe, m. rexviaSvili

soxumis ilia vekuas fizika-teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo el–fosta: sipt@sipt.org

araorganuli minanqrisagan miRebulia eleqtrosaizolacio da antisublimaciuri da nafaris masalebi p- GeTe da n- PbTe, Senadnobebis Termoelementebis StoebisaTvis Seqmnilia maTi formirebis teqnologia.

Seswavlilia danafaris fiziko-qimiuri da antisublimaciuri Tvisebebi. 500-5200C temperaturebze mina-minanqrebiT dafarul Termoelementebis Stoebs axasiaTebs sublimaciis dabali maCvenebeli da SeuZliaT muSaoba 4500sT-ze meti drois ganmavlobaSi.

132

Èññëåäîâàíèå ñïåêòðîâ ôîòîýëåêòðè÷åñêîé ÷óâñòâèòåëüíîñòè â áëèæíåì äèàïàçîíå èíôðàêðàñíîãî èçëó÷åíèÿ p-n ñòðóêòóð, ñôîðìèðîâàííûõ íà ïîäëîæêàõ Si-Ge Ã. Áîêó÷àâà1, À. Ñè÷èíàâà1, È. Êóðàøâèëè1, Í.Ãàïèøâèëè1, Ã. Äàðñàâåëèäçå1, Á. Øèðîêîâ2, Í. Ñåìåíîâ2 Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà, óë. Ìèíäåëè 7,0186,Òáèëèñè, Ãðóçèÿ Íàöèîíàëüíûé íàó÷íûé öåíòð «Õàðüêîâñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò»,óë. Àêàäåìè÷åñêàÿ 1, 61108,Õàðüêîâ, Óêðàèíà. Ýë–ïî÷òà:sipt@sipt.org 1 2

Ðåçþìå. Ìåòîäîì ãàçîôàçíîé ýïèòàêñèè, âûñîêîòåìïåðàòóðíîãî äèôôóçèîííîãî ëåãèðîâàíèÿ è èîííîé èìïëàíòàöèè íà ïîäëîæêàõ Si-Ge ñ îðèåíòàöèåé (111) ñôîðìèðîâàíû p-n ñòðóêòóðû è èññëåäîâàíû ñïåêòðû ôîòî÷óâñòâèòåëüíîñòè â áëèæíåì äèàïàçîíå äëèíû âîëí èíôðàêðàñíîãî èçëó÷åíèÿ. Èññëåäîâàíèÿ ïðîâîäèëèñü íà ìîäèôèöèðîâàííîì ìîíîõðîìàòîðå ÌÄÐ-23 ñ àâòîìàòèçàöèåé óïðàâëåíèÿ è êîìïüþòåðíîé îáðàáîòêîé äàííûõ. Ïîêàçàíû âîçìîæíîñòè ìîäèôèöèðîâàíèÿ ñïåêòðîâ ôîòî÷óâñòâèòåëüíîñòè â áëèæíåé îáëàñòè äëèí âîëí ÈÊ èçëó÷åíèÿ p-n ïåðåõîäîâ íà ïîäëîæêàõ Si-Ge. Ïîä äåéñòâèåì îáëó÷åíèÿ áûñòðûìè ýëåêòðîíàìè è èîííîé èìïëàíòàöèåé ñôîðìèðîâàíà èíòåíñèâíàÿ ïîëîñà ñ ìàêñèìóìàìè ôîòî ý.ä.ñ. â äèàïàçîíå äëèí âîëí 1,8-2,5 ìêì.

Êëþ÷åâûå ñëîâà:p-n ñòðóêòóðà, ôîòî÷óâñòâèòåëüíîñòü, ìîíîõðîìàòîð, èíôðàêðàñíîå èçëó÷åíèå, ñïëàâû êðåìíèéãåðìàíèé

Ââåäåíèå

Ñïëàâû ñèñòåìû Si 1-xGe x (x≤0.06) ÿâëÿþòñÿ ïåðñïåêòèâíûìè ìàòåðèàëàìè äëÿ ñîâðåìåííîé òâåðäîòåëüíîé ìèêðî- è îïòîýëåêòðîíèêè. Ïðèáîðû íà áàçå Si-Ge îáëàäàþò ïðåèìóùåñòâàìè (áûñòðîòà äåéñòâèÿ, íèçêèé óðîâåíü øóìà, îïåðèðîâàíèå â îáëàñòè âûñîêèõ ÷àñòîò 2-110 ÃÃö, íèçêàÿ ñåáåñòîèìîñòü) ïî ñðàâíåíèþ ñ ïðèáîðàìè íà îñíîâå Si è, â ðÿäå ñëó÷àåâ, íà îñíîâå GaAs [1]. Îñîáî âàæíûì ÿâëÿåòñÿ íàëè÷èå âîçìîæíîñòè ïðèìåíåíèÿ Si-Ge â ðàäèàöèîííî-ïðî÷íûõ ïðèáîðàõ, ïîñêîëüêó òâåðäûå ðàñòâîðû íà áàçå Si-Ge ñ ìàëûì ïðîöåíòíûì ñîäåðæàíèåì Ge, à òàêæå ýïèòàêñèàëüíûå ñëîè Si1-xGex, îáíàðóæèâàþò áîëåå âûñîêóþ ðàäèàöèîííóþ ñòîéêîñòü, ÷åì Si [2]. Óâåëè÷åíèå ðàäèàöèîííîé ñòîéêîñòè ýòèõ ìàòåðèàëîâ îáóñëîâëåíî ñïîñîáíîñòüþ àòîìîâ Ge àííèãèëèðîâàòü ïåðâè÷íûå ðàäèàöèîííûå äåôåêòû â êðèñòàëëè÷åñêîé ðåøåòêå Si-Ge [3]. Ýòè îáñòîÿòåëüñòâà ñòèìóëèðóþò ðàñøèðåíèå èññëåäîâàíèé õàðàêòåðèñòèê ðåàëüíîé ñòðóêòóðû è ïîëóïðîâîäíèêîâûõ ñâîéñòâ ìàññèâíûõ êðèñòàëëîâ è ýïèòàêñèàëüíûõ ñòðóêòóð íà áàçå ñïëàâîâ Si-Ge. íàñòîÿùåé ðàáîòå ïðèâîäÿòñÿ ðåçóëüòàòû èññëåäîâàíèÿ ôîòî÷óâñòâèòåëüíîñòè â áëèæíåé îáëàñòè ÈÊ èçëó÷åíèÿ (0,9-2,5 ìêì) p-n ïåðåõîäîâ íà ìîíîêðèñòàëëè÷åñêèõ ïîäëîæêàõ Si+2àò.%Ge: (1014 ñì-3) ñ îðèåíòàöèåé (111).

Ìàòåðèàëû è ìåòîäû èññëåäîâàíèÿ

Îáúåìíûå êðèñòàëëû Si-Ge, ëåãèðîâàííûå áîðîì, ïîëó÷åíû ìåòîäîì ×îõðàëüñêîãî âûòÿãèâàíèåì èç ðàñïëàâà â êðèñòàëëîãðàôè÷åñêîì íàïðàâëåíèè [111] â ïîòîêå ñïåêòðàëüíî ÷èñòîãî àðãîíà. Èññëåäîâàíèÿ ñòðóêòóðû â îïòè÷åñêîì ìèêðîñêîïå ïîêàçàëè íåîäíîðîäíûå ðàñïðåäåëåíèÿ äèñëîêàöèé ñ

ïëîòíîñòüþ 103-104 ñì-2,p-n ïåðåõîäû ñôîðìèðîâàíû ìåòîäîì âûñîêîòåìïåðàòóðíîé äèôôóçèè ôîñôîðà èç ôîñôîðîñèëèêàòíîãî ïëåíêîîáðàçóþùåãî ïîêðûòèÿ íà ïëîñêîñòÿõ (111) ïðè òåìïåðàòóðå 1050 0Ñ â òå÷åíèå 0,5 ÷ â ïîòîêå ñóõîãî àçîòà. Ïîñëåäóþùèì îòæèãîì ïðè 900 0Ñ â òå÷åíèå 20 ìèí p-n ïåðåõîä îáðàçîâàëñÿ íà ãëóáèíå 0,6-0,8 ìêì. Èññëåäîâàí òàêæå p-n ïåðåõîä, ñôîðìèðîâàííûé äèôôóçèåé ôîñôîðà íà êîìïîçèöèè: ïîäëîæêà Si0,98Ge0,02: (1014 ñì-3) - áóôåð èäåíòè÷íîãî ñîñòàâà (0,3 ìêì) – ð-ñëîé (0,5 ìêì) ñ êîíöåíòðàöèåé áîðà äî 1013 ñì-3. Êîíöåíòðàöèÿ íîñèòåëåé òîêà â ð-ñëîå áûëà ïîâûøåíà äî 1015 ñì-3 èìïëàíòàöèåé èîíàìè áîðà ñ ýíåðãèåé 100 êý è ïîñëåäóþùèì èìïóëüñíûì îòæèãîì ïðè 900 0Ñ, 5 ñåê. Íà çàâåðøàþùåé ñòàäèè â ïðîöåññå äèôôóçèîííîãî ëåãèðîâàíèÿ â n-ñëîå êîíöåíòðàöèÿ íîñèòåëåé òîêà äîâåäåíà äî 8.1014 ñì-3. Îòæèãîì ïðè 900 0Ñ â òå÷åíèå 40 ìèí ãëóáèíà çàëåãàíèÿ p-n ïåðåõîäà ôèêñèðîâàëàñü íà óðîâíå 0,6 ìêì. Äëÿ èçó÷åíèÿ çàâèñèìîñòè ÝÄÑ õîëîñòîãî õîäà p-n ïåðåõîäà îò äëèíû âîëíû ïàäàþùåãî ñâåòà ïðîâåäåíà ìîäåðíèçàöèÿ ìîíîõðîìàòîðà ÌÄÐ-23. Àâòîìàòèçàöèÿ óïðàâëåíèÿ ìîíîõðîìàòîðîì è ñáîð äàííûõ îñóùåñòâëÿëèñü ïðè ïîìîùè ïðîãðàììíîãî àïïàðàòíîãî êîìïëåêñà íà áàçå ïåðñîíàëüíîãî êîìïüþòåðà è ïðîãðàììèðóåìîãî ëîãè÷åñêîãî êîíòðîëëåðà C200UAL006 (PLC). Ïîñòîÿííàÿ âåëè÷èíà ñâåòîâîãî ïîòîêà îáåñïå÷èâàëàñü ðåãóëèðîâàíèåì øèðèíû âõîäíîé ùåëè ìîíîõðîìàòîðà. Âåëè÷èíà ñâåòîâîãî ïîòîêà èçìåðÿëàñü âèñìóòîâûì áîëîìåòðîì ÁÌ6-Ê1Ó4 ñ èçìåðèòåëüíûì áëîêîì îò ñïåêòðîôîòîìåòðà ÈÊÑ-29. êà÷åñòâå èñòî÷íèêà èçëó÷åíèÿ èñïîëüçîâàëñÿ êàðáèäêðåìíèåâûé èçëó÷àòåëü ÊÈÌ (ãëîáàð). Òðåáóåìûé äèàïàçîí äëèí âîëí îáåñïå÷èâàëñÿ èñïîëüçîâàíèåì

133 äèôðàêöèîííîé ðåøåòêè 300 øòð/ìì, ðàáîòàþùåé â ïåðâîì ïîðÿäêå.Ñðåçàíèå íàêëàäûâàþùèõñÿ âíåøíèõ ïîðÿäêîâ ñïåêòðà íà ïåðâûé ðàáî÷èé ïîðÿäîê ïðîèçâîäèëîñü êðåìíèåâûì ôèëüòðîì, óñòàíîâëåííûì ïåðåä âõîäíîé ùåëüþ è ðàáîòàþùåì â ðåæèìå ïðîïóñêàíèÿ. Èññëåäóåìûé îáðàçåö ê èçìåðèòåëüíîé ãîëîâêå ïîäêëþ÷àëñÿ â âåíòèëüíîì (ôîòîâîëüòàè÷åñêîì) ðåæèìå. Èçìåðåíèå ÝÄÑ ïðîèçâîäèëîñü èçìåðèòåëüíîé ãîëîâêîé, ïîñòðîåííîé íà ìàëîøóìÿùåì îïåðàöèîííîì óñèëèòåëå ÎÐ07. Äëÿ óâåëè÷åíèÿ âõîäíîãî ñîïðîòèâëåíèÿ èñïîëüçîâàëàñü íåèíâåðòèðóþùàÿ ñõåìà âêëþ÷åíèÿ. Äëÿ îáåñïå÷åíèÿ ïðèåìëåìîé âåëè÷èíû ðåãèñòðèðóåìîãî ñèãíàëà áûë âûáðàí êîýôôèöèåíò óñèëåíèÿ 20000.  öåëÿõ óìåíüøåíèÿ øóìîâ ïèòàíèå óñèëèòåëüíîãî êàñêàäà îñóùåñòâëÿëîñü îò àêêóìóëÿòîðíîé áàòàðåè. Ïðîèçâîäèëàñü ðåãèñòðàöèÿ ïîêàçàíèé îñâåùåííîãî è íåîñâåùåííîãî îáðàçöà èïî ðàçíîñòè ïîêàçàíèé îïðåäåëÿëàñü âåëè÷èíà ÝÄÑ.

ïîäëîæêå ð-Si-Ge: íà 10-15% óìåíüøàåò ïîëóøèðèíó ìàêñèìóìà ôîòî÷óâñòâèòåëüíîñòè è ïðàêòè÷åñêè íå âëèÿåò íà åãî èíòåíñèâíîñòü. Ýòî ñâèäåòåëüñòâóåò îá óñòðàíåíèè ÷àñòè äåôåêòîâ, âûçûâàþùèõ ëîêàëüíóþ äåôîðìàöèþ êðèñòàëëè÷åñêîé ðåøåòêè â îáëàñòè p-n ïåðåõîäà. Ñïåêòð ôîòî÷óâñòâèòåëüíîñòè p-n ïåðåõîäà, ñôîðìèðîâàííîãî êîìáèíèðîâàíèåì ìåòîäîâ ãàçîôàçíîé ýïèòàêñèè, èîííîãî ëåãèðîâàíèÿ è âûñîêîòåìïåðàòóðíîé äèôôóçèè ôîñôîðà, õàðàêòåðèçóåòñÿ íèçêèì ôîíîì âïëîòü äî 2,5 ìêì, íà êîòîðîì â îáëàñòè 2,0-2,2 ìêì îáíàðóæèâàåòñÿ ðàñùåïëåííûé ìàêñèìóì (ðèñ.2.1).

Ýêñïåðèìåíòàëüíûå ðåçóëüòàòû

Èçìåðåíèÿ ôîòî ÝÄÑ â çàâèñèìîñòè îò äëèíû âîëíû ÈÊ èçëó÷åíèÿ ñòàíäàðòíîãî ôîòîýëåìåíòà íà ð-Si ñ îðèåíòàöèåé (111) è p-n ïåðåõîäà, ñôîðìèðîâàííîãî íà ð-Si+2àò.%Ge ñ îðèåíòàöèåé (111) ïîêàçàëè øèðîêèé ìàêñèìóì â îáëàñòè 0,9 ìêì è âåñüìà ñëàáûé ôîí, ïðîñòèðàþùèéñÿ â íàïðàâëåíèè äëèííûõ âîëí âïëîòü äî 2 ìêì (ðèñ.1.).

Ðèñ.1. Ñïåêòðû ôîòî÷óâñòâèòåëüíîñòè ôîòîýëåìåíòà íà áàçå Si ( ) è p-n ïåðåõîäà íà Si+2àò.%Ge:B ( )

Íà îñíîâàíèè ëèòåðàòóðíûõ äàííûõ ïðåäïîëàãàåòñÿ, ÷òî óêàçàííûé ìàêñèìóì ôîòî÷óâñòâèòåëüíîñòè îáóñëîâëåí ìåæçîííûìè ïåðåõîäàìè â çîííîé ñòðóêòóðå êðåìíèÿ. Ñðàâíåíèå ïîêàçûâàåò, ÷òî ìàêñèìóì ôîòî÷óâñòâèòåëüíîñòè, ñâÿçàííûé ñ p-n ïåðåõîäîì â Si-Ge, ñäâèíóò â ñòîðîíó äëèííûõ âîëí, ÷òî, âèäèìî, ñâÿçàíî ñî ñëàáûì âîçðàñòàíèåì ïàðàìåòðà êðèñòàëëè÷åñêîé ðåùåòêè, ò.å. ñ ïîÿâëåíèåì òåíäåíöèè óìåíüøåíèÿ øèðèíû çàïðåùåííîé çîíû â Si-Ge. Íàëè÷èå ñòðóêòóðíûõ äåôåêòîâ ñ ïëîòíîñòüþ103-104 ñì2 òàêæå ìîæåò áûòü ïðè÷èíîé ñäâèãà è çàìåòíîãî óøèðåíèÿ ìàêñèìóìà ôîòî÷óñòâèòåëüíîñòè p-n ñòðóêòóðû íà áàçå Si-Ge.Îòæèã â ïîòîêå ñóõîãî àçîòà ïðè 900 0Ñ â òå÷åíèå 1,5 ÷ îáðàçöà ñ p-n ïåðåõîäîì íà

Ðèñ.2. Ñïåêòðû ôîòî÷óâñòâèòåëüíîñòè p-n ñòðóêòóð íà ïîäëîæêàõ Si-Ge 1. Ñïåêòð ôîòî÷óñòâèòåëüíîñòè p-n ïåðåõîäà ñôîðìèðîâàííîãî êîìáèíàöèåé ãàçîôàçíîé ýïèòàêñèè è èîííîé èìïëàíòàöèè áîðà è âûñîêîòåìïåðàòóðíîé äèôôóçèè ôîñôîðà; 2. Ñïåêòð ôîòî÷óñòâèòåëüíîñòè p-n ïåðåõîäà, ñôîðìèðîâàííîãî âûñîêîòåìïåðàòóðíîé äèôôóçèåé ôîñôîðà è îáëó÷åííîãî âûñîêîýíåðãåòè÷åñêèìè ýëåêòðîíàìè; 3. Âëèÿèå èçîõðîííûõ îòæèãîâ (20 - 400 0C) íà ñïåêòð ôîòî÷óñòâèòåëüíîñòè p-n ïåðåõîäà, îáëó÷åííîãî âûñîêîýíåðãåòè÷åñêèìè ýëåêòðîíàìè.

Ñ ó÷åòîì òîãî, ÷òî âñå èññëåäóåìûå p-n êîìïîçèöèè ñîçäàíû íà èäåíòè÷íûõ ïîäëîæêàõ ð-Si-Ge, ìîæíî ïðåäïîëîæèòü, ÷òî â ôîðìèðîâàíèè íîâîãî ðàñùåïëåííîãî ìàêñèìóìà â îáëàñòè 2,0-2,2 ìêì ïðèíèìàþò ó÷àñòèå äåôåêòû ñòðóêòóðû, îáðàçîâàííûå ïðè èîííîé áîìáàðäèðîâêå êîìïîçèöèè ïîäëîæêà-áóôåð-ð-ñëîé. Î çíà÷èòåëüíîì âêëàäå ðàäèàöèîííûõ äåôåêòîâ â ôîðìèðîâàíèå ïîëîñû ñ íåñêîëüêèìè ìàêñèìóìàìè â îáëàñòè äëèí âîëí 1,8-2,4 ìêì ñâèäåòåëüñòâóþò ðåçóëüòàòû èññëåäîâàíèÿ îáðàçöîâ ñ p-n ïåðåõîäàìè íà ïîäëîæêå ð-Si+2àò.%Ge, ñôîðìèðîâàííûõ äèôôóçèåé ôîñôîðà èç ïëåíêîîáðàçóþùåãî ôîðôîðîñèëèêàòíîãî ïîêðûòèÿ, îáëó÷åííûõ ýëåêòðîíàìè ñ ýíåðãèåé 6 Ìý ôëþåíñîì 8x1012 ñì-2 íà êîìïëåêñå “Clinac” (ðèñ.2.2). Ïî ñðàâíåíèþ ñ ïðåäûäóùèì ñïåêòðîì íàáëþäàåòñÿ ðàñøèðåíèå â ñòîðîíó ìåíüøèõ äëèí âîëí è îäíîâðåìåííîå óâåëè÷åíèå èíòåíñèâíîñòè ïîëîñû ôîòî÷óâñòâèòåëüíîñòè.

134 Ïîñëå çàâåðøåíèÿ èçîõðîííûõ îòæèãîâ äî 4000Ñ â âàêóóìå ñ øàãîì 20 0 Ñ è ïðîäîëæèòåëüíîñòüþ âûäåðæêè ïðè êàæäîé òåìïåðàòóðå – 10 ìèí, íàáëþäàåòñÿ ðåçêîå óâåëè÷åíèå èíòåíñèâíîñòè è óñèëåíèå âçàèìíîãî ïåðåêðûâàíèÿ ìàêñèìóìîâ â èíòåãðàëüíîé ïîëîñå ôîòî÷óâñòâèòåëüíîñòè (ðèñ. 2.3). Èçâåñòíî [4,5], ÷òî â Si, ëåãèðîâàííîì Ge êîíöåíòðàöèåé ~1019-1020 ñì-3, áîëüøèíñòâî ðàäèàöèîííûõ äåôåêòîâ óñòðàíÿþòñÿ òåðìè÷åñêèìè èçîõðîííûìè îòæèãàìè äî òåìïåðàòóð 300-400 0Ñ èëè îíè òðàíñôîðìèðóþòñÿ â áîëåå ñëîæíûå êîìïëåêñû ñ ïîâûøåííîé òåðìè÷åñêîé ñòàáèëüíîñòüþ. Ðåçêîå âîçðàñòàíèå èíòåíñèâíîñòè íàáîðà ìàêñèìóìîâ ôîòî÷óâñòâèòåëüíîñòè â îáëàñòè 1,8-2,4 ìêì, âîçìîæíî ñâÿçàíî ñ îáðàçîâàíèåì ñëîæíûõ, òåðìè÷åñêè ñòàáèëüíûõ ðàäèàöèîííûõ äåôåêòîâ ïîä âîçäåéñòâèåì èçîõðîííûõ îòæèãîâ âïëîòü äî 400 0Ñ. Âûÿñíåíèå êîíêðåòíûõ ìåõàíèçìîâ è îöåíêà ïîòåíöèàëüíûõ âîçìîæíîñòåé ïðàêòè÷åñêîãî èñïîëüçîâàíèÿ íàáëþäàåìîãî èçìåíåíèÿ ñïåêòðîâ ôîòî÷óâñòâèòåëüíîñòè p-n ïåðåõîäîâ íà áàçå ñïëàâîâ Si-Ge ÿâëÿåòñÿ çàäà÷åé äàëüíåéøèõ èññëåäîâàíèé.

Çàêëþ÷åíèå

Ïðîàíàëèçèðîâàíû îáùèå è îòëè÷èòåëüíûå îñîáåííîñòè ñïåêòðîâ ôîòî÷óâñòâèòåëüíîñòè â äèàïàçîíå äëèí âîëí 0,8-2,5 ìêì p-n ñòðóêòóð, ñôîðìèðîâàííûõ ìåòîäàìè ãàçîôàçíîé ýïèòàêñèè è âûñîêîòåìïåðàòóðíîãî äèôôóçèîííîãî ëåãèðîâàíèÿ.  îáðàçöàõ îáëó÷åííûõ ýëåêòðîíàìè è èìïëàíòèðîâàííûõ èîíàìè áîðà îáíàðóæåíà èíòåíñèâíàÿ ïîëîñà ñ ìàêñèìóìàìè ôîòî-ý.ä.ñ. â îáëàñòè äëèí âîëí 1,8-2,5 ìêì. Ïîêàçàíî ðåçêîå âîçðàñòàíèå èíòåíñèâíîñòè óêàçàííîé ïîëîñû ôîòî-ý.ä.ñ. ïîä âëèÿíèåì èçîõðîííûõ îòæèãîâ äî 4000Ñ, ÷òî âîçìîæíî ñâÿçàíî ñ îáðàçîâàíèåì òåðìè÷åñêè ñòàáèëüíûõ ðàäèàöèîííûõ äåôåêòîâ â îáëàñòè p-n ïåðåõîäîâ.

Ëèòåðàòóðà: 1. F. P. Korshunov, V. P. Markevich, L. J. Murin, S. B. Lastovsky, Yu.V. Bogatyrev, N. V. Abrosimov. Influence of electron irradiation on characteristics of Si1-xGex p-n structures.

Vacuum 81(2007) 1171-1174.

2. H. Ohyama, J. M. Rafi, F. Compabadal, K. Takakura, E. Simoen, J. Chen, J. Vanhelemont. Comparison of electron irradiation effects on diodes fabricated on silicon and on germanium doped silicon subtrates. PhysicaB 404(2009), 4671-4673.

3. È. Ã. Àòàáàåâ, Ì. Ñ. Ñàèäîâ, Ë. È. Õèðóíåíêî, Â. È. Øàõîâöîâ, Â. Ê. Øèíêàðåíêî, Ë. È. Øïèíàð, À. È. Þñóïîâ. Î ìåõàíèçìå äåôåêòîîáðàçîâàíèÿ â ñïëàâàõ Si1Gex ïðè ýëåêòðîííîì îáëó÷åíèè. ÔÒÏ, ò. 27, âûï.3, 1987, x 570-575.

4. R. Takakura, F. Furukawa, S. Kuroki, K. Hayama, T. Kudou, K. Shigaku, E. Simoen. Radiation defects and degradation of C-doped SiGe diodes irradiated by electrons.Materials Science in Semiconductor Processing.9(2006), 292-295.

5. À. À. Áóãàé, Â. Ì. Ìàêñèìåíêî, Á. Ì. Òóðîâñêèé, Ë. È. Õèðóíåíêî, Â. È. Øàõîâöîâ, Â. Ê. Øèíêàðåíêî, Í. È. Ãîðáà÷åâà. Èññëåäîâàíèå ðàäèàöèîííûõ äåôåêòîâ â ñïëàâå Si-Ge ìåòîäîì ÝÏÐ è ÈÊ ñïåêòðîñêîïèè. ÔÒÏ, 1984, ò. 18, âûï. 11, 3020-3023.

Investigation of photoelectric sensitivity spectra in the near infrared radiation range of p-n structures formed on Si-Ge substrates G. Bokuchava1, A. Sichinava1, I. Kurashvili1, N. Gapishvili1, G. Darsavelidze1, B. Shirokov2, N. Semionov2 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli str.0186, Tbilisi, Georgia E-mail: sipt@sipt.org 2 National Science Center „Kharkov Institute of Physics and Technology“, 1 Academicheskaya St., Kharkov, 61108, Ukraine 1

By chemical vapor deposition, hightemperature diffusion doping and ion implantation of (111) Si-Ge substrates p-n structures have been formed. Photosensitivity spectra in the near infrared irradiation range have been investigated. Measurements have been conducted on a modified monochromator MDR-23 with automation control and computer data processing.

The possibilities of modifying of photosensitivity spectra in the near infrared irradiation range of p-n junctions on Si-Ge substrates have been shown. Characteristics of intensive photosensitivity bands in the range of 1,8-2,5 mcm formed by fast electrons irradiation and/or ion implantation have been analyzed.

Si-Ge fuZeSreebze formirebuli p-n struqturebis fotoeleqtruli mgrZnobiarobis speqtrebis kvleva infrawiTeli gamosxivebis axlo diapazonSi g. bokuCava1, a. siWinava1, i. yuraSvili1, n. gafiSvili1, g. darsaveliZe1, b. Sirokovi2, n. semionovi2 1

soxumis ilia vekuas fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo, el–fosta: sipt@sipt.org 2 erovnuli samecniero centri, xarkovis fizika– teqnikis instituti, xarkovi, ukraina (111) kristalografiuli orientaciis Si-Ge fuZeSreebze gazuri fazidan epitaqsiis, maRaltemperaturuli difuzuri legirebisa da ionuri implantaciis meTodebiT formirebulia p-n struqturebi da gamokvleulia maTi fotoeleqtruli mgrZnobiarobis speqtrebi infrawiTeli gamosxivebis talRis sigrZis axlo diapazonSi. kvlevebi ganxorcielebulia modificirebul MDR-23 monoqromatorze marTvis avtomatizaciisa da monacemTa kompiuteruli damuSavebis uzrunvelyofiT. naCvenebia infrawiTeli gamosxivebis talRis sigrZis axlo diapazonSi Si-Ge fuZeSreebze p-n gadasasvlelebis fotomgrZnobiarobis speqtrebis modificirebis SesaZlebloba.

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Photovoltaics-Research and -Application at the Science and Technology Park Berlin Adlershof K. Saritas1, K. Thiessen2 WISTA-MANAGEMENT-GMBH, Rudower Chaussee 17, 12489 Berlin, GER, saritas@wista.de Oberlandstraße 24 A, D-15366 Neuenhagen bei Berlin, GER, E-mail:k.u.k.thiessen@t-online.de 1 2

During the past twenty-five years in the territory of the institutes of the former East Germany Academy of Sciences, the largest Technology Park was formed in Berlin Adlershof,the fourth largest in Europe fields of research in Adlershof Photovoltaic energy systems in Adlershof Photovoltaics - areas of competence Criteria for success of solar energy clusters in Adlershof Center of photovoltaics and renewable energy (ZPV).

Keywords: Science and Technology Park, Photovoltaics, Renewable Energy, Research

Introduction The Berlin Adlershof Science City becamein the last twenty five years one of the most successful high-technology sites in Germany and Berlin’s largest media site. It is home to over 1,000 companies and scientific institutions (Jan 2015) on an area of 4.2 km² - embedded in an integrated urban planning concept. 15,931 people work and 6,235 study here.

The Science and Technology Park is at the heart of the Adlershof Science City. It encompasses 478 companies and ten non-university research institutes.

Adding to this are six scientific institutes of the Humboldt-UniversityBerlin (Chemistry, Geography, Computer Sciences, Mathematics, Physics and Psychology).

The Media City is home to 135 companies. In the immediate vicinity of science, technology, and media, a landscaped park and 380 private houses have been developed

Fig.1.

on an area of 66 ha. Large additional areas enable the Science and Technology Park to grow in the future. The near future years will see the completion of 1,400 housing units (“Living on Campus”) for about 2,500 people in the immediate vicinity to the Humboldt-University campus [1].

Research topics in Adlershof There are 16 research institutes in the Science City of Adlershof. Six of them are research institutes of the Humboldt-Universitätzu Berlin. Ten of the research institutes are so called non-university research institutions.

Since 15th June 2012, the Humboldt-University Berlin is ranked among the eleven “Excellence Universities” in Germany. To its current 38,000 students, originating from over 100 countries, the Humboldt-University offers a broad variety of studies, ranging from the humanities, social and cultural studies as well as natural and agricultural sciences

136 to human medicine, the study of which is located at the Charité Hospital.

Humboldt-University’s institutions are to be found on three different campuses.

The Erwin-Schrödinger Center houses the natural sciences library as well as IT and media services, providing state-of-the-art services for teaching and research.

Modern optics, molecular systems, mathematical physics and computational sciences are main fields of developing scientific collaboration amongst the different institutes.

The Integrative Research Institute for the Sciences

particular storage technologies, efficiency technologies, power generation, steering and consulting, planning and funding and base technologies. Adlershof had a very successful solar history around the year of 2009. Due to the unexpected loss of big solar companies like Solon, Soltecture and Global Solar only a few years later, the cluster widened its focus towards renewable energies and the emerging challenges. Not only solar technology, but energy technology in general became more and more part of the business and research models. Following non-research institutes contribute to the Energy Transition:

Fig.2. PV-Installations in Adlershof

(IRIS)Adlershof successfully connects Humboldt-University with non-university research institutions and high tech companies. [2] In 1992, the non-university research institutes formed the IGAFA regional network. It fosters cooperation amongst organizations and with universities and businesses, and generates synergies via scientific events, the joint welcoming of international guests, running of the meeting center and the distribution of literature.

975 publications and 350 conference talks are funded by the 174 million Euro budget, of which 53 million are derived from third-parties. In addition, 400 patents have been registered, forming the basis of the more than 20 successful new companies to emerge from the IGAFA’s institutes. Every year, more than 1,200 guest scientists work at the IGAFA institutes, of which 150 long term (over a month).

[3] Research institutes in the Science and Technology Park Adlershof are active in the fields of energy, optics sciences, material sciences, transportation, environment, microsystem technologies, analytics and space related issues.

The Energy Technology Network The energy technology network is formed by the trias of companies, the research institutes of the HumboldtUniversity Berlin and non-university research institutions.

About 60 companies are successful on energy topics, in

• Ferdinand-Braun-Institut (FBH)für Höchstfrequenztechnik • Helmholtz Zentrum für Materialien und Energie (HZB), Helmholtz Materials and Energy Center • DLR- Institut für Verkehrsforschung, Transportation Research Institute • Institut für Kristallzüchtung (IKZ), Leibniz Institute for Crystal Growth • Fraunhofer Institut für Angewandte Polymerforschung, Application Center for Innovative Polymer Technologies

PV-Installations PV-Installations can be found on roofs and facades more than thirty times in Adlershof. The first PV-plant in Adlershof was mounted on the facade of the Centre for Biotechnology and Environment in 1998. The vertical integration into the façade was chosen for shadowing and for optical purposes. This PV-installation was followed by a number of installations on rooftops and on façades. The following map shows the installations in Adlershof. Thetotal power ismore than 2 MWp. Many of them were produced and mounted from companies, which lived a great success story in the solar business. Worldwide known companies like Solon, Soltecture, Global Solar were located in Adlerhof. In the peak times around 2009 they had turnarounds beyond imaginations and forecasts. But the

137 “Solar Valley” more and more felt victim to the strong competition through Chinese products and also the cutback in government subsidies by the amendment of the German Renewable Energies Act (EEG).

Photovoltaics and Renewable Energies – Fields of Competence The ‘Renewable Energy and Photovoltaics’ technology field spans the entire supply chain; from research and development to production and sales. There is an emphasis on thin-film photovoltaics, fuel cell development and analysis, the production of hydrogen and energy storage technology. Companies such as Heliocentris, Silicor Materials, SENTECH Instruments or the Institute for Scientific Instruments (Institut für Gerätebau, ifg) are already benefitting from the unique blend of innovative technology, top-level research and economic promotion.

The leading research institutes for energy technology located at Adlershof are the Helmholtz Center Berlin (Helmholtz-Zentrum Berlin, HZB), the Center of Excellence for Thinfilm and Nanotechnology for Photovoltaics (Kompetenzzentrum Dünnschicht- und Nanotechnologie für Photovoltaik, PVcomB), the Leibniz Institute for Crystal Growth (Leibniz-Institutfür Kristallzüchtung, IKZ), the Institute for Analytical Science (ISAS), the Federal Institute for Materials Research and Testing (Bundesanstalt für Materialforschung und -prüfung, BAM), the German Association for Non-destructive Testing (Deutsche Gesellschaft für zerstörungsfreie Prüfung, DGzfP) and the National Metrology Institute (Physikalisch-TechnischeBundesanstalt, PTB). [4]

Center for Photovoltaics and Renewable Energies The Center for Photovoltaics and Renewable Energies (ZPV) is a WISTA-MANAGEMENT GMBH technology center located on Johann-Hittorf-Str. 8. Tailored to the needs of renewable energy companies, it offers manufacturing, laboratory, and office space on an area of 8,000 m².

Storage tech companies, solar architects, solar workers, planners, software developers, specialized lawyers and others benefit from a perfectly tuned infrastructure that is ready to use. The attractive building represents a dialogueoriented architecture built around transparency, social encounters, and communication. Its most striking design features include a high, light-flooded foyer with galleries, and a sculptural, freestanding spiral staircase that is open towards every floor. A total of nine laboratory modules for physics and chemistry as well as offices are located above the hall and workshop areas on the ground floor. Two rooftop gardens, meeting rooms, and a cafeteria offer many possibilities for social encounters and communication.

There are additional experimental sites on the foyer roof.

The building has been awarded Silver medal by the German Sustainable Building Council for its outstanding sustainability features in the categories ecology, economy, socio-cultural and functional aspects, technology, processes, and location.

Success Criteria of the PV and Renewable Energies-Cluster The success of the PV and Renewable Energies-Cluster is determined by several criteria.

To start with, the basis for research and developmentis outstanding. Six institutes from the Humboldt-University Berlin and ten non-university research institutes work in close vicinity to each other and many of them contribute to solutions in the energy sector. The focus on technology fields is a success driver as well. Scientists and entrepreneurs make use of synergies and develop a strong position in the energy market. Specialized facilities as the technology centers for different technology fields provide a perfectly tuned and highly equipped infrastructure in the production halls, physics and chemistry laboratories. Last but not least networking is very important. Not only in one´s regional cluster, but also worldwide through the participation in fairs and conferences.Following factors are decisive to generate a successful technology cluster: • Excellent R & D Basis • Focusing on Technology Fields • Specialized Facilities • Whole Value Chain • Proximity and Synergies in Adlershof • Networking - national and international

Fig.3. Center for Photovoltaics and Renewable Energies

Conclusions The previous content showed the variety and complexity of the Renewable Energies topic in the Science and Technology Park Berlin Adlershof. Thanks to the flexibility of the actors in the energy technology field, whether scientist or entrepreneur, Adlershof overcame a heavy crisis caused by the decline of solar production and nowadays gains worldwide recognition on other highly relevant energy topics, such as storage technologies. Younicos[5] is a very good example for success with storage solutions.

Thecore competence is the economic, safe, and stable integration of wind and solar power into existing grids. In cooperation with partners, Younicos designs, builds and operates up to 100 percent renewable energy systems. The

138 company demonstrated its promises in a project atGraciosa, the second-smallest Azorean islands. On this Portuguese island, the company provided evidence that renewables can be both technically and commercially superior to fossil fuels.

References: Website: 1. http://www.adlershof.de/en/facts-figures/adlershof-innumbers/ 2. http://www.adlershof.de/en/science-campus/humboldtuniversity/info/ 3. http://www.adlershof.de/en/science-campus/non-universityresearch/info/ 4. http://www.adlershof.de/en/technologies/renewable-energyphotovoltaics/info/ 5. http://www.younicos.com/en/home/

Photovoltaics-Research and -Application at the Science and Technology Park Berlin Adlershof K. Saritas 1, K. Thiessen2 WISTA-MANAGEMENT-GMBH, Rudower Chaussee 17, 12489 Berlin, GER, saritas@wista.de 2 Oberlandstraße 24 A, D-15366 Neuenhagen bei Berlin, GER, Ýë–ïî÷òà: k.u.k.thiessen@t-online.de

1

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fotoeleqtruli kvlevebi da gamoyeneba berlin-adlershofis mecnierebisa da teqnologiis parkSi k. saritasi1, k. tiseni2 WISTA-MANAGEMENT-GMBH, RudowerChaussee 17, 12489 Berlin, GER, saritas@wista.de 2 Oberlandstraße 24 A, D-15366 Neuenhagenbei Berlin, GER, el-fosta: k.u.k.thiessen@t-online.de 1

ukanaskneli ocdaxuTi wlis ganmavlobaSiyofili aRmosavleT germaniis mecnierebaTa akademiis institutebis teritoriaze berlin- adlershofSi Camoyalibda udidesi teqnoparki germaniaSi, sididiT meoTxe evropaSi - kvlevebis dargSi adlershofSi - teqnologiuri kvlevebis qseli adlershofSi - fotoeleqtruli energosistemebi adlershofSi (~ 2 megavati) - fotoeleqtroba- kompetenciis dargebi - adlershofis mzis energetikis klasteris warmatebis kriteriumebi - fotoeleqtrobisa da ganaxlebadi energiis centri (ZPV)- magniti novatorebisaTvis energiis mobrunebis sakiTxebSi.

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For holographic raster concentrator photodiode matrix Z. Vardosanidze1,2, G. Bokuchava1, T. Sulaberidze2, V. Kuchukhidze1, D. Berishvili1 Ilia Vekua Sukhumi Institute of Physics and Technology; Tbilisi, Georgia, E-mail: sipt@sipt.org 2 V. Chavchanidze Institute of Cybernetics of the Georgian Technical University 1

Abstract. Holographic raster systems containing anisotropic and isotropic structures have been created. Their properties are studied, respectively. It is established, that isotropic profile raster systems appear more acceptable for the fabrication of solar light concentrator in order to minimize losses.

Key Words: Holography, Polarization, Anisotropy, Isotropy, Fresnel lens, Raster systems.

High efficiency semiconductor photodiode batterymatrixes are basically used for the conversion of solar energy into electrical energy. Such matrixes are characterized by so-called passive zones conditioned by separate photodiode input window geometric shape (Fig.1).

In addition, mentioned Fresnel lens geometric aperture could be of any shape (e.g. an equilateral triangle, square and hexagonal (Fig.2)) and respectively, raster systems fabricated based on their unity, exclude existence of passive zones and light losses.

Fig.1

In particular, each photodiode input window, including bearing frame has acircular shape. Therefore, in case of their matrix fabrication, which may contain hundreds of photodiodes, and between the photodiodes will remian unallocated spaces resulting in fallen light loss in those zones. This loss is around 21.5 % range. Special light concentrators (lens rasters, in which each lens geometric aperture is square) are applied in order to correct and improve those errors. Using such raster concentrators allow to practically fix the mentioned problem, though they are characterized by certain defects: 1. Fabricating raster separate lens and correspondingly raster itself appear rather complex technologic process.

2. Fabricated rasters are non-compact and their mass is quite large.

3. Mentioned rasters are very expensive.

Holographic rasters can be used as concentrators with the aim to minimize those errors.Differing from ordinal raster systems, holographic rasterâ&#x20AC;&#x2122;s each element represents a zonal film so called Fresnel lens [1,2], which thickness ranges within10 â&#x20AC;&#x201C; 150mkm (Fig.2).

Fig.2

Envisaging that while light flow concentration photodiode efficiency is increased, light aperture losses are reduced to almost zero,and the holographic diffraction raster systems efficiency could get higher than 90% and their application appear rather advantageous. Namely, holographic systems are more compact and their mass islesser, the fabrication technology using further copy method is more simple and thus their price is significantly lower.

Fabricated by us hologragraphic rasters contain 25 and 99 elements (Fig. 3 a,b). Each element represent Fresnel phase micro lens, which sizes are 3x3 mm2. It is known that, generally zonal films may contain both optically isotropic, and optic anisotropic profile [3,4,5,]. Anisotropic structure holographic Fresnel lens allow to perform amplitude (intensity), polarization transformation, where isotropic profile holographic zonal plates perform only amplitude (intensi-

140 ty) transformation. In both cases diffraction efficiency is above 90%[6,7,8].

a

Diffraction images on lens are shown in Fig.6 a,b. According to observations, anisotropic profile lens work for one polarization, as expansion lens, and for its orthogonal polarization work as collecting lens.Such lens perform image inversion function, as shown in fig. 7 a, b.

The figure shows a and b images practically complete each other [6,7,8, 10].

b

Fig. 3

Fresnel holographic lens recording system scheme is given in fig. 4 [9]. Collimated laserbeam passes through the lens 1, which is fabricated from the double refraction material (in our case calcite), the lensis specifically cut out that is parallel to the optical axis of the lens flat surface.

a

b

Fig. 7

Raster system, which contains 25 square shape elements (Fig. 3 b) have been fabricated from the similar anisotropic profile microlenses, using scheme shown in Fig.4.

Microlenses recording has been performed by registered environmental positioning, fixed on the micrometric drive.

Diffraction images on the obtained raster and on its separate microlenses are given in fig.8 a,b., where diffraction efficiency is above 90%.

Fig.4

Therefore lens is characterized by double-focus length and forms mutually orthogonal polarization, various expansions, and two spherical waves.Lens 3 creates aperture imagein a plane, where photosensitive material is placed 4. Correspondingly, active interferences image is fixed on the photosensitive material and is modulated polarization and equal polarizings are distributed radially and in result we obtain Fresnel lens with anisotropic profile Fig. 5 a,b,c).

If observed by analyzer, when rotate, such lens haveFresnel zones corresponding variations clearly shown in Fig.5.

Fresnel lens with anisotropic profile are characterized by interesting properties. In particular, they simultaneously perform not only amplitude of light transformation, but polarizing transformation.

a Fig. 5

b

c

a

b

Fig. 8

The obtained raster system is characterized by one defect. It is selective towards the polarization. Though its diffraction efficiency is high (above 90%), but for one polarization it works as collecting microlens raster, and for orthogonal polarization it works as expansion microlens raster. Because the concentrators are mainly used for the solar radiation, but raster systemsare not assumed appropriate to use as solar light concentrators, because the sunâ&#x20AC;&#x2122;s light is not polarized and energy loss equals 50%.Anizotropic structure raster concentrators usage are recommended for special tasks, where polarization transformation has certain assignment â&#x20AC;&#x201C; e.g. while processing optical information.

Therefore, raster systems, where Fresnel microlens have isotropic structure are suitable to use for the light concentrators. Same holographic scheme is used to obtain raster system, fig.4, the difference is polarizer placed in the

141 scheme after the lens; 2. Polarizer 1 projects in one plane two spherical waves mutualorthogonal polarizations and polarized modulation of the total interference imagesobtained in registration material’s 4 planes,transforms into amplitude modulation. Polarization rotating allows to change interfering spherical waves intensity ratio for reaching holographic recording linear mode, or for the obtained Freshnel holographic microlens profile variations. Recording has been performed by He-Cd laser. Known photoresist has been used as registration material - bichromated gelatin, which absorption spectral properties are given in fig.9.

is 4%. Fig.11shows the obtained raster concentrator activity in a white (fig.11a) and blue (Fig.11 b laser radiation wavelength) light.

a

Fig. 11

b

The picture shows no losses accounted for the absence of passive zones in raster systems.

The process will be similar in case of equilateral triangle and hexagonal geometric aperture. In order to reach the raster diffraction system efficiency 90%, it is necessary each microlenses to operate in Bregg’s reflection mode, also photosensitive material layer thickness should be in the range of 50-100 mkm, which will be realized in the nearest future.Fig.12 a,b, shows point source diffraction images on the obtained raster system.

Fig. 9

The picture shows laser radiation wave length in the materials high absorption area, which is advantageous considering materials sensitivity. Photosensitive layer thickness is 5 – 7 mkm.

Fig. 12

a

b

Conclusions Raster system has been obtained theoretically, which can be used for photodiode matrix, as light concentrator without any losses. New approaches of axis holographic recording (developed by us)has been used for the development of the method.

References

Fig. 10

Fig.10 shows obtainedFresnel microlenses diffraction efficiency dependence on the exposure timein the gelatin matrix for various concentrations of ammonium bichromate.

According to the picture, maximal diffraction efficiency is 50% and it is reached at 80 sec. exposure time, on a gelatin film, in which ammonium bichromate concentration

1. Vud R. Physical Optics, L .; M .; ONTI, 1936, p.895.

2. Koler R., BerkchartK., LinL. Optical holography, M.; Mir, 1973, p.686.

3. Landsberg G. S. Optics, M.; “Nauka”, 1978, p. 920.

4. Dichbern R.Physical Optics, Ì.:“Nauka”, 1965. p. 637.

5. Sh.D.Kakichashvili, Z.V.Vardosanidze.Anisotropic profile zone plate, Letters ÆÒÔ, V.15, publ.17, ñ.41-44, 1989.

6. Z.V.Wardosanidze. Zone plate of an anisotropic profile, Proc.

SPIE, V.1574, pp.109-120,1991.

7. Z.V.Wardosanidze. Zone plate of an anisotropic profile, Abstract, International colloquium on diffractive optical elements DOE-91, Szklarskaporeba, Poland, pp.11, 14-17 may, 1991.

8. Z. V. Wardosanidze.Holographics Fresnel microlenses and rasters with an anisotropic profile, International conference, Abstracts, Micro- and Nano-optics for Optical Interconnec-

142 tion and Information Processing, Abstarcts, SPIE Annual meeting, San Diego, USA, Proceedings of SPIE Vol. #4455[4455-09], 29-31 July 2001.

9. Sh. D.Kakichashvili.Z.V.Vardosanidze.The method for obtaining a zone plate and a device for the realization,Copyright certificate ยน1746351, 1992.

10. Z.V.Wardosanidze.Holographic recording in the general case of linear polarization (coincident beams), Proc. of Institute of Cybernetics, Vol. 1, pp.131-137, 2001.

holografiuli rastruli koncentratori fotodiodebis matricisaTvis z. vardosaniZe1,2, T. sulaberiZe2, g. bokuCava1, v. kuWuxiZe1, d. beriSvili1 1

soxumis ilia vekuas fizika-teqnikis instituti; 2 saqarTvelos teqnikuri universitetis vl.WavWaniZis kibernetikis instituti el-fosta: sipt@sipt.org Seqmnilia anizotropuli da izotropuli struqturis mqone holografiuli rastruli sistemebi. gamokvleulia maTi Tvisebebi. dadgenilia, rom danakargebis minimizaciis TvalsazrisiT, mzis sinaTlis koncentratorebis dasamzadeblad ufro misaRebia izotropuli profilis mqone rastruli sistemebi.

143

Photoelectric properties of Si/Ge heterostructures with nanoscale objects V. Lysenko1, S. Kondratenko2, Ye. Melnichuk2, V. Lobanov3, M. Terebinska3, Yu. Kozyrev3 Institute of Semiconductor Physics, 41 Prospect Nauki, 03028, Kyiv, Ukraine Taras Shevchenko National University of Kyiv, 64/13 Volodymyrs’ka St., 01601, Kyiv, Ukraine 3 O.O. Chuiko Institute of Surface Chemistry,17 Generala Naumova St., 03164, Kyiv, Ukraine E-mail: :kondratenko@ukr.net 1 2

Abstract. Photogeneration and transport of nonequilibrium charge carriers, and the determination of photoresponce mechanisms in semiconductor SiGe/Si and SiGe/SiO2/p-Si heterostructures with nanoisland were investigated. The structures were grown by molecular beam epitaxy technique. The work generalizes the results of studies of morphological, structural, optical and electrical properties of heterostructures with nanoscale objects – quantum dots and quantum wells. It is shown that the photoconductivity of nanoheterostructures SiGe/Si in the infrared range depending on the component composition, size and magnitude of the mechanical stresses in nanoislands Si1-xGex is determined by interband and intraband transitions involving localized states of the valence band of the Ge nanoscale objects. The effects of long-decay photoconductivity and optical quenching of conductivity in SiGe/SiO2/p-Si heterostructures with SiGe nanoclusters was found to be caused by variations of the electrostatic potential in the near-suraface region of p-Si substrate and optically-induced spatial redistribution of trapped positive charges between SiO2/Si interface levels and localized states of Ge nanoislads.

Keywords: Ge-nanoclusters, photoconductivity, surface potential, quantum dots.

Introduction Germanium nanoclusters grown on/in silicon have been successfully applied in new optoelectronic, and memory devices. Due to spatial confinement of charge carrier’s motion in one, two or three directions, respectively, such nanostructures have unique fundamental properties and technological applications [1, 2]. Of particular interest is attracted by nanoelectronic devices and systems grown using epitaxy methods - vapor-phase, molecular-beam and liquid-phase - in which the formation and spatial arrangement of nanoscale elements was carried out using the effects of self-organization.

In heterosystem Si / Ge with nanoislands distributed across the surface of inherent nonuniform field of mechanical stresses. Interfaces and their quantum-size classes, wetting layer (WL) heterogeneity leads to spatial heterogeneity of local electro-physical properties of Ge nanoclusters and induced spatial variation of the electrostatic potential. These features, expectedly, will have an impact on the transport of charge carriers along the epitaxial layers.

Heterojunctions Si / Ge are reffered to the second type , in which there is a limitation of motion of holes in Ge nanoclusters. That’s why Ge nanoclusters can be considered as a long-term trap for holes, charge which a due to downward band bending in the underlying Si. Semiconductor heterostructures and especially semiconductor heterostructures with low-dimensional objects, including quantum wells, quantum wires and quantum dots, currently comprise the object of intensive study [1,3]. Of particular interest is attracted by nanoelectronic devices and systems grown using epitaxy methods - vapor-phase, molecular-beam and liquid-phase - in which the formation and spatial arrangement of nanoscale elements was carried out using the effects of self-organization. Knowledge of the electronic spectrum, transport, recombination, and pho-

togeneration in self-organized nanostructures is essential for creation of novel electronic and photonic devices.

Low-dimensional Ge/Si heterostructures have attracted considerable research interest in recent years, due to their significant potential to impact new electronic devices which are compatible with the available silicon technology. Optoelectronic devices based on SiGe dots grown on a Si substrate have been already proposed [4,5]. The lowdimensional silicon-germanium alloys have a wide range of applications, including quantum dot IR photodetectors, memory cells and spintronic devices. Widespread application of such system is the arrangement of SiGe quantum dots in the space-charge region of heterojunctions, Schottky diodes, p-n junctions or metal-oxide-semiconductor structures.

Experiment The molecular beam epitaxy (MBE) technique (“Katun’B” set-up, produced in Novosibirsk, Russia) was used to prepare multilayer Ge-Si(100) nanocluster arrays with the islands of various sizes and surface density. The (100) oriented wafers of n-Si with 7.5 and 20 Ohm×cm resistivity and diameter of 76 mm were used as substrates. In order to prepare multilayer quantum dot systems with regular nanoisland distribution over the substrate surface, we have proposed to use a system of Si1-xGex intermediate layers with a sub-critical thickness [5]. The Ge mole fraction x was gradually increased from layer to layer grown at gradually decreasing substrate temperature started from Ts=500oC. The growth process, in particular the moment of the 2D→3D transition in the Stranski-Krastanov growth regime, was controlled via RHEED (reflection high energy electron diffraction). To study the surface morphology, atomic force microscopy (AFM) measurements were carried out using an Ntegra AFM from NT-MDT with a closed loop scanner.

Standard Si cantilevers with tips having a half opening

144 angle of 10° were employed as probes. The growth of each Si intermediate layer was continued until a high-contrast Si(100)2x1 RHEED pattern was produced typical of clean Si. Thus, the multilayer Ge-Si(100) nanocluster arrays were grown at the temperature Ts=500oC. The Stranski-Krastanow growth of Ge nanoislands on Si(001) surface is an intermediary process characterized by both 2D WL and 3D island formation. Transition from the layer-by-layer epitaxy to nanoisland structure growth occurs at a critical layer thickness which is highly dependent on surface energies and lattice parameters. Germanium nanoclusters grown on/in silicon or silicon dioxide have been successfully applied in new nanoelectronic, optoelectronic and memory devices due to quantum confinement effect and possibility of integration within Si-based technology.

Micro Raman scattering spectra of the investigated structures were recorded at room temperature using automated Raman diffraction spectrometer T-64000 Horiba Jobin-Yvon equipped with CCD detector. The line 488 nm of Ar-Kr laser of 3 mW was used for excitation. Raman spectra were measured for the geometry z(x,y) - x, where axes x, y, z correspond to [100], [010] and [001] crystallographic directions, correspondingly. Ohmic Au–Si contacts of rectangular shape and dimensions of 4x1 mm were welded into epitaxial layers at 370 0C for lateral photoconductivity measurements. The distance between contacts on the sample surface was 5 mm. Current-voltage characteristics of the structures studied were found to be linear in the range from –10 V to +10 V at temperatures between 50 and 290 K. Lateral photoconductivity spectra were measured at excitation energies ranging from 0.48 to 1.7 eV under

ultrathin silicon oxide layer is mainly determined by the dynamics of changes of the SiOx film structure and physical properties during Ge deposition and is principally possible at temperatures below ~400oC, when the formation of voids in ultrathin SiO2 films is suppressed. Epitaxy at such low temperatures puts some limitations on the crystallinity and structural perfection of the obtained nanoclusters. Increasing of growth temperature up 430oC allows to grow epitaxial crystalline NI’s on silicon, while silicon oxide is destroyed due to thermal decomposition effect.

Results and Discussion Fig. 1a shows AFM image of the top layer of a typical sample with one layer of nanoislands large scatter and significant in size. The figure shows that the surface contains nanoislands size of the basics about 98 nm and a height of about 15 nm. The average surface density of nanoislands is ~ 1010 cm-2. Composition and values of elastic strains in investigated Ge/Si heterostructures were estimated using Raman spectroscopy. Typical Raman spectrum of Ge/Si heterostructure containing 5 layers of Ge quantum dots is given in fig.1b. It contains phonon bands corresponding to Ge-Ge, Si-Ge and Si-Si vibrations, which is typical for SiGe heterostructures with nanoislands, which makes possible to estimate content and strain values for Ge nanoislands [9]. Thus, Ge mole fraction and elastic strains in Ge nanoislands were found to be x = 0.91 ± 0.02 and, εxx = 0.01, correspondingly.

The Si1-xGex/Si heterostructures are refered to the second type, in which the potential well for holes is in the valence band of Si1-xGex (Fig.2a). Energy diagram of the

Fig. 1. The AFM image of the surface of nanoislands Ge, grown by MBE at 500oC on the surface of the substrate p-Si (001) (a) and Raman spectra (b) Si / Ge heterostructure with nanoislands Si1-xGex on the substrate p-Si (001) (sample 302.03.11).

illumination with a 250-W halogen lamp. The corresponding direct photocurrent signal was registered by a standard amplification technique. Spectral dependences were normalized to the constant number of exciting quanta using anonselective pyroelectric detector.

Non-epitaxial Ge nanoislands which are separated from the substrate attract special interest due to spatial separation of electron-hole pairs leading to reduction of recombination rate. NI’s growth at the silicon surface covered with

heterojunction is primarily determined by the values of the band gap and electron affinity of the contacting materials.

In unstrained Si1-xGex alloys the bandgap decreases monotonically with increasing of Ge content. Fig. 2b shows the results of numerical calculations of the energy spectra of holes in Si1-xGex quantum wells with width of 2 nm for different Ge contents. The analysis shows that the energy position of localized states with respect to top of Si valence band increases nonlinearly with x due to the depen-

145 dence of the effective mass of holes from the strain values in this system. Deep potential well in the valence band favor to accumulation of holes in Ge nanoislands in the wide temperature range. In the other word, the Ge nanoislands can be considered as a giant traps for holes. Positive charge of trapped holes induces downward band bending in the underlying p-Si substrate. Moreover, the band bending expected to be larger in the region beneath of nanoisland base.

Analyzing the energy diagrams of Si1-xGex/Si heterojunction we can conclude that the photosensitivity range of these structures is determined by the position of the Fermi level in the heterostructure, i.e. the concentration dopant in Si substrates and epitaxial films. Interband optical transitions are realized in the presence of electrons in quantum-sized states of the valence band nanoislands. For intraband transitions in the valence band, the Fermi level must be below at least the ground state of nanoislands.

of studying the shape of optical absorption spectra and energy and interband transitions possible in heterostructures with nanoscale objects.

Excitation of nonequilibrium charge carriers in Si/Ge heterostructures with Ge nanoislands causes conductivity changes in the space charge region of p-Si transport channel. Photoconductivity spectra (Fig. 3a) measured at excitation and steady temperatures 50-80-120 K contained two components. At hv > εg, Si (1.16 eV at 50 K), the main contribution to the photoconductivity gives electron-hole pairs photoexcited in the substrate p-Si due to interband transitions (see transition C in Fig.2a).

In the spectral region where Si is transparent, photoconductivity originates from interband electronic transitions involving localized states nanoislands Si1-xGex. The monopolar photoconductivity was observed in this case.

Interband electronic transitions between localized states of the valence band of SiGe nanoislands and delocalized

Fig. 2. Energy diagram of Si/Ge heterostructures with Ge nanoislands (a). The activation energies for localized holes of Si1-xGex quantum wells with width of 2 nm and different content of Ge (b).

Development of efficient optoelectronic devices requires information on energy, oscillator strengths, and selection rules for interband and intrabend transitions. Fluorescent measurements do not reflect all transitions possible in heterogeneous in size and composition of deformations heterostructures. Opportunities of absorption spectroscopy are severely limited by the fact that the passage of radiation through nanoscale quantum dot layer is absorbed only by its small part (~ 10-4 - 10-5). As a result, the direct measurement of the absorption spectra of quantum dots is rather difficult task which requires a very sensitive technique and long-time measurements. One of methods which makes possible to study the absorption spectra in nanoscale semiconductor structures is an in-plane photocurrent spectroscopy. The value of photoconductivity is proportional to the number of photogenerated charge carriers, and thus the absorption coefficient. Photocurrent spectroscopy is a direct, sensitive and relatively simple method

states of the conduction band of silicon surrounding can be observed in low-dimentional Si-Ge heterostructures. The spectral range of interband transitions is determined by Ge contents of QDs, strain values, and confinement energy for holes in the valence band [10]. Transitions A and B (Fig.2a) are possible if ground states are partially filled by electrons. These transitions cause the appearance of nonequilibrium electrons in the Si spacer layers and WLs, which are transport channel, while photoexcited holes are localized in Ge. Measurements of infrared photoconductivity in Ge-NC/ SiO2/Si structures made it possible to evaluate their electronic spectrum. The PC spectra measured at temperatures 50, 80, and 120 K (Fig.4) give information about energies of electronic transitions in Ge-NC/SiO2/p-Si structure. The inplane photocurrent in the range hv > εG,Si is mainly originated from band-to-band transitions in c-Si. For light excitations with photon energy below band gap of Si hv < εG,Si

146

Fig. 3. Photoconductivity spectra of Si / Ge heterostructure with nanoislands Si1-xGex on the substrate p-Si (001).

Fig. 4. In-plane PC spectra of Ge-NC/SiO2/Si measured at 50 K, 80 K, and 120 K and HR-TEM images of Ge NCs grown on silicon oxide.

(εG,Si=1.17 eV at 77 K ), the electronic transitions from valence band to conduction band of NCs give main contribution to PC. However, generation of photocurrent in the range 0.8 < hv < εG,Si for Ge-NC/SiO2/Si is also possible due to transitions between tails of the density of states in the near-surface c-Si [11], the optical absorption spectra of which are described by Urbach law. The electron transitions through the states of Ge-NC/SiO2 and Si/SiO2 interfaces may also be observed, however their contribution to PC is expected to be small due to high probability for recombination through interface state.

The contribution of electron-hole pairs photoexcited in Si is observed, when the quanta energy exceed the band gap value. In the spectral range hv < 1.1 eV, in which c-Si is transparent, interband indirect transitions take place via the states in the valence and conduction bands of nanoclusters. Non-equilibrium carriers photoexcited in nanoclusters do not contribute into carrier transport directly. In order to contribute into the lateral current, the non-equilibrium electrons and holes should be spatially separated. As

for Ge/Si heterojunctions, studied systems referred to type II, where strong confinement for holes in the region of Ge nanoclusters occurs. In the studied heterostructures, electrons can tunnel through the oxide SiOx film into the nearsurface silicon region and make contribution into conductivity. At the same time, non-equilibrium holes are localized in the valence band of Ge nanoclusters, however, they can affect the potential relief in the near-surface region of Si substrate, and hence, make an indirect effect on the system conductivity.

Thus, photoconductivity of the structures in the range of Si transparency is unipolar – intrinsic absorption of light in nanoclusters leads to an increase of the electron concentration in the Si potential well near the SiOx-Si interface and to an increase of the surface conductance. In this case, the shape of lateral photoconductivity spectra reflects main features of intrinsic absorption of light in nanoclusters.

The edge of PC spectrum of the investigated structures at hv > ε 0 is described by the dependence typical for the indirect band semiconductors:

147

α ( hv ) =

C 2 ( hv − ε 0 ) hv

where C is a constant, ε 0 is the width of the optical band gap. At excitement with quanta hv<å0 the Urbach tail is observed due to the crystal structure disorder.

Photocurrent spectroscopy and X-ray diffraction demonstrate that the nanoclusters have the local structure of body-centred-tetragonal Ge, which exhibit an optical adsorption edge at ε 0 = 0.48 eV. Taking into account quantum-size effect, this is in a good agreement with the theoretical calculations of electronic and optical properties of bulk body-centered-tetragonal Ge and Si, according to which the band gap width for the mentioned polytypes is 0.38 and 0.86 eV, respectively [12].

Conclusions The mechanism of photoconductivity in the Ge/Si generally, which are referred to the second type heterostructures, depends on quantum energy of exciting illumination. The lateral photoconductivity observed in the range 0.63 – 1.0 åV below fundamental absorption edge of c-Si was caused by interband transitions from the ground state of a Ge nanoislands to the conduction band of a silicon surrounding. Photoexcited holes was found to be localized in Ge nanoislands, while photoelectrons are supposed to be free in the conduction band of Si giving contribution to the monopolar photoconductivity. In the case of excitation of Ge/SiO2/Si structures an interband transitions in Ge create localized holes in Ge directly, leading to optically-induced spatial redistribution of trapped positive charges between SiO2/Si interface levels and localized states of GeNCs, which enhance variation of electrostatic potential in underlying Si and, therefore, decay of surface conductivity under stationary photoexcitation. Observed results demonstrate that hole trapping by Ge-NCs and interface states have a significant effect on in-plane transport in the GeNCs/SiO2/Si structures.

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8. Kondratenko S.V. Morphology and photoelectric properties of Si-Ge quantum-sized structures / Yu.N. Kozyrev, M.Yu. Rubezhanska, V.S. Lysenko [òà ³í.] // International Work-

shop “In situ characterization of near-surface processes”, Eisenerz, 30 may - 3 June, 2010.: abstract of book. – Eisenerz, Austria, 2010. – Ð. 40.

9. S.V. Kondratenko, A.S. Nikolenko, O.V. Vakulenko, M.Ya. Valakh, V.O. Yukhymchuk, A.V. Dvurechenskii, A.I. Nikiforov // Nanotechnology V. 19, P. 145703 (2008).

10. S. V. Kondratenko, S. L. Golovinskiy, A. S. Nikolenko and O. V. Vakulenko Semiconductor science and technology 21 (7), 857 (2006).

11. V.S. Lysenko, Yu.V. Gomeniuk, Yu.N. Kozyrev, M.Yu. Rubezhanska, V.K. Sklyar, S.V. Kondratenko, Ye.Ye. Melnichuk, C. Teichert. Effect of Ge nanoislands on lateral photoconductivity of Ge-SiOx-Si structures (2011) Advanced Materials Research 276: 179-186.

12. B.D. Malone, S.G. Louie, M.L. Cohen. Electronic and optical properties of body-centered-tetragonal Si and Ge (2010) Phys.Rev.B. 81: 115201-115205.

nanozomebiani obieqtebis Semcveli Si/Ge heterostruqturebis fotoeleqtronuli Tvisebebi v. lisenko1, z. kondratenko2, i. melniCuki2, v. lobanovi3, m. terebinski3, i. kozirevi3 1 naxevargamtarebis fizikis instituti, mecnierebis prospeqti 41, 03028, kievi, ukraina.

2 kievis taras SvCenkos erovnuli universiteti, vladimirskas q. 64/13, 01601, kievi, ukraina 3 o. Cuikos zedapirebis qimiis instituti, general naumovis q., 17, 03164, kievi, ukraina el-fosta: Kondratenko@ukr.net.

gamokvleulia nanokunZulebiani naxevargamtaruli SiGe/Si da SiGe/SiO2/p-Si Tvisebebi heterostruqturebSi arawonasworuli muxtis matareblebis generacia da gadatana, gansazRvrulia fotogamtarobis meqanizmebi. struqturebi Seqmnilia molekulur-sxivuri epitaqsiis meTodiT. naSromSi ganzogadoebulia nanozomebiani qvanturi wertilebisa da qvanturi ormoebis Semcveli heterostruqturebis morfologiuri, struqturuli, optikuri da eleqtruli Tvisebebis kvlevis Sedegebi. naCvenebia, rom komponentebis Semcvelobaze, zomebsa da meqanikuri Zabvebis mniSvnelobebze damokidebuli SiGe/Si heterostruqturebis fotogamtaroba gansazRvrulia Si1-xGex nanokunZulebSi zonaTa Sorisi da zonis Sida gadasvlebiT, rac moicavs savalento zonis lokalizirebul mdgomareobas Ge-s nanozomebian obieqtebSi. gamovlenilia fotogamtarobis gaxangrZlivebuli Sesusteba da gamtarobis optikuri Caqroba SiGe nanoklasterebis Semcvel SiGe/SiO2/p-Si nanostruqturebSi, romelic ganpirobebulia eleqtrostatikuri potencialis variaciiT p-Si fuZeSreebis zedapirul areSi da optikurad-inducirebuli sivrceSi gadanawilebul areSi CaWerili dadebiTi muxtebiT SiO2/Si sasazRvro doneebsa da Ge-s nanokunZulebSi lokalizirebul mdgomareobebs Soris.

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Ðàçâèòèå íàïðàâëåíèÿ ïðåîáðàçîâàòåëåé ýíåðãèé íà áàçå ïîëóïðîâîäíèêîâûõ p-n ïåðåõîäîâ Ê. Êîáàõèäçå1, Í. ×õåíêåëè2 Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà, óë. Ìèíäåëè 7, 0186,Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà: sipt@sipt.org 2 ÎÎÎ ‘’Äîì Ñîëíöà’’ Òáèëèñè, óë. Òöêíåòñêàÿ, 8/4, Ýë–ïî÷òà: sun@sun.org.ge Ðåçþìå.  ðàáîòå ðàññìîòðåíû ýòàïû ðàçâèòèÿ íàïðàâëåíèé ïðåîáðàçîâàòåëåé ýíåðãèé íà áàçå ïîëóïðîâîäíèêîâûõ p-n ñòðóêòóð â Ñóõóìñêîì Ôèçèêî-Òåõíè÷åñêîì Èíñòèòóòå èì. È.Í. Âåêóà. Êîðîòêî îïèñûâàþòñÿ òåõíîëîãèè ïîëó÷åíèÿ ñòðóêòóð è ìåòîäû èõ èñïûòàíèÿ. Ðàññêàçàíî îá èññëåäîâàíèè âîçîáíîâëÿåìûõ ýíåðãîðåñóðñîâ â âûñîêîãîðíûõ ðåãèîíàõ Ãðóçèè. Ïðèâåäåíà êàðòà – Ñîëíå÷íûé êàäàñòð Ãðóçèè è ïðèìåðû – ïðàêòè÷åñêîãî èñïîëüçîâàíèÿ Ñîëíå÷íîé ýíåðãèè.

Êëþ÷åâûå ñëîâà : Êðåìíèé, ãåðìàíèé, p-n ñòðóêòóðà, áåòà ýëåìåíò, Ñîëíå÷íûé ýëåìåíò, òåðìîôîòîýëåêòðî ýëåìåíò, ïðåîáðàçîâàòåëü ýíåðãèè

 êîíöå 60-ûõ è â íà÷àëå 70-ûõ ãîäîâ ïðîøëîãî âåêà, ðàçðàáîòêà òåõíîëîãèè è èçãîòîâëåíèå òåðìîýëåêòðî ìàòåðèàëîâ è áàòàðåé â Ñóõóìñêîì ÔèçèêîÒåõíè÷åñêîì Èíñòèòóòå èì. Âåêóà (ÑÔÒÈ) äîñòèãëà ñâîåãî ïèêà ñîâåðøåíñòâà.  ñâÿçè ñ ýòèì â Ãëàâíîì Óïðàâëåíèè Ìèíèñòåðñòâà Ñðåäíåãî Ìàøèíîñòðîåíèÿ (ÌÑÌ) áûëî ïðèíÿòî ðåøåíèå ïàðàëëåëüíî ðàçâèâàòü äðóãèå íàïðàâëåíèÿ òåõíîëîãèè ïðåîáðàçîâàòåëåé ýíåðãèè. Íàïðèìåð, ïðåîáðàçîâàòåëè íà áàçå ïîëóïðîâîäíèêîâûõ p-n ñòðóêòóð (ïîäîáíûå Ñîëíå÷íûì ýëåìåíòàì) ñïîñîáíûå ïðåîáðàçîâûâàòü ðàçëè÷íûå âèäû ýíåðãèè, êàê íàïðèìåð ÿäåðíóþ è òåðìîèçëó÷åíèå â ýëåêòðè÷åñêóþ.  ñàìîì íà÷àëå ïîñòàíîâêè çàäà÷è, ðóêîâîäñòâîì ÌÑÌ áûëî îãîâîðåíî, ÷òî Èíñòèòóòó íå ðåêîìåíäîâàëîñü çàíèìàòüñÿ òåõíîëîãèÿìè ïîëó÷åíèÿ Ñîëíå÷íûõ ýëåìåíòîâ (ÑÝ), ïîñêîëüêó ýòî íàïðàâëåíèå áûëî ïðåðîãàòèâîé Ìèíèñòåðñòâà Ýëåêòðîííîé Ïðîìûøëåííîñòè.  ýòîì íàïðàâëåíèè ïåðâûìè ðàáîòàìè áûëè ðàçðàáîòêè òåõíîëîãèè ò.í. àòîìíûõ ýëåìåíòîâ íà áàçå ìîíîêðèñòàëëè÷åñêèõ êðåìíèåâûõ p-n ñòðóêòóð. Ðàáîòû ïðîâîäèëèñü â ïîäðàçäåëåíèè 460. Íàä òåìîé ðàáîòàëè: íà÷àëüíèê ëàáîðàòîðèè Øâàíãèðàäçå Ð.Ð., ðóêîâîäèòåëü íàó÷íîé ãðóïïû Äæàìàãèäçå Ø.Ç., ðóê. ïîäãðóïïû ×àìàãóà À.Õ., íàó÷íûå ñîòðóäíèêè Öèíöàäçå Í., Ñàëàêàèÿ Î., Ôðåíêåëü Å., ×åðêàñîâà À. Àòîìíûå ýëåìåíòû ðàáîòàþò íà áåòà-âîëüòàè÷åñêîì ýôôåêòå, êîòîðûé ÿâëÿåòñÿ àíàëîãîì ôîòîýëåêòðè÷åñêîãî ýôôåêòà (ïðîèñõîäÿùåì â ÑÝ), ñ òîé ðàçíèöåé, ÷òî îáðàçîâàíèå ýëåêòðîí-äûðî÷íûõ ïàð â êðèñòàëëè÷åñêîé ðåøåòêå ïîëóïðîâîäíèêà, ïðîèñõîäèò ïîä âîçäåéñòâèåì áåòà-÷àñòèö (áûñòðûõ ýëåêòðîíîâ), à íå ôîíîíîâ (êâàíòîâ ñâåòîâîãî èçëó÷åíèÿ), êàê â ÑÝ [1].  ìîíîêðèñòàëè÷åñêîì êðåìíèè Ð-òèïà ïëàíàðíûé p-n ïåðåõîä ñôîðìèðîâàëñÿ ìåòîäîì äèôôóçèè

ôîñôîðà â ñðåäå êèñëîðîäà. Íà ïåðâîé ñòàäèè äèôôóçèè íà ïîäëîæêå êðåìíèÿ îáðàçîâàëàñü ïëåíêà ôîñôîðà-ñèëèêàòíîãî ñòåêëà, à äàëåå èç òâåðäîé ôàçû ïðîèñõîäèëî ïðîíèêíîâåíèå ôîñôîðà âî âíóòðü ìîíîêðèñòàëëà. Ãëóáèíà çàëåãàíèÿ p-n ïåðåõîäà ñîñòàâëÿëà 2-3 ìêì. Òîëùèíà ïîäëîæåê áûëà ïîðÿäêà 300 ìêì, à äèàìåòð 18 ìì.

Ðèñ. 1. Ñòðóêòóðà áåòà ýëåìåíòà. 1- Ëèöåâîé êîíòàêò; 2- n - îáëàñòü; 3- p- îáëàñòü; 4- òûëüíûé êîíòàêò.

Ïîñëå äèôôóçèè íà ñòðóêòóðó ìåòîäîì âàêóóìíîãî íàïûëåíèÿ íàíîñèëèñü àëþìèíåâûå îìè÷åñêèå êîíòàêòû – ñ ëèöåâîé ñòîðîíû êîëüöåîáðàçíûå, à ñ òûëüíîé -ñïëîøíûå. Ñ öåëüþ ïàéêè òîêîîòâîäîâ, íàïûëÿëñÿ ñëîé ñåðåáðà (âòîðîé ñëîé îìè÷åñêèõ êîíòàêòîâ) òåì æå ìåòîäîì.  ëàáîðàòîðèè èçìåðÿëèñü ñâåòîâûå è òåìíîâûå âîëüò-àìïåðíûå õàðàêòåðèñòèêè (ÂÀÕ) ïîëó÷åííûõ áåòà-ýëåìåíòîâ, ñîðòèðîâàëèñü è îòïðàâëÿëèñü â ñîîòâåòñòâóþùèå ïðåäïðèÿòèÿ ÌÑÌ. Òàì íàíîñèëè ñëîé ðàäèîíóêëèäà ñòðîíöèÿ – Sr90 è êîììóòèðîâàëè â âûñîêîâîëüòíóþ áàòàðåþ. Âûõîäíàÿ ìîùíîñòü òàêèõ áàòàðåé áûëà ðàññ÷èòàíà íà ìèëèâàòíûå ýíåðãèè, ñ ýôôåêòèâíîñòüþ ïðåîáðàçîâàíèÿ ïîðÿäêà 2%. Èçäåëèå – àòîìíàÿ áàòàðåÿ, ñîáðàííàÿ íà áàçå êðåìíèåâûõ p-n áåòà-ýëåìåíòîâ, èçãîòîâëåííûõ â ÑÔÒÈ, ïîëó÷èëà äèïëîì òðåòüåé ñòåïåíè íà Âûñòàâêå Äîñòèæåíèé Íàðîäíîãî Õîçÿéñòâà.  íà÷àëå 80-òûõ ãîäîâ â ÑÔÒÈ â ïîäðàçäåëåíèè 460 íà÷àëèñü ðàáîòû ïî ðàçðàáîòêå òåõíîëîãèè ïîëó÷åíèÿ òåðìîôîòîýëåêòðî ïðåîáðàçîâàòåëåé (ÒÔÝÏ) íà áàçå

149 ãåðìàíèåâûõ p-n ñòðóêòóð. Íàä òåìîé ðàáîòàëè: íà÷àëüíèê ëàáîðàòîðèè Øâàíãèðàäçå Ð.Ð., ðóêîâîäèòåëü ãðóïïû Äæàìàãèäçå Ø.Ç., ðóê. ïîäãðóïïû ×àòîâ Â.À., íàó÷íûå ñîòðóäíèêè Êîáàõèäçå Ê.À., Òîäóà À.À.,×àòîâà Ë.À., Ôðåíêåëü Å., ×åðêàñîâà À. ÒÔÝÏ ïîäîáåí ÑÝ ñ òîé ðàçíèöåé, ÷òî îí ïðåîáðàçóåò ëó÷èñòóþ ýíåðãèþ èçëó÷àòåëÿ – íàãðåòîãî òåëà (èìèòàöèÿ èñêóññòâåííîãî Ñîëíöà). Ôîòî÷óâñòâèòåëüíîñòü ãåðìàíèÿ ñîîòâåòñòâóåò ñïåêòðó èçëó÷åíèÿ ñåðîãî òåëà, íàãðåòîãî äî òåìïåðàòóðû 1600 Ê. Ðàçðàáîòàííûå ÒÔÝÏ-è äîëæíû áûëè áûòü èñïîëüçîâàíû äëÿ ýëåêòðîïèòàíèÿ ñèñòåìû ðàêåòîíîñèòåëÿ ïðè ñòàðòå-âçëåòå (äî îòäåëåíèÿ ðàêåòîíîñèòåëÿ). Ðàçìåùåííûå ÒÔÝÏ â ñîïëè ðàêåòû, äîëæíû áûëè ïðåîáðàçîâàòü ëó÷èñòóþ ýíåðãèþ îãíÿ, ïîëó÷åííîãî ñãîðàíèåì ðàêåòíîãî òîïëèâà, â ýëåêòðè÷åñêóþ.

ñëîé) è òûëüíóþ ñòîðîíû, ìåòîäîì âàêóóìíîãî íàïûëåíèÿ íàíîñèëèñü îìíûå êîíòàêòû, òîëùèíîé 1ìêì [2]. Ïîñêîëüêó â ðàáî÷åì ñîñòîÿíèè â ãåðìàíèåâîì ÔÏ îáðàçóåòñÿ ïëîòíîñòü òîêà ïîðÿäêà 1ñì 2 , î÷åíü ñóùåñòâåííî ïîëó÷àòü íèçêîå ñîïðîòèâëåíèå ïåðåõîäà êîíòàêòîâ ìåòàëë-ïîëóïðîâîäíèê (íèçêèé êîýôôèöèåíò ðàñòåêàíèÿ). Ñ ýòîé öåëüþ íà ëèöåâîé ñòîðîíå ñòðóêòóðû, èñïîëüçóÿ ìåòîä ôîòîëèòîãðàôèè, ôîðìèðîâàëè îìè÷åñêèé êîíòàêò â âèäå ò.í. «ãðåáåíêè». Øèðèíà ìåòàëëè÷åñêîé êîíòàêòíîé ïîëîñêè áûëà 100 ìêì, à ïðîìåæóòîê ìåæäó êîíòàêòíûìè ëèíèÿìè ñîîòâåòñòâîâàë 1000 ìêì (êîíòàêòû çàòåìíÿëè ïðèìåðíî 10% àêòèâíîé ïîâåðõíîñòè ÔÝ). Èçãîòàâëèâàëè ÔÝ êàê êðóãëîé, äèàìåòðîì 18 ìì, òàê è êâàäðàòíîé ôîðìû 15x15 ìì. Òîëùèíà ïëàñòèí ìåíÿëàñü îò 100 äî 300 ìêì.

Ðèñ. 2. Ìîäåëü ÿäåðíîãî ÒÔÝÏ-à. 1- Ìåäíûé êîðïóñ; 2ÒÔÝÏ; 3- îõëàäèòåëü; 4- ýêðàí; 5- ìîëèáäåíîâûé øàð; 6ðàäèîèçîòîï.

Êðîìå ýòîãî, ãåðìàíèåâûå ÒÔÝÏ-è âîçìîæíî èñïîëüçîâàòü äëÿ ïðåîáðàçîâàíèÿ ëó÷èñòîé ýíåðãèè òåëà, íàãðåòîãî îò ðàäèîàêòèâíîãî âåùåñòâà. Ðàäèîèçîòîï ïîìåùàåòñÿ âî âíóòðü òóãîïëàâêîãî ìåòàëëà ìîëèáäåíîâîãî øàðà. Âîêðóã øàðà íà îõäàæäàåìûé ìåäíûé êîðïóñ (êîæóõ) ðàçìåùàþòñÿ ýëåêòðîêîìóòèðóåìûå ãåðìàíèåâûå òåðìîôîòîýëåìåíòû (ÃÒÔÝ). Ñïåöèàëüíî ïîäîáðàííûé èçîòîï ïðè ðàñïàäå íàãðåâàåò ìîëèáäåíîâûé øàð äî òåìïåðàòóðû 1800 Ê. Ëó÷èñòóþ ýíåðãèþ èñïóñêàåìóþ íàãðåòûì ìîëèáäåíîâûì øàðîì ãåðìàíèåâûé ÒÔÝÏ íåïîñðåäñòâåííî ïðåîáðàçóåò â ýëåêòðè÷åñêóþ ýíåðãèþ.  ìîíîêðèñòàëëå ãåðìàíèÿ p-n ïåðåõîä ôîðìèðîâàëñÿ äâóìÿ ìåòîäàìè: æèäêîôàçíîé ýïèòàêñèåé è äèôôóçèåé. Îáà ïðîöåññà ïðîõîäèëè â ñðåäå âîäîðîäà. Èñïîëüçîâàëñÿ ãåðìàíèé Ð òèïà ñ óäåëüíûì ñîïðîòèâëåíèåì îò 0.01 äî 20 Îì.ñì. Ìåòîäîì æèäêîôàçíîé ýïèòàêñèè áûëè ïîëó÷åíû ñòðóêòóðû n+p- p+ ñ òîíêèì (ìåíåå 2 ìêì) n+ ñëîåì. Íà ëèöåâóþ (n+

Ðèñ. 3. Ñòðóêòóðà ÃÔÝ-à. 1- n - îáëàñòü; 3- p- îáëàñòü; 3- òûëüíûé êîíòàêò; 4- ëèöåâîé êîíòàêò -«ãðåáåíêè».

Èçìåðåíèå ñâåòîâûõ ÂÀÕ ïîëó÷åííûõ ïðîâîäèëèñü íà ñïåöèàëüíî ñêîíñòðóèðîâàííîé óñòàíîâêå.  âàêóóìíîé êàìåðå, ñ ïîìîùüþ ýëåêòðîííîé ïóøêè, íàãðåâàëàñü ãðàôèòîâàÿ øàéáà (äèàìåòð 30 ìì, òîëùèíà 5 ìì) äî òåìïåðàòóðû 1800 Ê. Íàä èçëó÷àòåëåì ó êâàðöåâîãî îêíà ðàñïîëàãàëñÿ ÔÝ ïðèïàÿííûé ê ìåäíîìó ôëàíöó. Ôëàíåö èçíóòðè è êâàðöåâàÿ òðóáà îõëàæäàëèñü ïðîòî÷íîé âîäîé. Ñâåòîâûå ÂÀÕ ñíèìàëèñü ñ ïîìîùüþ ñàìîïèñöà. Äëÿ èñïûòàíèÿ ãåðìàíèåâûõ ÒÔÝÏ ïðèáëèæåííûì ê ðåàëüíûì ðàáî÷èì óñëîâèÿì áûëà ñêîíñòðóèðîâàíà ñïåöèàëüíàÿ óñòàíîâêà. Ãðàôèòîâûé ñòåðæåíü äèàìåòðîì 15 ìì íàãðåâàëñÿ ñ ïîìîùüþ âîëüôðàìîâîé ñïèðàëè. ÃÔÝ êâàäðàòíîé ôîðìû ïðèïàèâàëèñü íà ìåäíûé êîðïóñ, êîòîðûé îõëàæäàëñÿ ïðîòî÷íîé âîäîé.

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Ðèñ. 4. Ýñêèç óñòàíîâêè äëÿ èçìåðåíèå ñâåòîâûõ ÂÀÕ ãåðìàíèåâîãî ÒÔÝ-å. 1- Ìåäíûé ôëàíåö; 2- ÔÝ; 3- êâàðöåâûé êîëïàê ñ îêíîì; 4 – ãðàôèòîâàÿ øàéáà; 5– ýëåêòðîííàÿ ïóøêà; 6- ìåòàëëè÷åñêàÿ ðóáàøêà; 7- âîäÿíîå îõëàæäåíèå; 8- ôëàíåö; 9- âàêóóì.

Íà ïîñëåäíåì ýòàïå ðàçðàáîòêè ãåðìàíèåâûå ÔÏ áûëè èñïûòàíû íà ðàäèàöèîííîå îáëó÷åíèå íà ðåàêòîðàõ: â èíñòèòóòå ôèçèêè èì. Àíäðîíèêàøâèëè (Òáèëèñè) è â èíñòèòóòå ôèçèêè èì. Êóð÷àòîâà (Ìîñêâà). Èçìåðåíèå Ñâåòîâûõ ÂÀÕ äî è ïîñëå îáëó÷åíèÿ ïîêàçàëè ðàäèàöèîííóþ ñòîéêîñòü äëÿ òîãî óðîâíÿ (äîçû) îáëó÷åíèÿ â êîòîðîì èì ïðåäñòîÿëî íàõîäèòüñÿ â ðåàëüíîì ðàáî÷åì ðåæèìå.  ÑÔÒÈ ïàðàëëåëüíî áûëè íà÷àòû ðàáîòû ïî òåõíîëîãèè ïîëó÷åíèÿ ÒÔÝ íà áàçå GaAs. Ýêñïåðèìåíòû ïðîâîäèëèñü íà óñòàíîâêå ãàçîôàçíîé ýïèòàêñèè. Óñòàíîâêà áûëà ðàçðàáîòàíà è èçãîòîâëåíà â ãîñóäàðñòâåííîì èíñòèòóòå ðåäêèõ ìåòàëëîâ. Èç-çà êîðîòêîãî âðåìåíè ðàáîòû (1-2 ãîäà) îñîáûå ðåçóëüòàòû íå áûëè ïîëó÷åíû. Ñ 90-ãî ãîäà ïðîøëîãî ñòîëåòèÿ â ÑÔÒÈ ñòàëî âîçìîæíûì çàíèìàòüñÿ ðàçðàáîòêîé òåõíîëîãèé ÑÝ è áàòàðåé. Áûëè ïîëó÷åíû êðåìíèåâûå ÑÝ äèàìåòðîì 40 ìì, ýôôåêòèâíîñòüþ ïîðÿäêà 10%. Èç íèõ áûëè ñîáðàíû ìàëîìîùíûå ìîäóëè îò 5 äî 20 Âàòò. Áûëà òàêæå ñêîíñòðóèðîâàíà è ñîáðàíà Ñîëíå÷íàÿ áàòàðåÿ òèïà «ñîìáðåðî». Ýòà ìîäåëü ìîùíîñòüþ 15 Âàòò îäåâàëàñü íà ãîëîâó ÷åëîâåêà è ñëóæèëà äëÿ ýëåêòðîïèòàíèÿ ðó÷íîé ÷àåóáîðî÷íîé ìàøèíû â ìîáèëüíîì ðåæèìå.  ýòîì æå ïåðèîäå âåëèñü ïîäãîòîâèòåëüíûå ðàáîòû ïî ïîëó÷åíèþ ÑÝ íà áàçå àìîðôíîãî êðåìíèÿ. Íî ê ñîæàëåíèþ èç-çà èçâåñòíûõ ñîáûòèé â Àáõàçèè â 1993 ãîäó íàì ïðèøëîñü îñòàâèòü òåõíîëîãè÷åñêóþ áàçó Èíñòèòóòà â ïîñåëêå Àãóäçåðà. Ïîñëå ïåðåáàçèðîâêè â Òáèëèñè ó Èíñòèòóòà íå áûëî òåõíè÷åñêèõ âîçìîæíîñòåé äëÿ äàëüíåéøåé ðàáîòû â íà÷àòîì íàïðàâëåíèè - ïî óëó÷øåíèþ ýôôåêòèâíîñòè ÑÝ.  Òáèëèñè ïðîäîëæèëèñü ðàáîòû ïî ïðàêòè÷åñêîìó ïðèìåíåíèþ Ñîëíå÷íîé Ýíåðãèè.

Ðèñ. 5. Ýñêèç óñòàíîâêè äëÿ èçìåðåíèÿ ýôôåêòèâíîñòè ãåðìàíèåâûõ ÒÔÝÏ. 1-Òîðöîâûé îòðàæàþùèé ýêðàí; 2- âîëüôðàìîâàÿ ñïèðàëü; 3- ãðàôèòîâûé ñòåðæåíü; 4- ãåðìàíèåâûå ÔÝ; 5- ìåäíûé êîðïóñ; 6- âîäÿíîå îõëàæäåíèå.

Äëÿ óëó÷øåíèÿ ýôôåêòèâíîñòè èçëó÷àòåëÿ ýíåðãèè äëèííîâîëíîâîé ÷àñòè ñïåêòðà íà ÃÔÝ ñ òûëüíîé ñòîðîíû ìåòîäîì âàêóóìíîãî íàïûëåíèÿ ôîðìèðîâàëè çåðêàëüíî îòðàæàþùóþ ñòðóêòóðó Al-Ge. Ñ òîé æå öåëüþ íà ÃÔÝ ñ ëèöåâîé ñòîðîíû òàêèì æå ìåòîäîì íàíîñèëè ìíîãîñëîéíûé (15-17 ñëîåâ) èíòåðôåðåíöèîííûé ôèëüòð. Èñïûòàíèÿ â òàêèõ óñëîâèÿõ ãåðìàíèåâûõ ÒÔÝÏ ïîêàçàëè ýôôåêòèâíîñòü ïðåîáðàçîâàíèÿ îêîëî 5% . ×òî áûëî âïîëíå ïðèåìëåìî äëÿ ïîñòàâëåííîé çàäà÷è.

Ðèñ. 6. Ñîëíå÷íûé êàäàñòð Ãðóçèè.

 2007-2009 ãîäàõ â ðàìêàõ ïðîåêòà Íàöèîíàëüíîãî Íàó÷íîãî Ôîíäà Ãðóçèè áûëè èññëåäîâàíû ýíåðãîðåñóðñû âîçîáíîâëÿåìûõ èñòî÷íèêîâ ýíåðãèè â âûñîêîãîðíûõ, íå ýëåêòðîôèöèðîâàííûõ äåðåâíÿõ Õåâè, Ïøàâè è Õåâñóðåòè. Äëÿ èçìåðåíèÿ Ñîëíå÷íîé

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Ðèñ. 7. Èíñòàëèðîâàííûå àâòîíîìíûå ÔÝÑ-û .

1-Ìîíàñòûðü Ôèòàðåòè; 2- ñåìåííàÿ ãîñòèíèöà â Òóøåòè.

ðàäèàöèè è ñêîðîñòè âåòðà áûëè èñïîëüçîâàíû ñîâðåìåííûå èçìåðèòåëüíûå ïðèáîðû HOBO êîìïàíèè ONSET.  ðàìêàõ ïðîåêòà áûë òàêæå îöåíåí ãèäðîïîòåíöèàë äåâÿòè ãîðíûõ ðó÷üåâ. Íà îñíîâå èññëåäîâàíèÿ è èñõîäÿ èç ýêîíîìè÷åñêîé öåëåñîîáðàçíîñòè, áûë ñäåëàí âûáîð ìåæäó âèäàìè âîçîáíàâëÿåìûõ èñòî÷íèêîâ ýíåðãèè.Áûëè ïðåäëîæåíû íîâûå ïîäõîäû ýëåêòðîñíàáæåíèÿ âûñîêîãîðíûõ, íå ýëåêòðîôèöèðîâàííûõ äåðåâåíü ñ èñïîëüçîâàíèåì ìåñòíûõ, âîçîáíîâëÿåìûõ ðåñóðñîâ [3]. Áûëà ðàçðàáîòàíà ìåòîäèêà ðàñ÷åòà è ïðîåêòèðîâàíèÿ ñîëíå÷íûõ ôîòîýëåêòðî ñèñòåì, ïðèìåíèòåëüíî äëÿ Ãðóçèè. Íà îñíîâàíèè ìåòåîðîëîãè÷åñêèõ äàííûõ è äàííûõ ïîëó÷åííûõ ïðàêòè÷åñêèìè èçìåðåíèÿìè áûë ñîñòàâëåí Ñîëíå÷íûé êàäàñòð Ãðóçèè, ïðèìåíèòåëüíî ê ïîëóïðîâîäíèêîâîé ôîòîýíåðãåòèêå. Ïàðàëëåëüíî áûëè îñóùåñòâëåíû ïðàêòè÷åñêèå

èíñòàëÿöèè àâòîíîìíûõ Ñîëíå÷íûõ ìèêðî ÔÝÑ (ïèêîâàÿ ìîùíîñòü îò 50 äî 900 Âàòò) íà íå ýëåêòðîôèöèðîâàííûõ îáúåêòàõ – ìîíàñòûðÿõ, äåðåâíÿõ, ñåìåéíûõ ãîñòèíèöàõ è äð.

Çàêëþ÷åíèå Ðàçðàáîòêè ïðîõîäÿùèå â ÑÔÒÈ â Ñóõóìè ïî ïîëó÷åíèþ ðàçëè÷íûõ ïðåîáðàçîâàòåëåé íà áàçå p-n ñòðóêòóð çàâåðøèëèñü ñëåäóþùèìè ðåçóëüòàòàìè: 1. Ðàçðàáîòàí àòîìíûé áåòà-ýëåìåíò íà áàçå êðåìíèÿ, èç êîòîðûõ íà ñîîòâåòñòâóþùèõ ïðåäïðèÿòèÿõ ÌÑÌ áûëè ñîáðàíû àòîìíûå áàòàðåè óñïåøíî ðàáîòàþùèå â êîñìîñå.

2. Ðàçðàáîòàí è èñïûòàí â ïðèáëèæåííîì ê ðåàëüíîìó ðåæèìó ÒÔÝÏ, ïîêàçàâøèé óäîâëåòâîðèòåëüíûå ýëåêòðè÷åñêèå ïàðàìåòðû.

3. Áûëè ïîëó÷åíû ÑÝ è ñîáðàíû ìàëîìîùíûå áàòàðåè.

152 Ðàáîòû ïðîäîëæåííûå â ÑÔÒÈ â Òáèëèñè áûëè òàêæå âàæíû: 1. Ðàçðàáîòàíà ìåòîäèêà ðàñ÷åòà ïàðàìåòðîâ Ñîëíå÷íûõ ÔÝÑ ïðèìåíèòåëüíî ê Ãðóçèè.

2. Ñîñòàâëåí Ñîëíå÷íûé êàäàñòð Ãðóçèè, ïðèìåíèòåëüíî ê ïîëóïðîâîäíèêîâîé ôîòîýíåðãåòèêå.

3. Èññëåäîâàíû âîçîáíîâëÿåìûå ýíåðãîðåñóðñû âûñîêîãîðíûõ íå ýëåêòðîôèöèðîâàííûõ ðåãèîíîâ Ãðóçèè.

4. Áûëè ïðåäëîæåíû íîâûå ïîäõîäû ýëåêòðîñíàáæåíèÿ âûñîêîãîðíûõ, íå ýëåêòðîôèöèðîâàííûõ äåðåâåíü ñ èñïîëüçîâàíèåì ìåñòíûõ, âîçîáíîâëÿåìûõ ðåñóðñîâ.

5. Îñóùåñòâëåíû ïèëîòíûå ïðîåêòû ïî ìèêðî ÔÝÑ. Ïî âûøå èçëîæåííîé òåìàòèêå îïóáëèêîâàíî îêîëî 40 íàó÷íûõ ðàáîò è çàùèùåíû äâå äèññåðòàöèè.

P.S.  ñâÿçè ñ íåäîñòóïíîñòüþ ïå÷àòíûõ ìàòåðèàëîâ, â âûøåèçëîæåííûõ ôàêòàõ íå õâàòàåò êîíêðåòíûõ äàííûõ - öèôð, ãðàôèêîâ. Òàêæå ìîãëè ïðîñêîëüçíóòü êîå-êàêèå íåòî÷íîñòè, çà ÷òî è ïðèíîñèì ñâîè èçâèíåíèÿ.

Ëèòåðàòóðà 1. Â.Ì. Êîäþêîâ, À.Ï. Ëàíöìàí, À.À. Ïî÷òàêîâ è äð. ßäåðíûå (àòîìíûå) áàòàðåè ñ ïîëóïðîâîäíèêîâûì ïðåîáðàçîâàòåëåì íà îñíîâå êðåìíèÿ. Ñáîðíèê òðóäîâ Ðàäèàöèîííàÿ òåõíèêà. Âûï. 8, Àòîìèçäàò , 1972 ã.

2. Ø.Ç. Äæàìàãèäçå, Ê.À. Êîáàõèäçå, À.Ì. Òîäóà, Â.À. ×àòîâ è äð. Ýôôåêòèâíîñòü âîçâðàùåíèÿ ê èçëó÷àòåëþ ýíåðãèè äëèííîâîëíîâîé ÷àñòè ñïåêòðà ïðè ïîìîùè òûëüíûõ îòðàæàþùèõ êîíòàêòîâ ãåðìàíèåâûõ òåðìîôîòîïðåîáðàçîâàòåëåé. Ñîîáùåíèÿ Àêàäåìèè Íàóê Ãðóçèíñêîé ÑÑÐ, 138 N 1, 1990.

3. Ê.À. Êîáàõèäçå, Ë.Ê. Êîáàõèäçå, Í.Ñ. ×õåíêåëè è äð. Ïåðñïåêòèâà èñïîëüçîâàíèÿ ñîëíå÷íûõ ôîòîýëåêòðî ñèñòåì äëÿ âûñîêîãîðíûõ ñåëåíèé, Ìåæäóíàðîäíûé íàó÷íûé æóðíàë «Àëüòåðíàòèâíàÿ ýíåðãèÿ è ýêîëîãèÿ», N 12, 2005.

Development directions of the energy converters based on semiconductor p-n junctions K. Kobakhidze1, N. Chkhenkeli2 1 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli str. Tbilisi, Georgia E-mail: sipt@sipt.org 2 Sun House, 8/4 Tskneti str., Tbilisi, Georgia E-mail: sun@sun.org.ge

The given work reviews development stages of directions of energy converters on the base of semiconducting p-n structures in Ilia Vekua Sukhumi Institute of Physics and

Technology. Technologies for obtaining structures and methods for their testing are shortly described. An overview of the research of renewable energy resources in high mountainous places of Georgia is given. Solar cadaster of Georgia and examples of practical use of solar energy are shown.

energiis gardamqmnelebis mimarTulebebis damuSaveba p-n naxevargamtaruli gadasasvlelebis bazaze k. kobaxiZe1, n. Cxenkeli2 1

ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo, el–fosta: sipt@sipt.org 2 Sps „mzis saxli“ wyneTis q. 8/4, Tbilisi, saqarTvelo. el–fosta: sun@sun.org.ge naSromSi ganxilulia ilia vekuas soxumis fizika-teqnikis institutSi naxevargamtaruli pn struqturebis bazaze gardamqmnelebis mimarTulebis ganviTarebis etapebi. mokled aRwerilia struqturebis miRebis teqnologiebi da maTi gamocdis meTodebi. moTxrobilia saqarTvelos maRalmTian regionebSi ganaxlebadi energoresursebis kvlevis Sesaxeb. mocemulia saqarTvelos mzis kadastri da mzis energiis praqtikuli gamoyenebis magaliTebi.

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Bulk nanocomposites by adiabatic explosion consolidation of powders N. Chikhradze1,2, G. Abashidze1, M. Chikhradze 2,3 LEPL G. Tsulukidze Mining Institute, 7, E. Mindeli Str., 0186, Tbilisi, Georgia; Georgian Technical University, 75, Kostava Str., 0175, Tbilisi, Georgia; 3 F. Tavadze Institute of Metallurgy and Materials Science, 15, Kazbegi Str., 0111, Tbilisi, Georgia E-mail: n.chikhradze@gtu.ge 1 2

Abstract. This paper consists of a experimental investigation of multifunctional bulk nanocomposites based on Titanium, Nickel, Aluminum and Boron. The crystalline Ti, Ni, Al coarse elementary pure (at list 99%) powders and amorphous Boron were used as precursors. The blend with different Ti, Ni, Al, B powders were prepared. The high energetic planetary ball mill is used for blend processing, mechanical alloying, amorphization and nanopowder production. Phase composition and particle sizes of the blend components were controlled by X-ray diffraction system. The optimal technological regimes for nanopowder preparation were determined experimentally. Ball milled nano blend compacted by explosive consolidation technology and nanostructured bulk composite materials are fabricated. The technological parameters of the nanocomposites fabrication and the structure-properties relationship are discussed in the paper.

Keywords: Composites, Materials, Nanocomposites, Nanoparticles, Nanopowder, Nanotechnology

Introduction Intermetallics, fabricated in Al-Ni-Ti-B system are characterized by unique physical-mechanical properties. They have high specific strength under tensile and compression conditions, good high temperature corrosion, oxidation and wear resistant properties. Intermetallics/Composite materials obtained in Ti-Al-Ni-B system are attractive for aerospace, power engineering, machine and chemical applications [1, 2, 3, 4, 5, 6, 7].

According the phase diagrams in Ti-Al-Ni-B system may be obtained composites/intermetallics with wide spectrum of phase composition, in crystalline and amorphous (brittle and ductile) structures. Depending on the composition and structure, the synthesis intermetallics/composites exhibit different special properties. The interest on the system is increased due to development of composited with nanostructure.

The nanocrytalline materials are fabricated with a grain sizes up to 100nm. Because of their extremely fine grain size, nanocrystalline (<100 nm) materials exhibit unique combination of physical, mechanical, and chemical properties. Titanium-Nickel-Aluminum-Boron based nanocomposites exhibit the potential for enhanced behavior in comparison with coarse grain material (>1 Îźm) [8, 9, 10, 11, 12 ].

There are known several conventional methods for obtaining of nanostructured materials, including: hot isostatic pressing (HIP), spark plasma syntheses (SPS), mechanical alloying (MA), laser engineered net shaping (LE) and etc.

The HIP normally requires use of high pressure and high temperature for extended period of time. Because this results in significant coarsening of the nanometer sized particles/grains and as result, it is related with losses of nanostructure effects. MA involves repeated cold welding, fracturing, and re-welding of powder particles in a high-energy ball mill. Due to the specific advantages offered by this

technique, MA is used to synthesize a variety of nanopowders and nanocomposites. SPS method has significant limitations for production large scale nanocomposites. As an attractive, may be considered the following methods: a) Controlled devitrification of amorphous solids (CDA) and b) Self propagating high temperature syntheses (SHS). The CDA requires the generation of the amorphous precursor and MA combined with appropriate consolidation techniques. SHS is based on the burning of powder combustion exothermal systems, running in stable regime. During the exothermal chemical reaction the phase composition of samples are formed. The next development of SHS was synthesis of structures in thermal explosion mode. This method combines, preheating, combustion and densification. Data about fabrication of bulk nanocrytalline intermetallics/nanocompostes in Ti-Al-Ni-B system by SHS based technologies is not reported.

The main conclusions of above review are as fellow: Discussed technologies doesnâ&#x20AC;&#x2122;t allow fabricate the bulk materials in Ti-Al-Ni-B system, with amorphous and nanostructure; Cost save production of necessary quantity of nanopowders and handling of precursor before consolidation is problem as well.

The disadvantages of considered technologies may be classified as fellow: Problems caused with nanopowders preparation, including: Control of particles sizes; Chemical instability, separation and etc; Storage/preservation and handling for obtaining bulk samples; Problems caused with fabrication bulk nanostructured samples, including: Limitations on sizes and geometry of bulk material; Energy consumable (beside the SHS); Needs complicated facility/equipments; Coarsening of grains under high temperature for extended period of time processing (amorphous and nanostructures are lost); Integration

154 of different technological regimes in one cycle is impossible (syntheses + cladding + welding).

Therefore, development of effective methods for nanopowder production and novel and innovative technologies for consolidation/synthesis of large scale bulk nanostructured samples is actually.

Based on the above-mentioned review, main objectives of the investigations were: I. Elaborate industrial friendly technology for obtaining amorphous and nanopowders, as a precursors for synthesis of bulk materials II. Determine shock wave parameters for fabrication bulk nanostructured materials by explosive consolidation

Experimental procedure As an starting elemental powders were used: coarse Ti (99.0% purity, average particle size ≤ 200μ), crystalline Ni, (electrolytic, complexometric, 99% purity, spherical morphology), coarse Al (assay: ≥ 97.0%; complexometric; form: grit, produced by “SIGMA-ALORICH Co”, St. Louis, USA), as well as Al-nanocrytalline (Purity: 99 %; APS: 18 nm, Max < 50 nm; SSA: 40 - 60 m2/g; morphology: spherical; Bulk density: 0.08 - 0.20 g/cm3; True density: 2.70 g/cm3) provided by MTI corporation, Richmond, USA and Amorphous Boron (B-99.6%; specific surface 14m2/g).

Preliminary determination/selection of blend compositions was made on the base of theoretical investigations and thermodynamic analyses of the Ti-Al-Ni-B system.

Considered blend compositions (at %) for ball mill processing and shock compaction were Al40Ni25Ti25B10 and Al45Ni25Ti25B5.

Amorphous and Nanopowder Fabrication Precursors were sorted by vibratory sieves by particle sizes: (-0,063, + 0) mm; (-0.16, + 0.063) mm; (-0.315, + 0.16) mm; +0.315mm. For production of large quantities of nanopowders an attractive method is controlled crystallization from amorphous condition [7]. For obtaining the amorphous structures (as a precursor for nanopowders preparation) was applied the method of mechanical alloying (MA): transformations the coarse Al-Ti-Ni-B blend to amorphous and nanostructure during the processing in high energetic ball mill; For MA, amorphization and nanopowder production, the high energetic “Fritsch” Planetary premium line ball mill was used. The mill was equipped with Zirconium Oxide jars and balls. Ratio ball to powder by mass was 10:1. The milling processing parameters was: Times: 5h; 12h; 24h.

36h; Speed of the jars rotation was 500 rpm. In all processing conditions, by x-ray investigations identified diffraction lines of elementary Al, Ni, Ti and B, oxides of titanium and aluminum. During the MA, the syntheses of Titanium and Nickel alluminades (TiAl, TiAl3, Ti3Al, NiAl, NiAl2) are confirmed, if the processing time exceeds 5 hours.

Explosive Compaction Technique The next important stage of the research was selection of efficient/rational technology for fabrication of bulk nanocomposites. As an alternative of conventional compaction technologies, it is proposed the shock wave compaction of nano powders for fabrication bulk samples.

The motivation was preliminary works, were demonstrated that explosive consolidation (EC) of metal-ceramic compositions is not only feasible but can produce materials near theoretical densities [17, 18, 19, 20, 21, 22, 23, 24]. It was clear, that preliminary ball milling of the Ti-Ni-Al mixture (due fragmentation, mechanical alloying and critical reduction of particles sizes) should significantly increase the sintering ability of the blend and improve the compacting process and mechanical alloying of selected powder compositions. The major advantages of EC for bulk nanomaterials production are: realization of high pressure; short processing time; super high cooling rate (adiabatic cooling).

The shock wave loading of high exothermic reactants allows generate in situ process of shock wave induced syntheses + shock consolidation. Technology doesn’t require additional energy supply from outside sources. High cooling rate is guaranteed, because the dynamic compression is accompanied with adiabatic cooling and as a result preserve the amorphous and nanostructure.

The investigations of shock induced SHS were subject of investigations of leading scientific groups [14, 16, 17].

Number of investigations for understanding of EC SHS compacting mechanism was performed in GeorgiaTech (Atlanta, USA) by Prof. N. Thadhani and his group. The application of blend with nanopowders (as a precursors for obtaining bulk materials) using EC SHS does not reported yet.

For shock wave generation (explosive compaction experiments) the industrial explosives and new explosives obtained from decommissioned weapons (prepared on the base of gun powder) was used in the experiments. The major energetic characteristics of explosives are presented in table 1.

The EC experiments were performed at the underground explosive chamber.

Table 1.

Some energetic characteristics of used explosives Name of Explosives NH4NO3 ANFO (AN) 79%NH4NO3+ 21%C6H2(NO2)3CH3 60%AN+40%, ПП9/7 C3H6O6N6

1439 3815

1.0 0,8

Pressure on St.3, P x 10-9 N/m2 1.5 4-5

4300

0.8-1.0

10

895

3.6-4.2

2920 5439

0.98 1.1-1.82

3 20

948-976 950

5.2 8.6

Energy of Gravimetric density, explosion, ρ , gr/cм3 Ем, кJ/kg

Gas Speed of a volume of detonation, explosion, D, km/c V, l/kg 980 1.8-2.0 980-990 2.8

Consolidation of the samples was performed in two stages. The Al-Ti-Ni-B powder blend was charged in low carbon steel tube container and at the first stage the pre-densification of the mixtures was

155 performed under static press (intensity of loading P=500-1000 kg/cm2).

A cardboard box was filled with the powdered explosive and placed around the cylindrical powder container. The experiments performed at room temperature. The shock wave pressure (loading intensity) were varied in range 3-20Gpa. In set conditions the explosive was detonated by electricaldetonator. The explosive compaction schemes are shown in (Fig. 1).

drical axis symmetric experimental set up the criteria for selection of container (internal diameter (d) and wall thickness (δ)) may be expressed in the following form:

A < Ep + Econ; Edestr. = Adestr. x M; M = = ρ x πh [d2- (d-2δ)2]/4 =ρ x πhδ (d- δ) Where, A – Full energy of explosive; Ep - Energy consumed on plastic deformation of the container; Econ.- Energy consumed on consolidation of the powder; Adestr - Energy for full destruction of material’s unit mass; M – Mass of container; ñ-density of material, h-length of cylindrical tube.

For preliminary selection of explosives and configuration around the sample, computer modeling was used. The calculated results were validated experimentally.

The optimal pressure rate for consolidation was estimated as P=10GPa. In this condition the configuration of loading/unloading waves in powder and container allows, initiate the syntheses in the reaction mixture, simultaneously consolidate it and fixed the phase composition under adiabatic cooling. The photographs of the container and compact obtained in optimal regimes are shown on Fig. 3.

Following bulk compacts were recovered in different shapes and prepared for investigations.

Table 2.

Characteristics of powder and bulk compositions

Fig. 1. Scheme of explosive compaction setups: a) Schematic view of assembly for fabrication bulk rod: (1) electrical detonator, (2) explosive’s container, (3) explosive, (4) steel tube, (5) reaction mixture, (6) steel plugs, (7) base table, (8) detonator seizer; b) General view of assembly

Results of explosive compaction Fabrication of bulk nanocomposites from nanopowders requires selection of the compaction technological parameters. The tree main factors must consider for optimization of shock wave compaction regime: 1.Selection of explosive, mass and geometry (Developed pressure, detonation velocity, positive phase duration, impulse, configuration, and amount); 2.Selection and determination of powder container parameters, (material, mechanical behavior, geometry, internal diameter, free volume, wall thickness, dimensions); 3. Powder related parameters: composition, charging density, particle sizes and their distribution). Number of investigation was dedicated by several researchers to investigate shock compaction process. Professor R. Pruemmer [24] did detailed analyses on explosive compaction of powders. But, for explosive compacting of nanopowders (with dramatically changed free surfaces, reactivity and exothermal rate) the topic requires additional theoretical and experimental investigations for obtaining accurate data on technological parameters. Selection of container’s material for per particular cases needs the detailed investigations as well. For selection of container parameters cylin-

Fig.2. Photograph of samples obtained in optimal technological regimes: (a) loaded container; (b) Bulk TiNiAlB nanocomposite rod before mechanical treatment

The density of specimens were determined (cut from different part of samples), by the Archimedean method.

Investigations on hardness were performed under the loading 20gr. Measurement of tensile strength was performed

156 using indirect method - “Brazilian” test. The tensile rate was calculated by expression σt = Pmax / d x h; where: Pmax is maximal destructive strength under static press; d-diameter of cylindrical sample and h-height of cylindrical sample.

The schematic view of tensile test and sample after compression under static press are shown on fig. 4. Experimentally determined characteristics of compositions are presented in table #2. The SEM pictures of samples are presented on Fig. 4.

- Selected rational technology for fabrication of bulk amorphous and nanostructured materials by shock wave induced syntheses - Obtained, bulk nanostructural compacts with advanced physical-mechanical properties;

Acknowledgement The work is supported by the research grant of Shota Rustaveli national Science Foundation (Grant agreement # 31/82).

References:

Fig. 3. a) Tensile test scheme: (1) destruction line; (2) sample cross section; (3) static press. b) Al40Ni35Ti25 composite, destructed under compression.

Fig. 4. SEM pictures of Bulk TiNiAlB composites: a) Al45Ni25Ti25B5; P=5GPa; b) Al45Ni25Ti25B5, P=10GPa; c) Al40Ni25Ti25B10 , P=5GPa; d) Al40Ni25Ti25B10; P=10GPa;

By investigations established, that the structure of bulk samples is not uniform. Structure represented from nanosized and coarse grains;

Conclusions - Elaborated effective technology/regimes for obtaining nanopowders and nanocomposites in Al-Ni-Ti-B system;

1. The Second World Space Congress, held 10-19 October, 2002 in Houston, TX, USA., p.I-4-03IAF abstracts, 34th COSPAR Scientific Assembly 2. R. Mania, M. Dabrowski et all, Some application of TiAl Micropowders Produced by Self-Propagating High Temperature syntheses, International Journal of Self-Propagating High-Temperature Synthesis. 2003 vol. 12 no. 3 s. 159–164 3. E. A. Levashov, B. R. Senatulin et all, Peculiarities of the Functionally Graded Targets in Combustion Wave of the SHSSystem with Working Layer Ti-Si-B, Ti-Si-C, Ti-B-N, TiAl-B, Ti-C, Book of Abstracts. IV Int. Symposium on SHS, Technion, Haifa, Israel, Feb. 17-21, 2002, p. 35 4. A.G.Merzhanov, A.N.Pityulin. Self-Propagating High-Temperature Synthesis in Production of Functionally Graded Materials. Proceedings of 3 rd Int. Symp. on FGM, Lausanne, Switzerland, pp.87-94 (1995).

5. A.N.Pityulin, A.E.Sytschev, A.S.Rogachev, A.G.Merzhanov.

One-Stage Production of Functionally Graded Materials of the Metal-Hard Alloy Type by SHS Compaction. Proceedings of 3 rd Int. Simp. on FGM, Lausanne, Switzerland, pp.

101-108 (1995).

6. Tavadze, “A new SHS Method for Special Ferroalloys Production”, First Armenian-Israel Workshop on SHS (AIW2005), p. 33, Yerevan 7. D. H. Kim, W. T. Kim, Formation and Crytallization of Al-NiTi Amorpous Alloys, Materials Science and Engineering A 385 (2004) 44-53, ELSEVIER 8. N. Das, G. K. Dey et all, On Amorphization and Nanocomposite Formation in Al-Ni-Ti System by Mechanical Alloying, PRAMANA Journal of Physics, Indian Academy of Sciences, Vol. 65, No. 5, November 2005, pp. 831-840 9. Z. H. Zhang, B. Q. Han, Syntheses of Nanocrystalline Aluminum Matrix Composites Reinforced With in Situ Devitrified Al-Ni-La Amorphous Particles, University of California Postprints, Paper 39, 2006 10. J. Hebeisen, P. Tylus, D. Zick, D. K. Mukhopadhyay, K. Brand, C. Suryanarayana, F. H. Froes, “Hot Isostatic Pressing of Nanostructured g-TiAl Powders”, Metals and Materials, Vol. 2. No. 2 (1996) pp. 71-74 11. J.R. Groza, “Nonconventional Pressure-Assisted Powder Consolidation Methods”, Journal of Materials Engineering and Performance, V. 2(2) 1993 pp. 283-290 12. C. Suryanarayana, T. Klassen, E. Ivanov, “Syntheses of Nanocomposites and Amorphous Alloys By Mechanical Alloying”, J. Materials Science, (2011) 46.6301-6315 13. Oniashvili, “Design and SHS of new Functionally gradient materials (FGM)”, VII International Symposium on SHS, Crakow

157 14. G. Tavadze, G. Oniashvili, “SHS technology- Resource save technology for obtaining materials”, Metsniereba da teqnika, #6, 1998 15. www.ism.ac.ru/handbook/31fgm.htm 16. L. Lu, M. O. Lai and H. Y. Wang, Syntheses of Titanium Diboride TiB2 and Ti-Al-B metal matrix composites, Journal of Materials Science, Springer Netherlands, v. 35, #1, 2000 17. R. Prummer, Explosive Working of Porous Materials, Springer-Verlag Berlin Heldelberg, New York, 1987 18. N. N. Thadhani, Shock- Induced Chemical reactions in Exotermic Intermetallic-Forming Powder Mixture Systems, Proceeding of ICCES’05, 1-10 December, 2005, India, p. 394 19. L. Kecskes, A. Peikrishvili, N. Chikhradze, A. Dgebuadze, Hot Explosive Fabrication of Nano-crystalline W-based powders, Book: “ Advances in Powder Metallurgy & Particulate Materials, Orlando, USA, 2002 20. L.J.Kecskes, R.H.Woodman, N. Chikhradze A.Peikrishvili Processing of Aluminum Nickelides by Hot Explosive Consolidation, International Journal of Self-Propagating HighTemperature Synthesis Volume 13, #1, 2004 21. N. Chikhradze, K. Staudhammer, F. Marquis, M. Chikhradze, Explosive Compaction of Me-Boron Containing Composite Powders, Proceeding of Powder Metallurgy World Congress & Exhibition, PM2005, Prague, Czech Republic, V.3, pp.

163-173, 2005 22. G. Mamniashvili, N. Chikhradze et all, Shock-Wave Compaction and Investigation of Fe-Ni-Al Powder Composition, “Physica Mettallov I Metalovedenie”, 2006 23. N. Chikhradze, C. Politis, H. Henein, Formation of Ultrafine Grained Bulk Si and Si-Ge Alloys by Shock Wave Compaction Technology, Proceeding of PM2010 World Congress – Nanotechnology, v. 1, pp. 321-326 24. N. Chikhradze, A. Gigineishvili, M. Chikhradze, Explosive Fabrication of Intermetallics In TiAl System from Nano Al and Coarse Ti Powders, Published by the American Institute of Physics* http://dx.doi.org/10.1063/1.3663163

moculobiTi nanokompozitebis miReba adiabaturi afeTqebiT fxvnilebis konsolidaciiT n. CixraZe1,2, g. abaSiZe1, m. CixraZe2,3 1 ssi p grigol wulukiZis samTo instituti, e. mindelis q. 7, 0186, Tbilisi, saqarTvelo 2 saqarTvelos teqnikuri universiteti, kostavas q. 75, 0175, Tbilisi, saqarTvelo 3 ssi p ferdinand TavaZis metalurgiisa da masalaTmcodneobis instituti, yazbegis q. 15, 0111, Tbilisi, saqarTvelo el–fosta: n.chikhradze@gtu.ge

statiaSi warmodgenilia titanis, nikelis, aluminis da boris bazaze mravalfunqciuri moculobiTi nanokompozitebis miRebis eqsperimentuli kvlevis Sedegebi. sawyis masalebad gamoyenebul iqna aranakleb 99% sisufTavis Ti, Ni, Al-is msxvilmarcvlovani kristaluri fxvnilebi da amorfuli bori. Ti, Ni, Al, B-is fxvnilebisgan momzadda sxvadasxva Sedgenilobis kazmi. narevis mosamzadeblad (rac iTvaliswinebs meqanikur legirebas, amorfizaciisa da nanokazmis formirebas), gamoyenebul iqna maRalenergetikuli planetaruli nanowisqvili. kazmis fazuri Sedgenilobis da nawilakTa zomebis kontroli xorcieldeboda rendgenodifraqciuli sistemis meSveobiT. nanofxvnilis formirebis optimaluri teqnologiuri reJimebi dadginda eqsperimentulad. wisqvilSi formirebuli nanokazmis konsolidacia da nanostruqturuli moculobiTi kompozitebis miReba ganxorcielda adiabaturi afeTqebiT kompaqtirebis teqnologiiT. statiaSi ganxilulia nanokompozitebis struqturisa da Tvisebebis kavSiri konsolidaciis teqnologiuri parametrze.

158

Boron isotope enriched graphene based neutron sensors P. Kervalishvili1, V. Labunov2, E. Hristoforou3, M. Mostafavi4, P.D. Oliveira4, P. Yannakopoulos5 Georgian Technical University, 75, Kostava Str., 0175, Tbilisi, Georgia, Belorussian State University of Informatics and Radioelectronics 3 National Technical University of Athens 4 University Paris Sud - LCP CNRS 5 Piraeus University of Applied Sciences E-mail: kervalp@yahoo.com 1 2

Abstract. Novel neutron radiation sensors are developed by utilization of the exceptional electronic properties of Graphene in the field effect transistor architecture (GFET), where Graphene is located on the electrically biased radiation absorbing semiconductor substrate enriched by neutron high absorbing Boron isotope-B10.

The combination of very high sensitivity of graphene to ionization-induced local electric field, when graphene is near â&#x20AC;&#x153;Dirac pointâ&#x20AC;?, and high neutrons absorption due to Boron isotopes-B10 intercalated into in the underlying semiconductor substrate, create possibility to fix neutron flux by electrical measurements very precisely, and give opportunity to measure neutron density up to single neutrons of very high energy.

In GFET Graphene is deposited on an electrically gated, radiation absorbing semiconductor substrate. In Si-based GFETs an insulating SiO2 layer between graphene and substrate has also been used. The field can be varied to set the optimum point on the Dirac curve for a sharp change in graphene resistance with the change of electric field. The drain and source electrodes supply the current through the graphene and are used to measure the voltage drop across the graphene.

Keywords: Boron isotope, graphene, semiconductor substrate, neutron sensor

Introduction The weapons of mass destruction threats facing the world are constantly evolving and have grown more complex since the end of the Cold War. After the breakup of the Soviet Union, Russia and other former soviet republics inherited the worldâ&#x20AC;&#x2122;s largest arsenal of chemical, biological, radiological and nuclear materials. On the other hand, the use of nuclear processes for getting electric and thermal energy, which becomes more and more popular in developed countries, requires extensive radiation monitoring, as there are always risk factors of the radiation leakage and environmental pollution in nuclear - power stations (the last case - Japan, March 2011)times higher than the forbidden zone width (It seems that additional energy is spent on phonons oscillations).

Launch new sources of neutrons to the United States, Japan and Europe, Stimulates monitoring activation incentiveactivation in this direction and attracts significant financial volume for development. The need to develop a long-termstrategy and coordination of research activities related to security issuesmoved foreground.

Protection of radiation and nuclear security of the population and nature is among the most actual problems which face the countries of former Soviet Union, the most part of which is polluted as a result of nuclear-radiation accidents and catastrophes, production of nuclear arms and destruction, production nuclear explosions. In the same way there is a danger of escalation of situation as a result of utilization of the components of destroyed aging nuclear plants, failure of about 150 atomic submarines and nuclear weapon.

For radiation safety there is need of development of sensory elements and sensory systems for instantaneous responding to variation of nuclear radiation. In order to be useful as a part of Artificial Intelligence systems, the sensors and sensory systems might be designed as a miniature instrument providing information transmission and processing about nuclear radiation. In this case they often can be applied to various areas of engineering, medicine, nuclear power installations, space power systems etc., where it is necessary to work as the precise temperature measurement instrument in hazardous conditions. The main parts of the nuclear radiation systems are sensitive elements, sensors and sensory systems.

Problem There are a variety of solid state detectors available today for measuring the neutron irradiation, especially the semiconductor detectors. The main and the best sensory material for semiconductor sensors was and still is an ultra pureGe (density 2.3 gr/cm3) and Si (density 5.3 gr/cm3) monocrystals. They work as ionization chambers except that rather than gas, the semiconductor materials such as Silicon or Germanium are used. Whenever a radiation particle comes to surface and later enters to the body of the sensory elements it generates the charge carrier. Then the high voltage accelerates the free electrons, which cause them to ionize additional (non equilibrium) electron-hole pair, which under the influence of voltage moves towards electrodes. This causes a current to be produced. The current is roughly proportional to the quantity and energy of the radiationtimes higher than the forbidden zone width (It

159 seems that additional energy is spent on phonons oscillations) [1,2].

The main parameters that must be paid attention during the selection of sensory elements and detectors are: Registration efficiency;Spatial resolution capacity;Time parse capacity; Area of registering work; compactness and design simplicity for usage; Reliability usageand low index values ; For producers are important its Manufacturing technology.

In the area of the creation of neutron detectors primarily the most widely developed the hybrid construction and its manufacturing technology. From all positive constructive elements, characterized for existing detectors, better sampling allows a better variant. But as a rule they all have complicated construction and manufacturing process is sufficiently complex and hard working. They are also characterized by large dimensions and for performance from 200-up to 2000v high voltage[3].

Crystalline Germanium and Silicon are very sufficient sensory elements for preparation solid state detectors, but their specific resistivity is relatively low and is not sufficient (about 104 Ohm.cm for Si and 102 Ohm.cm for Ge). To increase the electro-resistivity is necessary to be used special events, such as adding special mixtures or being cold at low temperature (approximately at liquid nitrogen temperature). To create an electron - hole pair it needs to be spent 3.5 eV power in Silicon and approximately 3.0 eV in Germanium. These values approximately three times higher than the forbidden zone width (It seems that additional energy is spent on phonons oscillations). The energy for creation an electron - hole pairs in semiconductors ten times smaller than one in gas. This means that signal amplitude receiving from semiconductor detectors is ten times higher than from ion detectors. Also ten times is less dispersion of amplitude distribution, which means that the detector has better ability to parse the energy.

Unlike Hybrid design detectors, semiconductor detectors are more fast, have high parse ability. It should be noted that they are sensitive to gamma radiation, and is therefore easy radiation damage as result.

In development of neutron detectors an important role fulfils appearing of new materials. Development of new technologies (especially for their massive production) and creation the microstructures of needed parameters, receiving decisions on of new constructional elements and detectors created on micro and nanostructure, study and working out of the fundaments of new technological methods is one of the main task of last developments [4].

The detector of ionized radiation which is fabricated on the basis of GaAs and GaAlAs isolated layer with a barrier contact has a high boundary sensitivity and lower noise level, high energy resolution giving the possibility of registration of weak ionized flows. The detector which is fabricated on the diamond basis and is equipped by additional amplifiers, has high reliability and gives a possibility for increase the signal amplitude. The detector of high sensitivity of ionized radiation comprises the semiconductor

mono-crystalline layer and galvanically isolated areas from each other, a micro-structural layer of weakly doped diamond [5].

Compared to the analogies, Boron stable isotopes doped new nanosensory elements and on their basis creating devices will have higher sensitivity and resolution, small dimensions, and what is important, for their functioning will be use much smaller energy power (low voltage and current). Usage of that micro equipment could revolutionary change the conditions of control, measurement and prevention of neutron radiation waste [6.7].

In its turn usage of Boron isotopes as doping elements in Germanium and Silicon nanofilms, is giving principal priorities to these semiconductor materials due to Boron very well-known nuclear - chemical properties. 11B practically not absorbs neutrons in wide range of energy (very suitable form gamma radiation detectors) 10B opposite – is a strong absorber of thermal and high energy (high speed) neutrons, following which, a shallow acceptor for Germanium and Silicon it changes its charge because of Lithium appearance as result of nuclear-chemical reaction stimulated by neutron irradiation. Lithium is a shallow donor for Germanium and Silicon, charge carriers concentration changes, which create possibility to fix neutron fluence by electrical measuring instrument very precisely. These gives us opportunity to measure neutron density up to neutrons’ very high energy [8-11].

Graphene-based Ultrasensitive Advanced Radiation Detector A new approach was used to detect ionizing radiation.

Novel ionizing radiationsensors which were developed by utilization of the exceptional electronic properties of Graphene in the field effect transistor architecture was designed[12]. It is necessary to highlight that this is the only research work which is done by the Pennsylvania State University, and Purdue University, West Lafayette, IN. There are no such developments in Europe.

Graphene is a monolayer of graphite with unique electronic properties. Graphene has a high carrier mobility, reaching 10 times or greater than that of Si at room temperature. Graphene is a low-noise electronic material (even at room T), and has a resistance, which is very sensitive to local change of carrier density when graphene is near the charge neutrality point, or “Dirac point”. Graphene (semimetal) resistance stays finite unlike MOSTFET channel [13].

The sensitivity of Graphene resistance to small changes in the electric field can be exploited to sense radiation.

The sharpness of the resistance response of the graphene to the change of the external electric field suggests the possibility for its use as a high-gain preamplifier integrated into a graphene-basedradiation detector (GRD) [14].

In GFET Graphene is deposited on an electrically gated, radiation absorbing semiconductor substrate. In Sibased GFETs an insulating SiO2 layer between graphene and substrate has also been used. A gate voltage is applied between the graphene and the back of the absorber,

160 producing an electric field across the device. The field can be varied to set the optimum point on the Dirac curve for a sharp change in graphene resistance with the change of electric field. The drain and source electrodes supply the current through the graphene and are used to measure the voltage drop across the graphene. While one can use twoterminal measurements in many practical situations, the use of four metal electrodes on the graphene give more accurate four-terminal resistance measurements (Fig.) [15,16].

The detection principle is based on the high sensitivity of graphene to ionization-induced local electric field perturbations in the electrically biased substrate, i. e on dependence of the graphene resistance on the local electric field. Such sensors based on GFET could be employed to detect the radiation induced charge carriers produced in semiconductor absorber substrates, even without the need for charge collection (not relying on collecting ionized charges, appearance of ionized charges changes electric field).

It was experimentally demonstrated promising performance of graphene field effect transistors for detection of visible light, X-rays, alpha particles, gamma-rays and neutrons.

The used technologies to make graphene are: exfoliation from graphite, epitaxial growth, chemical vapor deposition (CVD) [17].

GFET can work with variety of semiconductor absorber substrates,with potentially relaxed temperature, carrier mobility, purity, and lifetime constraints. The radiation detection was carried out with following GFET: exfoliated graphene on Si, epitaxial grapheneon SiC and CVD graphene on CdTe, GaAs. In all cases substrates were undoped.

Best suited for gamma/neutron interaction are wide bandgap substrates (SiC, CZT etc.): they perform room T response/high T operation. For high energy resolution best suited are narrow bandgap substrates (InSb) - less stringent requirement on substrate mobility etc.

In the case of GFET with Si absorber, the device did not demonstrate any response at room temperature. Thus the experiments carried out with Si based GFET were done at liquid helium (4.3 K) temperature. In is expected, that for room temperature operation it needs larger bandgap substrate. The SiC absorber-based GFET shows good response to X-rays, gamma-photons and light photons at room temperature.

Results and Conclusions In a case of graphene-based detector sensitive to thermal neutrons, a boron- or lithium-loaded absorber material was used in order to achieve conversion of neutron to heavy charged particles.

A boron layer was deposited on the bottom of the SiC wafer to act as a neutron-sensitive converter, with the alpha particle or Li ion being absorbed and detected in the SiC. This approach, as with most neutron detectors, requires detectors on the order of a few Îźm thick, which severely limits the intrinsic efficiency. Alternatively, a design in which substrate also serves as a converter (for example, boron carbide or boron nitride), could offer superior performance due to full energy deposition in the neutron capture reaction. But the detectors on the basis of these materials havethe very complicated technology.They are rather expensive and are not compatible with the mass production nanomicroelectronics technology.

The approach which uses graphene as the preamplifier, combined with recent advances in graphene production, and Si as substrate could allow for the mass production of inexpensive neutron detectors with integrated pre-amplifiers. These devices could then be used in a large variety of applications ranging from discrete single detectors to large arrayed configurations. The special advantages of Si based GFETs would be realised in the case of Si substrate enriched by the isotopes of Boron. Among the major advantages is achieving high-energy resolution at room temperature and operation at low-voltage.

The next steps of the experimental and theoretical works we are planning are: - labor out the theoretical bases for fabrication of nanosensory elements on the basis of semiconductor materials enriched by the isotopes of Boron. Refining the existing methodology and representation of innovative nanosensorsy of a new construction on the basis of GFET, the unification of which in future will be possible in electronic and intellectual networks, the will be able to function in rude pollution environment. The object of the research is â&#x20AC;&#x201C; the nanofilms the fabrication of GFET neutron detectors with Semiconductor substrates doped by B10isotope.

- The neutron nanosensory GFET elements of monolithic construction with the high resolution and sensitive capacity of a new type on the basis of semiconductor C nanostructures doped by the B10isotope.

- The GFET nanosensitive elements and the sensor systems.

- Modeling of constructional and physical parameters of GFET sensor elements created on the basis of semiconductor nanostructures doped by isotope B10.

- The optimization of the area of registering working area, compactness, and constructional simplicity in a new construction of nanosensory elements.

- Creation of a prototype and introducing of relative

161 corrections in microelectronic technology with allowance of its technological while processing the method of fabrication of GFET sensor element prototype.

It is known that for raising the sensitivity of the element it is necessary to increase the area. With this aim on the surface of monolithic crystal it will be created several small micrometer width and depth channels which divides the active elements from each other, and by it the sensitive surface (including the side surface) of the active element will be increased and, which is the main, in the element totally the leakage current will be considerably reduced.

Therefore, compared with the existing analogies nanosensory elements and created on the basis of it devices will have a higher sensitivity and resolution capacity to the respect of the radiation, small size (10x10 mm2) and a monolithic structure. For their operation will require much less energy (low voltage power supply), so they can be used to monitor the hard-to-reach places.

For fabrication of nanosensitive elements, as the basis the standard technology of preparation of microelectronic integral circuits will be used which gives a possibility to create a great quantity of elements simultaneously. The elements created by such method will have slightly different from each other and stable parameters, on their fabrication there will be spent lesser energy-carriers, materials and labor, which considerably reduces their first cost and increase their work reliability.

Acknowledgment The work is carrying out in the framework of the European Project NANOMAT-EPC N 608906

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7. P. Kervalishvili. “Some neutron Absorbing Elements and Devices for Fast Nuclear Reactors Regulation Systems”. NATO Conference Nuclear Safety and Security, Yerevan, Armenia, May 26-29, 2009.

8. Yu. A.Bykovskii, P.Kervalishvili, I.N. Nikolaev, “Neutron Fluence Sensor Based on Boron Carbide”, Technical Physics Letters, vol. 19, issue 7, 1993, pp. 457-458.

9. Kervalishvili P., Berberashvili T., Chakhvashvili l., Yannakopoulos P., Davaris A. “Nuclear radiation nanosensors and nanosensory systems”, International Scientific Conference eRA-6 The SynEnergy Forum. Piraeus, Greece 19-24 September 2011.

10. Kervalishvili P., Berberashvili T., Chakhvashvili L. “About some novel nanosensors and nanosensory systems”, Nanostudies, vol.4, 155-164. 2011.

11. P. J. Kervalishvili, T.M. Berberashvili, L.A. Chakhvashvili, G. Goderdzishvili, P. Yannakopoulos, A. Davaris. Nuclear radiation nanosensors and nanosensory systems. eRA-6 The Synenergy Forum, International scientific conference, Piraeus, Greece 19-24 September, 2011.

12. I. Jovanovic, E.Cazalas, I. Childres, A.lPatil, Oz. Koybasi, and Y. P. Chen, “Graphene Field Effect Transistor-Based Detectors for Detection of Ionizing Radiation”, IEEE, 9781-4799-1047-2/13/$31.00 2013.

13. V A Labunov, A L Danilyuk, A L Prudnikava, I Komissarov, B G Shulitski, C Speisser, F Antoni, F Le, S L Prischepa, “Microwave absorption in nanocomposite material of magnetically functionalized carbon nanotubes”, 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737119], Journal of Applied Physics 07/2012; 112(024302):24302241107.

14. A L Prudnikava, B G Shulitski, V A Labunov, K I Yanushkevich, O F Demidenko, F P Korshunov, V K Tochilin, A S Basaev,”The influence of electron irradiation on the magnetic properties of carbon nanotubes filled with Fe-phases composite”, Journal of Physics Conference Series 02/2010; 200(7):072076.

15. Vladimir Labunov, Boris Shulitski, AlenaPrudnikava, Alexander Basaev,”Multilevel composite nanostructures based on the arrays of vertically aligned carbon nanotubes and planar graphite layers”, physica status solidi (a) 01/2011; 208:453458. · 16. S. K. Lazarouk, A. A. Leshok, V. A. Labunov, V. E. Borisenko, “Efficiency of avalanche light-emitting diodes based on porous silicon”, Semiconductors 12/2004; 39(1):136-138.

17. Ivan Komissarov, Yuri Shaman, Julia Fedotova, Boris Shulitski, Sergei Zavadsky, Julia Kasiuk, Anatoly Karoza, Alexander Pyatlitski, Dmitry Zhigulin, PavloAleshkevych, PiotrDluzewski, SerghejPrischepa, HenrykSzymczak, Vladimir Labunov, “Structural and magnetic investigation of single wall carbon nanotube films with iron based nanoparticles inclusions synthesized by CVD technique from ferrocene/ethanol solution”, Physica Status Solidi (C) Current Topics in Solid State Physics 06/2013; 10(7-8):1176–1179.

18. Paata Kervalishvili, Vladimir Labunov,EvangelosHristoforou, MehranMostafavi, Hans Stroeher, PanosYannakopoulos, “Development of Boron-10 isotope enriched Graphene based neutron sensors”, International Conference on diamond and carbob materials, 6-10 September 2015, Bad Homburg, Germany.

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neitronebis sensorebi boris izotopiT gamdidrebuli grafenis fuZeze p. kervaliSvili1, v. labunovi2, e. kristofore3, m. moxtafavi4, p. oliveini4, iana kopudosi5 1 saqarTvelos teqnikuri universiteti, kostavas q. 75, 0175, Tbilisi, saqarTvelo 2 belorusiis informatikisa da radioteqnikis saxelmwifo universiteti 3 aTenis erovnuli teqnikuri universiteti 4 parissudis universiteti - LCP CNRS 5 gamoyenebiTi mecnierebis pireos universiteti el-fosta: kervalp@yahoo.com

grafenis metad maRali mgrZnobiarobaa roca grafeni aris ionizaciiT identificirebuli lokaluri velisadmi „dirakis wertilTan“ axlos da B10 izotopebis neitronebis STanTqmis maRali ubnis saSualebas iZleva eleqtruli gazomvebiT maRali sizustis dafiqsirdeba neitronebis nakadis. es iZleva saSualebas neitronebis simkvrivis metad maRali energiis erTeuli danneitronamde. damuSavebulia axali neitronuli radiaciis sensorebi velis efeqtis tranzistorebis arqiteqturaSi grafenis iSviaTi eleqtronuli Tvisebebis gamoyenebiT, sadac grafeni lokalizebulia eleqtrulad wanacvlebul radiaciis mSTanTqmel naxevargamtarul fuZeSreze, romelic gamdidrebulia neitronebis Zlierad mSTanTqmeli izotopiT - B10. ionizaciis inducirebuli lokaluri velisadmi grafenis metad maRali mgrZnobiarobisa, roca grafeni imyofeba „tirakis wertilis“ miaxloebaSi da naxevargamtarul fuZeSreSi ganTavsebuli boris izotopebi neitronis STanTqmis maRali kombinireba warmoqmnis eleqtronuli gazomvebiT maRali sizustis unaris neitronebi snakadis faqtorebis SesaZleblobas, dasaSualebas iZleva gaizomos didi sizustiT, ganisazRvros neitronebis simkvrive metad maRali energiis erTeulidan neitronamde.

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Mechanical properties of the bulk nanobiomaterial A. Gerasimenko, L. Ichkitidze, V. Podgaetsky, S. Selishchev National Research University of Electronic Technology (MIET), MIET, Zelenograd, Moscow, 124498 Russia E-mail: leo852@inbox.ru Abstract.The mechanical properties of a bulk nanobiomaterial (BNBM) prepared from the aqueous dispersion of bovine serum albumin and carbon nanotubes under laser radiation are investigated. In the experiment, the varied parameters were radiation power and time, nanotube type and concentration, and drying time and temperature. The obtained BNBM material exhibits high hardness (~350 MPa) and tensile strength (~35 MPa) at the low density (1200÷1250 kg/m3). The hardness of the prepared BNBM exceeds that of dried albumin by a factor of 4-5. Specifics hardness 0.28 MPa/(kg/m3) and the strength of ~ 0.026 MPa/(kg/m3) of nanobiomaterial matches human porous bone tissue. It is proposed the possible mechanism of hardening to form a bulk nanobiomaterial framework of nanotubes. The investigated material is promising for medicine and aerospace structures.

Keywords: bovine serum albumin; carbon nanotubes; bulk nanobiomaterial; laser radiation; hardness.

Introduction Carbon nanotubes (CNTs) exhibit high values of the mechanical characteristics. In particular, the Young’s modulus E of single-wall carbon nanotubes (SWCNTs) is ~ 5 TPa [1], which exceeds the value for high-resistance steel by a few orders of magnitude. The situation is similar in multiwall carbon nanotubes (MWCNTs). In addition, using small amounts of CNTs, the thermal, electrical, and other parameters of materials were improved, which stimulated deep interest in application of CNTs in modern engineering, including medical practice [2]. However, the attained maximum values tensile strength σ ≈ 5 MPa and E ≈ 40 MPa were still much lower than the corresponding parameters of the human porous bone tissue (HPBT, σ ~50 MPa, E ≈ 15 GPa, and hardness Hv≈ 500 MPa [3]).

The analysis of many studies on risk and safety of application of CNTs and nanomaterials and products fabricated on their basis allows drawing the following conclusions: the toxicity of CNTs depends on the efficiency of their purification from different impurities, including catalytic metals; the toxicity of SWCNTs is higher than that of MWCNTs; the toxicity of SWCNTs is lower than that of asbestos particles subcutaneously introduced in test animals (muridae); and functionalized CNTs are less toxic than non-functionalized ones [4,5].According to the latter conclusion, nanomaterials for biomedical applications should be created on the basis of functionalized CNTs. This approach was used in [6,7] for fabrication nanobiomaterials from a bovine serum albumin (BSA) matrix filled with CNTs. In this case, the BSA matrix functionalizes CNTs [8].

The aim of this study was to investigate the mechanical properties of bulk nanobiomaterials (BNBMs) synthesized from albumin and carbon nanotubes (BSA+SWCNT or BSA+MWCNT) under laser radiation.

Materials and Experimental Methods Sample preparation and experimental conditions were considered in detail in [6,7]. Here, we provide just a brief

description. As a matrix material, BSA with 98% purity (Heat Shock Isolation, Amresco Inc.,USA) was used. The fillers were MWCNT and CWCNT produced by different companies, including “Taunit” MWCNTs of the MWCNT-MD type [9], and carboxylated SWCNTs of the Pastek-SWCNT90 type [10].

Samples of the BNBM with the composition BSA+SWCNT or BSA+MWCNT were prepared as follows: (i) BSA was dissolved in distilled water in a concentration of 25 wt.%. The obtained solution was dispersed in a magnetic stirrer for the time t =1÷2 h and exposed in an ultrasonic bath at the temperature T= 40÷50°C for the time t =2 h; (ii) The albumin solution was added with CNTs in the concentration C =1÷4 g/l (0.1÷0.4 wt.%). The obtained aqueous dispersion with the composition BSA+CNT was dispersed in an ultrasonic bath for 3÷4h; (iii) The BSA+CNT dispersion was decanted by removal of the forming precipitates for the time t =24 h; (iv) The obtained dispersion was irradiated by a diode laser with the generation wave length λgen= 0.97 μm, the radiation power on the fiber output£10 W, and the specific power of ≤ 5 W/cm2 for 2÷10 min, up to evaporation of water and obtaining a dark nanomaterial; (v) The obtained BNCM samples were dried in air at room temperature or at T =30°C. Depending on the experimental parameters (albumin concentration, CNT type and concentration, laser irradiation power and time, and drying temperature and time), the BNBM consistency varied from paste to glass-like. Then a material retained its form and strength for a year and more, while the analogous products obtained from aqueous solutions of albumin with CNT using other techniques (heating or ultrasonic exposure) without laser irradiation decomposed into separate flakes for a few days after drying.

The same occurred upon ordinary drying of the albumin aqueous solutions.

164 Below we presenta typical view of the prepared samples: BSA dried from the albumin aqueous solution(25 wt.% BSA) at room temperature (Figure 1, a) and BNBM dried from the aqueous dispersion 25 wt.% BSA+0.4 wt.% MWCNT at a temperature of 30°C (Figure 1, b). Figure 1 shows the BNBM obtained under laser radiation using the technique described above (dispersion 25 wt.% BSA+0.4 wt.% MWCNT).

The samples were tablets 16÷20mm in diameter with a thickness of 4÷5 mm and a mass of 1.5÷2g. Density ρ of the samples was measured by hydrostatic weighting in a benzine. Vickers hardnessof the BNBM samples was determined on a microhardness tester.

Tensile strength σ was measured on samples in the form of plate bridges with a width of ~2 mm and a thickness of ~ 1 mm with a narrow central area with the square

a

It can be seen that the HV and σ values for the BNBM with CNTs are higher than the values for the BSA matrix by a factor of 5÷7 and are comparable with the corresponding parameters of the human porous bone tissue or aluminum.

Of special interest are density ρ, specific hardness HV /ρ , and specific strength σ /ρ. These parameters are given in Table 1 together with the values for the investigated materials and some other well-studied materials since the prepared BNBM has a low density, which exceeds the density of water by only 25%, and fairly high hardness (~350 MPa) and tensile strength (~35 MPa), the specific hardness and tensile strength of this material are comparable with those of the natural human porous bone tissue (see Table1).

The crack density is especially high on the dried BSA surface, which apparently strongly degrades the strength of the material. However, CNTs not only strengthen the

b

c

Fig. 1. BSA and BNBM (25 wt.% BSA+0.4 wt.% MWCNT) prepared after evaporation of the liquid component from the BSA solution and from the BSA+CNT dispersion using different techniques: (a) BSA, (b) BNBM after thermostating at T=30°C, and (c) BNBM after laser beam irradiation

BSA matrix, but also eliminate small cracks (Figure 2). The crack width in the investigated BNBM samples was £ 50 μm; in the cracks with a width of ≤5 μm we observed CNTs connecting the opposite crack edges (see Figure 1). The sample contains SWCNTs ~1nm in diameter, but they mainly have a shape of bundles ~7 nm in diameter or larger and are aggregated in accordance with the technical data [10]. In view of this, we may assume that here we observed the CNT bundles in the crack gap.

The same aqueous dispersion BSA+CNT demonstrated its high efficiency when used as a biological solder for laser welding of biological tissues [11,12]. The laser welds Table 1. Comparable physical and mechanical parameters of different materials*

165 of pig skin and cartilage had a strength of a few MPa. The physical mechanism of weld strengthening at the laser welding with the use of the BSA+CNT dispersion (biological solder) is apparently analogous to the mechanism of the investigated formation of the strong bulk nanobiomaterial under laser radiation.

Conclusions Study of the bulk nanobiomaterials based on the bovine serum albumin matrix filled with carbon nanotubes

a

References: 1. B. Yakobson and Ph. Avouris: Mechanical properties of carbon nanotubes,Carbon Nanotubes, Topics Appl. Phys., 80, (2001), 287–327.

2. N. Grobert:Carbon nanotubes - becoming clean. Materials today, 10(1-2), (2007), 28–35.

3. L. Hench and R. Jones: Biomaterials, Artificial Organs and Tissue Engineering. Woodhead Publishing. Print Book, 2005,ISBN: 978 1855737372, – 304 p.

4. Y. Zhu, X. Zhang, J. Zhu and et al.: Cytotoxicity of phenol red

b

Fig. 2. Typical cracks on the surface of BNBM (25 wt.% BSA+0.3wt.%S WCNT): (a) scale 20 μm (optical microscope) and (b) scale 500 nm (electron microscope)

Thus, the bulk nanobiomaterial consisting of the albumin matrix and carbon nanotube filler in both the bulk and liquid form will be useful for medical practice, including the creation of bone tissue implants, biological solders for laser welding of tissues,connection ligaments and tendons to bone and other applications [13-15].

Acknowledgement We are grateful to Profs. Yu.P. Masloboev for useful discussions and D.I. Ryabkin for help in the experiments.This work was financially supported by the Ministry of Education and Science of the Russian Federation (agreement No. 14.575.21.0089, RFMEFI57514X0089).

in toxicity assays for carbon nanoparticles,Int. J. Mol. Sci., 13, (2012), 12336–12348.

5. P. Jackson, N.R. Jacobsen, A. Baun and et al.: Bioaccumulation and ecotoxicity of carbon nanotubes,Chemistry Central Journal, 7(154), (2013), 1–21.

6. L. Ichkitidze, V. Podgaetsky, A. Prihodko and et al.: Bulk Composite Nanomaterial with Multiwall Carbon Nanotubes,Mater. Scien.Appl., 3(10), (2012), 728–732.

7. A.Yu. Gerasimenko, A.A. Dedkova, L.P. Ichkitidze and et al.: A study of preparation techniques and properties of bulk nanocomposites based on aqueous albumin dispersion,Optics and Spectroscopy,115(2), (2013), 283–289.

8. X. Zhao, R. Liu, Z. Chi, and et al.:New in sightsin to behavior of bovine serum albumin adsorbed onto carbon nanotubes: comprehensive spectroscopic studies, J. Chem. Phys., B, 114(16),(2010), 5625–5631.

9. www.nanotam@yandex.ru 10. A.V. Krestinin, A.P. Kharitonov, Yu.M. Shul’ga, and et al. : (2009). Production and characterization of fluorinated single-walled carbon nanotubes, Nanotechnologies in Russia, 4, (2009), 60–78.

11. A.Yu. Gerasimenko, O.V. Gubarkov, L.P. Ichkitidze, and et al.: Nanocomposite solder for laser welding of biological tissues,Semiconductors, 45(13), (2011), 93–98.

12. L.P. Ichkitidze, I.V. Komlev, V.M. Podgaetsky, and et al.:The method of laser welding of biological tissue,Russian Federation Patentno. 2425700, 2011.

166 13. I. Bobrinetskiy, A. Gerasimenko, L. Ichkitidze and et al.:Cell Adhesive nanocomposite materials made of carbon nanotube hybridized with albumin, American Journal of Tissue Engineering and Stem Cell, l(1), (2014), 27–38.

14. A.Yu., Gerasimenko, L.P. Ichkitidze, V.M. Podgaetsky and S.V. Selishchev: Biomedical applications of promising nanomaterials with carbon nanotubes,Biomedical Engineering, 48(6), (2015), 310–314.

15. L. Hench and I. Thompson (2010). Twenty-first century challenges for biomaterials,J. R. Soc. Interface, 7, (2010), S379– S391.

myari nanobiologiuri masalis meqanikuri Tvisebebi a. gerasimenko, l. iCqitiZe, v. podgaecki, s. seliSCevi

eleqtronuli teqnikis nacionaluri sakvlevi universiteti, zelenogradi, moskovi, ruseTi el-fosta: leo852@inbox.ru gamokvlevuli iqna myari nanobiologiuri masalis (mvbm) meqanikuri Tvisebebi. mvbm damzadebuli iqna wylis dispersiidan lazeruli dasxivebis Sedegad. dispersia Seicavda msxvilfexa rqosani saqonlis albumins da naxSirbadis nanomilakebs. eqsperimentSi icvleboda: lazeruli gamosxivebis simZlavre, naxSirbadis nanomilakebis ti pi da koncentracia, nimuSis gaSrobis dro da temperatura. miRebul mvbm- Si aRsaniSnavia Semdegi Tvisebebi: maRali sixiste (∼350 mpa), rRvevis maRali simtkice (∼ 35 mpa) da dabali simkvrive (1200÷1250 kg/m3). miRebuli mvbm sixiste 4-5 jer aWarbebs albuminis sixistes, xolo misi dayvanli sixiste (∼ 0.28 mpa/(kg/m3)) da dayvanli simtkice (∼ 0,026 mpa/(kg/m3)) Seesabamebian adamianis forovani Zvlis qsovilis parametrebs. gamokvleuli myari nanobiologiuri masala perspeqstiulia medicinaSi, aero da kosmosur teqnikaSi.

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Íåéòðîííî-àêòèâàöèîííûé àíàëèç îñîáî ÷èñòûõ ìàòåðèàëîâ â èíñòèòóòå ÿäåðíîé ôèçèêè ÀÍ Ðóç È. Ñàäûêîâ, Ó. Ñàëèõáàåâ Èíñòèòóò ßäåðíîé Ôèçèêè ÀÍ ÐÓç, ï.Óëóãáåê, 100214, ã. Òàøêåíò, Óçáåêèñòàí

Ýë–ïî÷òà: ilkham@inp.uz

Ðåçþìå. Äàííàÿ ñòàòüÿ ïîñâÿùåíà îáçîðó ðàáîò ïî íåéòðîííî-àêòèâàöèîííîìó àíàëèçó âûñîêî÷èñòûõ âåùåñòâ â Èíñòèòóòå ÿäåðíîé ôèçèêè ÀÍ ÐÓç. Çà 40 ëåò åå ñóùåñòâîâàíèÿ, â ëàáîðàòîðèè àêòèâàöèîííîãî àíàëèçà ÷èñòûõ ìàòåðèàëîâ ÈßÔ ÀÍ ÐÓç ðàçðàáîòàíû âûñîêî÷óâñòâèòåëüíûå è ìíîãîýëåìåíòíûå ìåòîäèêè èíñòðóìåíòàëüíîãî è ðàäèîõèìè÷åñêîãî íåéòðîííî-àêòèâàöèîííîãî àíàëèçà áîëåå 40 ðàçëè÷íûõ îñîáî ÷èñòûõ ìàòåðèàëîâ, ìåòàëëîâ, ñïëàâîâ, ðÿäà ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ, òàêèõ êàê êðåìíèé, êàðáèä êðåìíèÿ, ãåðìàíèé, ñëîæíûå ïîëóïðîâîäíèêîâûå òâåðäûå ðàñòâîðû òèïà À2Â6, À 4 6 è äð., ïðèìåíÿåìûõ â îïòî- è ìèêðîýëåêòðîíèêå, àâèàêîñìè÷åñêîé ïðîìûøëåííîñòè, ìåäèöèíå è äð îòðàñëÿõ íàóêè è òåõíèêè. Ðàçðàáîòàííûå ìåòîäèêè ïîçâîëÿþò îïðåäåëÿòü â àíàëèçèðóåìûõ ìàòåðèàëàõ 20-35 ïðèìåñíûõ ýëåìåíòîâ ñ ïðåäåëàìè îáíàðóæåíèÿ îò 10 ppm äî 0,01 ppt ïðè sr 0,15-0,2.

Êëþ÷åâûå ñëîâà: âûñîêî÷èñòûå âåùåñòâà, ïîëóïðîâîäíèêè, íåéòðîííî-àêòèâàöèîííûé àíàëèç, ðàäèîõèìè÷åñêîå ðàçäåëåíèå.

Áóðíîå ðàçâèòèÿ ìèêðî- è îïòîýëåêòðîíèêè â íà÷àëå ñåìèäåñÿòûõ ãîäîâ, îáóñëîâèëî ïîëó÷åíèÿ íîâûõ ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ è âûñîêî÷èñòûõ âåùåñòâ ñ çàäàííûìè ñâîéñòâàìè. Ñîäåðæàíèå ïðèìåñíûõ ýëåìåíòîâ â ýòèõ ìàòåðèàëàõ ëèìèòèðîâàëàñü n . 10 -7 – n . 10 -8 % ìàññ. è íèæå, à ëåãèðîâàííûõ êîìïîíåíòîâ n . 10 -5 – n . 10 -7 %. Äëÿ òåõíîëîãèè ïîëó÷åíèÿ âûñîêî÷èñòûõ âåùåñòâ è ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ íà èõ îñíîâå òðåáîâàëèñü ìåòîäû àíàëèòè÷åñêîãî êîíòðîëÿ, êîòîðûå îáåñïå÷èâàëè íóæíûå ïðåäåëû îáíàðóæåíèÿ è ê òîìå æå áûëè ìíîãîýëåìåíòíûìè. Îäíèì èç òàêèõ ìåòîäîâ ÿâëÿåòñÿ íåéòðîííî-àêòèâàöèîííûé àíàëèç. Äëÿ ðåøåíèÿ äàííîé çàäà÷è â èíñòèòóòå ÿäåðíîé ôèçèêè ÀÍ ÐÓ â 1974 ã. áûëà ñîçäàíà ëàáîðàòîðèÿ àêòèâàöèîííîãî àíàëèçà ÷èñòûõ ìàòåðèàëîâ. Íà çàðå ñâîåãî ñóùåñòâîâàíèÿ â ëàáîðàòîðèè ðàçâèâàëèñü â îñíîâíîì òðè íàïðàâëåíèÿ èíñòðóìåíòàëüíûé íåéòðîííî-àêòèâàöèîííûé àíàëèç, òðåêîâàÿ àâòîðàäèîãðàôèÿ è îïðåäåëåíèå àëüôà àêòèâíûõ âåùåñòâ â èîíèçàöèîííîé êàìåðå ñ èñïîëüçîâàíèåì ãîðèçîíòàëüíîãî êàíàëà ðåàêòîðà [1-3].  êîíöå ñåìèäåñÿòûõ ãîäîâ ïðîøëîãî ñòîëåòèÿ, ñ ïîÿâëåíèåì íîâûõ ïîëóïðîâîäíèêîâûõ ìàòåðèàëîâ òèïà À3Â5, À2Â6,À4Â6 (AsGa, AsIn, CdxHg1-xTe, CdxMn1-xTe, è äð ñ ñèëüíî àêòèâèðóþùåéñÿ ìàòðèöåé íà÷àëè ðàçâèâàòüñÿ ðàäèîõèìè÷åñêèé âàðèàíò íåéòðîííîàêòèâàöèîííîãî àíàëèçà [4-6], à òàêæå ðåíòãåíîðàäèîìåòðè÷åñêèé ìåòîä àíàëèçà [7-8], äëÿ îïðåäåëåíèÿ êîìïîíåíòíîãî ñîñòàâà ýòèõ ìàòåðèàëîâ è ðàçëè÷íûõ ñïëàâîâ èñïîëüçóþùèõñÿ äëÿ ïîëó÷åíèÿ òðàíçèñòîðîâ. Ïðèìåíåíèå ðàäèîõèìè÷åñêîãî âàðèàíòà

è ïîëóïðîâîäíèêîâûõ äåòåêòîðîâ âûñîêîãî ðàçðåøåíèÿ è ýôôåêòèâíîñòè äàëî íîâûé òîë÷îê â ðàçâèòèè íåéòðîííî-àêòèâàöèîííîãî àíàëèçà â ëàáîðàòîðèè. Åñëè ðàíüøå îñíîâíûìè îáúåêòàìè àíàëèçà áûëè âûñîêî÷èñòûé àëþìèíèé, êðåìíèé è ãåðìàíèé, òî â âîñüìèäåñÿòûõ ÷èñëî àíàëèçèðóåìûõ îáúåêòîâ â ëàáîðàòîðèè ïåðåâàëèëî çà 20.  èõ ÷èñëå òàêèå ñèëüíî àêòèâèðóþùèåñÿ ìàòåðèàëû êàê òåëëóðèä êàäìèÿ, òåëëóðèä êàäìèÿ ðòóòè, òåëëóðèä ìàðãàíöà ðòóòè, àðñåíèä ãàëëèÿ, èõ êîìïîíåíòû, ìîëèáäåí, âîëüôðàì, öèíê, ñâèíåö, óðàí è äð.  äåâÿíîñòûõ ãîäàõ ÷èñëî àíàëèçèðóåìûõ îáúåêòîâ äîøëà äî 40 [9-12]. Ê íàñòîÿùåìó âðåìåíè â ëàáîðàòîðèè àêòèâàöèîííîãî àíàëèçà ÷èñòûõ ìàòåðèàëîâ ðàçðàáîòàíû ìåòîäèêè âûñîêî÷óâñòâèòåëüíîãî è ìíîãîýëåìåíòíîãî èíñòðóìåíòàëüíîãî íåéòðîííî-àêòèâàöèîííîãî àíàëèçà C, Si, Mn, Mo, Sn, Re, W, Pb, U è äð. îñîáî ÷èñòûõ ìàòåðèàëîâ, à òàêæå áîðèäîâ, ñèëèöèäîâ, êàðáèäîâ ðàçëè÷íûõ ýëåìåíòîâ [912].  îñîáî ÷èñòûõ ãðàôèòå è êðåìíèè ïîñëå 50 ÷àñîâîãî îáëó÷åíèÿ â ïîòîêå íåéòðîíîâ 1014 íåé.ñì2.ñ-1 ìåòîäèêà ïîçâîëÿåò îïðåäåëÿòü áîëåå 35 ïðèìåñíûõ ýëåìåíòîâ ñ ïðåäåëàìè îáíàðóæåíèÿ îò 1 ppb äî 0,01 ppt (1.10-7 – 1.10-12 % ìàññ) â Mo, Sn è W áîëåå 20 ýëåìåíòîâ ñ ïðåäåëàìè îáíàðóæåíèÿ îò 10 ppm äî 0,1 ppb òàáë. 1. Ïðè èíñòðóìåíòàëüíîì ÍÀÀ Mo è W áûëè ïðîâåäåíû èññëåäîâàíèÿ ïî âûáîðó îïòèìàëüíûõ óñëîâèé îáëó÷åíèÿ: ñïåêòðà íåéòðîíîâ, âðåìåíè îáëó÷åíèÿ îõëàæäåíèÿ è èçìåðåíèÿ, à òàêæå ïî ó÷åòó ñàìîýêðàíèðîâàíèÿ è âîçìóùåíèÿ ïîòîêà íåéòðîíîâ. Èñïîëüçîâàíèå ðàäèîõèìè÷åñêîãî âàðèàíòà íåéòðîííî-àêòèâàöèîííîãî àíàëèçà ïîçâîëèëà ðàñøèðèòü

168 êðóã àíàëèçèðóåìûõ ìàòåðèàëîâ è ñíèçèòü ïðåäåëû îáíàðóæåíèÿ îïðåäåëÿåìûõ ýëåìåíòîâ â ñèëüíîàêòèâèðóþùèõñÿ ìàòåðèàëàõ. Òàê ñ ïðèìåíåíèåì ðàäèîõèìè÷åñêîãî âàðèàíòà ñòàëî âîçìîæíûì ïðîâîäèòü íåéòðîííî-àêòèâàöèîííûé àíàëèç òàêèõ ñèëüíî àêòèâèðóþùèõñÿ ìàòåðèàëîâ êàê As, Se, Cd, In, Sb, Te, Re, Hg, U è èõ ñîåäèíåíèé [13-17]. Ïðè ðàçðàáîòêå ìåòîäèê ðàäèîõèìè÷åñêîãî íåéòðîííî-àêòèâàöèîííîãî àíàëèçà äëÿ îòäåëåíèÿ, îïðåäåëÿåìûõ è ìåøàþùèõ ðàäèîíóêëèäîâ â îñíîâíîì ïðèìåíÿëè âûñîêîýôôåêòèâíûå è ñåëåêòèâíûå ìåòîäû ðàçäåëåíèÿ, êàê èîíîîáìåííàÿ è ýêñòðàêöèîííàÿ õðîìàòîãðàôèÿ. Ïðè ýòîì èçó÷àëè êîýôôèöèåíòû ðàñïðåäåëåíèÿ êàê ïðèìåñíûõ òàê è ìàòðè÷íûõ ðàäèîíóêëèäîâ (ðèñ.1), êðèâûå ýëþèðîâàíèÿ ïðèìåñíûõ ýëåìåíòîâ (ðèñ.2) è ïðîôèëè ðàñïðåäåëåíèÿ ìàðòè÷íûõ ðàäèîíóêëèäîâ ïî äëèíå êîëîíêè (ðèñ.3). lg D In 4 Fe 3

Se Mo Ga

Sn

2

Cd Te Zn Cu Sb W

1 Ag

0 Sc -1

-2

0

1

2

3

4

5

6

7

Ðèñ.1. Êîýôôèöèåíòû ðàñïðåäåëåíèÿ íåêîòîðûõ ýëåìåíòîâ ïðè èõ ýêñòðàêöèè ÒÁÔ èç ðàñòâîðîâ HBr.

Ai /A0

Ba, K, Na, Cs, Cd, Ga, Ir, Mn; Ag, Cr, Ni(Co), Cu, Zn, Fe, Sb; As, In, Se, Te, Sc, U, Th, La-Lu;

0.6 0.4 0.2 0

5

10

15

20

25

30

35

V, мл Ðèñ. 2. Êðèâûå ýëþèðîâàíèÿ ïðèìåñíûõ ýëåìåíòîâ â ñèñòåìå Dowex-1 - 1 M HNO3

40

Ai/ A 0

0.20

1

0.15 0.10

2

0.05 0

0.5

1.0

1.5

2.0

2.5

3.0

L , см Ðèñ. 3. Ïðîôèëü ðàñïðåäåëåíèÿ Pt (1) è Pd (2) ïî äëèíå êîëîíêè.Âûñîòà ñëîÿ ñîðáåíòà – 5 ñì, äèàìåòð êîëîíêè – 0,7 ñì.

Îäèí èç îñîáåííîñòåé íåéòðîííî-àêòèâàöèîííîãî àíàëèçà â òîì, ÷òî ìàòðè÷íûìè ðàäèîíóêëèäàìè ÿâëÿþòñÿ íå òîëüêî ðàäèîíóêëèäû ýëåìåíòîâ ñàìîé îñíîâû, à òàêæå è ðàäèîíóêëèäû äðóãèõ ýëåìåíòîâ îáðàçóþùèõñÿ ïðè èõ îáëó÷åíèè ñ íåéòðîíàìè. Òàê ïðè àíàëèçå òåëëóðèäà êàäìèÿ ðòóòè, ðàäèîíóêëèäû îïðåäåëÿåìûõ ýëåìåíòîâ íåîáõîäèìî îòäåëÿòü íàðÿäó ñ ðàäèîíóêëèäàìè êàäìèÿ, òåëëóðà è ðòóòè òàêæå è îò ðÿäà äî÷åðíèõ ðàäèîíóêëèäîâ ñåðåáðà, èíäèÿ, îëîâà, ñóðüìû, éîäà è çîëîòà êîòîðûå èìåþò ðàçíûå õèìè÷åñêèå ñâîéñòâà. Ïðè ýòîì äëÿ âûäåëåíèÿ îïðåäåëÿåìûõ ýëåìåíòîâ íåîáõîäèìî èñïîëüçîâàòü íåñêîëüêî ñòàäèé ðàçäåëåíèÿ, ÷òî ñèëüíî îñëîæíÿåò ïðîöåññ îòäåëåíèÿ è óâåëè÷èâàåò âðåìÿ àíàëèçà. Äëÿ óïðîùåíèÿ è óìåíüøåíèÿ âðåìåíè àíàëèçà íàìè ðàçðàáîòàíà ìåòîäèêà àíàëèçà, ãäå äëÿ îòäåëåíèÿ ðàäèîíóêëèäîâ ïðèìåñíûõ ýëåìåíòîâ îò ìàòðè÷íûõ èñïîëüçîâàëè êîìáèíèðîâàííóþ êîëîíêó, êîòîðàÿ èìååò äâà ñëîÿ èîíîîáìåííî-õðîìàòîãðàôè÷åñêèé ñ Dowex 1x8 è ýêñòðàêöèîííî-õðîìàòîãðàôè÷åñêèé ñ ÒÁÔ. Ýòî ïîçâîëèëî çà îäíó ñòàäèþ îòäåëèòü îêîëî 20 ïðèìåñíûõ ýëåìåíòîâ îò âñåõ ìàòðè÷íûõ ðàäèîíóêëèäîâ [5]. Ðàçðàáîòàííûå ìåòîäèêè äàþò âîçìîæíîñòü îïðåäåëÿòü 25-35 ýëåìåíòîâ ñ ïðåäåëàìè îáíàðóæåíèÿ n.10-6-n.10-10 %, à äëÿ íåêîòîðûõ ýëåìåíòîâ äî n.10-12 %. Õàðàêòåðèñòèêè ìåòîäèê íåéòðîííî-àêòèâàöèîííîãî àíàëèçà íåêîòîðûõ îáúåêòîâ ïðåäñòàâëåíû â òàáëèöå 1. Íàðÿäó ñ âûñîêî÷èñòûìè âåùåñòâàìè ïðîâîäÿòñÿ àíàëèçû ïî îïðåäåëåíèþ ðåäêèõ, ðàññåÿííûõ è áëàãîðîäíûõ ìåòàëëîâ â îòõîäàõ ìåòàëëóðãè÷åñêîé è õèìè÷åñêîé ïðîìûøëåííîñòè [18, 19].  ëàáîðàòîðèè ïðîâîäÿòñÿ òàêæå àíàëèçû ïî îïðåäåëåíèþ êîìïîíåíòíîãî ñîñòàâà è ïðèìåñåé ñ âûñîêèì ñîäåðæàíèåì äî 0,05% ìàññ. ìåòîäîì ðåíòãåíîðàäèîìåòðè÷åñêîãî (ðåíòãåíîôëóîðåñöåíòíîãî) àíàëèçà ñ èñïîëüçîâàíèåì êðåìíå-ëèòèåâîãî äåòåêòîðà ïðè âîçáóæäåíèè èñòî÷íèêàìè 241Am, 109Cd,

169 Co è 55Fe. Ìåòîä ïîçâîëÿåò çà íåñêîëüêî ìèíóò èäåíòèôèöèðîâàòü îáðàçåö íåèçâåñòíîãî ñîñòàâà, îïðåäåëèòü êîìïîíåíòíûé ñîñòàâ ñïëàâîâ, òâåðäûõ ðàñòâîðîâ, îïðåäåëÿÿ ýëåìåíòû îò êàëèÿ äî óðàíà [20].

57

Òàêæå ïðîâîäÿòñÿ ðàáîòû ïî îïðåäåëåíèþ ðàäèîíóêëèäîâ 90Sr, 137Cs, 235U, 226Ra è äð. â ïèùåâîé è ñòðîèòåëüíîé ïðîäóêöèè, ñ èñïîëüçîâàíèåì ñöèíòèëëÿöèîííûõ äåòåêòîðîâ.

Òàáëèöà 1. Ïðåäåëû îáíàðóæåíèÿ ïðèìåñíûõ ýëåìåíòîâ â íåêîòîðûõ èññëåäóåìûõ ìàòåðèàëàõ Объекты анализа C*, Si*, SiC*, органические соединения Ge Al Ti, V Mn W*, WSi2* Mo*, MoSi2* Mo Cd Te Re, NH4ReO4 Hg U** Pt, Pd CdxHg1-xTe, CdxMn1-xTe Pb, PbS

Определяемые элементы Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Br, Zr, Mo, Pd, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Ta, W, Re, Ir, Pt, Au, Th, U Na, K, P, Sc, Cr, Co, Cu, Zn, Se, Sr, Mo, Pd, Ag, Cd, Sb, Te, Cs, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Ta, W, Re, Ir, Pt, Au Mg, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Br, Zr, Mo, Pd, Ag, Cd, In, Sn, Sb, Cs, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Ta, W, Re, Ir, Pt, Au, Th, U Na, K, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Zr, Mo, Pd, Ag, Cd, Sn, Sb, Te, Cs, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Yb, Hf, Ta, W, Re, Ir, Pt, Th, U Na, K, Sc, Cr, Co, Ni, Cu, Zn, Ga, As, Se, Sr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Ta, W, Re, Ir, Au, Th, U Na, K, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Zr, Mo, Ag, Sn, Sb, Cs, Hf, Ta, Os, Ir, Th, U Na, K, Ca, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Zr, Ag, Sn, Sb, Cs, Hf, Ta, W, Re, Ir, Au, Th, U Na, K, Sc, Cr, Co, Ni, Cu, Zn, As, Se, Sr, Rb, Ag, Cs, Ba, La, Ce, Eu, Sm, Gd, Hf, Ho, Tb, W Na, K, Sc, Cr, Mn, Fe, Co, Ni, Zn, Ga, As, Sr, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Na, K, Sc, Cr, Mn, Fe, Co, Ni, Cu, As, Se, Ag, Cd, In, Cs, Ba, La, Sm, Eu, Gd, Tb, Dy, Yb, Hf, Re, U Na, K, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, Zr, Mo, Ag, Cd, In, Sn, Sb, Te, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Yb, Hf, Ta, W, Ir, Th, U Na, K, Sc, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Se, In, Sn, Sb, Cs, Ba, La, Sm, Eu, Gd, Tb, Ho, Yb, Hf Na, K, Sc, Cr, Co, Fe, Ni, Cu, Zn, Ga, As, Rb, Ag, Cd, In, Sb, Te, Sm, Eu, Gd, Tb, Dy, Hf, W, Re, Au Ag, As, Ba, Cd, Ce, Co, Cr, Cs, Cu, Eu, Fe, Ga, Gd, Ho, In, Ir, K, La, Mo, Mn, Na, Ni, Rb, Sb, Sc, Se, Sm, Sr, Te, Tb, Th, U, Yb, Zn Na, K, Sc, Cr, Mn, Co, Ni, Cu, As, In, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf Na, K, Sc, Cr, Mn, Co, Ni, Cu, Zn, Ga, In, Cs, Ba, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Yb, Hf, Au

Clim, в ppm (мкг/г) 0,1 – 1.10-8

0,1 – 1.10-6 0,1 – 1.10-6 0,1 – 1.10-7 0,1 – 1.10-6 10 – 1.10-3 0,1 – 1.10-4 0,1 - 1.10-5 1 – 1.10-4 1 – 1.10-4 1 – 1.10-4 0,1 – 1.10-4 0,1 – 1.10-5 0,1 – 1.10-5 0,1 – 1.10-4 0,01 – 1.10-7

* - àíàëèçû ïðîâåäåíû èíñòðóìåíòàëüíûì ÍÀÀ. ** - àíàëèçû ïðîâåäåíû â êîìáèíàöèè ðàäèîõèìè÷åñêîãî ÍÀÀ ñ ïðåäâàðèòåëüíûì êîíöåíòðèðîâàíèåì äî îáëó÷åíèÿ. Îñòàëüíûå àíàëèçû ïðîâåäåíû ñ ðàäèîõèìè÷åñêèì ÍÀÀ. Ëèòåðàòóðà [1]. Ì.Ì.Óñìàíîâà, Ò.À.ßíêîâñêàÿ, Å.Ï.Õîëÿâêî, À.À.Õîäæàìáåðäèåâà: Íåéòðîííî-àêòèâàöèîííûå ìåòîäû èññëåäîâàíèÿ ïðèìåñíîãî ñîñòàâà îñîáî ÷èñòîãî ãåðìàíèÿ, Äîêëàäû ÀÍ ÓçÑÑÐ, N11 (1976), 24-25 [2]. Á.Ï.Çâåðåâ, Ì.Ì.Óñìàíîâà, Â.Ï.Ëàð÷åíêî, Í.Æóìàåâ: Îïðåäåëåíèå êîíöåíòðàöèîííûõ ïðîôèëåé áîðà â êðåìíèè ìåòîäîì òðåêîâîé àâòîðàäèîãðàôèè êîñûõ øëèôîâ, Çàâîäñêàÿ ëàáîðàòîðèÿ, ò.45, N2 (1979), 144-146 [3]. Ì.Ì.Óñìàíîâà, Ò.À.ßíêîâñêàÿ, À.À.Õîäæàìáåðäèåâà è äð.: Èññëåäîâàíèå ïðèìåñíîãî ñîñòàâà òèòàíà è åãî îêèñè

ñ ïîìîùüþ íåéòðîííî-àêòèâàöèîííîãî àíàëèçà, Äîêëàäû ÀÍ ÓçÑÑÐ, N10 (1979), 50-51 [4]. Óñìàíîâà Ì.Ì., Êóçíåöîâ Ð.À., Ñàäûêîâ È.È., Õîëÿâêî Å.Ï.: Íåéòðîííî-àêòèâàöèîííûé àíàëèç òåëëóðèäà êàäìèÿ ðòóòè, Òåç.äîêë. 5-Âñåñîþçíîå ñîâåùàíèå ïî àêòèâàöèîííîìó àíàëèçó è äð. ðàäèîõèìè÷åñêèì ìåòîäàì, Òàøêåíò, (1987), 224 [5]. Óñìàíîâà Ì.Ì., Êóçíåöîâ Ð.À., Ñàäûêîâ È.È., Õîëÿâêî Å.Ï.: Íåéòðîííî-àêòèâàöèîííûé àíàëèç òåëëóðèäà êàäìèÿ ðòóòè è åãî êîìïîíåíòîâ, Ñá.ñòàòåé «Àêòèâàöèîííûé àíàëèç», Òàøêåíò: «Ôàí», 1990, 181-186

170 [6]. Êóçíåöîâ Ð.À., Ñàäûêîâ È.È.: Ìåòîäèêà íåéòðîííîàêòèâàöèîííîãî àíàëèçà òåëëóðèäà ìàðãàíöà ðòóòè, Ïðåïðèíò ÈßÔ ÀÍ ÐÓ, Ð-10-393, Òàøêåíò, (1991), 11 [7]. Ì.Ì. Óñìàíîâà, Í.Ì.Ìóõàìåäùèíà, Ë.Ê.Êàãàíîâ, Â.Þ. Âîäçèíñêèé: Ðåíòãåíîðàäèîìåòðè÷åñêèé ìåòîä îïðåäåëåíèÿ ñòåõèîìåòðè÷åñêîãî ñîñòàâà ñåëåíèäà öèíêà, Òåç.äîêë. V Âñåñîþçíîãî ñîâåùàíèÿ ïî âûñîêî÷èñòûì âåùåñòâàì, ã.Ãîðüêèé, (1987), 236-237 [8]. Ì.Ì. Óñìàíîâà, Í.Ì.Ìóõàìåäùèíà, Ò.Ñ.Õóäàéáåðäèåâ: Ðåíòãåíîðàäèîìåòðè÷åñêîå îïðåäåëåíèå Re â MoRe ñïëàâàõ, Çàâîäñêàÿ ëàáîðàòîðèÿ, ò.51, N2 (1985), 40-41 [9]. Kolotov V.P., Dogadkin N.N., Nekrasova N.N, Sadikov I.I.: Radiochemical neutron activa-tion determination of phosphorus in high pure germanium, J. of Radioanal. and Nucl. Chem., V. 168, N2 (1993), 465-470 [10]. Karandashev V.K., Grashulene S.S., Sadikov I.I.: Use of the extraction-chromatographic system tributylphosphate - HBr solutions in analysis of high-purity materials [11]. Ìèðñàãàòîâ Ø., Ìóçàôôàðîâà Ñ.À., Ñàäûêîâ È.È.: Èññëåäîâàíèå ïðèìåñíîãî ñîñòàâà ïëåíîê òåëëóðèäà êàäìèÿ ìåòîäîì íåéòðîííî-àêòèâàöèîííîãî àíàëèçà è èõ âëèÿíèå íà ôîòîýëåêòðè-÷åñêèå ñâîéñòâà ýòèõ ñòðóêòóð, Ãåëèîòåõíèêà, N 5 (1996), 20-25 [12]. Êîëîòîâ Â.Ï., Äîãàäêèí Í.Í., Ñàäûêîâ È.È., è äð. Àêòèâàöèîííûé àíàëèç îñîáî ÷èñòîãî îëîâà, Æóðí. àíàëèò. õèìèè, ò.51, N12, (1996), 1315-1321 [13]. Sadikov I.I., Karandashev V.K.: Radiochemical neutron activation analysis of high purity cadmium, Uzb.Phys. Journal, N 4 (1998), 69-74 [14]. Ñàäûêîâ È.È., Óñìàíîâà Ì.Ì., Ñàëèìîâ Ì.È., Ñàäûêîâà Ç.Î.: Ðàäèîõèìè÷åñêèé íåéòðîííî-àêòèâàöèîííûé àíàëèç âûñîêî÷èñòîãî ðåíèÿ è ïåððåíàòà àììîíèÿ, Æóðí. àíàëèò. õèìèè, ò. 56 (2001), N 6, 601-604 [15]. Ñàäûêîâ È.È.Óñìàíîâà Ì.Ì., Ñàëèìîâ Ì.È.: Íåéòðîííîàêòèâàöèîííûé àíàëèç âûñîêî÷èñòîãî ìîëèáäåíà ðàäèîõèìè÷åñêèì ðàçäåëåíèåì: Àòîìíàÿ ýíåðãèÿ, ò. 90, âûï. 1 (2001), 69-74 [16]. Ñàäûêîâ È.È., Ðàõèìîâ À.Â.: Âûñîêîýôôåêòèâíîå ðàäèîõèìè÷åñêîå îòäåëåíèå íåïòóíèÿ ( 239Np) ïðè ðàäèîõèìè÷åñêîì íåéòðîííî-àêòèâàöèîííîì àíàëèçå (ÐÍÀÀ) ÷èñòîãî óðàíà, Àñïèðàíò è ñîèñêàòåëü, N 2 (2008), 134-139 [17]. I.I. Sadykov, A.V.Rakhimov, M.I.Salimov and all: Neutron activation analysis of pure uranium: Preconcentration of impurity elements, J. of Radioanal. and Nucl. Chem., Vol. 280,No.3 (2009), 489-493 [18]. I.I.Sadikov, M.I.Salimov, Z.O.Sadikova: Neutron activation determination of gold and silver content in gold mining tails, VII Eurasian Conference “Nuclear Science and its Application 2124 October 2014, Baku, Azerbaijan [19]. È.È.Ñàäèêîâ, Ì.È.Ñàëèìîâ, Í.Á.Áàáàåâ, Ç.Î.Ñàäèêîâà: Èçâëå÷åíèå îñìèÿ èç ñáðîñíûõ ðàñòâîðîâ ìåòàëëóðãè÷åñêîãî ïðîèçâîäñòâà, Äîêë. ÀÍ ÐÓç, N 1 (2014), 54-56 [20]. N.M Mukhamedshina, A.A. Mirsagatova, V.G. Zinovev: Determination of ZnSe(Te) stoichiometry and dopant content by X-ray analysis, J. of Radioanal. and Nucl. Chem., Vol. 264, No 1 (2005), 97-100.

Neutron Activation Analysis of High Purity Materials in Institute of Nuclear Physics of Uzbekistan Academy of Science I. Sadikov, U. Salikhbaev Institute of Nuclear Physics of Uzbekistan Academy of Science , settl.Ulugbek, 100214, Tashkent, Uzbekistan E-mail: ilkham@inp.uz

This article reviews the work on neutron activation analysis of high-purity substances in the Institute of Nuclear Physics, Academy of Sciences of Uzbekistan. Over 40 years in the laboratory activation analysis-friendly materials INP Uzbekistan developed highly sensitive and multi-element technique instrumental and radiochemical neutron activation analysis of more than 40 different ultrapure materials, metals, alloys, and a number of semiconductor materials such as silicon carbide, silicon, germanium, compound semiconductor solid solutions A2B6, A4B6, etc., used in optoelectronics and microelectronics, aerospace, medicine and other fields of science and technology. The developed technique allows to determine in the analyzed materials 20-35 impurity elements with detection limits of 10 ppm to 0,01 ppt at sr 0,15-0,2.

zesufTa masalebis analizi neitronuli aqtivaciis meTodiT uzbekeTis respublikis mecnierebaTa akademiis birTvuli fizikis institutSi i. sadikovi, u. salixbaevi

uzbekeTis respublikis mecnierebaTa akademiis birTvuli fizikis instituti, ulugbekis das, 100214, taSkenti, uzbekeTi el-fosta: ilkham@inp.uz naSromi eZRvneba uzbekeTis respublikis mecnierebaTa akademiis birTvuli fizikis institutSi zesufTa masalebze neitronuli aqtivaciis meTodiT Catarebuli Sromebis mimoxilvas. sufTa masalebis aqtivaciuri analizis laboratoriaSi, misi arsebobis 40 wlis ganmavlobaSi 40-ze meti dasaxelebis zesufTa masalebisaTvis damuSavda instrumentuli da radioqimiuri neitronuli aqtivaciis analizis maRali mgrZnobelobisa da mravalelementuri meTodikebi . aseve metalebis, Senadnobebisa da mTeli rigi naxevargamtaruli masalebisaTvis, rogorebic arian siliciumi, siliciumis karbidi, germaniumi, A2B6 da A4B6 tipis rTuli naxevargamtaruli myari xsnarebi da sxv., romlebic gamoiyenebian opto da mikroeleqtronikaSi, aviakosmosur mrewvelobaSi, medicinaSi da mecnierebisa da teqnikis sxva dargebSi. damuSavebuli meTodikebi saSualebas iZlevian, sakvlev masalebSi, ganisazRvros 20-35 minarevi elementi 10 ppm-dan 0,01 ppt-mde sazRvrebSi, sr 0,15-0,2-is pirobebSi.

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Íàíîãåòåðîñòðóêòóðû äëÿ ðåíòãåíîâñêèõ ñåíñîðîâ Ð. Ìåëêàäçå1,2, À. Äèäåáàøâèëè1.2, Ã. Êàëàíäàäçå1.2, Ã. Ïåðàäçå1, Ò. Ìàêàëàòèÿ1, Ç. ×àõíàêèÿ1.2, Ê. ×èòàÿ2 Èíñòèòóò ìèêðî- è íàíîýëêåêòðîíèêè, ïð.È.×àâ÷àâàäçå, 13, 0179 Òáèëèñè, Ãðóçèÿ, ÍÏÊ «Ýëåêòðîííàÿ òåõíèêà», ÍÈÈ ïðèêëàäíûõ ïîëóïðîâîäíèêîâûõ òåõíîëîãèé, ÒÃÓ, ïð.È.×àâ÷àâàäçå, 13, 0179 Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà: rmelkadze@yahoo.com, zaurchak@mail.ru 1 2

Ðåçþìå.  íàñòîÿùåå âðåìÿ áîëüøîå âíèìàíèå óäåëÿåòñÿ ïèêñåëüíûì ïîëóïðîâîäíèêîâûì ñåíñîðàì äëÿ äåòåêòèðîâàíèÿ ðåíòãåíîâñêîãî èçëó÷åíèÿ â äèàïàçîíå 10 – 70 êýÂ.  äàííîé ðàáîòå ïðåäñòàâëåíà òåõíîëîãèÿ ïîëó÷åíèÿ ìåòîäîì ìîëåêóëÿðíî-ëó÷åâîé ýïèòàêñèè ïîëóïðîâîäíèêîâûõ íàíîãåòåðîñòðóêòóð GaAs/AlGaAs/InGaAs íà ïîëóèçîëèðóþùèõ ïîäëîæêàõ GaAs, êîòîðûå áëàãîäàðÿ âûñîêîìó ïîãëîùåíèþ ðåíòãåíîâñêèõ ëó÷åé îáëàäàþò áîëüøèì êîýôôèöèåíòîì äåòåêòèðîâàíèÿ. Èçìåðåíû ýëåêòðîôèçè÷åñêèå ñâîéñòâà íàíîãåòåðîñòðóêòóð ñ äâóìåðíûì ýëåêòðîííûì ãàçîì. Ñíÿòû ñïåêòðû ôîòîëþìèíåñöåíöèè äëÿ îïðåäåëåíèÿ ýíåðãåòè÷åñêèõ óðîâíåé êâàíòîâûõ ÿì. Ðàçðàáîòàíà òîïîëîãèÿ äëÿ òåõíîëîãèè ñîçäàíèÿ ðåíòãåíîâñêèõ ñåíñîðîâ (ÐÑ) ñ PHEMT òðàíçèñòîðàìè äëÿ óñèëåíèÿ ñ÷èòûâàþùåãî çàðÿäà, ÷òî ïîâûøàåò ÷óâñòâèòåëüíîñòü äåòåêòîðà. Ïðåäñòàâëåíà ýëåêòðîííàÿ âåðñèÿ èííîâàöèîííîé ñèñòåìû äëÿ ñ÷èòûâàíèÿ ñèãíàëîâ.

Êëþ÷åâûå ñëîâà: ÌËÝ, íàíîãåòåðîñòðóêòóðà, ðåíòãåíîâñêèé ñåíñîð.

Ââåäåíèå  ïîñëåäíåå âðåìÿ áîëüøîå âíèìàíèå óäåëÿåòñÿ ðàçðàáîòêå ïîëóïðîâîäíèêîâûõ ïèêñåëüíûõ äåòåêòîðîâ ðàçëè÷íîãî âèäà èîíèçèðóþùèõ èçëó÷åíèé äëÿ ïðèìåíåíèÿ â òàêèõ îáëàñòÿõ, êàê ôèçèêà âûñîêèõ ýíåðãèé, êîñìè÷åñêèå èññëåäîâàíèÿ, ìîíèòîðèíã îêðóæàþùåé ñðåäû, ìåäèöèíà è äð. Áëàãîäàðÿ âûñîêîé ÷óâñòâèòåëüíîñòè ïîëóïðîâîäíèêîâûõ ñåíñîðîâ, â ìåäèöèíå ñòàëî âîçìîæíûì ñíèçèòü äîçó ðåíòãåíîâñêîãî îáëó÷åíèÿ ïàöèåíòîâ äî 20 êý äëÿ ìàììîãðàôèè è äî 60 êý äëÿ ðàäèîãðàôèè.  îñíîâíîì íà ñåãîäíÿøíèé äåíü ïðåäïî÷òåíèå îòäàåòñÿ ãèáðèäíûì ïèêñåëüíûì èëè ïîëîñêîâûì äåòåêòîðàì íà êðåìíèè, êîòîðûå ñîñòîÿò èç äâóõ ÷àñòåé: ñåíñîðíîé ìàòðèöû è ÷èïà ñî ñ÷èòûâàþùåé ýëåêòðîííîé ñõåìîé. Îñíîâíûì íåäîñòàòêîì òàêèõ äåòåêòîðîâ ÿâëÿþòñÿ òðóäíîñòè, ñâÿçàííûå ñ ñîåäèíåíèåì ýòèõ äâóõ ÷àñòåé (òàê íàçûâàåìàÿ ôëèï-÷èï òåõíîëîãèÿ) [1]. Êðîìå òîãî, òðåáîâàíèå ê äåòåêòîðàì âûñîêîãî ïðîñòðàíñòâåííîãî ðàçðåøåíèÿ ïðèâîäèò ê óìåíüøåíèþ ðàçìåðîâ ïèêñåëåé è, ñëåäîâàòåëüíî, ê óìåíüøåíèþ ïåðâè÷íîãî ñèãíàëà. Ýòî îñîáåííî âàæíî â ñëó÷àå ìàëûõ äîç îáëó÷åíèÿ. Ðåøåíèåì ýòîé ïðîáëåìû ÿâëÿåòñÿ ðàçðàáîòêà ìîíîëèòíûõ äåòåêòîðîâ, â êîòîðûõ ñåíñîðíàÿ ìàòðèöà è ñ÷èòûâàþùàÿ ñèñòåìà èçãîòîâëÿþòñÿ â åäèíîì ÷èïå. Êðîìå òîãî, ïîëóïðîâîäíèêîâûå ìàòåðèàëû íà îñíîâå GaAs, áëàãîäàðÿ áîëåå âûñîêîìó ÷åì Si êîýôôèöèåíòó ïîãëîùåíèÿ ðåíòãåíîâñêèõ ëó÷åé, ïîçâîëÿþò ñîçäàâàòü ðàäèàöèîííî ñòîéêèå äåòåêòîðû, ðàáîòàþùèå ïðè 300Ê ñ áîëüøèì êîýôôèöèåíòîì äåòåêòèðîâàíèÿ [2, 3].

 äàííîé ðàáîòå ïðåäñòàâëåíû ðåçóëüòàòû èññëåäîâàíèé ïî âûðàùèâàíèþ ìåòîäîì ìîëåêóëÿðíîëó÷åâîé ýïèòàêñèè íàíîãåòåðîñòðóêòóð GaAs/AlGaAs/ InGaAs íà ïîëóèçîëèðóþùåé ïîäëîæêå GaAs äëÿ ñîçäàíèÿ ðåíòãåíîâñêèõ ïèêñåëüíûõ ìàòðèö ñ âûñîêèì ðàçðåøåíèåì.

Ìàòåðèàëû è ìåòîäèêà èçìåðåíèé Íàíîãåòåðîñòðóêòóðû GaAs/AlGaAs/InGaAs áûëè âûðàùåíû íà óñòàíîâêå ìîëåêóëÿðíî-ëó÷åâîé ýïèòàêñèè ÓÝÏÌÀ-12,5 ñ âåðòèêàëüíîé êîìïîíîâêîé òåõíîëîãè÷åñêîãî ìîäóëÿ è ìîäóëÿ çàãðóçêè-âûãðóçêè (ðèñ.1).

Ðèñ. 1. Óñòàíîâêà ìîëåêóëÿðíî-ëó÷åâîé ýïèòàêñèè ÓÝÏÌÀ-12,5

177  òåõíîëîãè÷åñêèé ìîäóëü âñòðîåíî àíàëèòè÷åñêîå îáîðóäîâàíèå: êâàäðóïîëüíûé ìàññ-ñïåêòðîìåòð äëÿ îïðåäåëåíèÿ îñòàòî÷íûõ ãàçîâ è ïîòîêà ìàòåðèàëà èç èñòî÷íèêà; äèôðàêòîìåòð îòðàæåííûõ áûñòðûõ ýëåêòðîíîâ ñ ýëåêòðîííîé ïóøêîé 40 êýÂ.  ïðîöåññå ðîñòà îïðåäåëÿåì ñòðóêòóðó è ìîðôîëîãèþ ïëåíîê ïî äèôôðàêöèîííîé êàðòèíå íà ëþìèíåñöåíòíîì ýêðàíå. Îæå-ñïåêòðîìåòð ïîçâîëÿåò îïðåäåëèòü õèìè÷åñêèé ñîñòàâ è ìîëüíóþ äîëþ â InyGa1-yAs è AlxGa1-xAs. Ðîñò ïëåíîê ïðîõîäèò â âûñîêîì âàêóóìå ∼10-9 Ïà, êîíòðîëü òåìïåðàòóðû ïîäëîæêè è ýôôóçèîííûõ ÿ÷ååê îñóùåñòâëÿåòñÿ ïèðîìåòðîì è W-Re òåðìîïàðàìè, ñîîòâåòñòâåííî. Ýêñïåðèìåíòàëüíûå îáðàçöû áûëè âûðàùåíû íà ïîäëîæêàõ ïîëóèçîëèðóþùåãî GaAs ñ êðèñòàëîîãðàôè÷åñêîé îðèåíòàöèåé (100), ñ ïîâåðõíîñòíîé ïëîòíîñòüþ äèñëîêàöèé 450 ñì-2. Àðõèòåêòóðà âûðàùåííûõ íàíîãåòåðîñòðóêòóð äëÿ PHEMÒ-òðàíçèñòîðîâ ïðåäñòàâëåíà íà ðèñ.2. Ñïåêòðû ôîòîëþìèíåñöåíöèè ñíèìàëè íà óñòàíîâêå ÑÄË-2 ñ èñïîëüçîâàíèåì Íå-Nå ëàçåðà (λ - 632,8 íì, ìîùíîñòü 22,5 ìÂò) ïðè òåìïåðàòóðå 77 Ê è 300 Ê.

ïðîèñõîäèò â ïîäëîæêå ïîëóèçîëèðóþùåãî GaAs, ñíàáæåííîãî äâóìÿ êîíòàêòàìè ñíèçó è ñâåðõó. PHEMÒòðàíçèñòîð Ò1 ïîäêëþ÷åí ê êîíäåíñàòîðó Ñ2 èñòîêîì, çàòâîð ïîäñîåäèíåí ê èñòî÷íèêó ïèòàíèÿ, à ñòîê – ê øèíå äàííûõ. Ïðè Ñ2 >> Ñ1 çà âðåìÿ DÒ (ðàññòîÿíèå ìåæäó ìàðêåðàìè) ïðîèñõîäèò ñ÷èòûâàíèå èíôîðìàöèè ñ äåòåêòîðà. Òàêîå ïîäêëþ÷åíèå òðàíçèñòîðà õàðàêòåðèçóåòñÿ âûñîêèì êîýôôèöèåíòîì óñèëåíèÿ ïî íàïðÿæåíèþ è íèçêèì âõîäíûì ñîïðîòèâëåíèåì. Ýòî ïîçâîëÿåò ïîâûñèòü ÷óâñòâèòåëüíîñòü ñõåìû è åå áûñòðîäåéñòâèå.

Ðèñ. 3. Òîïîëîãèÿ ðåíòãåíîâñêîãî ïèêñåëüíîããî ñåíñîðà ñ ÐÍÅÌÒ-òðàíçèñòîðîì

Ðåçóëüòàòû ýêñïåðèìåíòà

Ðèñ. 2. Àðõèòåêòóðà íàíîãåòåðîñòðóêòóðû PHEMÒ òðàíçèñòîðà

Ðåíòãåíîâñêèé ïèêñåëüíûé ñåíñîð ñ ÐÍÅÌÒ-òðàíçèñòîðîì èçãîòîâëÿëè ìåòîäîì âçðûâíîé ôîòîëèòîãðàôèè ïî ðàçðàáîòàííîé íàìè òîïîëîãèè (ðèñ.3). Äëÿ ðàçðàáîòêè äàííîé òîïîëîãèè áûëà èñïîëüçîâàíà ýêâèâàëåíòíàÿ ñõåìà îäèíî÷íîãî ñåíñîðà ñ òðàíçèñòîðîì è ïðîâåäåíî ìàòåìàòè÷åñêîå ìîäåëèðîâàíèå, äåìîíñòðèðóþùåå åãî àìïëèòóäíî-âðåìåííóþ çàâèñèìîñòü (ðèñ.4). Ïðè âîçäåéñòâèè íà äåòåêòîð ðåíòãåíîâñêîãî èçëó÷åíèÿ âîçíèêàþùèé èìïóëüñíûé ýëåêòðè÷åñêèé òîê, ïðîïîðöèîíàëüíûé èíòåíñèâíîñòè îáëó÷åíèÿ (èììèòàòîð èìïóëüñíîãî èçëó÷åíèÿ), çàðÿæàåò êîíäåíñàòîð Ñ2.  ýòîì ñëó÷àå íàïðÿæåíèå íà Ñ2 áóäåò ïðîïîðöèîíàëüíî èíòåíñèâíîñòè îáëó÷åíèÿ. Ýòî âñå

Ðîñò ìíîãîñëîéíûõ íàíîãåòåðîñòðóêòóð íà ïîäëîæêàõ ïîëóèçîëèðóþùåãî GaAs îñóùåñòâëÿëñÿ ìåòîäîì ìîëåêóëÿðíî-ëó÷åâîé ýïèòàêñèè ñî ñêîðîñòüþ 0.1 – 0.2 íì/ñ, à òåìïåðàòóðà ïîäëîæêè ïðè âûðàùèâàíèè GaAs è Al-xGa-1-õAs ñîñòàâëÿëà 580 – 620î Ñ, ïðè âûðàùèâàíèè InyGa-1-yAs - 450 – 480î Ñ. Ìîëüíàÿ äîëÿ õ è ó èçìåíÿëàñü â ïðåäåëàõ 0.1 – 0.25. Îáúåìíîå è δëåãèðîâàíèå GaAs è AlGaAs îñóùåñòâëÿëîñü îñàæäåíèåì Si. Êîíöåíòðàöèþ ñâîáîäíûõ íîñèòåëåé è èõ ïîäâèæíîñòü îïðåäåëÿëè ìåòîäîì Âàí-äåð-Ïàó è íåðàçðóøàþùèì áåñêîíòàêòíûì ìåòîäîì «ÑÂ× ìàãíèòîñîïðîòèâëåíèÿ». Êîíöåíòðàöèÿ ñâîáîäíûõ íîñèòåëåé ñîñòàâèëà (0.9 – 1.1)1012ñì-2, à ïîäâèæíîñòü – (4500 ÷ 5200) ñì2/ ñ. Ïèêè ñïåêòðîâ ÔË íàáëþäàþòñÿ íà äëèíàõ âîëí 2625 íì è 3550 íì, ÷òî ñîîòâåòñòâóåò çîííûì ïåðåõîäàì â In0.2Ga0.8As è â InAs. Íà ïîëó÷åííûõ ãåòåðîñòðóêòóðàõ ñ êâàíòîâûìè ÿìàìè ñîçäàâàëèñü ÐÍÅÌÒ-òðàíçèñòîðû, ÂÀÕ ïðèâåäåíû íà ðèñ. 5.

.

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Ðèñ. 4. Ýêâèâàëåíòíàÿ ñõåìà îäèíî÷íîãî ñåíñîðà ñ òðàíçèñòîðîì, C1=1fF, C2=1pF, T1=HEMT

ïîäàâàëè íàïðÿæåíèå îò 100  äî 400  è òîêè óòå÷êè ìåíÿëèñü îò 2 íÀ äî 50 íÀ, ÷òî õàðàêòåðíî äëÿ ñàìîãî ýòîãî ìàòåðèàëà, à õàðàêòåðèñòèêè òðàíçèñòîðîâ íå ìåíÿëèñü. Ýòè èññëåäîâàíèÿ ïîêàçàëè ïðàâèëüíîñòü ðàñ÷åòîâ ìàòåìàòè÷åñêîãî ìîäåëèðîâàíèÿ è âûáîðà òîïîëîãèè; âûñîêèé óðîâåíü òåõíîëîãèè êàê ïîëó÷åíèÿ ìåòîäîì ÌËÝ íàíîãåòåðîñòðóêòóð ñ äâóìåðíûì ýëåêòðîííûì ãàçîì, òàê è ñîçäàíèÿ ðåíòãåíîâñêîãî ñåíñîðà ñ ÐÍÅÌÒòðàíçèñòîðîì.

Çàêëþ÷åíèå Ðèñ. 5. ÂÀÕ ÐÍÅÌÒ-òðàíçèñòîðà

Îìè÷åñêèå êîíòàêòû ñòîêà è èñòîêà ôîðìèðîâàëè íàíåñåíèåì Au/Ge/Ni/Au ñ ïîñëåäóþùèì ôîòîííûì îòæèãîì â òå÷åíèå 6 – 7 ñ. Äëèíà çàòâîðà Ti/V/Au êîíòàêòà Øîòòêè ñîñòàâëÿëà 0.8 ìêì ïðè øèðèíå 40 – 100 ìêì. Òîêè óòå÷êè íå ïðåâûøàëè 0.1ìÀ. Äèôôåðåíöèàëüíîå ñîïðîòèâëåíèå êàíàëà íà óðîâíå 50% ìàêñèìàëüíîãî òîêà íàñûùåíèÿ ñîñòàâëÿåò 0.5 ìÎì. Ïîðîãîâîå íàïðÿæåíèå òðàíçèñòîðà ñîñòàâëÿåò 0.01 – 0.03 Â, êðóòèçíà ïðè 300 Ê – 250 ÷ 300 ìÑì/ìì. Îáùèé ðàçìåð êðèñòàëëà ðåíòãåíîâñêîãî ñåíñîðà ñ ÐÍÅÌÒ-òðàíçèñòîðîì ñîñòàâëÿëà 0.207 õ 0.207 ñì2, êîòîðûé ïîñëå ñêðàéáèðîâàíèÿ ïîìåùàëñÿ â êîðïóñ ñ ìèíèìàëüíûì ïîãëîùåíèåì ðåíòãåíîâñêîãî èçëó÷åíèÿ. Âåëè÷èíà åìêîñòè Ñ2 ñîñòàâèëà 4 – 5 ïô, ñîïðîòèâëåíèå êîíòàêòà Øîòòêè â çàêðûòîì è îòêðûòîì ñîñòîÿíèè ñîñòàâèëî 20 ìÎì è 10 Îì ñîîòâåòñòâåííî. Íà îáðàçöû ïîëóèçîëèðóþùåãî GaAs òîëùèíîé 380 – 400 ìêì

Ìåòîäîì ÌËÝ ïîëó÷åíû íàíîãåòåðîñòðóêòóðû GaAs/AlGaAs/InGaAs ñ äâóìåðíûì ýëåêòðîííûì ãàçîì. Ïîäâèæíîñòü ýëåêòðîíîâ ñîñòàâèëà 4500 ÷ 5200 ñì2/ Â.ñ ïðè êîíöåíòðàöèè ñâîáîäíûõ íîñèòåëåé (0.9 – 1.1)1012 ñì-2. Ïî ðàçðàáîòàííîé òîïîëîãèè íà ýòèõ ãåòåðîñòðóêòóðàõ áûëè ñîçäàíû ðåíòãåíîâñêèå ñåíñîðû ñ ÐÍÅÌÒ-òðàíçèñòîðàìè, èìåþùèìè êðóòèçíó 250 ÷ 300 ìÑì/ìì ïðè 300 Ê. Ïðåäñòàâëåíà ýëåêòðîííàÿ âåðñèÿ èííîâàöèîííîé ñèñòåìû ñ÷èòûâàíèÿ ñèãíàëîâ.

Ëèòåðàòóðà 1. T. Lezhneva, R. Melkadze and V. Khvedelidze: GaAs PixelDetector Technology for X-ray Medical Imaging: A Review, Russian Microelectronics, 34 (2005), 229-241.

2. M. Kroening, I. Besse, T. Baumbach, A. Bertold, R. Melkadze, T. Lezhneva, V. Khvedelidze, G. Kalandadze: Materials Investigation of Galium Arseniide for Direct Converting Energy Sensitive X-Ray Detectors, the 10th SPIE International Symposium Nondestructive Evaluation for Health Monitoring and Diagnostics, 6-10 March 2005, San Diego, California, USA.

179 3. D. Boardman, P. Sellin: Design and Characterization of HEMT for Use in Monolithic GaAs X-Ray Imaging Sensor, Nuclear Instruments and Methods in Physics Research, A466 (2001), 226-231.

nanoheterostruqturebi rentgenuli sensorebisTvis r. melqaZe1,2, a. didebaSvili1,2, g. kalandaZe1,2, g. feraZe1, T. makalaTia1, z. Waxnakia1,2, k. Citaia2

Nanoheterostructure for X-Ray Sensors R. Melkadze1,2, A. Didebashvili1.2, G. Kalandadze1.2, G. Peradze1, T. Makalatia1, Z. Chakhnakia1.2, K. Chitaia2 Institute of Micro- and Nanoelectronics, 13, Chavchavadze ave., Tbilisi, Georgia 2 RPC “Electron Technology”, Research Institute of Applied Semiconductor Technologies of Iv.Javakhishvili Tbilisi State University, 13, Chavchavadze ave., Tbilisi, Georgia E-mail: rmelkadze@yahoo.com, zaurchak@mail.ru

1

At present, much attention is given to pixel semiconductor sensors for X-ray detection in the range of 10-70keV. This paper presents a technology of growth of GaAs-AlGaAs-InGaAs semiconductor nanoheterostructures by molecular beam epitaxy on GaAs semi-insulating substrates, which due to the high X-ray absorption have a high detection coefficient. Electrophysical properties of 2DEG nanoheterostructures are measured. Photoluminescence spectra are taken to determine energy levels of the quantum wells.

A topology for X-ray sensors (XRS) with the PHEMT transistors allowing one to increase the sensitivity of the detector is developed. An electronic version of the innovative system for signal readout is presented.

1

mikro da nanoeleqtronikis instituti, WavWavaZis gamz. 13, 0179, Tbilisi, saqarTvelo 2 ssk „eleqtronuli teqnika“, gamoyenebiTi naxevargamtaruli teqnologiebis samecniero– kvleviTi instituti, WavWavaZis gamz. 13, 0179, Tbilisi, saqarTvelo el-fosta: rmelkadze@yahoo.com, zaurchak@mail.ru dResdReobiT didi yuradReba eqceva naxevradgamtarul piqselur sensorebs rentgenuli gamosxivebis deteqtirebisTvis 10 –70 kev diapazonSi. naSromSi warmodgenilia GaAs/AlGaAs/InGaAs nanoheterostruqturebis miRebis teqnologia GaAs–is naxevradgamtarul safenze molekulur– sxivuri epitaqsiis meTodiT (mse), romlebsac axasiaTebT rentgenuli sxivebis STanTqmis didi unari da aqedan gamomdinare xasiaTdebian deteqtirebis maRali koeficientiT. gazomil iqna organzomilebiani nanoheterostruqturebis eleqtrofizikuri parametrebi. kvanturi ormoebis energetikuli doneebis gansazRvrisTvis gadaRebulia fotoluminescenciis speqtrebi. damuSvda rentgenuli sensorebis topologia PHEMT tranzistorebiani teqnologiisTvis, romelic uzrunvelyofs wamkiTxvelis muxtis gaZlierebas da Sesabamisad amaRlebs deteqtirebis mgrZnobiarobas. warmodgenilia signalebis wamkiTxvelis inovaciuri sistemebis eleqtronuli versia.

180

Development of technology for production of new types, eco-safe, composite fire-extinguishing and fire- protective materials L. Gurchumelia1, F. Bejanov2, M. Tsarakhov1, Z. Khutsishvili1, L. Nadareishvili1 TSU Rafael Agladze Institute of Inorganic Chemistry and Electrochemistry, 11, Mindeli str., Tbilisi, 0186, Georgia G.Tsulukidze Mining Institute of the Ministry of Education and Sciences of Georgi, 7, Mindeli str., Tbilisi, 0186, Georgia E-mail: l_gurchumelia@yahoo.com 1 2

Abstract. This work addresses the development of technology for production of novel, eco-safe, composite fire-extinguishing powders based of local mineral raw materials and elaboration of new types, eco-safe fire-protective materials on the basis of such composite powders. The technology for production of these materials differs from the serial production technology. Such powders, will be made by mechanical blending of raw materials, does not require modification with expensive, halogen-inclusive hydrofobizators. Fire-protective materials are manufactured only by mechanical mixing of binders -organic polymeric compounds and fillers- high-dispersed composite fire-extinguishing powders of our preparation, which in composite materials are functioning, in itself, as efficient inert flame retardants. Therefore such fireprotective and fire-extinguishing materials are far cheaper than imported analogues.

Keywords:eco-safe, fire-extinguishing powders, fire-protective materials, halogen-free.

Introduction Fires are unsolved problems of world civilization. No less dangerous are the cases of population chocking and poisoning by fire, which is caused, mainly by combustion products as well as by toxicity of using safety precautions.

Unfortunately, the statistics confirms that traditional safety precautions, for the present, are sufficiently expensive, not universal and less efficient. Therefore, before the whole world there arises the problem of fire suppression and development of such safety precautions, which will provide inhibition of burning of matter in the zone of inflammation and decrease of toxic materials emission. The use of ecosafe, fire-extinguishing and fire-protective means, occur topical among the mentioned measures, and powder ones are admitted to be most efficient fire- extinguishers as unique means against any type of fires [1,2]. But, It is known, that at present fire-extinguishing powders of serial production represents the fine dispersed mineral salts with expensive, halogen containing hydrophobizative additives.Thus, most of them are halogen-containing and do not meet the contemporary demands, first of all with the view of effective, and universal use. Therefore, at present one of the most important problems is the elaboration of halogen-free, non-toxic, eco-safe, inexpensive fire-extinguishing and fire-protective materials [2,3]. With consideration of the above said in our work we describe the ways of development of technology for production of novel, halogen-free, eco-safe, highly efficient, universal, composite fire-extinguishing powders based of local mineral raw materials and elaboration of new types, eco-safe, highly effective fire-protective materials on the basis of such composite powders. The technology for production of these materials differs from the serial production technology. Such composite fire-extinguishing powders will be made by me-

chanical blending of local mineral raw materials: zeolite, clay shale and perlite, it does not require the additional chemical processing and modification with expensive, halogen-inclusive hydrofobizative additives. Fire-protective materials are manufactured only by mechanical mixing of binders -organic polymeric compounds and fillers - highdispersed composite powders of our preparation, which in composite materials are functioning as efficient inert flame retardants. Therefore such fire-protective and fire-extinguishing materials are far cheaper than imported analogues.

Materials and Methods Raw materials: zeolites, clay shales and perlites were selected according to their high operating properties and due to the factors indicating the reduction of burning processes. This is enabled with chemical and thermo gravimetric analysis. As it is well known, such raw materials mainly are silicate origin and contain alkali and alkalineearth metal carbonates, bicarbonates, silicates, hydroxides of Fe and Al and crystallization water. Therefore at their intensive heating incombustible gases, water steam and metal oxides are separated. Released incombustible gases and water steam in flame zone are functioning as phlegmatizer and in surface zone cause the formation of swelled layer. The latter, protective film of metal oxides, swelled and coke layer create “fire-limiting” effect [4]. This is indicative of the fact, that they are characterized by high homogenous effect. Along with it, it should be noted that high-dispersed composite powders of zeolites, perlites and clay shales are characterized by high heterogenous effect, which means heterogeneous removal of reaction active centers at the surface of solid particles of the powder. High values of recombination coefficient of atomic oxygen (γ0 = 2,7 •10-3_ 6,5•10-3) are also indicative of this fact [4,5].

181 Hence, mentioned composite powders on flame zone perform homogenous as well as heterogenous inhibition of combustion process and in surface zone they form protective layer, which hinders heat transfer to combustive material and excludes direct contact of combustive material with air. Here it should be noted, that zeolite in composite powders plays the role of hydrophobizators. Therefore, we can surmise that the introduction in zeolite containing composite powders of ammophos and dolomites, which are highly hygroscopic, but characterized inhibition effect of burning products, will not cause significant changes of operating properties, but will considerably increase fireextinguishing ability. Experimental researches are also indicative of this fact [5.6]. Experimental data has shown, that clay shales are characterized with lower fire-extinguishing ability (G- 4.2kg/m2), but 2-times higher coefficients of heterogeneous recombination of oxygen atoms (γ0- 6.5× 10-3) compared to zeolites (G -2.6 kg/m2, γ0- 2.7 × 10-3) and perlites ( G -2.2 kg/m2, γ0- 2.6× 10-3). While, when clay shales are added to zeolites, perlites, ammophos and dolomites heterogeneous effect of composite powders increases considerably (G -1.1 – 1.8 kg/m2, γ0- 3.0 × 10-3 - 3.3 × 10-3) [5,7]. Thus, such composite powders are characterized by high inhibition properties and fire-extinguishing ability similarly to flame retardants. From the all above-mentioned one can suggest, that composite fire-extinguishing powders of our preparation can be successfully used as fillers, which in fire-protective materials are functioning as efficient inert flame retardants.

It is well known, that the main components of surface protective compounds are: binders, flame retardants and fillers. Organic as well as inorganic compounds are used as binders. Inorganic binders are characterized by lesser operating properties: low strength, high hygroscopicity and solubility, low atmosphere-resistance and etc. Therefore organic compounds are used as binder every so often. As a rule, organic compounds are qualified as easily combustible compounds and for decrease of their combustibility an addition of efficient flame retardants is necessary [8].

According to whether they interact with polymers or with initial monomers, flame retardants of inert or reactive type are found. Reactive flame retardants – chloro and phosphoroganic monomers participate directly in the processes of polymerization and polycondensation and form copolymers by high fire-resistance, but every so often by low operating properties. It should be also noted, that the use of reactive flame retardants is associated with quite expensive and complex processes, which are not studied completely yet. The use of inert flame retardants aren’t associated directly with polymer production, it mixes mechanically with polymer in the course of its processing, which simplify and expand, to some extent, the possibilities of preparation of new fire-resistant compounds. But, along with it, they are characterized by a number of disadvantages: migration at materials surface, elution ability by water and other washing means and etc.[8,9].

Fire-extinguishing powders of our preparation, similarly to inert flame retardants, don’t participate in the pro-

cess of polymer preparation, their mechanical mixing with polymeric binders is possible in the course of processing, and in contrast to them are characterized by high operating properties: they have low caking capacity, are eco-safe, practically insoluble, resistant against atmospheric and chemical action and their elution doesn’t takes place.

Thus, composite fire-protective materials will be prepared only by mechanical mixing of binders and fillers, don’t need in chemical treatment and addition of expensive flame retardants. Polyurethane resins were selected as binders, popularity of which is due to low price and simple technological process of production. Along with it, polyurethane resins, in comparison with binders, used in series, have a number of advantages: eco-safety, low combustibility, high adhesion strength practically with material of all type; high water proof and anticorrosive properties; heat-and frostresistance.

Estimation of fire-resistance of fire-protective materials is performed by the complex of fire-technical characteristics (combustibility, ignition, flame proportion, smoke formation and toxicity), selecting of which is carried out in accordance with materials function and fields of application [9]. Fire-protective materials not only should effectively protect materials surface against fire, but they should retain their properties, the variation of which reduces cover efficiency. The efficiency ofcover is determined not only by their inhibition properties and fire-resistance ability, but also by their operating properties, among which the most important are: adhesion strength, impact strength, hygroscopisity and artificial ageing [9,10].

Results Experimental researches were carried out for wood materials for preparation of fire- protective cover. Polyurethane resins and sodium polymetaphospates were used as binders and as filler- composite fire-extinguishing powders of our preparation. Operating properties were studied by standard laboratory methods [9]. The results of experimental researches are given in Table 1.

Fire-technical characteristics will be determined by various standard methods of fire testing. Main characteristics of combustibility: time of independent combustion tcr (sec); degree of material failure (mass loss) -

Sm (%) and

degree of failure lengthwise - S L % . In the course of studying combustibility of materials in an initial stage it is established combustible group by the method of “fire tube” (GOST 1708-71 - “ Fire tube” Method for determination of fire-resistance). Classifying of materials by combustibility is carried by the following manner: incombustible material - mass loss <9%; hardly combustible material mass loss 9-20%: combustible material - mass loss >20%.

The results of experimental researches are given in Table 2.

Experimental results show, that fire-protective materials, prepared on the basis of polymetaphosphutes, are characterized by higher fire-resistance, but by lower operating

182 Table 1. Operating properties of fire-protective materials

Table 2. Fire-resistance of fire-protective materials

properties in comparison with fire-protective materials, prepared on the basis of polyurethane resins. Moreover we have established that by increase of filler content in polyurethane resins fire-resistance sharply enhances and operating properties vary slightly. From all above-mentioned it may be suggested, that for polyurethane resins the selection optimal amount of mentioned fillers is possible and in the case of its addition fire-protective materials by high operating properties and by high fire-resistance is obtained.

Conclusions - Composite fire-extinguishing powders of local mineral raw materials: zeolite, clay shale and perlite are halogenfree, eco-safe, highly efficient and universal. They will be made by mechanical blending of raw materials, does not require modification with expensive, halogen-inclusive hydrofobizators. Thus, they are far cheaper than imported analogues.

- Obtained fire-extinguishing powders can be successfully used as fillers, which in fire-protective materials are functioning as efficient inert flame retardants and fire-protective materials will be prepared only by mechanical mixing of binders - polyurethane resins and fillers â&#x20AC;&#x201C; obtained fire-extinguishing powders.

- Fire-protective materials of our preparation are inexpensive, eco-safe, very effective and universal. They can be used to protect building materials and constructions of any type from fire.

References: 1. F.Takahashi, G.Linteris and V.Katta: Physical and Chemical Aspects of Cup-Burner Flame Extinguishment,Halon Options Technical Working Conference 15th Proceedings, Next Generation Fire Suppression Technology Program, May2426,2005, Albuquerque, NM, pp.1-10.

2. A.BaratovA. and L.Vogman,Fire- extinguishing powder compositions, Stroyizdat, Moscow,1982.

3. G.Schreiberg, P.Porret. Fire-extinguishing Means, Ă&#x152;., 1985.

4. L.Gurchumelia, F.Bejanov, G.Baliashvili andN.Sarjveladze N.: Development of Novel Composite Fire-extinguishing Powders on the Basis of Mineral Raw Materials,Modelling, monitoring and management of Forest Fires, Wit Press publishes leading books in Science and Technology,Toledo,Spain,2008, p p . 6 1 - 7 1 . h t t p : / / l i b r a r y. w i t p r e s s . c o m / p a g e s / PaperInfo.asp?PaperID=19595 5. D.Petviashvili, K.Sulaberidze, G.Bezarashvili, L.Gurchumelia and G.Abashidze: Investigation of heterogeneous recombination of oxygen atoms on solid surfaces of different composition. Series Chemistry, Tbilisi, #4(2009), vol. 35.

183 6. L.Gurchumelia, G.Bezarashvili, M.Chikhradze, O.Chudakova: Investigation of performance properties of novel composite fire-extinguishing powders based on mineral raw materials,Materials Characterisation. Wit Press publishes leading books in Science and Technology, New Forest,UK, 2009, pp.337-347. (http://library.witpress.com/pages/ PaperInfo.asp?PaperID=20159).

7. L.Gurchumelia, F.Bejanov, V.Tkemaladze, and L.Tkemaladze: Establishment the conditions of effective extinguish of fire extinguishing powders,Proceedings of G.Tsulukidze Mining institute, Tbilisi, 2013, pp 64-67.

8. I.Aleksandrov, T.Smirnov,Fire-protective materials, M., VNIIPI, 1991, pp .89.

9. To study problems of providing long-life of fire-protective covers and to develop recommendations,Report by theme: 72004, MIPL GU MChS, Moscow, 2005, p. 121-136.

10. A.Chernuxa andA.Kolenov: Investigation of performance properties of fire-proof covers,Collection of scientific works, Volume 27, 2010, pp. 226-220.

axali ti pis kompoziciur i kompoziciuri cecxlmaqri fxvnilebisa da cecxldamcavi safarebis damzadebis teqnologiis SemuSaveba l. RurWumelia1, f. beJanovi2, m. caraxovi1, z. xuciSvili1, l. nadareiSvili1 1 Tsu, r. aglaZis araorganuli da eleqtroqimiis instituti, mindelis q. 11, 0186, Tbilisi, saqarTvelo 2 ssi p grigol wulukiZis samTo instituti, e. mindelis q. 7, 0186, Tbilisi, saqarTvelo elâ&#x20AC;&#x201C;fosta: l_gurchumelia@yahoo.com

naSromSi aRwerilia axali, kompoziciuri, ekologiurad usafrTxo da iafi cecxlmaqri fxvnilebisa da maT safuZvelze axali tipis cecxldamcavi safarebis damzadebis gzebi. aRwerili teqnologia mniSvnelovnad gansxvavdeba aRniSnuli masalebis seriuli warmoebis teqnologiisagan. cecxlmaqri fxvnilebi mzaddeba mineraluri nedleulis meqanikuri SereviT da ar saWiroebs ZviradRirebuli hidrofobizatorebis damatebas. cecxldamcavi safarebi mzaddeba mxolod Semkvreli nivTierebebis poliureTanuli fisebis da Semavseblis-miRebuli cecxlmaqri fxvnilebis (romlebic asruleben anti pirenis rols) meqanikuri SereviT. avtorTa azriT, es mniSvnelovnad amcirebs cecxlmaqri da cecxldamcavi masalebis TviTRirebulebas.

184

Nontraditional methods of recovery of gold from antimony ores and concentrates Ts. Gagnidze, R. Chagelishvili, N. Chavtasi I. Javakhishvili Tbilisi State University, R.Agladze Institute of Inorganic Chemistry and Electrochemistry, 0179 Tbilisi, Georgia E-mail: ts.gagnidze@mail.ru Abstract. It is established the possibility of the use of thiokarbamide method of gold extraction from residues of vacuumthermal processing of gold containing antimony ore of Zophito deposit(Upper Racha, Georgia). Experimentally studied the influence of the main technological factors on the thiourea leaching process of residues and established optimum leaching conditions. The method for gold extraction from the residues of vacuum-thermal treatment of the concentrate of goldcontaining antimony ore of Zopkhito (deposit) has been established by eco-friendly electrochemical method. The effect of main technological parameters on the process of electrochemical leaching of the residues has been studied in the presence of a selective ligand, thiourea, in chloride system and optimal conditions of leaching have been established providing for the gold extraction from gold-containing residues by 82-90 % in the conditions of so-called “soft” oxidation without release of molecular chlorine at the anode and eco-contamination.

Keywords: gold, extraction, electrochemical processing, gold-containing antimony ores.

Up to date, the problem of mining and processing of mineral raw materials is still associated with technical and environmental difficulties. Therefore, development of modern technologies and their effective application to industry are considered as the most important national problems. Relevance of the topic increases when it comes to the mining of precious metals and in particular gold.

In this connection, of a special interest are the occurrences of gold-bearing antimony ores of Caucasian Region (e.g. Zopkhito, Georgia). The conventional technologies for processing these particular ore types still apply open-top furnaces characterized with high toxicity, and hence environmental unfriendliness.

Present work offers a new technology for the complex processing of gold-bearing antimony ores. Together with workability, the developed process is environmentally friendly that being very important for the protection of unique nature of the Caucasus region. With this, application of the technology to industry promotes solving social problems to support steady development of the region.

A new technology for integrated processing of goldbearing antimony ores has been developed in order to solve certain problems in the gold-mining industry. The technology based on vacuum thermal processes allows not only extraction of gold but also production of associated materials – antimony sulfide (Sb2S3) and metallic antimony (Sb).

Table 1. Content of basic components in the concentrates

To increase the complexity of the use of gold-containing antimony ores and concentrates of Zopkhito deposit the vacuum-thermal method of their treatment is selected which was used at high-temperature vacuum plant (10-5MPa, 400-6000C), created in F.Tavadze Institute of metallurgy and materials science. As a result of vacuum – thermal processing of the concentrate the antimony sulfide (Sb2S3) and high-purity antimony are produced and gold (already removed by protective sulfide layer) remained in the cinder by 100%. Gold extraction from gold-containing concentrate of such type by high extent is possible by hydrometallurgical method.

Hydrometallurgical cyanide method [1,2] is widely used in world practice to extract precious metals from gold-containing raw material. The method is characterized by high toxicity, high prices and low selectivity. Also the neutralization of cyanide solutions presents a serious problem.

Of all known gold solvents we consider thiocarbamide ThiO or [CS(NH2)2] the best candidate to meet contemporary requirements (low toxicity, kinetic activity, selectivity with respect to precious metals, reasonable prices, etc) [3].

Besides, after the extraction of gold and silver, it is possible to regenerate thiocarbamide solutions, to multiply use of these solutions in leach circuits and create zero-discharge hydrometallurgical technology.

To testing were subjected the concentrates with the following content of basic components (Table 1)

185 For the gold dissolution is used thiourea acid solutions, in which trivalent iron sulphate introduced as oxidant. The process of Au dissolution in thiourea (CS(NH2)2 or Thio) may be presented by the following most probable reaction : Au + nThio + Fe(Thio)23+→Au (Thio)2+ + Fe(Thio)n2+ where, apparently, n=4.

Established optimum leaching conditions: Compozition of the solution – ThiO-0,5 %; Fe2(SO4)3-0.8 %; H2SO40.8 %. Mode of Leaching: duration – 4 hours; Solid to liquid 1:3; Rotation speed of mixer 200 rev/min; Temperature – 18-25 0C. In these conditions, the degree of the gold extraction is 82-87 %.

However upon using the method of thiocarbamide leaching, certain difficulties arise with subsequent extraction of gold from the solutions (adsorption on an activated carbon, desorption of gold with subsequent electrolysis of the concentrated solution) [4].

So-called hydrochlorination method [5] is considered as one of the real alternatives of cyanide method of processing of the residues of vacuum-thermal treatment of gold-containing antimony ore. It was shown [6] that in concentrated chloride solutions the normal potential of Cl2/ Cl- electrode is more positive (1.242 V) than of Au3+/Au electrode (1.012 V) which allows to oxidize metallic gold by molecular chlorine, dissolved in the solution: 2Au+3Cl2+2HCl →2HAuCl4 (1) The system Cl2-NaCl-HCl-H2O, in which the concentration of hydrochloric acid comprises 0.5 M HCl and is characterized by the highest value of red-ox potential, was used by us to process gold-containing quarzites by the method of electrochlorination leaching [7]. The process of electrochemical leaching of gold-containing raw material proceeds at the anode by separation of molecular chlorine which oxidizes the gold with a formation of anionite complex [AuCl4]- with unstability constant K=1.2 10-12(pK=11.2) [8]. Because of negative charge the complex can not pass to the catholyte by migration and, respectively, is unable to discharge at the cathode by the formation of metallic gold and remains in the anolyte. Therefore the process of gold extraction from the solution by mentioned method requires the additional operations which hinders the leaching process. Also, methods disadvantage lies in the necessity of high red-ox potential (higher power consumption) and environmental contamination by excess molecular chlorine, separated at the anode in the course of leaching.

To simplify the electrochemical technology of processing of gold-containing ores and concentrates and to elaborate eco-safe and highly-efficient method the investigations were carried out in aqueous solutions, containing chlorides of alkali metals, by addition of such ligand which forms strong complex compounds with gold. In accordance with [3] the smaller is standard red-ox potential of aqueous solutions of complex gold-containing system, the stronger complex compound with gold is formed. We may judge about thermodynamic possibility of easiness of gold

oxidation by the value of the reduction of red-ox potential of complex former ligand at its introduction in the system.

Finally this will be determined by kinetic parameters of the process.

On the basis of experiments [9] thiourea was chosen as selective complex former with gold which is characterized by penetration into internal sphere of complex compounds of some heavy metals with the formation of new strong complex compounds [10]. By the addition of thiourea in chloride system red-ox potential of the solution reduces from 1.0 to 0.4 V. Such low red-ox potential of the system allows to direct the electrochemical process of leaching of gold-containing ore in the conditions of so-called “soft” oxidation without release of chlorine at the anode and environmental contamination [9,11]. In mentioned conditions gold polarization in anode area and its passing into the solution takes place; as a result, cathionite complex compounds with thiourea [Au(ThiO2)]+ are formed with unstability constant K=10-23(pK=22) [3] by the reaction: Au + 2ThiO +Cl- = [Au(ThiO2)]+Cl- + e(2) As is seen cathionite complex of thiourea with gold is considerably more stable than chloride anionite one which is due to low (0.38 V) standard potential of the reaction (2).

Along with it, because of (the presence of) positive charge the passing of gold cathionite complex into cathode area by migration and its discharge at the cathode by the formation of metallic gold is made possible. Mentioned process of electrochemical leaching considerably simplifies gold passing from the ore to the solution and its following extraction since these processes are performed in the same electrochemical apparatus.

The process was carried out at pilot plant of our elaboration(Fig.1).

.

Fig.1. Scheme of stationary electrolyzer. 1-electrolyzer body; 2-cathode; 3-anode; 4-mixer; 5-diaphragm; 6- electrolytic key; 7-Pt-electrode; 8-Ag/AgCl reference electrode.

186 The experiments were performed to establish the effect of electrolyte composition and of process regime on the indexes of gold extraction by electrochemical method from the residue of vacuum-thermal treatment of the concentrate of gold-containing antimony ore.

Thus quantitative indexes of gold electrochemical extraction from the concentrate (gold-containing residue) attains maximum value (82-90 %) by the use of the solution: 0.5MKCl+0.5MThiO+0.03MNa2S in potentiostatic regime: ϕa - 0.5±0.05 V, t=22-320C, grinding degree: 0.16 mm and pH<1.

On the basis of obtained experimental results the continuous technological process for gold extraction from the residue (or ore concentrate) of vacuum-thermal treatment of gold-containing antimony ore of Zopkhito deposit was elaborated and for realization of this process-electrochemical reactor was created with the electrodes of highly-developed surface carbon-fiber materials which are characterized by high efficiency, especially, in the solutions, containing electro-active components of low concentration (Fig.2).

Fig.2. Electrochemical reactor 1-reactor body-graphite anode; 2-anode operating surface; 3reactor cover; 4-current leading rim; 5-pulpsupplying branch pipe; 6-pulp discharging chute; 7- diaphragm-cathode cell; 8cathode cassette with current lead; 9-cathodes; 10-carbon material tightly reeled up on the cathode; 11-pump-mixer; 12pump driving shaft; 13-pump shaft isolating pipe enclosure casing; 14-pump shaft bearings;15-catholyte supplying pipe; 16-siphon drain for spent catholyte; 17- intermediate vessel; 18- solution level; 19-trajectory of pulp circular movement

In the course of ore leaching in anode area the gold dissolving and the formation of the cathionite complex with thiourea takes place. The complex after migration

through filtering, thermally treated perchlorovinyl diaphragm enters in cathode area where gold is discharged at the cathode, manufactured from carbon-fiber material and free ligand-containing solution is returned to anode area for pulp preparation.

Below (Fig.3) the continuous technological scheme of the process of electrochemical leaching of the residue of vacuum-thermal treatment of the concentrate of gold-containing antimony ore is presented.

Thus on the basis of experimental results it may be concluded that the efficient processing of residue of vacuum-thermal treatment of gold-containing antimony ore of Zopkhito deposit is possible by 82-90% gold extraction by electrochemical method using chloride electrolyte to which thiourea - selective complex former with gold is added. The process proceeds in the conditions of so-called “soft” oxidation without release of molecular chlorine and environmetal contamination.

Fig.3. Basic technological scheme of electrochemical leaching of the residue of vacuum-thermal treatment of gold-containing antimony 0re.

References: 1. Izvlechenie zolota iz upornikh rud i concentratov. Pod. red.Lodeishchikova, V.V., M.:Nedra, 1968, 287 .

2. Texhnika i tekhnologia izvlechenia zolota za rubezhom. Pod. red. Lodeishchikova, V.V. M.:Metallurg. 1973, 246-252.

3. Paddefet, I., Chimia zolota, M.: Mir, 1982, 259.

4. Bek, R.,.Shuraeva L., Electrochimia, 2006, 42(4), 340-346.

5. Gidrometallurgia zolota. Pod red..Laskkorina, I.V., M.:Nauka, 1980, 198.

187 6. Gagnidze, T.,.Gvelesiani, J., Gvelesiani, G., Lezhava, T., Mamporia, M. Sak.Mets.Acad. Matsne.Chimii ser. 2000, 26( 34), 35-39.

7. Gvelesiani, J., Lezhava, T., Gagnidze, Ts., Mamporia, M., Adamia, T. Sak.Mets.Acad.Matsne.Chimii ser. 2006, 32(12), 167-175.

8. Winand, R., Hydrometallurgy. 1991, 27, 285-316.

9. Gagnidze, Ts., Gvelesiani J. i dr. Khsnari okroshemtsveli sulfiduri nedleulis gadamushavebisatvis, Sakpatenti, 2011, 5220(1).

10. Sorokin. I. i dr. Issledovanie anodnogo travlenia tonkikh zolotikh plenok, Electronnaya technika, ser.14.1974,1, 20.

11. Gagnidze,Ts., Gvelesiani, J. i dr. Sac. Metsn.Akad. Matsne, Chimiis ser. 2011, 37(1-2), 2005-2012.

anTimonis madnebidan da koncentratebidan oqros amoRebis aratradiciuli meTodi c. gagniZe, r. CageliSvili, n. xavTasi

Tsu, r. aglaZis araorganuli da eleqtroqimiis instituti, mindelis q. 11, 0186, Tbilisi, saqarTvelo el–fosta: ts.gagnidze@mail.ru narCenebidan oqros amosaRebad, Seswavlilia zofxiTos (zemo raWa) oqroSemcveli anTimonis madnis vakuum-Termuli damuSavebis Tiokarbamiduli meTodis gamoyenebis SesaZlebloba da dadgenilia gamotutvis optimaluri pirobebi.

SemoTavazebulia anTimonis oqroSemcveli madnis vakuum-Termuli damuSavebis narCenebidan oqros amoRebis, alternatiuli, ekologiurad usafrTxo, eleqtroqimiuri meTodis gamoyeneba. narCenebis eleqtroqimiuri gamotutvis procesi Seswavlilia qloridul sistemaSi seleqtiuri kompleqswarmomqnelis-TioSardovanas Tanaobisas. dadgenilia gamotutvis optimaluri pirobebi, rac uzrunvelyofs oqroSemcveli narCenebidan oqros amoRebas 82-90%-iT e.w. „rbili“ daJangvis reJimis pirobebSi anodze molekuluri qloris gamoyofis da garemos dabinZurebis gareSe.

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Âîçìîæíûå ìåòàëë-äèýëåêòðèê ïåðåõîäû è íàíîðàçìåðíîå ðàçäåëåíèå ôàç â äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ Ó. Êóðáàíîâ, Ç. Õóäàéáåðäèåâ, Ý. Êàðèìáàåâ, Ñ. Äæóìàíîâ. Èíñòèòóò ÿäåðíîé ôèçèêè ÀÍ ÐÓç, 100214, Òàøêåíò, Óçáåêèñòàí Ýë–ïî÷òà: ukurbanov@inp.uz, dzhumanov@inp.uz Ðåçþìå. Íàìè èçó÷åí âîçìîæíûé ìåõàíèçì ïåðåõîäîâ ìåòàë-äèýëåêòðèê è ðàçäåëåíèå íàíîðàçìåðíûõ ôàç â äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ â ïðåäåëàõ íåñîáñòâåííûõ è ñîáñòâåííûõ áîëüøèõ ïîëÿðîíîâ è ïðåäëîæåíî åäèíîå îïèñàíèå ýòèõ âçàèìîñâÿçàííûõ ÿâëåíèé. Ïðåäïîëàãàåòñÿ, ÷òî â òàêèõ ïîëÿðíûõ ìàòåðèàëàõ íîñèòåëÿìè çàðÿäà ÿâëÿþòñÿ íåñîáñòâåííûå (ñâÿçàííûå ñ ïðèìåñÿìè) è ñîáñòâåííûå áîëüøèå ïîëÿðîíû. Ïîêàçàíî, ÷òî íîñèòåëüäåôåêò-ôîíîí è íîñèòåëü-ôîíîí ñèëüíûå âçàèìîäåéñòâèÿ ñîâìåñòíî ñ íåîäíîðîäíîñòüþ çàðÿäà ïðîÿâëÿþòñÿ â ëîêàëèçàöèè çàðÿäà, óïîðÿäî÷åíèè ïîëÿðíûõ íîñèòåëåé ñ ôîðìèðîâàíèåì ðàçíûõ ñâåðõðåøåòîê è ïîëÿðíûõ çîí, ìåòàë-äèýëåêòðèê ïåðåõîäîâ è ðàçäåëåíèè íàíîðàçìåðíûõ ôàç. Îíè ñîïðàâîæäàþòñÿ ôîðìèðîâàíèåì ïîëîñ â êóïðàòàõ â øèðîêîé îáëàñòè ëåãèðîâàíèÿ. Ïîêàçàíî, ÷òî â ëåãèðîâàííûõ La2-xSrxCuO4 è YBa2Cu3O7-b êóïðàòàõ ñòàòè÷åñêàÿ (èçîëèðóþùàÿ) è äèíàìè÷åñêàÿ (ìåòàëëè÷åñêàÿ) ïîëîñà ñîñóùåñòâóåò â îáëàñòè ëåãèðîâàíèÿ õ=0,030,13. Ïîëó÷åííûå ðåçóëüòàòû â êîëëè÷åñòâåííîì îòíîøåíèè íàõîäÿòñÿ â ñîîòâåòñòâèè ñ ýêñïåðèìåíòàëüíûìè äàííûìè â òàêèõ ìàòåðèàëàõ ñ âûñîêîé Òc.

Êëþ÷åâàå ñëîâà: ëåãèðîâàííûå êóïðàòû, ïåðåõîäû ìåòàëë-äèýëåêòðèê, ðàçäåëåíèå íàíîðàçìåðíûõ ôàç, ïîëÿðîííûå íîñèòåëè çàðÿäà.

Ââåäåíèå Ëåãèðîâàííûå ìåäíî-îêñèäíûå ñîåäèíåíèÿ (êóïðàòû) ÿâëÿþòñÿ íåîäíîðîäíûìè ñèñòåìàìè (ãäå ïðèìåñè è íîñèòåëè çàðÿäà ðàñïðåäåëÿþòñÿ íåðàâíîìåðíî), ïðè÷åì íåäîëåãèðîâàííûå êóïðàòû ÿâëÿþòñÿ áîëåå íåîäíîðîäíûìè, ÷åì ñâåðõëåãèðîâàííûå êóïðàòû [1-2].  òàêèõ íåîäíîðîäíûõ ìàòåðèàëàõ ÿâëåíèÿ ëîêàëèçàöèè íîñèòåëåé è ìåòàëëäèýëåêòðèê ïåðåõîäû (ÌÄÏû) î÷åíü îñëîæíÿþòñÿ ìíîãèìè ôàêòîðàìè, òàêèìè êàê íåîäíîðîäíûìè ðàñïðåäåëåíèÿìè ïðèìåñåé (äîïàíòîâ) è íîñèòåëåé çàðÿäà, íîñèòåëü-äåôåêò-ðåøåòî÷íûìè è íîñèòåëüðåøåòî÷íûìè âçàèìîäåéñòâèÿìè, ñïåöèôè÷åñêèìè âèäàìè óïîðÿäî÷åíèÿ íîñèòåëåé çàðÿäîâ, êîòîðûå ÷àñòî áûëè ïðîèãíîðèðîâàíû â ñóùåñòâóþùèõ òåîðåòè÷åñêèõ ïîäõîäàõ ê ïðîáëåìå ëîêàëèçàöèè íîñèòåëåé è ÌÄÏîâ â êóïðàòíûõ âûñîêîòåìïåðàòóðíûõ ñâåðõïðîâîäíèêàõ (ÂÒÑÏ).  ÷àñòíîñòè, ñèëüíûå ýëåêòðîííûå êîððåëÿöèè âûçûâàþò ëîêàëèçàöèþ íîñèòåëåé è ìîòòîâñêîãî ìåòàëë-äèýëåêòðèê ïåðåõîäà â íåëåãèðîâàííûõ êóïðàòàõ, êîòîðûå ÿâëÿþòñÿ ìîòòõàááàðäîâñêèìè äèýëåêòðèêàìè ñ ïåðåíîñîì çàðÿäà (ÏÇ) [3-5]. Îäíàêî, íå î÷åâèäíî, êàêèå ïðîöåññû áóäóò äîìèíèðîâàòü â ëåãèðîâàííûõ êóïðàòàõ. Ýëåêòðîííûå ñâîéñòâà ëåãèðîâàííûõ êóïðàòîâ ñóùåñòâåííî îòëè÷àþòñÿ îò òàêèõ ñâîéñòâ îáû÷íûõ ìåòàëëîâ è íåëåãèðîâàííûõ êóïðàòîâ. Ïîòîìó, ÷òî ýëåêòðîííàÿ ñòðóêòóðà êóïðàòîâ ðåçêî èçìåíÿåòñÿ ñ ëåãèðîâàíèåì è íèçêîýíåðãåòè÷åñêàÿ ýëåêòðîííàÿ ñòðóêòóðà ëåãèðîâàííûõ êóïðàòîâ âåñüìà îòëè÷àåòñÿ îò âûñîêîýíåðãåòè÷åñêîé ýëåêòðîííîé ñòðóêòóðû ìîòò-õàááàðäîâñêîãî

äèýëåêòðèêà ñ ÏÇ.  ëåãèðîâàííûõ êóïðàòàõ ýëåêòðîííàÿ íåîäíîðîäíîñòü è óïîðÿäî÷åíèå íîñèòåëåé çàðÿäîâ èãðàþò âàæíóþ ðîëü â íàíîðàçìåðíîì ðàçäåëåíèè ôàç â ðåàëüíîì ïðîñòðàíñòâå [1,6,7], êîòîðàÿ òåñíî ñâÿçàíà ñ ëîêàëèçàöèåé íîñèòåëåé è ìåòàëë-äèýëåêòðèê ïåðåõîäàìè â ýòèõ ìàòåðèàëàõ. Ïîêà ìåõàíèçìû ëîêàëèçàöèè íîñèòåëåé, ìåòàëë-äèýëåêòðèê ïåðåõîäîâ è íàíîðàçìåðíîãî ðàçäåëåíèÿ ôàç â ëåãèðîâàííûõ íåîäíîðîäíûõ êóïðàòàõ íå î÷åíü õîðîøî ïîíÿòíû.  ýòîé ðàáîòå íàìè èçó÷åíû âîçìîæíûå ìåõàíèçìû ìåòàëë-äèýëåêòðèê ïåðåõîäîâ è íàíîðàçìåðíîãî ðàçäåëåíèÿ ôàç â íåîäíîðîäíûõ äûðî÷íîëåãèðîâàííûõ êóïðàòàõ. Ìåõàíèçìû ëîêàëèçàöèè è ñåãðåãàöèè íîñèòåëåé  ïðîöåññå ð-òèïà ëåãèðîâàíèÿ êóïðàòîâ ñïåðâà êâàçè-ñâîáîäíûå äûðêè, èìåþùèå ìàññó mb ïîÿâëÿþòñÿ â âàëåíòíîé çîíå êèñëîðîäà.  ïîëÿðíûõ êóïðàòàõ ýòè äûðî÷íûå íîñèòåëè çàðÿäà âçàèìîäåéñòâóþò êàê ñ êîëåáàíèÿìè ðåøåòêè òàê è ñ äåôåêòàìè êðèñòàëëè÷åñêîé ðåøåòêè (íàïðèìåð, ëåãèðóþùèå äîïàíòû èëè ïðèìåñè) è àâòîëîêàëèçóþòñÿ ëèáî âáëèçè äåôåêòîâ (íåñîáñòâåííàÿ àâòîëîêàëèçàöèÿ äåôåêòîâ) èëè â áåçäåôåêòíîé äåôîðìèðóåìîé ðåøåòêå (ñîáñòâåííàÿ àâòîëîêàëèçàöèÿ ôîíîíîâ). Òàêèì îáðàçîì, îñíîâíûå ñîñòîÿíèÿ òàêèõ äûðî÷íûõ íîñèòåëåé ÿâëÿþòñÿ èõ àâòîëîêàëèçîâàííûå (ò.å. ëîêàëèçîâàííûå íåñîáñòâåííûå è ñîáñòâåííûå ïîëÿðîííûå) ñîñòîÿíèÿ, ëåæàùèå â ýíåðãåòè÷åñêîé ùåëè ÏÇ êóïðàòîâ [8]. Áîëüøàÿ ñòåïåíü èîííîñòè êóïðàòîâ η = ε∝/ε0<<1 (ãäå ε∝ è ε0 ÿâëÿþòñÿ

196 ñîîòâåòñòâåííî âûñîêî÷àñòîòíûå è ñòàòè÷åñêèå äèýëåêòðè÷åñêèå ïîñòîÿííûå) óñèëèâàåò ïîëÿðíîå ýëåêòðîí-ôîíîííîå âçàèìîäåéñòâèÿ è ñêëîííîñòü ê îáðàçîâàíèþ ïîëÿðîíà. Äåéñòâèòåëüíî, îñíîâíûìè íîñèòåëÿìè çàðÿäà â äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ ÿâëÿþòñÿ áîëüøèå ïîëÿðîíû [8,9] è ñèëüíûå ýëåêòðîíôîíîííûå âçàèìîäåéñòâèÿ ÿâëÿþòñÿ îòâåòñòâåííûìè çà âîçðàñòàíèå ìàññû ïîëÿðîíîâ ìàññû mp= (2-3) mb [10] (ãäå çîííàÿ ìàññà mb ðàâíà ìàññå ñâîáîäíîãî ýëåêòðîíà må). Îáðàçîâàíèå ïî÷òè ìàëîãî ïîëÿðîíà Ôðeëèõà [11] â êóïðàòàõ ïðåäñòàâëÿåòñÿ âîçìîæíûì. Ñîãëàñíî ðàáîòå [8], ýíåðãèÿ îñíîâíîãî ñîñòîÿíèÿ èëè ýíåðãèè ñâÿçè EIp íåñîáñòâåííûõ ïîëÿðîíîâ áóäåò áûñòðî âîçðàñòàòü ñ óìåíüøåíèåì å” îò 5 äî 3 èëè ñ óâåëè÷åíèåì η îò 0 äî _ (0.11-0.18) ý (äëÿ å = 3.5 - 4.5 è η = 0.12 è ðàâíî EIp ~ ” _ 0.12) è EIp ~ (0.086-0.14) ý (äëÿ ε∝ = 4 è η = 0-0.12).  òî âðåìÿ ýíåðãèè ñâÿçè Åð ñîáñòâåííûõ ïîëÿðîíîâ çàìåòíî _ óìåíüøàåòñÿ ñ óâåëè÷åíèåì η îò 0 äî 0.12 (ò.å. Åð ~ (0.085 - 0.065) ý äëÿ ε∝ = 4 è η = 0-0.12), íî E p óâåëè÷èâàåòñÿ îò 0.054 ý äî 0.09 ý ñ óìåíüøåíèåì ε∝ îò 4.5 äî 3.5 ïðè η = 0.10. Ìû ñ÷èòàåì, ÷òî íîñèòåëüäåôåêò-ôîíîííûå è íîñèòåëü-ôîíîííûå âçàèìîäåéñòâèè âìåñòå ñ íåîäíîðîäíîñòüþ ðàñïðåäåëåíèÿ çàðÿäîâ èãðàþò âàæíóþ ðîëü â äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ è ÿâëÿþòñÿ îòâåòñòâåííûìè çà ëîêàëèçàöèè è ñåãðåãàöèè íîñèòåëåé, êîòîðûå ìîãóò ïðîÿâëÿòüñÿ ÷åðåç ëîêàëüíîå (íàíîðàçìåðíîå) ðàçäåëåíèÿ ôàç â ðåàëüíîì ïðîñòðàíñòâå è îáðàçîâàíèÿ ïîëîñ (ñòðàéïîâ) (ò.å. ïîëÿðîííûå íîñèòåëè îáðàçóþò ìåòàëëè÷åñêèå äîìåíû, ðàçäåëåííûå äèýëåêòðè÷åñêèìè äîìåíàìè [8,12]).  ýòèõ ìàòåðèàëàõ, íåîäíîðîäíîå ïðîñòðàíñòâåííîå ðàñïðåäåëåíèå ïîëÿðîííûõ íîñèòåëåé ïðèâîäèò ê èõ ñåãðåãàöèè â áîãàòûõ è îáåäíåííûõ íîñèòåëÿìè îáëàñòÿõ. Óïîðÿäî÷åíèå ïîëÿðîííûõ íîñèòåëåé è îáðàçîâàíèå èõ ñâåðõðåøåòîê Òåïåðü îáñóäèì óïîðÿäî÷åíèå ïîëÿðîííûõ íîñèòåëåé, êîòîðûå ìîãóò ïðèâåñòè ê îáðàçîâàíèþ ðàçëè÷íûõ ñâåðõðåøåòîê (èëè ñóðåêñòðóêòóð) â ÂÒÑÏìàòåðèàëàõ. Ïðè óâåëè÷åíèè óðîâíÿ ëåãèðîâàíèÿ îò ñëàáîëåãèðîâàííîé îáëàñòè äî íåäîëåãèðîâàííîé îáëàñòè è ïðè óïîðÿäî÷åíèè íåñîáñòâåííûõ è ñîáñòâåííûõ ïîëÿðîíîâ, îáðàçóþòñÿ ðàçëè÷íûå ñâåðõðåøåòêè ýòèõ ïîëÿðîííûõ íîñèòåëåé ïðè èõ íåîäíîðîäíîì ïðîñòðàíñòâåííîì ðàñïðåäåëåíèè.  ÷àñòíîñòè, íåñîáñòâåííûå ïîëÿðîíû (ò.å. áîëüøèå ïîëÿðîíû çàõâà÷åííûå ïðèìåñÿìè) ìîãóò îáðàçîâûâàòü ñâåðõðåøåòêó ñ ïîñòîÿííîé ðåøåòêè à è êîîðäèíàöèîííûì ÷èñëîì z . Âîçìîæíî, óïîðÿäî÷åíèå òàêèõ ïîëÿðîííûõ íîñèòåëåé, ëîêàëèçîâàííûõ âáëèçè ïðèìåñåé ïðèâîäèò ê îáðàçîâàíèþ ïðîñòûõ êóáè÷åñêèõ, îáúåìíî-öåíòðèðîâàííîé êóáè÷åñêîé è ãðàíåöåíòðèðîâàííîé êóáè÷åñêèõ ñâåðõðåøåòîê ñ z = 6, 8 è 12, ñîîòâåòñòâåííî, è ê îáðàçîâàíèþ ðàçëè÷íûõ ýíåðãåòè÷åñêèõ çîí â ùåëè ÏÇ êóïðàòîâ. Øèðèíà ýòèõ ýíåðãåòè÷åñêèõ çîí ìîæåò áûòü îïðåäåëåíà â ïðèáëèæåíèè ñèëüíîé ñâÿçè èç ñîîòíîøåíèÿ

, ãäå

(1)

èíòåãðàë ïåðåñêîêà ìåæäó

áëèæàéøèìè (ñîñåäÿìè) ïðèìåñíûìè öåíòðàìè, m* ìàññà íåñîáñòâåííûõ ïîëÿðîíîâ.  îáåäíåííûõ íîñèòåëÿìè îáëàñòÿõ, ïðîâîäèìîñòü âîçìîæíà â óçêîé ïðèìåñíîé çîíå, â êîòîðîé íåñîáñòâåííûå ïîëÿðîíû ïåðåñêàêèâàþò îò îäíîãî ïðèìåñíîãî öåíòðà íà äðóãîé ïðèìåñíîé öåíòð. Òîãäà êàê, ìåõàíèçì ïåðåíîñà çàðÿäîâ â áîãàòûõ íîñèòåëÿìè îáëàñòÿõ (ò.å. â äîñòàòî÷íî øèðîêîé ïðèìåñíîé çîíå, ëåæàùåé â ùåëè ÏÇ êóïðàòîâ, êàê ïîêàçàíî íà Ðèñ. 1à) ñòàíîâèòñÿ çîííûì äâèæåíèåì íîñèòåëåé. Îïðåäåëåíèå êðèòè÷åñêîãî óðîâíÿ ëåãèðîâàíèÿ n=nc, ïðè êîòîðîì ïåðåõîä èçîëÿòîð-ìåòàëë (èëè ÌÄÏ) ïðîèñõîäèò â êóïðàòàõ î÷åíü ñëîæíàÿ ïðîáëåìà, êîòîðàÿ îñòàåòñÿ íåðåøåííîé äî ñèõ ïîð. Ìîæíî îæèäàòü, ÷òî ñîáñòâåííûå áîëüøèå ïîëÿðîíû àíàëîãè÷íî êàê íåñîáñòâåííûå ïîëÿðîíû (ïðèìåñíûå öåíòðû) îáðàçóþò ðàçíûå ñâåðõðåøåòêè è øèðèíû ïîëÿðîííûõ çîí îïðåäåëÿåòñÿ èç ñîîòíîøåíèÿ ,

(2)

ãäå Jp ÿâëÿåòñÿ èíòåãðàëîì ïåðåñêîêà, êîòîðûé îïðåäåëÿåòñÿ èç

, m p ìàññà

ñîáñòâåííûõ ïîëÿðîíîâ, à ð ïîñòîÿííàÿ ðåøåòêè ïîëÿðîííîé ñâåðõðåøåòêè.

Ðèñ. 1. a) Ñõåìàòè÷åñêàÿ çîííàÿ ñòðóêòóðà (ïëîòíîñòü ñîñòîÿíèé êàê ôóíêöèÿ ýíåðãèè ε) íåëåãèðîâàííûõ êóïðàòîâ. LHB: íèæíÿÿ çîíà Õàááàðäà. UHB: âåðõíÿÿ çîíà Õàááàðäà. OVB: âàëåíòíàÿ çîíà êèñëîðîäà. I: ïðèìåñíàÿ (äåôåêòíàÿ) çîíà. εF ýíåðãèÿ Ôåðìè ïðèìåñíîé çîíû. b) Ñõåìàòè÷åñêàÿ çîííàÿ ñòðóêòóðà (ïëîòíîñòü ñîñòîÿíèé êàê ôóíêöèÿ ýíåðãèè ε) íåëåãèðîâàííûõ êóïðàòîâ. P: ïîëÿðîííàÿ çîíà. εF ýíåðãèÿ Ôåðìè ïîëÿðîííîé çîíû.

 ñëó÷àå óçêèõ ïîëÿðîííûõ çîí, ïîëÿðîííûé òðàíñïîðò òàê æå, êàê è â ïðèìåñíîé çîíå ñòàíîâèòñÿ ïðûæêîâûì ÷òî âûçâàíî âíóòðèçîííûìè ïðûæêîâûìè ïðîöåññàìè [8,13]. Îäíàêî, ïðè îïðåäåëåííîì óðîâíå ëåãèðîâàíèÿ n = n c èëè x =x c =n c /n a (ãäå n a = 1 /V a

197 ïëîòíîñòü àòîìîâ êðèñòàëëè÷åñêîé ðåøåòêè, Va îáúåì çàíèìàåìûé ìîëåêóëîé CuO2 â êóïðàòàõ), øèðèíà çîíû áîëüøèõ ïîëÿðîíîâ (Ðèñ.1á) ïðåâûøàåò íåêîòîðîå êðèòè÷åñêîå çíà÷åíèå, âûøå êîòîðîãî ïîëÿðîííûé òðàíñïîðò ñòàíîâèòñÿ ìåòàëëè÷åñêèì. Íèæå ìû ïîïûòàåìñÿ íàéòè óñëîâèÿ, ïðè êîòîðûõ ÌÄÏ è íàíîðàçìåðíîå ðàçäåëåíèå ôàç ïðîèñõîäÿò â ëåãèðîâàííûõ êóïðàòàõ. Âîçìîæíûå ìåòàëë-äèýëåêòðèê ïåðåõîäû è íàíîðàçìåðíîå ðàçäåëåíèå ôàç  îòëè÷èå îò ìîòòîâñêîãî è àíäåðñîíîâñêîãî ìåõàíèçìîâ ëîêàëèçàöèè íîñèòåëåé, äðóãèå ìåõàíèçìû, òàêèå êàê ñèëüíûå íîñèòåëü-äåôåêò-ôîíîííûå è íîñèòåëü-ôîíîííûå âçàèìîäåéñòâèè ìîãóò òàêæå âûçâàòü ëîêàëèçàöèè íîñèòåëåé è ÌÄÏû â ëåãèðîâàííûõ êóïðàòàõ. Óñëîâèå ëîêàëèçàöèè èëè äåëîêàëèçàöèè íîñèòåëåé ìîæíî îïðåäåëèòü èñïîëüçóÿ ïðèíöèï íåîïðåäåëåííîñòè ∆p∆x ≥ ћ/2 (3) ãäå Δp è Δx ñîîòâåòñòâåííî íåîïðåäåëåííîñòè èìïóëüñà è êîîðäèíàòû íîñèòåëÿ. Âûøåïðèâåäåííîå ñîîòíîøåíèå íåîïðåäåëåííîñòè ìîæíî ïåðåïèñàòü â âèäå

,

(4)

ãäå ΔE è Δk íåîïðåäåëåííîñòè â ýíåðãèè è âîëíîâîì âåêòîðå íîñèòåëÿ. Âûðàæåíèå

(8) è (9) Òîãäà ïîëó÷èì ñëåäóþùèå êðèòåðèè äëÿ íîâûõ ÌÄÏîâ èç ñîîòíîøåíèé (6) è (7): (10) è (11) Äëÿ ïðîñòîé êóáè÷åñêîé, îáúåìíî-öåíòðèðîâàííîé è ãðàíåöåíòðèðîâàííîé êóáè÷åñêîé ñâåðõðåøåòîê ñ z= 6, 8 è 12, ïîñòîÿííûå ðåøåòêè ìîãóò áûòü îïðåäåëåíû ñîîòâåòñòâåííî èç ñîîòíîøåíèé 2R=a (èëè 2Rp=ap), (èëè (èëè

è .

 ñëó÷àå ïðîñòîé êóáè÷åñêîé ñâåðõðåøåòêè ïîëÿðîíîâ, âûðàæåíèÿ (10) è (11) ìîæíî ïåðåïèñàòü â âèäå

â

óðàâíåíèå (4) ïðåäñòàâëÿåò íåîïðåäåëåííîñòü êèíåòè÷åñêîé ýíåðãèè íåñîáñòâåííûõ ïîëÿðîíîâ. Ñ äðóãîé ñòîðîíû, â ïðèìåñíîé çîíå íåîïðåäåëåííîñòü êèíåòè÷åñêîé ýíåðãèè íîñèòåëåé ïîðÿäêà ýíåðãèè Ôåðìè εIF ïîëÿðîííûõ íîñèòåëåé è íåîïðåäåëåííîñòü â èõ âîëíîâîì âåêòîðå ñîñòàâëÿåò îêîëî 1/à. Òàêèì îáðàçîì, ñîîòíîøåíèå (4) ìîæåò áûòü çàïèñàíî â âèäå (5) Äàëåå, íåîïðåäåëåííîñòü ýíåðãèè ΔE áîëüøîãî ïîëÿðîíà ñâÿçàííàÿ ñ ïðèìåñüþ ñîñòàâëÿåò ïîðÿäîêà EIp, à íåîïðåäåëåííîñòü êîîðäèíàòû Δx ýòîãî íîñèòåëÿ ñîñòàâëÿåò ïîðÿäêà ðàäèóñà ïðèìåñíîãî öåíòðà R. Òàêèì îáðàçîì, óñëîâèå ëîêàëèçàöèè íîñèòåëåé èëè íîâîãî ÌÄÏ ìîæåò áûòü çàïèñàíî â âèäå (6) Òî÷íî òàê æå, ÌÄÏ ìîæåò òàêæå îáóñëîâëåí ñèëüíûì íîñèòåëü-ôîíîííûì âçàèìîäåéñòâèåì è êðèòåðèé äëÿ òàêîãî ÌÄÏ ìîæíî çàïèñàòü â âèäå ,

Ýíåðãèÿ Ôåðìè íåñîáñòâåííûõ è ñîáñòâåííûõ ïîëÿðîíîâ äàþòñÿ âûðàæåíèÿìè

(7)

ãäå ε F ýíåðãèÿ Ôåðìè ñîáñòâåííûõ áîëüøèõ ïîëÿðîíîâ, Rp ðàäèóñ ýòèõ ïîëÿðîíîâ. Ðàññìîòðèì òåïåðü âîïðîñ î âîçìîæíîñòè âûøåóêàçàííûõ íîâûõ ÌÄÏîâ â ëåãèðîâàííûõ êóïðàòàõ.

è

(12)

(13) Ìîæíî îöåíèòü xc1 è xc2 ïîëîãàÿ, ÷òî m* ~_ 2.2me è mp ~_ 2me äëÿ äûðî÷íî-ëåãèðîâàííûõ êóïðàòîâ. Äàëåå ìû èñïîëüçóåì ðàñ÷èòàííûå çíà÷åíèÿ EIp ~_ (0.103 - 0.130) ý (ïðè ε∝= 4 è η = 0.04 - 0.10), Ep ~_ (0.068 - 0.078) ý (ïðè ε∝ = 4 è η = 0.04 - 0.10) äëÿ La2 - xSrxCuO4 (LSCO) è EIp ~_ (0.135 - 0.171) ý (ïðè ε∝ = 3.5 è η = 0.04 - 0.10), Ep ~_ (0.090 - 0.102) ý (ïðè ε∝ = 3.5 è η = 0.04 - 0.10) äëÿ YBa2Cu3O7- δ (YBCO) [8]. Ïðèíèìàÿ âî âíèìàíèå, ÷òî ñîîòâåòñòâóþùèå çíà÷åíèÿ Va â LSCO è YBCO ïðèáëèçèòåëüíî ðàâíû 190A3 è 100A3, ìû ïîëó÷àåì na ~_ 0.53·1022 ñì-3 (äëÿ LSCO) è n a ~_ 10 22 ñì -3 (äëÿ YBCO). Èñïîëüçóÿ ïðèâåäåííûå âûøå çíà÷åíèÿ ïàðàìåòðîâ (m*, mp, EIp, E p è n a ), ìû íàõîäèì çíà÷åíèÿ êðèòè÷åñêèõ êîíöåíòðàöèè xc1 ~_ 0.092 - 0.130 è xc2 ~_ 0.043 - 0.052 äëÿ LSCO è xc1 ~_ 0.073 - 0.104 è xc2 ~_ 0.034 - 0.042 äëÿ YBCO. Ýòè ðåçóëüòàòû íàõîäÿòñÿ â ðàçóìíîì ñîãëàñèè ñ ñóùåñòâóþùèìè ýêñïåðèìåíòàëüíûìè äàííûìè ïî ÌÄÏàì è íàíîðàçìåðíûì ðàçäåëåíèÿì ôàç (ò.å. îáðàçîâàíèþ ñòðàéïîâ) â ëåãèðîâàííûõ êóïðàòàõ (ñì.

[3, 6, 14,15]).

198 Âèäíî, ÷òî â íåîäíîðîäíûõ äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ ÌÄÏû è íàíîðàçìåðíûå ðàçäåëåíèÿ ôàç â áîãàòûõ íîñèòåëÿìè ìåòàëëè÷åñêèõ (ïðè õ ≥ xc1, õñ2) è îáåäíåííûìè íîñèòåëÿìè äèýëåêòðè÷åñêèõ (ïðè õ < xc1, xc2) îáëàñòÿõ ìîãóò ïðîèñõîäèòü â øèðîêîì äèàïàçîíå êîíöåíòðàöèè äûðîê íà÷èíàÿ îò õ~0.03 (ñëàáîëåãèðîâàííàÿ îáëàñòü) äî õ~0.13 (íåäîëåãèðîâàííàÿ îáëàñòü, âêëþ÷àÿ “ìàãè÷åñêîå ëåãèðîâàíèå õ = 1/8”). Èç ïðèâåäåííûõ âûøå ðåçóëüòàòîâ ñëåäóåò, ÷òî ìåòàëëè÷åñêèå è äèýëåêòðè÷åñêèå ôàçû â ýòèõ ìàòåðèàëàõ ñîñóùåñòâóþò ïðè çíà÷åíèÿõ ëåãèðîâàíèÿ ëåæàùèõ â èíòåðâàëå 0.035 ≤ õ ≤ 0.130 è ïîäàâëåíèå ñâåðõïðîâîäèìîñòè äîëæíî ïðîèñõîäèòü â íåäîëåãèðîâàííûõ êóïðàòàõ ïðè çíà÷åíèè ëåãèðîâàíèÿ îêîëî õ = 1/8(=0.125) èç-çà óâåëè÷åíèÿ äèýëåêòðè÷åñêèõ îáëàñòåé ïðè õ <0.13.

Âûâîäû

Íàìè èçó÷åíû íîâûå ìåõàíèçìû ÌÄÏîâ è íàíîðàçìåðíîãî ðàçäåëåíèÿ ôàç â íåîäíîðîäíûõ äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ è ïðåäëîæåíû êîëè÷åñòâåííûå òåîðåòè÷åñêèå îïèñàíèÿ ýòèõ âçàèìîñâÿçàííûõ ÿâëåíèé. Ïðè ýòîì ïðåäïîëàãàëîñü, ÷òî îñíîâíûìè íîñèòåëè çàðÿäà â ýòèõ ëåãèðîâàííûõ ìîòò-õàááàðäîâñêèõ äèýëåêòðèêàõ ÿâëÿþòñÿ íåñîáñòâåííûå è ñîáñòâåííûå áîëüøèå ïîëÿðîíû è ñèëüíûå íîñèòåëü-äåôåêò (äîïàíò)-ðåøåòî÷íûå è íîñèòåëü-ðåøåòî÷íûå âçàèìîäåéñòâèÿ âìåñòå ñ íåîäíîðîäíîñòÿìè ðàñïðåäåëåíèÿ íîñèòåëåé çàðÿäà ÿâëÿþòñÿ îòâåòñòâåííûìè çà ëîêàëèçàöèè è ñåãðåãàöèè íîñèòåëåé, óïîðÿäî÷åíèå ïîëÿðîííûõ íîñèòåëåé, îáðàçîâàíèþ óçêèõ ïðèìåñíûõ è ïîëÿðîííûõ çîí â ùåëè ÏÇ êóïðàòîâ, íîâûå ÌÄÏû è íàíîðàçìåðíûå ðàçäåëåíèÿ ôàç íà äèýëåêòðè÷åñêèå (îáåäíåííûå íîñèòåëÿìè) è ìåòàëëè÷åñêèå (áîãàòûå íîñèòåëÿìè) îáëàñòè â âèäå ñòàòè÷åñêèõ è äèíàìè÷åñêèõ ïîëîñ (ñòðàéïîâ). Íàøè ðåçóëüòàòû ïîêàçûâàþò, ÷òî â LSCO è YBCO íîâûå ÌÄÏû âîçìîæíû êàê â ñèëüíî íåäîëåãèðîâàííûõ (õ ≈ 0.03 – 0.05) òàê è â óìåðåííî íåäîëåãèðîâàííûõ (õ ≈ 0.05 – 0.13) êóïðàòàõ. ßñíî, ÷òî ïîäàâëåíèå ñâåðõïðîâîäèìîñòè (ò.å. òàê íàçûâàåìàÿ 1/ 8 àíîìàëèÿ) â äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ âûçâàíû ÌÄÏàìè è îáðàçîâàíèåì äèýëåêòðè÷åñêèõ è ìåòàëëè÷åñêèõ ïîëîñ (íàíîðàçìåðíûå ðàçäåëåíèÿ ôàç).  ýòèõ ñèñòåìàõ ìåòàëëè÷åñêèå è äèýëåêòðè÷åñêèå ïîëîñû ñîñóùåñòâóþò ïðè õ ≈ 0.03-0.13. Íàøè òåîðåòè÷åñêèå ïðåäñêàçàíèÿ ñîãëàñóþòñÿ ñ ýêñïåðèìåíòàëüíûìè äàííûìè íà ÌÄÏàì è îáðàçîâàíèþ ñòðàéïîâ â LSCO è YBCO. Ýòà ðàáîòà ïîääåðæàíà ãðàíòîì “Ô2- ÔA-Ô120” Àêàäåìèè íàóê Ðåñïóáëèêè Óçáåêèñòàí.

Ëèòåðàòóðà: 1. T. Kato, T. Noguchi, R. Saito, T. Machida and H. Sakata: Gap distribution in overdoped La2-xSrxCuO4 observed by scanning tunneling spectroscopy, Physica C 460-462 (2007) 880.

2. S. Dzhumanov, O.K. Ganiev, Sh.S. Djumanov: Pseudogap formation and unusual quasiparticle tunneling in cuprate superconductors: Polaronic and multiple-gap effects on the tunneling spectra, Phys. B. 427 (2013) 22.

3. M. Imada, A. Fujimori, Y. Tokura: Metal-insulator transitions, Rev. Mod. Phys. 70 (1998) 1039.

4. P. Phillips: Colloquium: Identifying the propagating charge modes in doped Mott insulators, Rev. Mod. Phys. 82 (2010) 1719.

5. S. Dzhumanov. Theory of Conventional and Unconventional Superconductivity in the High-Tc Cuprates and Other Systems, 2013, New York: Nova Science Publishers.

6. M. Hücker, G.D. Gu, J.M. Tranquada, M.V. Zimmermann, H.-H. Klauss, N.J. Curro, M. Braden, B. Büchner: Coupling of stripes to lattice distortions in cuprates and nickelates, Physica C 460462 (2007) 170; S. Strässle, J. Roos, M. Mali, K. Conder, E. Pomjakushina, H. Keller: 139La NMR and NQR investigations of the superconductor LaBa2Cu3O7"ä, Physica C 460-462 (2007) 890.

7. A.N. Pasupathy, A. Pushp, K. K. Gomes, C. Parker, J.Wen, Z. Xu, G. Gu, S. Ono, Y. Ando, A. Yazdani: Electronic origin of the inhomogeneous pairing interaction in the high-Tc superconductor Bi2Sr2CaCu2O8+ä, Science 320 (2008) 196.

8. S. Dzhumanov, P.J. Baimatov, O.K. Ganiev, Z.S. Khudayberdiev, B.V. Turimov: Possible mechanisms of carrier localization, metal–insulator transitions and stripe formation in inhomogeneous hole-doped cuprates, J. Phys. Chem. Solids 73 (2012) 484.

9. D. Emin. Polarons, 2013, Cambridge University Press, Cambridge.

10. D.N. Basov, T. Timusk: Electrodynamics of high-Tc superconductors, Rev. Mod. Phys. 77 (2005) 721.

11. A.S. Alexandrov, P.E. Kornilovitch: Mobile small polaron, Phys. Rev. Lett. 82 (1999) 807; A.S. Alexandrov, B.Y. Yavidov: Small adiabatic polaron with a long-range electron-phonon interaction, Phys. Rev. B 69 (2004) 073101.

12. S. Dzhumanov, E.X. Karimboev, U.T. Kurbanov, O.K. Ganiev, Sh.S. Djumanov: Temperature-independent pseudogap and thermally activated c-axis hopping conductivity in layered cuprate superconductors, Superlattices and Microstructures, 68 (2014) 6.

13. F.Walz: The Verwey transition - a topical review, J. Phys.: Condens. Matter 14 (2002) R285.

14. N. Ichikawa, S. Uchida, J.M. Tranquada, T. Niemöller, P.M. Gehring, S.- H. Lee, J.R. Schneider: Local Magnetic Order vs Superconductivity in a Layered Cuprate, Phys. Rev. Lett. 85 (2000) 1738.

15. S. Komiya, Y. Ando, X.F. Sun, A.N. Lavrov: c-axis transport and resistivity anisotropy of lightly to moderately doped La2"xSrxCuO4 single crystals: Implications on the charge transport mechanism, Phys. Rev. B 65 (2002) 214535.

199

metal-dieleqtrikuli gadasvlebi da fazebis nanozomiseuli gancalkeveba xvr elurad legir ebul xvrelurad legirebul kupratebSi u. yurbanovi, z. xudaiberdievi, e. karimbaevi, s. jumanovi

uzbekeTis respublikis mecnierebaTa akademiis birTvuli fizikis instituti, 100214, taSkenti, uzbekeTi el-fosta: ukurbanov@inp.uz, dzhumanov@inp.uz Seswavlilia metal-dieleqtrikze SesaZlebeli gadasvlebis meqanizmebi da nanozomebis fazebis gancalkeveba gareSe da Sinagani didi polaronebis sazRvrebSi. SemoTavazebulia aRniSnuli urTierTmonaTesave movlenebis erTiani aRwera. migvaCnia, rom arsebuli muxtis matareblebi, aseT polarul masalebSi warmoadgenen did, gareSe (minarevTan bmuli) da Sinagan polaronebs. naCvenebia, rom muxtis matarebeli-defeqti-fononisa da muxtis matarebeli-fononis Zlieri urTierTqmedebebi, muxtebis araerTgvarovnebasTan erToblivad, vlindebian muxtis matareblebis lokalizaciaSi, polaronuli matareblebis mowesrigebaSi sxvadasxva zemesrisa da polaronuli zonebis formirebiT, nanozomebis fazuri gancalkevebiT, rasac Tan sdevs zolebis formireba sustad da Zlierad legirebul kupratebSi. naCvenebia, rom legirebul La2-xSrxCuO4 da YBa2Cu3O7- δ kupratebSi statikuri(saizolacio) da dinamiuri (metaluri) zolebi Tanaarseboben legirebis X = 0,03-0, 13 intervalSi. Cveni Sedegebi raodenobrivad TanxvedraSia eqsperimentul monacemebTan mocemul, maRali Tc-s masalebSi.

Possible metal-insulator transitions and nanoscale phase separation in hole-doped cuprates U. Kurbanov, Z. Khudaiberdiev, E. Karimbaev, S. Dzhumanov Institute of Nuclear Physics of Uzbekistan Academy of Science, 100214, Tashkent, Uzbekistan, E-mail: ukurbanov@inp.uz, dzhumanov@inp.uz We study the possible mechanisms of metal-insulator transitions (MITs) and nanoscale phase separation in hole-doped cuprates within the extrinsic and intrinsic large polarons and propose a unified description of these interrelated phenomena. We argue that the relevant charge carriers in these polar materials are extrinsic (impurity-bound) and intrinsic large polarons. We show that the strong carrier-defect-phonon and carrier-phonon interactions together with the charge inhomogeneities result in the carrier localization, the ordering of polaronic carriers with the formation of different superlattices and polaronic bands, the MITs and nanoscale phase separation, which are accompanied by the stripe formation in the lightly to underdoped cuprates. We demonstrate that in doped cuprates La2-xSrxCuO4 and YBa2Cu3O7-ä the static (insulating) and dynamic (metallic) stripes coexist in the doping range x = 0.03-0.13. Our results are in quantitative agreement with experimental findings in these high-Tc materials.

200

Íèçêîòåìïåðàòóðíûé ìåòîä ïîëó÷åíèÿ íàíîïëåíîê GaN À. Áèáèëàøâèëè, Ð. Ãóëÿåâ, Í. Äîëèäçå, Ã. Ñõèëàäçå, Ç. Äæèáóòè Èíñòèòóò ìèêðî - è íàíîýëåêòðîíèêè, ïð. È. ×àâ÷àâàäçå, 13, 0179 Táèëèñè, Ãðóçèÿ, Ýë–ïî÷òà:amiran.bibilashvili@tsu.ge Ðåçþìå: ðàáîòå ïîêàçàíà âîçìîæíîñòü ïîëó÷åíèÿ íàíîïëåíîê GaN ïðè îòíîñèòåëüíî íèçêèõ òåìïåðàòóðàõ (300-7000Ñ) ìåòîäîì ìàãíåòðîííîãî ðàñïûëåíèÿ ãàëëèÿ â àòìîñôåðå àçîòà, ñ ïîñëåäóþùèì èìïóëüñíûì ôîòîííûì îòæèãîì. Ïîêàçàíî, ÷òî èìïóëüñíûé ôîòîííûé îòæèã ôîðìèðóåò ïîëèêðèñòàëëè÷åñêèå âêðàïëåíèÿ â èçíà÷àëüíî àìîðôíîì íèòðèäå ãàëëèÿ.

Êëþ÷åâûåñëîâà:Íèòðèä ãàëëèÿ, âûñîêî÷àñòîòíàÿ ïëàçìà, ìàãíåòðîííîå ðàñïûëåíèå, èìïóëüñíûé ôîòîííûé îòæèã

Ââåäåíèå Íèòðèä ãàëëèÿ (GaN), êàê ìàòåðèàë, âûçûâàåò áîëüøîé èíòåðåñ ó÷eííûõ-èññëåäîâàòåëåé, ïîñêîëüêó ñîçäàííûå íà åãî îñíîâå ïðèáîðû èìåþò ìíîæåñòâî óíèêàëüíûõ ñâîéñòâ: âûñîêèé êîýôôèöèåíò óñèëåíèÿ, ñâåòîèçëó÷åíèå â øèðîêîì äèàïàçîíå ñïåêòðà, ñòàáèëüíàÿ è íàäeæíàÿ ðàáîòà â óñëîâèÿõ ïîâûøåííûõ òåìïåðàòóð è ðàäèàöèè. Âîçìîæíîñòü èçãîòîâëåíèÿ íà åãî îñíîâå øèðîêîçîííûõ áåñïðîâîäíûõ öåïåé, ìàëîãàáàðèòíûõ è íàäeæíûõ ðàäàðîâ àâèàöèîííîãî è êîñìè÷åñêîãî íàçíà÷åíèÿ, äåëàåò ýòîò ìàòåðèàë åùe áîëåå ïåðñïåêòèâíûì[1]. Ïîëó÷åíèå GaN â âèäå êðèñòàëëà çàòðóäíåíî èç-çà âûñîêèõ òåìïåðàòóð ïëàâëåíèÿ. Åãî ôîðìèðîâàíèå âîçìîæíî â óñëîâèÿõ âûñîêèõ òåìïåðàòóð è äàâëåíèé, ÷òî òðåáóåò ñëîæíóþ è äîðîãóþ àïïàðàòóðó è òåõíîëîãèþ. Âìåñòå ñ òåì, ïîëó÷åííûå ñòðóêòóðû àìîðôíûå, è äëÿ ïîëó÷åíèÿ ïîëèêðèñòàëëîâ íåîáõîäèìà ïîñëåäóþùàÿ âûñîêîòåìïåðàòóðíàÿ îáðàáîòêà (âûøå 10000Ñ). Âñe ýòî âìåñòå âçÿòîå çàòðóäíÿåò âíåäðåíèå äàííîãî ìàòåðèàëà â ïðîèçâîäñòâî. Ïî ýòîìó ïðåäïî÷òèòåëüíåå ïîëó÷åíèå GaN â âèäå ïëeíîê [2]. Òîíêèå ïëeíêè íàíîñòðóêòóð ÿâëÿþòñÿ íàíîñèñòåìàìè, â êîòîðûõ íàíîðàçìåðû ïðîÿâëÿþòñÿ òîëüêî â îäíîì íàïðàâëåíèé – ïî òîëùèíå, à îñòàëüíûå äâà íàïðàâëåíèÿ – ìèêðîðàçìåðíûå. Ýòî îáñòîÿòåëüñòâî äàeò âîçìîæíîñòü ñîçäàòü íà îñíîâå GaN áûñòðîäåéñòâóþùèå ïðèáîðû ðàçíîãî íàçíà÷åíèÿ. Ñóùåñòâóþò ðàçëè÷íûå ìåòîäû ïîëó÷åíèÿ íàíîïëeíîê: ìîëåêóëÿðíî-ëó÷åâàÿ èëè æèäêîñòíàÿ ýïèòàêñèÿ, ïàðàôàçîâîå õèìè÷åñêîå îñàæäåíèå (CVD), âûäåëåíèå èç êîëëîèäíûõ ðàñòâîðîâ è îñàæäåíèå, òåõíîëîãèÿ Ëåíãìþðà-Áëîíäæåòà, ïîëó÷åíèå èç ìåòàëîîðãàíè÷åñêîãî ðàñòâîðà ñ ïîìîùüþ õèìè÷åñêîé ðåàêöèè â ñîïðîâîæäåíèè ãàçîòðàíñïîðòà (MOCVD) è ò.ä.[3]. Âñå ýòè ìåòîäû èìåþò ñâîè ïîëîæèòåëüíûå è îòðèöàòåëüíûå ñòîðîíû.  ÷àñòíîñòè - âûñîêîòåìïåðàòóðíûå ïðîöåññû, à ïðè îòíîñèòåëüíî íèçêèõ òåìïåðàòóðàõ ïðîöåññ ïðîòåêàåò ñëèøêîì

íåòåõíîëîãè÷íî ìåäëåííî. Ïîýòîìó, æåëàòåëüíî íàéòè òåõíîëîãè÷åñêèé ìåòîä, êîòîðûé èñêëþ÷àåò ïîëíîñòüþ, èëè õîòÿ áû ÷àñòè÷íî, âûøå óïîìÿíóòûå íåäîñòàòêè. òàêîì ñëó÷àå, âîçìîæíî ïîëó÷èòü âûñîêîêà÷åñòâåííûå ïëeíêè è óñòàíîâèòü ôèçè÷åñêèå ìåõàíèçìû ïðîöåññîâ. Çíàíèå ìåõàíèçìîâ íåîáõîäèìî, ïîñêîëüêó êà÷åñòâî êàæäîãî ïîñëåäóþùåãî ñëîÿ ñèëüíî çàâèñèò îò êà÷åñòâà ïðåäûäóùåãî íàíåñeííîãî ñëîÿ.  íàñòîÿùåé ðàáîòå îïèñûâàåòñÿ ðàçðàáîòêà òåõíîëîãè÷åñêîãî ïðîöåññà ïîëó÷åíèÿ íàíîïëeíîê GaN ìåòîäîì ìàãíåòðîííîãî ðàñïûëåíèÿ ãàëëèÿ â àòìîñôåðå àçîòà, è ðåçóëüòàòû èññëåäîâàíèÿ âëèÿíèÿ ïîñëåäóþùåãî èìïóëüñíîãî ôîòîííîãî îòæèãà (ÈÔÎ) íà ïàðàìåòðû ïîëó÷åííîãî íàíîñëîÿ. Ïðåäëàãàåìûé òåõíîëîãè÷åñêèé ìåòîä íèçêîòåìïåðàòóðíûé è õàðàêòåðèçóåòñÿ âûñîêîé ñêîðîñòüþ ôîðìèðîâàíèÿ [4,5].

Ìàòåðèàë è ìåòîäèêè èçìåðåíèé Òåõíîëîãèÿ ïîëó÷åíèÿ íàíîïëåíîê.  ýêñïåðèìåíòàõ ïîëó÷åíèÿ íàíîñëîåâ GaN,â êà÷åñòâå ïîäëîæåê ïðèìåíÿëèñü ïëàñòèíû ñàïôèðà (Al2O3) ìàðêè 60Ñ250, ïîâåðõíîñòè êîòîðûõ äî íà÷àëà ýêñïåðèìåíòà î÷èùàëèñü õèìè÷åñêè ïî ñòàíäàðòíîé òåõíîëîãèè. Ôîðìèðîâàíèå íàíîïëåíîê GaN ïðîâîäèëîñü íà ìîäåðíèçèðîâàííîé âàêóóìíîé óñòàíîâêå - íà ìàãíåòðîíå äèàìåòðîì 100 ìì, ââèäå ìèøåíè, ïîìåùàëñÿ ãàëëèè (÷èñòîòà 99.998%), êîòîðûé ðàñïûëÿëñÿ â âûñîêî÷àñòîòíîé ïëàçìå àçîòà è íàïûëÿëñÿ íà ïîäëîæêó, ðàñïîëîæåííóþ âûøå ìàãíåòðîíà íà ðàññòîÿíèè 75 ìì, â ðàçëè÷íûõ óñëîâèÿõ òåõíîëîãè÷åñêèõ ïðîöåññîâ. Òåìïåðàòóðà ïîäëîæêè ñîñòàâëÿëà 300-5000Ñ, òîê ðàñïûëåíèÿ - I = 0,2-0.3À, íàïðÿæåíèå - U = -360Â, ìàêñèìàëüíîå âðåìÿ íàïûëåíèÿ t = 10ìèí.  ðåçóëüòàòå ïîëó÷àëèñü ïëåíêè òîëùèíîé â èíòåðâàëå 50÷55íì. Ïîä âàêóóìíûì êîëïàêîì, ïîñëå çàïóñêà ãàçîîáðàçíîãî àçîòà,

201 óñòàíàâëèâàëîñü äàâëåíèå P=6·10–4ìì ðò.ñò. Ïîñëå îêîí÷àíèÿ ïðîöåññà íàïûëåíèÿ ïðîâîäèëñÿ ÈÔÎ â ðàçëè÷íûõ ðåæèìàõ. Èìïóëüñíûé ôîòîííûé îòæèã î ñóùåñòâëÿëñÿ íà îðèãèíàëüíîé óñòàíîâêå èìïóëüñíîãî ôîòîííîãî îáëó÷åíèÿ (ÓÈÔÎ) (ðèñ.1), ïîçâîëÿþùåãî: îáëó÷àòü îáðàçöû ñ îáåèõ ñòîðîí; ìåíÿòü ñïåêòðàëüíûé ñîñòàâ îáëó÷åíèÿ â øèðîêîì ýíåðãåòè÷åñêîì äèàïàçîíå: 0,3 – 6,2 ýÂ;ìåíÿòü ïëîòíîñòü ìîùíîñòè èçëó÷åíèÿ(W) è äëèòåëüíîñòü ñâåòîâîãî èìïóëüñà (t)äî W= 375 Âò.ñì-2 è îò t=0,1 äî 1000 ñåê, øàãîì 0,1 ñåê, ñîîòâåòñòâåííî; èçìåðÿòü è ðåãóëèðîâàòü òåìïåðàòóðó íàãðåâà îáðàçöîâ ñ ïîìîùüþ ïîäáîðà äåðæàòåëåé ñ ðàçëè÷íîé òåïëîïðîâîäíîñòüþ, óäàëåíèåì íàãðåòîãî âîçäóõà èëè ïðîäóâîì ïàðàìè æèäêîãî àçîòà; ðàáîòàòü â ñðåäå êèñëîðîäà èëè èíåðòíûõ ãàçîâ.

Ðèñ.1. ñõåìà óñòàíîâêè ÈÔÎ

Äëÿ ïðîâåäåíèÿ ïðîöåññîâ êðèñòàëëèçàöèè îáðàçöû ïîìåùàëèñü íà êâàðöåâóþ ïëàñòèíó â óñòàíîâêå ÈÔÎ. Èìïóëüñíûé ôîòîííûé îòæèã ñ öåëüþ êðèñòàëëèçàöèè ïîëó÷åííûõ ïëeíîê GaN ïðîâîäèëñÿ â ñëåäóþùèõ ðåæèìàõ: ïëîòíîñòü ìîùíîñòè –60-100 Âò/ñì 2 ; äëèòåëüíîñòü èìïóëüñà – 5-20 ñåê; ìàêñèìàëüíàÿ òåìïåðàòóðà íàãðåâà îáðàçöà - 700 0C. ïðîöåññå ýêñïåðèìåíòà ãîòîâûå ñòðóêòóðû (GaN/Al2O3) è îòäåëüíûå ïîäëîæêè ñàïôèðà îäíîâðåìåííî ïîäâåðãàëèñü ÈÔÎ. Èçìåðåíèå øåðîõîâàòîñòè ïîâåðõíîñòè ïðîâîäèëîñü íà óñòàíîâêå ALPHA STEP-200 PROFILOMETER. Ýòî óñòðîéñòâî ÿâëÿåòñÿ ìåõàíè÷åñêèì ïðîôèëîìåòðîì, êîòîðûé èçìåðÿåò ðåëüåô ïëeíêè ñ ïîìîùüþ ìåõàíè÷åñêîãî ïåðåìåùåíèÿ èãëû ïî ïîâåðõíîñòè. Äèàìåòð èãëû ñîñòàâëÿë 12 ìêì, à íàæèì ïðè ñîïðèêîñíîâåíèé ≈ 8.5 ìã. Èçìåðåíèÿ òîëùèíû ïëeíîê ïðîâîäèëèñü ñ ïîìîùüþ èíòåðôåðîìåòðà NANOSPEC è îïòè÷åñêîãî ìèêðîñêîïà Leitz.Äàííàÿ óñòàíîâêà äàeò âîçìîæíîñòü èçìåðèòü òîëùèíû â èíòåðâàëå 100A - 30000A, ñ ïîãðåøíîñòüþ èçìåðåíèÿ 3-5%. Óñòàíîâêà ÿâëÿåòñÿ ìèêðîýëåêòðîìåòðîì, ðàáîòàþùåì â äèàïàçîíå 4008000íì. Ðåíòãåíîñòðóêòóðíûé àíàëèç ïðîâîäèëñÿ íà ðåíòãåíîâñêîì äèôðàêòîìåòðå ÄÐÎÍ–4. Ðàáî÷èé ðåæèì ñîñòàâëÿë: íàïðÿæåíèå - V=19êÂ; òîê - I=15ìÀ;

ñêîðîñòü ïåðåäâèæåíèÿ ãîíèîìåòðà –50 â ìèí; äèàïàçîí èçìåðåíèÿ 4·103 èìï/ì. Èçëó÷àòåëåì èñïîëüçîâàëàñü êîáàëüòîâàÿ òðóáêà (λ=1.7889Å). Êîëëèìàöèÿ ëó÷à îáåñïå÷èâàëàñü 3 îòâåðñòèÿìè øèðèíîé 1 ìì. Ñïåêòðû îïòè÷åñêîãî ïðîïóñêàíèÿ ñíèìàëèñü íà äâóõ ñïåêòðîìåòðàõ: Agilent 8453 –UV-VIS(äèàïàçîí äëèí âîëí 190-1100 íì), è Varian 660 FT-IR speqtrometerVIS(äèàïàçîí äëèí âîëí 6000-400 íì). Òàêèì îáðàçîì, óñòàíîâêè îáåñïå÷èâàëè ñíèìàòü ñïåêòðû ïîëó÷åííûõ íàíîïëeíîê â øèðîêîì äèàïàçîíå äëèí âîëí îò 190 äî 6000 íì (0.2 ÷ 6.5 ýÂ)

Ðåçóëüòàòû Íà ðèñ. 2. ïîêàçàíû ðåçóëüòàòû èññëåäîâàíèÿ øåðîõîâàòîñòè ïîâåðõíîñòè ñàïôèðà äî è ïîñëå íàíåñåíèÿ íàíîïëeíêè íèòðèäà ãàëëèÿ. Êàê âèäíî èç ðèñóíêà ýòîò ïàðàìåòð ïî÷òè íå ìåíÿåòñÿ.

à)

á) Ðèñ.2. Ïðîôèëü ïîâåðõíîñòè ñàïôèðîâîé ïîäëîæêè äî (à) è ïîñëå (á) íàíåñåíèÿ íàíîïëeíêè íèòðèäà ãàëëèÿ

Ðèñ.3. Ðåíòãåíî-äèôðàêöèîííàÿ êàðòèíà ñòðóêòóðû GaN/ Al2O3 äî ÈÔÎ.

202 óâåëè÷åíèå â ïëeíêå öåíòðîâ ïîãëîùåíèÿ..

Ðèñ.4. Ðåíòãåíî-äèôðàêöèîííàÿ êàðòèíà ñòðóêòóðû GaN/ Al2O3 ïîñëå ïåðâîãî èìïóëüñàôîòîííîãî îòæèãà

Ðèñ.6. Çàâèñèìîñòü êîýôôèöèåíòà ïðîïóñêàíèÿ íàíîñëîÿGaN/Al2O3 îò äëèíû âîëíû (èíôðàêðàñíàÿ îáëàñòü): 1 – äî ÈÔÎ, 2 – ïîñëå ïåðâîãî èìïóëüñà ÔÎ è 3 – ïîñëå âòîðîãî èìïóëüñà ÔÎ.

Ðèñ.5. Ðåíòãåíî-äèôðàêöèîííàÿ êàðòèíà ñòðóêòóðû GaN/ Al2O3 ïîñëå âòîðîãî èìïóëüñà ôîòîííîãî îòæèãà

Èçìåðåíèÿ òîëùèí ïîëó÷åííûõ ïëeíîê ïîêàçàëè, ÷òî îíè ñîñòàâëÿþò 0.1÷0.15 ìêì. Íà ðèñ. 3-5 ïîêàçàíû ðåçóëüòàòû ðåíòãåíîäèôðàêöèîííûõ èçìåðåíèé. Êàê âèäíî èç ðåíòãåíîãðàìì, â íà÷àëå (äî ÈÔÎ), ãðàôèê ìîíîòîííûé è êàêèõ ëèáî èíòåðåñíûõ ïîëîñ íå íàáëþäàåòñÿ, õîòÿ, ìîæíî çàìåòèòü çàðîäûøè äâóõ áóäóùèõ ïîëîñ. Ïîñëå ïåðâîãî æå èìïóëüñà ôîòîííîãî îòæèãà, íà ðåíòãåíîãðàììå ÷eòêî âûðèñîâûâàåòñÿ ðåíòãåíî-äèôðàêöèîííûå ïîëîñû, ÷òî óêàçûâàåò íà ïîÿâëåíèå ïîëèêðèñòàëëè÷åñêèõ âêðàïëåíèé â ñëîå íèòðèäà. Äàëüíåéøèé ÈÔÎ åùe áîëüøå óâåëè÷èâàåò èíòåíñèâíîñòü ïîëîñ, ò.å. ìîæíî ïðåäïîëîæèòü, ÷òî ïîëèêðèñòàëëè÷åñêèå âêðàïëåíèÿ óâåëè÷èëèñü â ðàçìåðàõ. Íà ðèñ. 6. ïðèâåäåíû ñïåêòðû ïðîïóñêàíèÿ íàíîñòðóêòóðû GaN/Al 2O3, äî è ïîñëå ÈÔÎ. Äëÿ èñêëþ÷åíèÿ âëèÿíèÿ âêëàäà ñàïôèðà, ñïåêòðû íîðìèðîâàëèñü îòíîñèòåëüíî ïîäëîæêè. Êàê âèäíî èç ðèñóíêà 6, äî ôîòîííîãî âîçäåéñòâèÿ â îáðàçöå íàáëþäàåòñÿ ïîëíîå îïòè÷åñêîå ïðîïóñêàíèå (80-90%), òîãäà êàê, ïîñëå ïåðâîãî æå èìïóëüñà ÔÎ ÷eòêî âûðèñîâûâàþòñÿ 3 çàìåòíûå ïîëîñû ïîãëîùåíèÿ - - 2360 íì (0.52 ýÂ), 1454 íì (0.85 ýÂ) è 1279 íì (0.97 ýÂ). Ýòè ïîëîñû ñîõðàíÿþòñÿ è ïîñëå ïîñëåäóþùåãî èìïóëüñà ÔÎ.Ïðåäïîëîæèòåëüíî ýòè ïîëîñû äîëæíû áûòü ñâÿçàíû ñ ïîãëîùåíèåì íà ïîÿâèâøèõñÿ ïîñëå ÈÔÎ ïîëèêðèñòàëëè÷åñêèõ âêðàïëåíèÿõ (ñì.ðèñ. 3-5). Íå òðóäíî çàìåòèòü, ÷òî ïîñëå ÈÔÎ ïðîïóñêàíèå óìåíüøåíèÿ âî âñeì äèàïàçîíå, ÷òî óêàçûâàåò íà

Ñïåêòðû îïòè÷åñêîãî ïîãëîùåíèÿ â âèäèìîé è óëüòðàôèîëåòîâîé îáëàñòè ïîêàçàëè, ÷òî â äàííîì äèàïàçîíå äëèí âîëí ïî ñðàâíåíèþ ñ íà÷àëüíûìè, ïîñëå ÈÔÎ çàìåòíûõ èçìåíåíèé íå íàáëþäàåòñÿ. Íèçêîòåìïåðàòóðíîå ôîðìèðîâàíèå ïîëèêðèñòàëëè÷åñêîãî íèòðèäà ãàëëèÿ (òåìïåðàòóðà îáðàçöà ïðè ÈÔÎ íå ïðåâûøàëà 7000C), î÷åâèäíî, ñâÿçàíî ñ ìåõàíèçìîì îïèñàííûì â ðàáîòàõ [6-8], êîãäà ïðè ÈÔÎ îñíîâíóþ ðîëü èãðàåò íå òåìïåðàòóðà îáðàçöà, à çàðÿäîâîå ñîñòîÿíèå åãî ýëåêòðîííîé ïîäñèñòåìû, èçìåíÿþùåéñÿ ïîä âëèÿíèåì ôîòîíîâ ðàçíîé ýíåðãèè.

Çàêëþ÷åíèå

Òàêèì îáðàçîì, èñõîäÿ èç ðåçóëüòàòîâ èññëåäîâàíèé ìîæíî çàêëþ÷èòü, ÷òî ïðè íèçêèõ òåìïåðàòóðàõ (îêîëî 3000Ñ) âîçìîæíî ôîðìèðîâàíèåíàíîïëåíîê GaN òîëùèíîé 0.1÷0.15 ìêì, ñòðóêòóðà êîòîðûõ âíà÷àëå àìîðôíàÿ, îäíàêî ïîñëå èìïóëüñíîãî ôîòîííîãî îòæèãà â îïðåäåëeííûõ ðåæèìàõ(òåìïåðàòóðà îáðàçöà íå ïðåâûøàåò 7000C), â íèõ ïðîÿâëÿþòñÿ ïîëèêðèñòàëëè÷åñêèå âêðàïëåíèÿ, ðàçìåð êîòîðûõ óâåëè÷èâàåòñÿ ñ ïîñëåäóþùèìè èìïóëüñàìè ÔÎ.  ôîðìèðîâàíèè ïîëèêðèñòàëëè÷åñêîãî íèòðèäà ãàëëèÿ îñíîâíóþ ðîëü èãðàåò çàðÿäîâîå ñîñòîÿíèå åãî ýëåêòðîííîé ïîäñèñòåìû, èçìåíÿþùåéñÿ ïîä âëèÿíèåì ôîòîíîâ ðàçíîé ýíåðãèè. Íàïûëeííûé íàíîñëîé GaN ïîâòîðÿåò øåðîõîâàòîñòü ïîäëîæêè. Ðàáîòà âûïîëíåíà â ðàìêàõ ïðîåêòà ##FR/592/6160/13 íàöèîíàëüíîãî íàó÷íîãî ôîíäà Ãðóçèè èì. Øîòà Ðóñòàâåëè

Ëèòåðàòóðà: 1. G.A. Kachurin, S.G. Cherkova, V.A.Volodin, et al. // Semiconductors, 2006, 40, #1, 72; 2. I.E.Tyschenko, K.S.Zhuravliev, A.B.Talochkin, V.P.Popov. // Semiconductors, 2006, 40, #4,420;

203 3. Y. Kazanova, M. Fujii, Hayashi, K. Yamamoto. // Sol.St.Commun. 1996, 100, 227; 4. M.Fujii, A.Mimura, Hayashi, K.Yamamoto.// Appl. Phys. Lett., 1999, 75,184; 5. À.Í. Áëàóò-Áëà÷åâ «Ïîëèêðèñòàëëè÷åñêèå ïëåíêè íèòðòäà ãàëëèÿ, âûðàùåííûå ìàãíåòðîííûì ðàñïûëåíèåì», ÔÒÏ, 2001, òîì 35, âûï.6, ñò.718.

6. Ç.Â.Äæèáóòè, Í.Ä.Äîëèäçå, Ã.Ø.Íàðñèÿ, Ã.Ë.Ýðèñòàâè. Î âîçìîæíîñòè ïîíèæåíèÿ òåìïåðàòóð îòæèãà ðàäèàöèîííûõ äåôåêòîâ â èìïëàíòèðîâàííîì èîíàìè êàðáèäå êðåìíèÿ. Ïèñüìà â ÆÒÔ, 1997,23,19,26-30.

7. N.D.Dolidze, Z.V.Jibuti, V.N.Mordkovich, B.E.Tsekvava.

About the Electronic Mechanism of Melting of Semiconductors. // GEN, ¹4, 84-87, 2005.

8. S. A. Avsarkisov, Z. V. Jibuti, N. D. Dolidze, and B. E. Tsekvava. Laser Stimulated Low-Temperature Crystallization of Amorphous Silicon. // Technical Physics Letters, 2006, Vol. 32, No. 3, pp. 259–261.

Low-Temperature Method of Formation of GaN Nanofilms A. Bibilashvili, R.Gulyaev, N.Dolidze, G.Skhiladze, Z.Jibuti Institute of Micro- and Nanoelectronics, 13, Chavchavadzeave., 0179, Tbilisi, Georgia E-mail: amiran.bibilashvili@tsu.ge The possibility of formation of GaN nanofilms at relatively low temperatures (300-700oC) by magnetron sputtering of gallium in the atmosphere of nitrogen followed by a pulsed photon annealing is reported. It is shown that the pulsed photon annealing produces polycrystalline inclusions in the initially amorphous gallium nitride

GaN nanofirebis miRebis dabaltemperaturuli meTodi a. bibilaSvili, r. gulievi, n. doliZe, g. sxilaZe, z. jibuti

mikro da nanoeleqtronikis instituti, i.WavWavaZis prosp. 13, 0179, Tbilisi, saqarTvelo el–fosta: amiran.bibilashvili@tsu.ge naSromSi naCvenebia GaN–is nanofirebis miRebis SesaZlebloba SedarebiT dabal temperaturebze (300-7000C) azotis atmosferoSi galiumis magnetronuli gafrqvevis da Semdgomi impulsuri fotonuri gamowvis saSualebiT. naCvenebia, rom impulsuri fotonuri gamowva Tavidan amorful, galiumis nitridSi warmoSobs polikristalur CanarTebs.

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Fabrication and study of Alumina based matrix composite ceramics R. Chedia1,2, T. Kuchukhidze1, G. Bokuchava1, A. Khvadagiani3 , V. Gabunia1, N. Jalagonia1 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli Str., 0186, Tbilisi, Georgia Iv. Javakhishvili Tbilisi State University, P. Melikhishvili Institute of Physical and Organic Chemistry, 0186 Tbilisi, Georgia 3 State Military Scientific-Technical Center “Delta”, 0144, Tbilisi, Georgia E-mail:sipt@sipt.org 1 2

Abstract. In this study obtaining methods of matrix ceramic composites with different compositions by high temperature pressing technology have been discussed. Following ceramic composites have been obtained α-Al2O3-Y2O3-ZrO2, αAl2O3-SiC-MgO, α-Al2O3-B4C-Y2O3, α-Al2O3-WC-MxOy (where M is rare earth metals). Ceramic composites are obtained in hightemperature vacuum furnace with different temperature and pressure conditions. Received ceramics do not have open pores and their density reaches 99.5 % of TD. Keywords: ceramic matrix composite, α-Al2O3, high temperature furnace.

Introduction Ceramic matrix composites (CMC) are widely applied in many fields of science and technology thanks to their unique physical-mechanical properties. In practice, most widely used are composite ceramic materials which are characterized of high flexural strength, fracture toughness corrosion resistance, chemical inertness, biocompatability, etc.

Alumina-based ceramic materials are the cheapest, because aluminum is widely met in nature (~8 wt%) and the methods of its production are well developed. Improvement of the physical-mechanical properties of ceramics to a certain degree became possible by reducing the size of particles of sintered powders to nano sizes and reduction of the time of sintering, because during thermal treatment the grain sizes dramatically increase, which negatively affects their performance attributes. To raise the fracture toughness, doping of sintered powder composites with different compounds (MgO, ZrO2, SiC, etc.) is used; dopants represent grain size growth inhibitors, which facilitate the production of nanostructured ceramic materials. Fibers of different types of compounds of aligned structure improve resilience of ceramic matrix composites. Compounds of different structure (nanofibers, nanotubes, nanosheets, etc.) are known to improve the physical-mechanical properties of composite material. Fabricated cutting tools for machining steel based alloys, because they are characterized as longer tool life able to cut difficult to machine such as hardened steel nickel alloys. Ceramic composites based on Al2O3 are widely used as structural material for biomedical implants, which characterized with (~30 year) long-term biocompatibility [1-8].

Recently special attention is paid to reinforced ceramic composites with carbonaceous materials. Given the unique physical-mechanical properties of graphene, the

production of graphene-based ceramic matrix composites has been given much attention during the last decade.

Many examples of graphene-based oxide and non-oxide ceramic materials are currently known, from which it can be concluded that the incorporation of graphene into a material leads to a change in its physical-mechanical properties.

The results received for raising fracture toughness, flexural strength and electrical conduction in ceramics are impressive. Metal-graphene and ceramic-graphene composites are found to have a wide range of application [9-13].

Patent and scientific literature describe obtaining methods of matrix ceramic composites, which includes two basic process: preparation of powdery composites and high temperature consolidation in various furnace.

Many methods are used for powdery consolidation.

Including fellow methods such as high temperature, microwave, spark-plasma, Induction synthesis and etc [14-17].

Their high temperature consolidation under pressure gives guarantee that will be obtained materials which have practically TD. Recently hot pressing furnaces with various modification are used in scientific research and practice.

One of them is high temperature furnace OXY-GON with pressure system up to 30 T, It has been used for consolidation of powdery composites.

Materials and Methods Materials and reagents Obtained α-Al2O3 by hydrolyze of aluminum isopropoxide (800C) in alkaline condition, for further drying and annealing of the gel (1200 0C). Y(CH 3COO) 3. 4H2O, Mg(CH3COO)2.4H2O, ZrO(CH3COO)2.2H2O, Polyvinylalcohol, Polyethylene glycol purchased from Sigma-Aldrich.

209 Fabrication of powdery composites Pressing powdery composites obtained by grinding of α-Al2O3 and other components (ZrO2, SiC, TiC, B4C, WC and etc) powdery’s suspensions in nano mills, It was added 0.05-10 % (mass) additive as dissolved salt. Mass ration of balls and powdery was equal 4:1. Nano mills (FRITCH planetary mill Pulverisette 7 premium line and RETCH PM 100) were used for grinding. Grinding process depends on content of powdery composites and grains hrs sizes of initial powdery (1-24 hrs). The suspension has dried at 1300C and further powders again dry grinding during 1 hrs in mill.

OXY-GON Furnace and obtaining of ceramic composites by hotpressing method

samples is sintered by program regime. Simultaneous sintering-pressing with pressure (50 MPa) was carried out during 20-60 min at maximal temperature.

XRD Samples phase analysis has been performed at XRD diffractometer DRON-3M (Cu-Ka, Ni Filter, 20C/min.).

Nanosizer Pressing powdery composites sizes (nanosizes) will be determined by Analysette 12 Dynasizer. 3% powdery composites suspension prepared in water by sonification during 30 min.

SEM and Optical microscopes Structural-morphologic investigation of ceramic composites has been performed by JEOL JSM-6510LV and Nikon ECLIPSE LV 150 microscope. Chemical content of these samples has been measured simultaneously with energy dispersive micro XRD analyzer.

Determination of microhardness Microhardness and modulus of Al2O3 have been studied according to ISO-14577 international standard at dynamic ultra microhardnesstester DUH-211S.

Results

Fig.1 High temperature vacuum furnace OXY-GON

OXY-GON High Temperature Vacuum Furnace System consists of remote control, cooling (chiller) water system, hot pressing chamber and press, which is equipped with a microprocessor. Treatment of pressure on samples is allowed by the software programmer: pressing simultaneously two buttons of press. Hotpressing chamber has double walls and is cooled down by water flow. Heating samples has been carried out by using two-segment heater, made from tungsten net, which is screened by both vertically and horizontally with tungsten and molybdenum plates.

Pressing and consolidating of the powdery composites have been carried out in high purity graphite moulds, inlayed with Graflex plates. Furnace characteristics are the following: PERFORMANCE: Maximum Operating Temperature - 20000C; Usable Work Zone -75*100 mm; Working Atmosphere - Inert gas to 2 PSIG and 1x10-2 Torr vacuum range; Ultimate Vacuum-1x10-2 Torr; Pressing maximum Force -27,215kg. UTILITY PEQUIREMENTS: Electrical 220 volt, 1 phase; Double walls chiller water:16 LPM, pressure 2-3 kg/cm2, max. inlet temperature - 21oC, pH to be 77.5. The furnace is cooled with running water or chiller(620oC). Cooling capacity-14.5 kW. Sintering powdery was placed in pressure shape of pre-annealing (14000C) graphite. First time the powdery was pressed with cold by furnace pressure at 2.5 MPa. When sintering chamber finishes vacuuming process the

Alumina is material which widely used for obtain of matrix ceramic composites. High temperature vacuum furnace (OXY-GON) have been used for obtaining of them.

Corundum ceramic samples, obtained in the OXY-GON furnace: α-Al2O3-Y2O3-ZrO2, α-Al2O3-SiC-MgO, α-Al2O3-B4CY2O3, α-Al2O3-WC-MxOy and other have the best physical-mechanical properties. Sintering temperature–150017500C, sintering time was 20-60 min at maximum temperature. Refrigeration of graphite pressure-shape have been in inert atmosphere. Obtained corundum product has black color, because there have been thermal dissociation and formation defect lattice of Al2O3 in vacuum. For purpose, relaxation (whiten) of product with defect structure have been annealing in high temperature furnace at air (16000C, 1 hrs).

Fig. 2 Typical temperature condition of powdery composites in high temperature vacuum furnace (OXY-GON)

210 Obtained ceramic samples with various thickness and cylindrical diameter forms.Their microhardnesswas established at dynamic and static conditions. Microhardnessis relatively high at small depth (load) and its value falls when depth (load) increases and goes at stationary value. Reason may be is obtaining condition of ceramics.

Relative density of ceramic materials depends on developed pressure at sample with hot pressing method (Fig.3).

ceramics, i.e. powdery which obtained by mix of magnesium and zirconium oxide with typical method without grinding. Ceramics have characterized by low mechanical properties which are obtained by sintering of nonactive powdery. Their fracture toughness is about 140–240 MPa and it’s depend on sintering temperature. Theoretical density (TD) of samples reaches 60–65%, and porosity increases up to 30–40%. Such as ceramic product uses for filter of suspensions or solutions and as thermoisolation materials.

In many cases foreign firms have not published composition of ceramics. It’s established, that parameters of ceramic composites, obtained in high temperature furnace OXY-GON are not lower in comparison with fabricated of foreign and sometimes physical-mechanical properties have improvement by 20–30 %. Density of obtained ceramics reaches 99–99.5 % of TD and they have not opening pores.

Special purpose ceramics preparation has been in OXYGON furnace in ceramics making new laboratory in the Institute. OXY-GON furnace have been purchased by cofinanced of “DELTA” and ceramic armor plates were fabricated depending on their tasks. ( Fig. 4).

Conclusions Fig. 3. Relative density depending on pressure of ceramic (Al2O3-Y2O3- MgO) samples obtained by high temperature vacuum furnace OXY-GON (16000C).

In this works, obtaining ceramic matrix composites was investigated, which is based on consolidation of powdery composites in high temperature vacuum furnace OXY-GON. Following pressing powdery composites α-Al2O3-Y2O3ZrO2, α-Al2O3-SiC-MgO, α-Al2O3-B4C-Y2O3, α-Al2O3-WCMxOy (where M is rare earth metals) have been obtained by ball milling. Ceramic composites are obtained by high temperature vacuum furnace with different temperature and pressure conditions. Ceramic products were obtained by sintering at 1500-1750oC (1 hr, 50 MPa), which is characterized by high flexural strength (370-500 MPa), microhardness and fracture toughness (3.2-4.8 MPa.m0.5) and without of open porosity. Their relative density achieves 99.5% of the TD.

Acknowledgements The financial support of ShotaRustaveli National Science foundation Grant ¹41/07 is gratefully acknowledged.

References:

Fig.4. Ceramic armor plates (a, b)

Nonactive powdery have been used for obtaining of

1. A. Kmallik, S. Gangadharan, S. Dutta and D. Basu. Micrometer size grains of hot isostatically pressed alumina and its characterization, Bull. Mater. Sci., 2010, 33(4), 445–449; 2. V. Lysenko, V. Mali, A. Anisimov. Microhardness of Ceramics Obtained by Different Methods from Nanopowders of Different Oxides, Athens J. of Sciences, 2014, 269-279; 3. H. Antonio, D. Aza, J. Chevalier, F. Gilbert. Slow-crackgrowth behavior of zirconia-toughened alumina ceramics processed by different methods. J. Am. Ceram. Soc., 2003, 86(1), 115-120; 4. Chih-Jen Wang, Chi-Yuen Huang, Yu-Chun Wu. Two-step sintering of fine Alumina-zirconia ceramics. 2008, Available online at WWW. sciencedirect.com;

211 5. M. Zakeri, M. R. Rahimipour. Effect of cup and ball types on mechano-chemical synthesis of Al2O3-TiC nanocomposite powder. Ceramics–Silikaty, 2012, 56(2), 130-134; 6. V. Naglieri, P. Palmero, L. Montanaro, J. Chvalier. Elaboratorionof Alumina –Zirconia composites: Role of the Zirconia Content on the Microstructure and Mechanical Properties.

Materials, 2013, 6, 2090-2102; 7. M. Vlasova, N. Kakazey, I. Rosales and al., Synthesis of Composite AlN-AlON-Al2O3 powders and ceramics prepared by High-pressure sintering. Science of Sintering, 2010, 42, 283295; 8. US 8030234 B2, 2011. Aluminum boron carbide composite and method to form said composite; 9. R. Benavente, A. Pruna, A. Borrell, M.D. Salvador, D. Pullini, F. Penaranda-Foix, D. Busquets. Fast route to obtain Al2O3based nanocomposites employing graphene oxide: Synthesis and sintering. J. Materials Research Bulletin, 2015, 64, 245251; 10. HarshitPorwal, Peter Tatarko, Salvatore Grasso, JibranKhaliq, Ivo Dlouhy, Mike J. Reece. Graphene reinforced alumina nano-composites. Carbon, 2013, 64, 359-369; 11. Yuchi Fan, Wan Jiang, Akira Kawasaki. Highly conductive few-layer graphene/Al 2O 3nanocomposites with tunable charge carrier type. J. Advanced Functional Materials, 2012, 22(18), 3882-3889. Doi:10.1002/adfm.201200632; 12. C.F. Gutierrez-Gonzalez, A. Smirnov, A. Centeno, A. Fernandez, B. Alonso, V.G. Rocha, R. Torrecillas, A. Zurutuza, J.F. Bartolome. Wear behavior of graphene/alumina composite. J. Ceramics International , 2015, 41(6), 7434-7438; 13. S.W. Kim, K.A. Khalil, K. Ogi. High-frequency induction heating sintering of ultra-fine Al2O3-(ZrO2+X%mol Y2O3) bioceramics. 2007, 29(30), 235-238; 14. N. Jalabadze, L. Nadaraia, A. Mikeladze, R. Chedia, T. Kukava, L. Khundadze. Spark Plasma Synthesis (SPS) Device for Sintering of Nanomaterials. Nanotech., 2009. 1, 67-70; 15. J. Zhang, L. Cao, Y. Yang, X. Shen. Step sintering of microwave heating and micro-wave plasma heating for alumina ceramics. J. Mater. Sci. Technol., 1999, 15(5), 419-422; 16. G. Suarez, Y. Sakka, Dense mullite zirconia composites obtained from the reaction sintering of milled stoichiometric alumina zircon mixtures by SPS. Ceram. Int. 2014, 40(3), 4461-4470; 17. Kai Wang, Yongfang Wang, Zhuangjun Fan, Jun Yan, Tong Wei. Preparation of graphenenanosheet/alumina composites by spark plasma sintering. J. Mat. Res. r Bull. 2011, 46(2), 315-318.

aluminis oqsidis bazaze matriculi kompozituri keramikebis miReba da kvleva r. Wedia1,2, T. kuWuxiZe1, g. bokuCava1, a. xvadagiani3, v. gabunia1, n. jalaRonia1 1

ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo 2 ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti, p. meliqiSvilis fizikuri da organuli qimiis instituti, Tbilisi, saqarTvelo 3 saxelmwifo samxedro samecniero–teqnikuri centri „delta“, Tbilisi, saqarTvelo el–fosta: sipt@sipt.org naSromSi Seswavlilia aluminis oqsidis fxvnilovani kompozitebis fuZeze sxvadasxva Semadgenlobis matriculi keramikuli kompozitebis miReba. maRaltemperaturuli cxlad dawnexvis meTodiT miRebul iqna Semdegi keramikuli kompozitebi α-Al2O3-Y2O3-ZrO2, α-Al2O3-SiC-MgO, αAl2O3-B4C-Y2O3, α-Al2O3-WC-MxOy (sadac M iSviaTmiwaTa metalebia). matriculi keramikuli kompozitebi miRebul iqna maRaltemperaturul vakuumur RumelSi sxvadasxva temperaturasa da wnevaze. miRebul keramikul kompozitebs ar gaaCniaT Ria forebi, xolo maTi fardobiTi simkvrive Teoriulis 99.5 % aRwevs.

212

Study of temperature dependence of some physical characteristics of electrolytic nickel coatings on copper T. Marsagishvili1, G. Mamniashvili2,G. Tatishvili1, N. Ananiashvili1, M. Gachechiladze1, J. Metreveli1 Ivane Javakhishvili Tbilisi State University, Rafiel Agladze Institute of Inorganic Chemistry and Electrochemistry.

Mindeli str.,11, 0186, Tbilisi, Georgia 2 Ivane Javakhishvili Tbilisi State University, E. Andronikashvili Institute of physics.

Tamarashvili str.,6, 0162,Tbilisi, Georgia E-mail: iice@caucasus.net, iph@iphac.ge 1

Abstract.Investigation of mechanic properties of nickel coatings of different thickness (Young modulus and internal friction) before and after heat treatment (950-10000C) is presented in this work. Nickel coatings are obtained from nickelplating persulphate and economic solutions on copper base.

Keywords:Heat treatment,internal friction, nickel-plating of copper, Young modulus.

Introduction

Obtaining of electrolytic coatings of metals is one of the most widespread methods in industry. Up to 1 milliardsquare meters of metal surface is coated by this method every year. Technologies of obtaining of coatings are developed in order to increase corrosion resistance, electroconductivity, heat resistance, hardness of product and many other properties.

Operation of product in conditions of high temperatures is often needed in modern technics. Therefore, study of structure and properties of coatings after heating is very important.

Structural and mechanical transformations, which may take place during heating of structural material, must not be disseminated on coatings automatically, because of peculiarity of their structure (superdispersion, heterogeneity, increased space of defects of crystalline structure, internal stress). Structure of coating may be changed purposefully by heat treatment of electrolytic coatings andincreased operational properties may be obtained. After heat treatmentimprovement of structure of the sample, decrease of distances between intergranularbounds, increaseofdiffusion zone between coating and base, and correspondingly, improvement of adhesion [1]takes place.

Present work concerns study of some mechanical properties (Young modulus and internal friction) of electrolytic nickel coatings on copper base. This gives important data about structure of solid state and maintainability of product during operation.

Measurement of internal friction is one of the sensitive methods, which is used for determination of such structural defects, relaxation and diffusion processes, which gives necessary information about processes passing in solid (metals and alloys) after strong mechanical and thermal influence on them [2-3]. Young (elasticity) modulus characterizes such property of material, which resists against stretching or compression during elastic deformation and shows quality of hardness.

Materials and Methods

Many electrolytes [4-5] are known, which are used for obtaining of nickel coatings. We selected two of them [69], which make possible to obtain less-strained and finecrystalline coatings of nickel on copper surface.

Composition of selected electrolytes (g/l): Nickel-plating sulfamic-acid electrolyte: nickel sulfate– 250-350, sulfamic-acid – 40-70, Boric acid–15-30, sodium chlorides –5-15.

Nickel-plating economical electrolyte: nickel sulfate – 140-180, sodium sulfate – 40-50, magnesium sulfate– 25-30, Boric acid – 20-25, sodium chlorides –5-10.

Under study samples (copper cathodes) were prepared for experiments previously. The samples were cut with specialaccuracy on electro-sparklingmachinetool.Nickel (99.99%) plates were used as anodes.

Five samples were selected for study of mechanical properties of coatings: coatings of thickness h=47 and h=106 microns, in nickel platingsulfamic acid electrolyte and coatings of thickness h=35, h=52 and h=80 microns, in economic solution.

Mechanical properties of obtained coatings - Young modulus and internal friction were studied by acoustic spectrometer before thermal treatment of the samples and after their quick burning at temperature 950-1000°C. The samples were placed in special chamber (helium medium) during 1 minute for burning. The measurements were carried out after cooling of the samples at room temperature.

Results

Spectra of temperature dependence of Q-1(internal friction)and E (Young modulus) for copper samples coated from nickel plating sulfamic acid to economical solutions before and after thermal treatment is given on Figures.

As can be seen from Figure 1, temperature dependence of internal friction is almost identical for both samples, but Young modulus is about 20% more for sample (Cu-Ni) of thickness h=106 microns than for coatings of thickness h=47 microns before heat treatment (Figure 2).

213

a

b

Fig.1. Spectra of temperature dependence of Young modulus (E) and internal friction (Q ) for nickel coatings of thickness h=47μ (a) and h=106μ (b) obtained in nickel plating sulfamicacidsolution before heat treatment of the sample.

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Fig.2. Spectra of temperature dependence of Young modulus (E) for nickel coatings of thickness h=47μ (lower curve) and h=106μ (upper curve) coated in nickel plating sulfamic acid solution before heat treatment of the samples.

Fig.4. Spectra of temperature dependence of Young modulus (E) for nickel coatings of thickness h=47μ (lower curve) and h=106μ (upper curve) coated in nickel plating sulfamic acid solution after heat treatment of the samples.

It is obvious from Figure3, that the form and the size of the curve of temperature dependence of internal friction is almost identical for both samples, but value of Young modulus is about 30% more for sample (Cu-Ni) of thickness h=106 microns than for sample of thickness h=47 microns after thermal treatment (Figure 4):

After analysis of given material one can say, that Young modulus increases for both samplesafterheat treatment.

Analogous measurements were carried out for samples obtained in nickel plating economical solutions.

It is obvious from Figure5that with increase of thickness of the coating Young modulus increases within the

a

b

Fig.3. Spectra of temperature dependence of Young modulus (E) and internal friction (Q-1) for nickel coatings of thickness h=47μ (a) and h=106μ (b) obtained in nickel plating sulfamic acid solution before heat treatment of the sample.

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a

b

c

Fig.5. Spectra of temperature dependence of Young modulus (E) and internal friction (Q ) for nickel coatings of thickness h=35μ (a), h=52μ (b) and h=80μ (c) coated in nickel plating economical solution before heat treatment of the sample.

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a

b

c

Fig.6. Spectra of temperature dependence of Young modulus (E) and internal friction (Q-1) for nickel coatings of thickness h=35μ (a), h=52μ (b) and h=80μ (c) coated in nickel plating economical solution after heat treatment of the sample.

studied limits of the temperature, and form of this dependence(E-T) is the same for all three cases.

Form of diagram of temperature dependence of internal friction (Q-1) is similarfor all three samples and increases monotonously from 1x10-3(room temperature) up to 5x10-3 420°K temperature.

The analysis of the curves shows, that after burning of the samples Young modulus increases in comparison with its initial value for all studied samples. Value of internal friction, at the room temperature, is slightly more before heat treatment, keeps its value within the studied temperature interval (300 - 420°K) and lies within the limits 3x10-3 - 5x10-3.

Conclusions It may be concluded, that for nickel coatings of all thicknesses obtained on copper base in nickel plating sulfamic acid solution and economical solutions the value of internal friction slightly differs from each other before and after heat treatment of the samples. And value of Young modulus is higher for coatings obtained in sulfamic acid solution, than for coatings obtained in economical solutions and numerically approaches Young modulus of copper(Cu – 110 GPa, Ni – 210 GPa). Obtained coatings may be used for such functional objectives, when elasticity and thermal stability of the product is necessary.

References: 1. I.M. Safarov, R.H. Hisamov, R.R. Mulyukov, I.I. Musabirov: Abnormal microhardness and electrical resistivity of the nanocrystalline nickel under annealing. www.letters on materials.v.2 (2012), 218-221

2. A.S.Nowick, D.S.Berry. “Inelastic Relaxation in Relaxation in Crystalline Solids”, Academic Press, New York/London, (1972) 3. Â.Ñ. Ïîñòíèêîâ. Òåìïåðàòóðíàÿ çàâèñèìîñòü âíóòðåííîãî òðåíèÿ ÷èñòûõ ìåòàëëîâ è ñïëàâîâ. Óñïåõè õèìè÷åñêèõ íàóê.Ò.LXTI,âûï. 1, (1958), 43-73 4. Ì.À.Áåëåíêèé,À.Ô.Èâàíîâ. Ýëåêòðîîñàæäåíèå ìåòàëëè÷åñêèõ ïîêðûòèé. Ñïðàâî÷íèê. Ìîñêâà «Ìåòàëëóðãèÿ» (1985),ãëàâà 15 5. Í.Â.Êîðîâèí, «Íîâûå ïîêðûòèÿ è ýëåêòðîëèòû â ãàëüâàíîòåõíèêå», «Ìåòàëëóðãèÿ», Ì., (1962), ñ. 19 6. Ñ.À.Ëîáàíîâ, Ïðàêòè÷åñêèå ñîâåòû ãàëüâàíèêó. Ëåíèíãðàä «Ìàøèíîñòðîåíèå», (1983), ãëàâà 18 7. À.Ì.ßìïîëüñêèé, Â.À.Èëüèí. Êðàòêèé ñïðàâî÷íèê ãàëüâàíîòåõíèêà. Ëåíèíãðàä. «Ìàøèíîñòðîåíèå», (1981), ãëàâà 18 8. Øàõîòèí È.Ì., Ýëåêòðîëèò íèêåëèðîâàíèÿ. Íîìåð ïàòåíòà 2172797 9. Äàñîÿí Ì.À. è äð. Òåõíîëîãèÿ ýëåêòðîõèìè÷åñêèõ ïîêðûòèé. Ëåíèíãðàä. «Ìàøèíîñòðîåíèå», (1989), ãëàâà15

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spilenZis fuZeze eleqtrolituri nikelis da fenebis zogierTi fizikuri maxasiaTeblis temperaturuli damokidebulebis Seswavla T. marsagiSvili1, g. mamniaSvili2, g. tatiSvili2, n.ananiaSvili1, m. gaCeCilaZe1, j. metreveli1 1

ivane javaxiSvilis sax. Tbilsis saxelmwifo universiteti, r. aglaZis araorganuli qimiisa da eleqtroqimiis instituti, mindelis q. 11, 0186, Tbilisi, saqarTvelo 2 ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti, e. andronikaSvilis sax. fizikis instituti, TamaraSvilis q., 6, 0162, Tbilisi, saqarTvelo el-fosta: iice@caucasus.net, iph@iphac.ge eleqtrolituri fenebis TermodamuSavebiT, mizanmimarTulad SeiZleba Seicvalos maTi struqtura da miRebul iqnas gazrdili saeqspluatacio monacemebi. TermodamuSavebis Semdeg xdeba nimuSis struqturis daxvewa, marcvalTSorisi sazRvrebis manZilis Semcireba, fenebis da fuZis Soris difuziis zonis gazrda da Sesabamaisad, adgeziis gaumjobeseba. samuSaoSi warmodgenilia spilenZis fuZeze, monikelebis persulfatiani da ekonomiuri xsnarebidan miRebuli sxvadasxva sisqis nikelis fenebis zogierTi fizikuri maxasiaTeblis (iungis moduli da Sinagani xaxuni) kvleva, Termul damuSavebamde da mis Semdeg (950-10000C). monikelebis Seswavlil xsnarebSi miRebuli yvela sisqis nikelis fenebis, Sinagani xaxunis sidide mcired gansxvavdeba erTmaneTisagan, nimuSebis TermodamuSavebamde da mis Semdeg, xolo iungis modulis sidide izrdeba TermodamuSavebis Semdeg, yvela nimuSisaTvis. miRebuli fenebi SeiZleba gamoyenebul iqnas funqciuri miznebisaTvis.

216

Impregnation of iron (II, III) compounds in wood and their reduction till nano zero-valent iron N. Jalagonia1, Ts. Ramishvili2, I. Jinikhashvili2, Q. Sarajishvili2, T. Korkia2, Z. Amiridze2, R. Chedia1,2 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli Str., 0186, Tbilisi, Georgia Iv. Javakhishvili Tbilisi State University, P. Melikhishvili Institute of Physical and Organic Chemistry, 5 Jikia str., 0186 Tbilisi, Georgia E-mail:sipt@sipt.org 1 2

Abstract.In the present study, we have described application of different renewable bioresources for impregnation with nano zero-valent iron (nZVI). Impregnation with nZVI was conducted in two stages: I. Saturation of biomaterials with solutions of Fe (II, III) compounds; II. Reduction of impregnated Fe (II, III) compounds in biomaterial by sodium borohydride. During reduction of Fe ions, black hybrid inorganic-organic sorbent is obtained, in which Fe content depends on time of biomaterials impregnation with salts, its nature and structure. The obtained impregnated biomaterials with nZVI have been studied by optical and electronic scanning microscope, XRD and atomic-absorption spectroscopy. The size of nZVI agglomerate was determination by laser sizer. It is established, that nZVI impregnated in biosorbents are active in degradation process of organochlorine pollutants (2,5–dichloroaniline, 1,4-dichlorobenzene). Analysis of model solutions was conducted by GC/MS. It is established, that by impregnation with Fe ions of biomaterials of oak wood, vine pruning, grape seed, pomegranate bark and citrus peel at 65÷70oC nZVI containing biosorbents are obtained.

Keywords: Nano zero-valent iron, Biomaterial, Impregnation, Remediation

Introduction The modern world is taking backstrokes from nature due to irrational and unforeseeable activity, which is expressed in global warming, health-ecological deterioration, impairment of the immune system, promotion of new diseases, food and drinking water quality worsening, increasing social and economic conflicts and etc. In recent years, great attention is paid to introduction of “green chemistry” methods into the modern technological processes for prevention of growing environmental threat. The method of “green chemistry” implies replacing of existing traditional technological processes with naturally occurring processes and renewable natural resources. One of the biggest problems of the modern world is water pollution by industrial, urban and agricultural sewage. There are plenty of causes of water pollution with heavy metals, and among them with radioactive nuclides and stable organic pollutants. Biopolymers of plant origin are characterized by a number of valuable properties. That is why they are successfully used in chemical, pharmaceutical, food industry and other fields. On the other hand they are widely used to remediate groundwater and wastewater from heavy metals and stable organic pollutants (Permeable Reactive Barriers). Especially noteworthy is the fact that Feo reduces several halogenous hydrocarbons, chlorine-containing pesticides, organic dyes, nitroso compounds, explosives and others. Their restoring ability is used for reduction of CrO4-2, Cr2O7-2,ClO4-,NO3- ions and elimination of Hg+2, Ni+2,Cd+2, Pb+2as well as of a number of radionuclides from water. [1-17]. That is why revealing of new reductants and

methods for reduction of Fe+2 and Fe+3 up to Feo is an actual problem. The objective of the present research is immobilization of ZVI in bioorganic materials and obtaining of hybrid organic-inorganic reactive barriers for water treatment.

Materials and Methods Materials and reagents FeSO4•7H2O - Iron (II) sulfate heptahydrate, FeCl3•6H2O -Iron (III) chloride hexahydrate, Chloroform, 2,5-Dichloroaniline, p-Dichlorbenzene, Acetic acid, Sodium borohydride (98%) have been purchased from Sigma-Aldrich. All chemicals have been used without purification. Other reagents hydrochloric, sulfuric, nitric acids, potassium hexacyanoferrate (III), potassium hexacyanoferrate (II) have been of analytical grade. All the solutions were prepared in deionized water.

Local plant wood-Alder (Alnus) and Pine-tree (Pinus) woods has been used as biomaterial. Different-size pieces have been made from the mentioned material and the samples humidity was 10÷12%. At the early stage, the samples were used without physical and chemical modification.

Wood samples have been collected from Adzharia region.

Impregnation iron (II,III) compounds in Biomaterials.

500 mL 20 % iron (II,III) compounds containing solution is acidifies with 2 mL sulfuric and place 5 g biomaterial sample under room temperature, then it is stirred with magnetic stirring during 8–48 hours and is filtered. Biomaterials on the filter was washed twice with 100 mL deionized

217 water and dried at 50ºC during 24 hours, and then at 105ºC during 12 hours. Obtained samples are kept in desiccator with zeolite (molecular sieve UOP Tipe 3A).

Reduction of the impregnated Fe (II,III) compounds in biomaterials.

Combination of methods 1.2 and 1.3 is used to obtain nZVI impregnated biomaterials. Wet samples of Fe+n/biomaterial (5-10 g) obtained by 1.2 method are placed in 0,5 L three necked flask, added by 200 ml deionized water and flushed with nitrogen flow during 30 min. The flask is cooled till 3ºC and added 50 mL 1M cooled sodium borohydride aqueous solution dropwise. Reaction mixture is stirred during 8 hours at the room temperature in a nitrogen area and then the solution is removed and the flask is filled with same water content and sodium borohydride new portion in same volume. After 8 hours the solution layer is removed from the samples and added 200 mL ethanol (96%). The flask content is stirred during 1 hour and ethanol is replaced by the acetone. After 3 hour the acetone is removed and the samples are dried in vacuum (1-2 Torr) at 50! during 6 hours. The samples are kept in zeolite desiccator under a nitrogen area.

XRD Impregnated samples for the XRD investigations were in 20x20x5 mm sizes. 3 g FeÚ/cotton has been wetted in paraffin ether solution, then dried in the air and pressed by 100 kgf/cm2 pressure. Samples phase analysis has been performed at XRD diffractometer DRON-3M (Cu-Ka, Ni Filter, 2!/min.)

Nanosizer nZVI powder agglomerat sizes (nanosizes) will be determined by Analysette 12 Dynasizer. 3% nZVI suspension prepared in water by adding 0,1% (mass) dispersant and sonification during 30 min.

SEM and optical microscopes Structural-morphologic investigation of immobilized biomaterials has been performed by JEOL JSM-6510LV and Nikon ECLIPSE LV 150 microscope. Chemical content of these samples has been measured simultaneously with energy dispersive micro XRD analyzer.

Atomic absorption spectrometry The concentration of metal ions in solutions, also in biomaterials Fe and other elements content has been defined by atomic-absorption spectrometry novAA 400; Corresponding elements standard-solutions have been purchased from Sigma-Aldrich.

GC/MS* The concentration of 1,4-dichlorobenzene and 2,5dichloraniline has been defined by GC/MS device - Gas chromatography–mass spectrometry 7890B/5892A-Agilent Technologies.In the program mode-column was heat-

ed during 5 min at 60oC, then-with 6oC/min speed up to 140oC, further the column temperature have been increased with 15oC/min speed up to 220oC and it was maintained during 3 min. Total analysis time is 26.66 min.

Results Impregnation of wood samples with metal salts and formation of complex compounds with materials containing wood depends on many factors. At this stage, we have studied absorption ability of Fe (II, III) compounds by chemically untreated wood and their subsequent reduction with sodium borohydride at 5÷20ÚC. Wood samples sizes varied from 50X5X5 to 40X5X5 mm. At room temperatures impregnation time reaches 4–48 hrs. Migration of iron (II, III) ions in wood raises by increasing impregnation time and it depends on the wood type. In coniferous plants Fe ions reach 13–16 mm during 24 hrs, while in wood of deciduous plants migration is 4-6 mm in the same time (Alder) .

From the iron compounds sulphates and chlorides were used and migration ability in their wood is similar. Migration front of Fe (II, III) ions in the wood were conducted by an easy method: woods flat surface practically is thin layered chromatographic plate and for revealing iron ions potassium ferrocyanide complexes (identification with K4[Fe(CN)6], K3[Fe(CN)6]) and potassium (ammonium) rhodanide (identification with NH4SCN, KSCN) were used.

Migration front of iron ions is clearly revealed on the wood samples by applying cotton soaked in these solutions and then squeezed. Colored area quickly spreads in vertical direction of cellulose fibers and boundary becomes more blurred and unequal. As expected, Fe ions in the wood basically migrate in vertical direction of the wood, as from top to bottom, as well from bottom to top.

It is established by using optical microscope, that ions horizontal migration is only ~500 mcm. (Obviously, in the dried wood aqueous solutions reaches in the plants from the roots and also from above-ground parts). However, during industrial impregnating methods materials reach in timber basically in horizontal direction.

Fe+2 impregnated wood by acting K3[Fe(CN)6] solution it will take blue color, due to Fe3[Fe(CN)6] complex formation. Similarly Fe+3 ions existing in wood with K4[Fe(CN)6] also takes blue color. In the same conditions potassium (ammonium) rhodanide gives dark red color to the impregnated wood with Fe+3. It is established, that in wood Fe (III) ions partially reduction up to Fe (II) with oxygen (identification by K3[Fe(CN)6]), on the other hand in the wood impregnated with Fe (II) ions oxidizes up to Fe (III). Therefore, in parallel with impregnation Fe ions oxidation and reduction have been partially performed. We have not established yet quantitative aspect of these processes. At the room tempearture for 24 hrs in the samples saturated with Fe (III) salts (saturation quality 100% size 20x10x10 mm). Fe content has been established by ISO11047–1998 standard with atomic-absorption spectrometry novAA 400 and Fe ions reaches in pine-3,73% and alder-5,615% respectively.

218 After saturation of biomaterials samples with iron compounds, they are washed with water and in conditions of stirring in flask are reducted with sodium borohydride cooled solution in inert area. By adding sodium borohydride samples take black color, adding of NaBH4 lasts for 10–15 min. Stirring is necessary, because biomaterials float in the water and in statistical conditions iron (II, III) ions existed in wood reductive unequally. Reduction of samples was carried out during 8-24 hrs with NaBH4 1% mas. solution, that was changed in every 8 hrs. It is established, that in pine wood Fe ions reductive during 24 hrs in migration up to 1÷1.5 mm.

horizontal surface is more than in vertical section, that indicates, that in reduction process partial migration of Fe ions from the inner areas of wood in vertical direction takes place. During drying of wood impregnated with iron (II, III) ions, migration of Fe ions in vertical direction is noticeable and Fe salts are crystallized on the surface of horizontal intersection. By their reduction on the surface concentration reaches 12-15% . Established existence of nZVI in impregnated wood (Fig.1).

In reduction process migration of Fe (II, III) ions is conducted also in the case of cotton, that is clearly shown

I

II

Fig. 1. SEM Micrograph (I) and energy dispersive micro XRD spectrum (II) of impregnated pine wood with nZVI

Reducer cannot reach in inner areas of wood. But in alder wood Fe ions reductive migration to 4÷5 mm. So that migration of Fe (II, III) ions and NaBH4 practically is the same, therefore in alder wood iron ions are reductive by 100%. This is approved by the fact, that the relevant reaction with potassium ferrocyanide (III) and ammonium rhodanide do not take place. At the same time, existence of iron ions in the inner districts of 100% impregnated pine wood is confirmed by identification colored reactions. It is established by electron microphotographic study and energy dissperive XRD analysis, that iron content on the

on SEM microphotograph. Existence of iron phase on the fiber surface is confirmed on XRD (Fig. 4) In same conditions in inert atmosphere (without wood) after reduction of Fe (II, III) compounds black nZVI powder has been obtained, which XRD and microphotographic images are given on fig. 5.

It is established, that size of obtained nZVI particle reaches ~100 nm. Without stabilizers nZVI is pyrophoricity and oxidize instantly in touch with air. Impregnated nZVI particles are stablizied by organic complexes existed in wood, so they are not characterized with pyrophoricity.

It is established by GC/MS method, that iron impregnated in wood is charcterized with ability of dehalogenation of organochlorine compounds. Identification tests have been established in model solutions, those contain 50 mg/ l 2,6-dichloroaniline and 1,4-dichlorobenzene. By using NZVI/wood sorbents, Cr+6 and Pb+2 ions were removed from model solutions, that was confirmed by method of atomic absorption analysis.

Conclusions

Fig. 2. XRD of impregnated pine wood with nZVI

Zero-valent iron is impregnated in different biomaterials (wood, cotton, biopolymers, agricultural residues). It is established, that in coniferous wood penetration of iron nanoparticles (migration front) is 2÷3 times higher than in deciduous plants with thick wood (alder, hornbeam, oak). Inclusion of iron nano-particles in the wood is implemented main-

219

I

II

Fig. 3. SEM Micrograph (I) and energy dispersive micro XRD spectrum (II) of impregnated alder wood with nZVI

I

II

Fig.4.SEM Micrograph (I) and XRD (II) of impregnated cotton with nZVI

I

II

Fig. 5. SEM Micrograph (I) and XRD (II) of nano zero-valent iron

ly in vertical direction. (from the top, as well as from the bottom), while iron nano-particles in horizontal direction reach the layers only with ~500 mcm thickness. Reduction of impregnated iron (II, III) compounds was conducted with solution of sodium borohydride, as a result nZVI impregnat-

ed black biosorbents are obtained. Reducted migrated front of iron in biosorbents is in 1,5ﾃｷ5 mm. Impregnated nZVI particles are active in degradation process dissolve chlorine compounds (2,5窶電ichloroaniline, 1,4窶電ichlorobenzene) and actively absorb heavy metal ions from water.

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17. D.M. Cirwertny, S.L. Bransford, and A.L. Roberts. Influence of the oxidizing spacies on the reactivity of iron-based bimetallic reductants. Environ. Sci. Technol., 41, (2007), 37343740.

rkinis (II, III) naerTebis impregireba merqanSi da maTi aRdgena nanonulvalentian rkinamde n. jalaRonia1, c. ramiSvili2, i. jiniyaSvili2, q. sarajiSvili2, T. qorqia2, z. amiriZe2, r. Wedia1,2 1 ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186,Tbilisi, saqarTvelo 2 ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti, p. meliqiSvilis fizikuri da organuli qimiis instituti, jiqias q. 5, 0186, Tbilisi, saqarTvelo el–fosta: sipt@sipt.org

mZime metalebisa da radionuklidebis, aseve polutantebis wyliani garemodan mosaSoreblad yvela zeperspeqtiuli abiopolimerebis fuZezeorganul–araorganuli hibriduli sorbentebis Seqmna. winamdebare naSromSi damuSavebulia merqanSi nanonulvalentiani rkina (nnvr) impregirebis meTodi. am mizniT merqnis nimuSebi damuSavebul iqna 20–30 % rkinis (II, III) naerTebiT 8–48 sT–is ganmavlobaSi. dadgenilia, rom rkinis ionebiT ufro swrafad iJRinTeba wiwvovani mcenareebis merqani, vidre foTlovani xis merqani. merqanSi rkinis ionebis gavrcelebis (SeRwevis) siRrme gansazRvrul iqna Fe+2da Fe+3 ionebis aRmomCeni reagentebis gamoyenebiT (K4[Fe(CN)6], K3[Fe(CN)6]), NH4SCN). rkinis ion¬ebis aRdgena nnvr–mde ganxorcielda natriumis borhidridis ganzavebuli wyalxsnarebiT ris Sedegad miRebulia (1–3%) nnvrSemcveli organularaorganuli sorbentebi, romlebic aqtiurad STanTqaven rogorc mZime metalebs, aseve advilad Slian wyalSi arsebul qlororganul naerTebs.

GC/MS*- Gas chromatography–mass spectrometry 7890B/ 5892A-Agilent Technologies have been purchased by fund (project 41/10) of ShotaRustaveli national science foundation.

221

Ïðèãîòîâëåíèå è ìåõàíè÷åñêàÿ ïðî÷íîñòü ïëåíîê íåêîòîðûõ ñîåäèíåíèé ðåäêîçåìåëüíûõ ýëåìåíòîâ Ç.Ó. Äæàáóà, À.Â. Ãèãèíåèøâèëè Ãðóçèíñêèé òåõíè÷åñêèé óíèâåðñèòåò. Óë. Êîñòàâà 7,0175,Òáèëèñè.Ãðóçèÿ. Ýë-ïî÷òà: z.jabua@hotmail.com Ðåçþìå. Ìåòîäîì âàêóóìíî-òåðìè÷åñêîãî èñïàðåíèÿ ðàçðàáîòàíà òåõíîëîãèÿ ïîëó÷åíèÿ êðèñòàëëè÷åñêèõ ïëåíîê Tm2S3, TmS, TmSe è LaBi íà ðàçëè÷íûõ ïîäëîæêàõ-êðåìíèé, ñèòàë, ëåèêîñàïôèð. Èçó÷åíà îòíîñèòåëüíàÿ ïðî÷íîñòü TmS, TmSe è LaBi. Ïîêàçàíà çàâèñèìèîñòü ïðî÷íîñòè îò ìàòåðèàëà ïîäëîæêè. Ïðèâåäåí âîçìîæíûé ìåõàíèçì óêàçàííîé çàâèñèìîñòè.

Êëþ÷åâûå ñëîâà: ïðî÷íîñòü, ïëåíêà, íàïûëåíèå, òåïëîâîåðàñøèðåíèå.

Ñîåäèíåíèÿ ðåäêîçåìåëüíûõ ýëåìåíòîâ ñ ñåðîé, ñåëåíîì è âèñìóòîì ÿâëÿþòñÿ òóãîïëàâêèìè ìàòåðèàëàìè è ñòðóêòóðû ñîçäàííûå íà èõ îñíîâå ìîãóò ðàáîòàò â øèðîêîé îáëàñòè òåìïåðàòóð [1]. Òåõíîëîãèÿ ïðèãîòîâëåíèÿ îáüåìíûõ ìàòåðèàëîâ ýòèõ ñîåäèíåíèè ðàçðàáîòàíà äîâîëüíî õîðîøî, ÷òî íåëüçÿ ñêàçàòü î òîíêèõ ïëeíêàõ. ×àñòî ñâîéñòâà òîíêèõ êðèñòàëëè÷åñêèõ ïëeíîê îòëè÷àåòñÿ îò ñâîéñòâ îáüåìíûõ ìàòåðèàëîâ, ïîýòîìó ðàçðàáîòêà òåõíîëîãèè ïðèãîòîâëåíèÿ îäíîôàçíûõ ïëeíîê ñòåõèîìåòðè÷åñêîãî ñîñòàâà è èçó÷åíèå èõ ôèçè÷åñêèõ ñâîéñòâ ïðåäñòàâëÿþò èíòåðåñ êàê ñ òî÷êè çðåíèÿ ïðàêòè÷åñêîãî ïðèìåíåíèÿ òàê è ïðîÿñíåíèÿ ìíîãèõ ïðîáëåìíûõ âîïðîñîâ ôèçèêè òâeðäîãî òåëà.  ïðåäñòàâëåííîé ðàáîòå âïåðâûå ðàçðàáîòàíà òåõíîëîãèÿ ïðèãîòîâëåíèÿ òîíêèõ ïëeíîê Tm2S3, TmS, TmSe è LaBi íà ïîäëîæêàõ èç êâàðöà, ìîíîíîêðèñòàëëè÷åñêîãî êðåìíèÿ, ñèòàëëà è ëåéêîñàïôèðà (ïîäëîæêè èìåëè ôîðìó ïðÿìîóãîëüíîãî ïàðàëåëåïèïåäà ðàçìåðàìè 8 õ 15 õ 1 ìì) è èçó÷åíà îòíîñèòåëüíàÿ ìåõàíè÷åñêàÿ ïðî÷íîñòü ïðèãîòîâëåííûõ ïëeíîê. Ïëeíêè Tm 2 S 3 áûëè ïðèãîòîâëåíû ìåòîäîì äèñêðåòíîãî âàêóóìíî-òåðìè÷åñêîãî èñïàðåíèÿ ïðåäâàðèòåëüíî ñèíòåçèðîâàííîãî ìàòåðèàëà. Ïîêàçàíà, ÷òî îïòèìàëüíûìè ðàçìåðàìè äëÿ íàïèëåíèÿ ïëeíîê ÿâëÿþòñÿ çeðíà ðàçìåðàìè ~100-130 ìêì. Ïðè íàïûëåíèè ïëeíîê òåìïåðàòóðà èñïàðèòåëÿ ðàâíÿëàñü ~2800K, òåìïåðàòóðà ïîäëîæêè - 870 - 920K, ðàññòîÿíèå îò èñïàðèòåëÿ äî ïîäëîæêè – 55 ìì, ñêîðîñòü íàïûëåíèÿ - ~ 90-105, òîëùèíà ïëeíîê èçìåíÿëàñü â ïðåäåëàõ 0,6 – 2,5 ìêì. Ïëeíêè èìåëè òeìíî-æeëòóþ îêðàñêó (ðèñ.1). Ðåíòãåíîäèôðàêòîìåòðè÷åñêèé àíàëèç ïîêàçàë, ÷òî ïëeíêè èìåþò êðèñòàëëè÷åñêóþ ñòðóêòóðó Tl2S3 θ ôîðìû (êóáè÷åñêàÿ ñèíãîíèÿ, ïðîñòðàíñòâåííàÿ ãðóïïà la3).

Ðèñ.1. Ïëeíêà Tm2S3 (ïîäëîæêà ñèòàëë, òîëùèíà – 1,8 ìêì)

Ðèñ.2. Ðåíòãåíîäèôðàêòîãðàììà ïëeíêè θ-Tm 2 S 2 (ïîäëîæêà ñèòàëë, òîëùèíà – 1,8 ìêì) Ïàðàìåòð ðåøeòêè ïëeíîê θ-Tm2S2 ðàññ÷èòàííûé èç ïðèâåäeííîé äèôðàêòîãðàììû ðàâíÿëñÿ a=12,44A, ÷òî õîðîøî ñîãëàñóåòñÿ ñ ëèòåðàòóðíûìè äàííûìè [2] äëÿ îáüåìíûõ êðèñòàëëîâ. o

222 Ïëeíêè TmS òàêæå ïðèãîòîâëåíû ìåòîäîì äèñêðåòíîãî âàêóóìíî-òåðìè÷åñêîãî èñïàðåíèÿ ïðåäâàðèòåëüíî ñèíòåçèðîâàííîãî ìàòåðèàëà. Ïîêàçàíà, ÷òî îïòèìàëüíûìè ðàçìåðàìè äëÿ íàïèëåíèÿ ïëeíîê ÿâëÿþòñÿ çeðíà ðàçìåðàìè ~ 80-90 ìêì. Ïðè íàïûëåíèè ïëeíîê òåìïåðàòóðà èñïàðèòåëÿ ðàâíÿëàñü ~2750K, òåìïåðàòóðà ïîäëîæêè - 720 – 1200 K, ðàññòîÿíèå îò èñïàðèòåëÿ äî ïîäëîæêè – 70 ìì, ñêîðîñòü íàïûëåíèÿ - ~68-75A/ñåê, òîëùèíà ïëeíîê èçìåíÿëàñü îò 0,9 äî1,2 ìêì. Ïëeíêè èìåëè æeëòóþ îêðàñêó (ðèñ.3).

ðàâíÿëàñü ~2750K, òåìïåðàòóðà ïîäëîæêè - 620 K, ðàññòîÿíèå îò èñïàðèòåëÿ äî ïîäëîæêè – 68 ìì, ñêîðîñòü íàïûëåíèÿ -7~0-85A/ñåê, òîëùèíà ïëeíîê èçìåíÿëàñü â ïðåäåëàõ 0,9 – 1,8 ìêì. Ïëeíêè èìåëè òeìíî æeëòóþ îêðàñêó (ðèñ.5). Ðåíòãåíîäèôðàêòîãðàììà ïëeíêè TmSe ïðèâåäåíà íà ðèñ.6, åe àíàëèç ïîêàçàë, ÷òî ïëeíêà èìååò êóáè÷åñêóþ ðåøeòêó òèïà NaCl ñ ïàðàìåòðîì a=5,62A, ÷òî õîðîøî ñîãëàñóåòñÿ ñ ëèòåðàòóðíûìè äàííûìè äëÿ îáüåìíûõ êðèñòàëëîâ [2].

Ðèñ.3. Ïëåíêè TmS (ïîäëîæêè ñëåâà íàïðàâî êâàðö, ñèòàëë, ëåéêîñàïôèð òîëùèíà – 1,1 ìêì)

Ñîãëàñíî ðåíòãåíîäèôðàêòîìåòðè÷åñêîìó àíàëèçó (ðèñ.4) ïëeíêè èìåëè êóáè÷åñêóþ ðåøeòêó òèïà NaCl ñ ïàðàìåòðîì a=5,39A ÷òî õîðîøî ñîâïàäàåò ñ ëèòåðàòóðíûìè äàííûìè äëÿ îáüåìíûõ êðèñòàëëîâ [2].

Ðèñ.5. Ïëeíêà TmSe (ïîäëîæêà ñèòàëë, òîëùèíà – 0,9 ìêì)

Ðèñ.4. Ðåíòãåíîäèôðàêòîãðàììà ïëeíêè TmS (ïîäëîæêà ëåéêîñàïôèð, òîëùèíà – 1,0 ìêì)

Ïëeíêè TmSe áûëè ïðèãîòîâëåíû ìåòîäîì äèñêðåòíîãî âàêóóìíî-òåðìè÷åñêîãî èñïàðåíèÿ ïðåäâàðèòåëüíî ñèíòåçèðîâàííîãî ìàòåðèàëà. Óñòàíîâëåíî, ÷òî îïòèìàëüíûìè ðàçìåðàìè äëÿ íàïûëåíèÿ ïëeíîê ÿâëÿþòñÿ çeðíà ðàçìåðàìè ~ 85-100 ìêì. Ïðè íàïûëåíèè ïëeíîê òåìïåðàòóðà èñïàðèòåëÿ

Ïëeíêè LaBi ïîëó÷åííû ìåòîäîì âàêóóìíîòåðìè÷åñêîãî èñïàðåíèÿ èç äâóõ íåçàâèñèìûõ èñòî÷íèêîâ La ëàíòàíà è ñóðüìû. Òåìïåðàòóðà èñïàðèòåëÿ ñîñòîâëÿëà T La=1890K, òåìïåðàòóðà èñïàðèòåëÿ Bi - TLa=1060 K, òåìïåðàòóðà ïîäëîæêè TÏ=1130 K. Ñêîðîñòü íàïûëåíèÿ ïëeíêè ðàâíÿëàñü ~78 A/ ñåê, òîëùèíà - 0,7-2,2 ìêì. Êàê âèäíî èç ðèñ.7 ïëeíêè èìåëè ÷eðíóþ îêðàñêó. Íà ðèñ.8 ïðèâåäåíà LaBi òèïè÷íàÿ ðåíòãåíîäèôðàêòîãðàììà ïëeíêè Àíàëèç ïîêàçàë, ÷òî ïëeíêà èìååò êóáè÷åñêóþ ðåøeòêó òèïà NaCl ñ a=6,52 A ïàðàìåòðîì ÷òî õîðîøî ñîãëàñóåòñÿ ñ ëèòåðàòóðíûìè äàííûìè äëÿ îáüåìíûõ êðèñòàëëîâ [2].

223 Ñïåöèàëüíûì ìåõàíèçìîì ïëèòà ïðèâîäèòñÿ â ïîñòóïàòåëüíîå äâèæåíèå âçàä-âïåðeä è ñ÷èòàåòñÿ ÷èñëî ïðîõîäîâ íóæíîå äëÿ ïîëíîãî èññòèðàíèÿ ïëeíêè. Äëÿ íàäeæíîñòè ýêñïåðèìåíòà âñå ïëeíêè äîëæíû èìåòü îäèíàêîâóþ òîëùèíó è íàãðóçêà íà íèõ äîëæíà áèòü îäèíàêîâîé.

Ðèñ.6. Ðåíòãåíîäèôðàêòîãðàììà ïëeíêè (ïîäëîæêà ëåéêîñàïôèð, TmSe òîëùèíà – 1,0 ìêì)

Ðèñ.7. Ïëeíêà LaBi (ïîäëîæêà ñèòàëë, òîëùèíà – 1,5 ìêì)

Ðèñ.9. Ñõåìà óñòàíîâêè äëÿ èññëåäîâàíèÿ ìåõàíè÷åñêîé ïðî÷íîñòè ïëeíîê: 1-ìàññèâíàÿ ïëèòà, 2-èññëåäóåìàÿ ïëeíêà, 3-ñòîéêà, 4-ïðóæèíà, 5-äèñê, 6-ñòåðæåíü,7ýëåêòðîäâèãàòåëü, 8-ýëåêòðè÷åñêèå ùóïàëüöà, 9-áëîê ïèòàíèÿ

Íàìè èññëåäîâàíà ìåõàíè÷åñêàÿ ïðî÷íîñòü ïëeíîê TmS, TmSe è LaBi (ìåõàíè÷åñêàÿ ïðî÷íîñòü ïëeíîê Tm2S3 íå èçó÷åíà ïîñêîëüêî, òîëùèíà ïëeíîê ïî ïëîùàäè ïîäëîæêè áûëà íåîäíîðîäíà).Òîëùèíà âñåõ ïëeíîê áûëà îäèíàêîâîé – 0,9 ìêì à íàãðóçêà âî âñåõ ýêñïåðèìåíòàõ ñîñòîâëÿëÿ 250 ãð. Ïîëó÷åíííûå ðåçóëüòàòû ïðèâåäåíû â òàáëèöå 1. Òàáëèöà 1. Îòíîñèòåëüíàÿ ìåõàíè÷åñêàÿ ïðo÷íîñòü ïëeíîê TmSe, TmS è LaBi

Ðèñ.8. Ðåíòãåíîäèôðàêòîãðàììà ïëeíêè LaBi (ïîäëîæêà ñèòàëë, òîëùèíà – 2,0 ìêì)

Ïîñëåäíåå âðåìÿ áîëüøîå âíèìàíèå óäåëÿåòñÿ ìåõàíè÷åñêèì ñâîéñòâàì ïëeíîê. Î ìåõàíè÷åñêîé ïðî÷íîñòè ïëeíîê ìîæíî ñóäèòü ïî òîé ðàáîòå êîòîðóþ íóæíî çàòðàòèòü äëÿ óäàëåíèÿ ïëeíêè ñ ïîâåðõíîñòè ïîäëîæêè. Íà ýòîì ïðèíöèïå ðàáîòàåò óñòàíîâêà ïðåäñòàâëåííàÿ íà ðèñ.9. Èññëåäóåìàÿ ïëeíêà (2) êðåïèòñÿ íà ïëèòå (2). Íà ïëeíêó îïèðàåòñÿ ñòåðæåíü (6), íà êîíöå êîòîðîé êðåïèòñÿ êóñîê çàìøè íà êîòîðóþ íàíîñèòñÿ àëìàçíàÿ ïàñòà. Ñâåðõó íà ñòåðæåíü óêëàäèâàþòñÿ ãðóçû ðàçëè÷íîé âåëè÷èíû.

Êàê âèäíî èç òàáëèöè ìåõàíè÷åñêàÿ ïðî÷íîñòü ïëeíîê íàïûëåííûõ íà îäíîé è òîéæå ïîäëîæêå óâåëè÷èâàåòñÿ ñ ïîñëåäîâàòåëíîñòüþ TmSe - TmS – LaBi, ÷òî ïî âèäèìîìó ñâÿçàíà ñ óìåíüøåíèåì ðàçíîñòè êîýôôèöèíòîâ òåïëîâîãî ðàñøèðåíèÿ ìàòåðèàëà ïîäëîæêè è ïëeíêè ñ ïðèâåäeííîé âûøå ïîñëåäîâàòåëüíîñòüþ (òàá.2).×åì ìåíüøå ðàçíîñòü ìåæäó êîýôôèöèíòàìè òåïëîâîãî ðàñøèðåíèÿ

224 ïîäëîæêè è ïëeíêè, òåì ìåíüøå ìåõàíè÷åñêîå íàïðÿæåíèå âîçíèêàåò ïðè îõëàæäåíèè ïëeíêè îò òåìïåðàòóðû íàïûëåíèÿ äî êîìíàòíîé òåìïåðàòóðû, ÷òî â ñâîþ î÷åðåäü âëèÿåò íà äåôåêòû âîçíèêøèå ïðè òàêîì îõëàæäåíèè è â èòîãå íà ìåõàíè÷åñêóþ ïðî÷íîñòü. Èç ðèñ.10 òàêæå âèäíî,÷òî ìåõàíè÷åñêàÿ ïðî÷íîñòü óâåëè÷èâàåòñÿ ñ ïîñëåäîâàòåëüíîñòüþ ìàòåðèàëà ïîäëîæêè êðåìíèé-ñèòàëë-ëåéêîñàïôèð, à èìåííî ïðî÷íîñòü ïëeíîê LaBi íàïûëåííûõ íà ëåéêîñàïôèðîâóþ ïîäëæêó âûøå ÷åì ïëeíîê íàïûëåííûõ íà êðåìíèåâóþ ïîäëîæêó. À ìåõàíè÷åñêàÿ ïðî÷íîñòü ïëeíîê íàïûëåííûõ íà ñèòàëëîâîé ïîäëîæêå çàíèìàþò ïðîìåæóòî÷íîå ïîëîæåíèå. Ýòîò ôàêò ìîæåò áûòü ñâÿçàí ñ òåì, ÷òî êîýôôèöèåíò òåïëîâîãî ðàñøèðåíèÿ ëåéêîñàïôèðà áëèæå ñêîýôôèöèåíòàìè òåïëîâîãî ðàñøèðåíèÿ ìàòåðèàëîâ ïëeíîê, â òî âðåìÿ êàê ðàçíîñòü àíàëîãè÷íûõ ïàðàìåòðîâ äëÿ êðåìíèÿ áîëüøå, à äëÿ ñèòàëëà çàíèìàåò ïðîìåæóòî÷íîå ïîëîæåíèå.

Preparation of some rare earth element compounds films and their mechanical strength

Òàáëèöà 2. Êîýôôèöèåíòû òåïëîâîãî ðàñøèðåíèÿ

zogierTi iSviaTmiwaTa elementis naerTebis firebis miReba da maTi meqanikuri simtkice

Z. Jabua, A. Gigineishvili Georgian Technical University, 77 Kostava Str. 0175, Tbilisi, Georgia.

E-mail: z.jabua@hotmail.com The method of vacuum - thermal evaporation developed technology of preparation of thin crystalline films of Tm2S3, TmS, TmSe and LaBi on different substrates – silicon, sittal andleuco-sapphire. Relative mechanical durability of the films is investigated. It is shown that the mechanical durability of the prepared films to depend on substrate material. The possible mechanism of such dependence is given

z. jabua, a. gigineiSvili

saqarTvelos teqnikuri universiteti, kostavas q. 77, 0175, Tbilisi, saqarTvelo el-fosta: z.jabua@hotmail.com

Ëèòåðàòóðà 1. GasgnierM.Rare earth compound (Oxides,Sulfides, Silicides, Boron,…) as thin films and crystalls. Phys.Stat.Solidi A.1989,v.114 , 11,p.11-71.

2. ßðåìáàø Å.È., Åëèñååâ À.À. Õàëêîãåíèäû ðåäêîçåìåëüíûõ ýëåìåíòîâ. Ì.,,,Íàóêà’’ ,1975, 258 ñ.

3. Ìàð÷åíêî Â.Í., Ñàìñîíîâ Ã.Â. Òåïëîâîå ðàñøèðåíèå íåêîòîðûõ ñóëüôèäîâ ÐÇÌ. ÔÒÒ. 1963, ò. 15, ñ. 631-635.

4. Íîâèêîâà Ñ.È., Àáðèêîñîâ Í.Õ. Òåïëîâîå ðàñøèðåíèå íåêîòîðûõ õàëêüêîãåíèäîâ ðåäêîçåìåëüíûõ ýëåìåíòîâ. ÔÒÒ. 1963, ò. 5, 7, ñ. 1913-1919.

5. Íîâèêîâà Ñ.È. Òåïëîâîå ðàñøèðåíèå òâeðäûõ òåë. Ì.,Íàóêà. 1974, 15.

vakuumur-Termuli aorTqlebis meTodiT damuSavebulia Tm2S3, TmS, TmSe da LaBi kristaluri firebis momzadebis teqnologia sxvadasxva fuZeSreze - siliciumi, sitali, leikosafironi. sruli gaxexvis meTodiT Seswavlilia TmS, TmSe da LaBi firebis fardobiTi meqanikuri simtkice, naCvenebia rom is damokidebulia fuZeSris masalaze. moyvanilia am damokidebulebis SesaZlo meqanizmi.

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Liquid-phase explosive fabrication of superconducting MgB2 composites A. Peikrishvili1,2, G. Mamniashvili3, T. Gegechkori3, B. Godibadze1, E. Chagelishvili1, M. Tsiklauri1, A. Dgebuadze1 Tsulukidze Mining Institute, 7 Mindeli str.0186, Tbilisi, Georgia; Tavadze Institute of Metallurgy &Materials Science, Tbilisi, 0168, Georgia; 3 Ivane Javakhishvili Tbilisi State University, Tbilisi, 0103, Georgia E-mail:akaki.peikrishvili@stcu.int 1 2

Abstract. Original two-stage liquid phase hot explosive compaction (HEC) procedure of Mg-B precursors above 900oC provides the formation of superconductivity MgB2 phase in whole volume of billets with maximal Tc = 38.5K without any further sintering.

The liquid phase HEC strongly solid state reaction rate similar to photostimulation, but in this case due to the high penetrating capability of shock-waves in whole volume of cylindrical billets and consolidation of MgB2 precursors near to theoretical density allows one to produce bulk, long-body cylindrical samples important for a number practical applications.

Keywords: explosion, superconductivity, consolidation, precursor, compaction

Introduction The rapid development of research of the conductors based on superconducting compound MgB2 makes them a very real prospect for technical applications at temperatures below 30 K. Reported achievements of all higher values of the critical current density in wires and tapes at moderate magnetic fields [1,2] lays out a strong hope that soon these conductors may be more economical at helium temperatures than industrial wires and cables based on NbTi and Nb3Sn. In the field of applied superconductivity, at temperatures 20 – 30 K MgB2 based conductors may seriously push out industrial tape-based HTSC materials.

Main way for getting of MgB2 is a solid-phase synthesis in particular modifications. As example, one of quite fruitful ones is the synthesis under high pressure [3]. As HTSC ceramics, compound MgB2 is brittle and therefore cannot be directly manufactured in the form of wire or ribbon. The most widely used method now to manufacture conductors based on MgB2 (as for HTSC ceramics) is the method “powder-in-tube” (PIT) [4]. It mainly is used in two ways: in situ and ex situ. In the in situ method PIT, thoroughly mixed stoichiometric mixture of magnesium and boron powders are pressed into a metallic tube, after which it runs into the wire. Superconducting core of MgB2 wire is a final result of wire annealing in temperature range, usually, 600-9500C. In ex situ PIT method, in contrast, a metal tube filled with already provisionally synthesized compound MgB2 is stretched into the wire.

Both options have their dignity and disadvantages.

In work [5], a novel method of photostimulated solidstate synthesis of oxide materials was developed enabling a dramatic increase of the solid-state reaction speed. The rate of solid-state reaction appears to be approximately two orders of magnitude higher compared with ordinary high-temperature solid-state reaction performed in furnace.

Experimental results given in [5] provide evidence of the photostimulated nature of performed solid state reaction

and demonstrated the possibility of production of HTSC and CMR oxides of light is usually limited by the sample thickness, one could expect that this method could be particularly effective in the preparation of oxide films having a high technological importance.

The current paper presents the first results of investigation of properties of superconducting MgB2 samples, obtained by HEC method. By this method similar effect for increasing speed of solid-state reaction of using photostimulated solid-state synthesis was obtained. Besides, due to the high penetrating capability of shock-waves with intensity of compression 10 GPa allows to fabricate bulk, high-density, long-body cylindrical billets with length near to 200 mm and diameter up to 30 mm. The HEC of cylindrical billets were conducted using half- automatic explosive device created at TMI allowingto consolidate different composition precursors near to theoretical density within the temperatures 20-12000C and with intensity of loading 5-10 GPa. The described HEC method allows to produce multilayer cylindrical tubes (pipes) when gap between the two metallic layers (e.g. Cu) is filled by superconducting MgB2 composites which could find important application for production of superconducting cables for simultaneous transport of hydrogen and electrical power in hybrid power transmission line with liquid hydrogen and MgB2 based superconducting cable [6].

Attempts to synthesize MgB2 using self-propagating high-temperature synthesis (SHS method) have been also reported [7].

However, the explosive compaction method to obtain highly dense MgB2 materials from Mg and B powders had not been employed until 2008 [8].

Explosive compaction of powders is widely used costeffective fabrication process due to its many advantages.

The process results in compacts of very good inter-particle bonding. The explosive compaction technique is based on the propagation of shock waves produced by a deto-

226 nating explosive, transmitting the waves through a thin steel cylindrical container to powder [8].

In this method, high shock pressure with duration of a few microseconds can be developed. Consolidation of the powder is caused by the container wall motion, accelerating towards the central axis of the container after detonation. An initial compressive stress wave is generated by explosion, followed by a sequence of wave reflections leading to collapse of the container and consequently of its content.

The result of this process is a dense compact provided that an adequate energy is released by explosion and transferred to the powder. The lack of sufficient energy leads to a highly porous material.

In [8] MgB2 samples were prepared using the PIT method, while the densification of materials was carried out under explosive loading. The experimental set-up is shown in Fig.1.

Fig.1. Experimental set-up [8]

The explosive was placed in a cylindrical tube made of PVC and the whole arrangement was mounted on a specially designed 25 mm thick steel plate which acted as a shock wave absorber. The ends of the steel container were filled with MgO powder and sealed with two plastic lids.

MgO powder was used to avoid loosing a part of Mg or B powder, since at the explosion an amount of the tube content is blown into the air together with the plastic lids.

The experiments were performed in an explosion proof room built on special foundation using PETN plastic explosive with mass ~ 350 g. A section of the sample after the explosive compaction is shown in Fig.2.

Fig.2. SEM micrograph of Mg flakes and B powder compact before sintering [8].

Since the explosive process is of a very small time duration and the maximum temperature inside of the steel container during the explosive consolidation did not exceed 250oC, which is significantly lower than the melting point of Mg 650oC ( 2000oC for B), therefore Mg and B could not react to produce the MgB2 phase. To produce MgB2, obtained compacts were heated up to 630oC with a temperature rise 5 K/min in argon atmosphere. The temperature remained constant at 630oC for 30 minutes, and then slowly rose to 960oC (with rate ~ 1 K/min) where it stayed for 90 minutes.

Then slow cooling was performed to 700oC (1K/min) and at end the physical cool-down to ambient temperature.

Synthesis of MgB2 in this case was initialized during sintering, when melting of the surface layer of Mg and following diffusion of B into Mg started. Gradually, melting not only on the surface region but also of the interior of Mg grains was performed as temperature rose and diffusion was completed leading to a fine MgB2 material as confirmed by XRD patterns.

The porosity of samples appeared to be nearly zero, indicating the importance of the explosive compaction technique when fabricating MgB2 from Mg and B powders.

Experimental results and their discussion In presented work we have applied the innovative hot explosive consolidation (HEC) method to fabricate a high dense cylindrical billets of MgB2 near to theoretical density with perfect structure and high superconductive characteristics. The offered method allows just after HEC to avoid a tedious and several hours long sintering procedure in the argon or helium gas flow [9].

The novelty of proposed non-conventional approach relies on the fact that the consolidation of solid high dense, long-body cylindrical MgB2billets from submicrometersized Mg and B powder blends is performed in two stages: 1. At the first stage a preliminary explosive compression of the precursors is carried out at room temperature with a loading intensity of 5-10 GPa to increase the initial density and to activate surfaces in the powder blend.

227 2. At the second stage the same already predensified cylindrical sample is reloaded by a primary explosive shock wave with a loading intensity of 10 GPa, but at temperatures about 1000oC. The first successful HEC of Mg-B powder blends was performed at temperature 1000 oC well above melting point of Mg phase at loading intensity 10 GPa providing critical temperature of superconducting transition Tc near 37 K, Fig.3b.

The mentioned confirms the important role of temperature in formation of superconductive MgB2 phase in whole volume of sample and corresponds with literature data where only after sintering processes above 9000C the formation of MgB2 phase with Tc=40K there took place. The difference of Tc between the HEC and sintered MgB2 composites may be explained with a rest of non-reacted Mg and B phases or existing some oxides in precursors, Fig.3a.

The mentioned could be checked by increasing HEC temperature or application of further sintering processes.

In Fig.4.views of MgB2 billets in steel jackets after predensification (Fig.4a) and after HEC procedure (Fig.4b) are shown.

In further experiments the application of pure Mg and crystalline and amorphous B powder blend prevented the formation of MgO in HEC billets and increased Tc of obtained MgB2 composites up to 38.5 K in case of pure amorphous boron powder without and postsintering of obtained samples. For these samples traces of oxidation (light places) on microstructures were not observed, Fig.6.

The experiments for HEC of precursors were performed under and above the melting point of Mg phase. The consolidation was carried out at 500, 700, 950 and 10000C temperatures with the loading intensity 10 GPa. It was experimentally established that the comparatively low-temperature consolidations at 5000C and 7000C give no results and obtained compacts have no superconducting properties.

The application of higher temperatures and consolidation at 10000C provides formation of MgB2 composition in

Fig.3. a) Traces of oxidation are observed on the microstructures (light places). b)Magnetic moment temperature dependence measurements in ZFC (zero field cooled) and FC (field cooled) modes, showing the superconducting transition at temperature near 37 K

The careful selection of initial Mg and B phases is important too and in case of consolidation Mg-B precursors with mentioned above corrections the chance to increase Tc of HEC samples essentially increases.

the whole volume of HEC billets with maximal value Tc =38.5 K without and further sintering procedure and corresponds to literature with Tc =40 K takes place.

In case of changed stoichiometry between the Mg and

228

Fig.4. Views of billets before (a) and after HEC procedure at 10000C and loading intensity 10 GPa (b).

Fig.5. Temperature dependences of the zero-field-cooled (ZFC) and field-cooled (FC) magnetic moment for HEC MgB2 composites at 10000C with intensity of loading 10 GPa in magnetic field 20 Oe. For these samples traces of oxidation (light places) on microstructures were not observed, Fig.6.

Fig.6. Microstructures of HEC MgB2 composites HEC at 10000C and loading intensity 10 GPa from pure Mg and B powder blends.

B and HEC of MgB1.8 composites at same 10000C temperature leads to the reducing Tc down to 35. K, Fig.6. The difference of Tcbetween the HEC and sintered

MgB2 compositions may be explained with rest non-reacted Mg and B phases or some existing oxides in precursors.

229

Fig.7. Magnetic moment temperature dependences in ZFC (zero field, cooled and FC (field cooled) modes at changed stoichiometry between Mg and B phases.

The mentioned could be checked by increasing HEC temperature or application of further sintering processes.

The careful selection of initial Mg and B phases is important too and in case of consolidation Mg-B precursors with mentioned above corrections the chance to increase Tc of HEC samples essentially increases.

Conclusion The liquid phase HEC of Mg-B precursors above the 9000C provides formation MgB2 phase in whole volume of billets with maximal Tc=38.5K. The type of applied B powder has influence on final result of superconductive characteristics MgB2 and in case of amorphous B precursors better results is fixed (38.5K against 37.5) in case of crystalline powder.

The purity of precursors is important factor and existing of oxygen in the form oxidized phases in precursors leads to reduced Tcand uniformity of HEC billets.

The hot shockwave consolidation procedure increases strongly photostimulationsimilar to the solid state reaction rate, but to difference to it allows one to produce bulk samples of different geometries important for practical applications.

References [1]. C.H.Jiang, T.Nakane, H.Hatakeyama, and H.Kumakura, “Enhanced Jcproperty in nano-SiC doped thin MgB2/Fe wires by a modified in situ PIT process”, Physica C. 2005, v.422, p.127-131.

[2]. M.J.Holcomb, “Supercurrents in magnesium diboride/metal composite wire”, Physica C: Superconductivity, 2005, v.423, p.103-118.

[3].T.A.Priknha, W.Gavwalek, Ya.M.Savchuk, V.E.Moshchil, N.V.Sergienko, A.B.Surzenko, M.Wendt, S.N.Dub, V.S.Melnikov, Ch.Schmidt, P.A.Nagorny, “High-pressure synthesis of a bulk superconductive MgB2-based material”, Physica C: Superconductivity, 2003, v.386, p.565-568.

[4].A.G.Mamalis, I.N.Vottea, D.E.Manolakos, “Explosive compaction/cladding of metal sheathed/superconducting grooved plates: FE modeling and validation”, Physica C: Superconductivity, 2004, v.408-410, p.881-883.

[5]. D. Daraselia, D. Japaridze, Z. Jibuti, A. Shengelaya, K. A. Müller, “Rapid Solid-State Synthesis of Oxides by Means of Irradiation with Light”, Journal of Superconductivity and Novel Magnetism, 2013, Vol. 26, No.10, pp 2987-2991.

[6]. V.V. Kostyuk, I.V. Antyukhov, E.V. Blagov, V.S. Vysotsky, B.I. Katorgin, A.A. Nosov, S.S. Fetisov, and V.P. Firsov “Experimental Hybrid Power Transmission Line with Liquid Hydrogen and MgB2 Based Superconducting Cable”, Technical Physics Letters, 2012, Vol. 38, No. 3, pp. 279–282.

[7].I.Zlotnikov, I.Gotman, E.Y.Gutmanas, “Processing of dense bulk MgB2 superconductor via pressure-assisted thermal explosion mode of SHS”, Journal of the European Ceramic Society, 2005, v.25, N15, p.3517-3522.

[8].A.G.Mamalis, E.Hristoforou, D.E.Manolakos, P.Svec, T.Prikhna, J.D.Theodorakopoulos, G.Kouzilos, “Explosive compaction and synthesis of MgB2 superconductor using the powder in tube technique”, Journal of optoelectronics and advanced materials, 2008, v.10, N5, p.1000-1004.

[9].A.Peikrishvili, G.Mamniashvili, E.Chagelishvili, B.Godibadze, M.Tsiklauri, A.Dgebuadze, and V.Peikrishvili.”Liquid-phase shock-assisted consolidation of superconducting MgB2 composites”, XII International Symposium on Explosive Production of New Materials: Science, Technology, Business, and Innovations (EPNM-2014), May 25-30, Cracow, Poland (2014).

Txevad fazian mdgomareobaSi afeTqebiT MgB2 zegamtari kompozitis miReba a. feiqriSvili1,2, g. mamniaSvili3, t. gegeWkori3, b. godibaZe1, e. CageliSvili1, m. wiklauri1, a. dgebuaZe1, 1

ssi p grigol wulukiZis samTo instituti, e. mindelis q. 7, 0186, Tbilisi, saqarTvelo 2 f.TavaZis metalurgiisa da masalaTmcodneobis instituti, 0168, Tbilisi, saqarTvelo 3 ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti, 0103,Tbilisi, saqarTvelo el–fosta: akaki.peikrishvili@stcu.int

originaluri, orsafexuriani cxlad Txevad fazuri afeTqebiT dawnexva Mg-B fxvnilebis narevis SemTxvevaSi 900oC temperaturis zemoT saSualebas iZleva yovelgvari Semdgomi Secxobis procesis gareSe miviRoT zegamtari MgB2 faza dawnexili namzadis mTel moculobaSi. miRebuli namzadebis maqsimaluri kritikuli temperaturis mniSvneloba dawnexvis parametrebisagan damokidebulebiT Seadgens Tc = 38.5K. Txevadfazian-myar mdgomareobaSi cxlad afeTqebiT dawnexvisas mimdinare reaqciebis siCqare iseTivea rogorc fotostimulirebis procesis SemTxvevaSi sadac procesebi zedapirul xasiaTs atarebs, Tumca ki dartymiTi talRebis maRali SeRwevadobis gamo warmodgenil SemTxvevaSi adgili aqvs nimuSis mTel moculobaSi Teoriuli simkvrivis maxloblobaSi MgB2 fazis dawnexvas, rac saSualebas iZleva miRebuli iqnas grZeltaniani cilindruli namzadebi sxvadasxva praqtikuli daniSnulebisaTvis.

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Investigation and design of metal to ceramic bonding technologies for particle acceleratorâ&#x20AC;&#x2122;s vacuum RF window V. Vardanyan, V. Avagyan CANDLE Synchrotron Research Institute, Acharyan 31,Yerevan, Armenia E-mail: vardanyan.vahagn@gmail.com, vvardanyan@asls.candle.am Abstract. Metal-ceramic junctions are widely using in particle accelerators as irreplaceable parts based on their unique characteristics. There are many different technologies for bonding metal to ceramics, and some technologies are developed special for particle accelerators [1]. Currently is intensively investigating, improving and designing advanced metal to ceramic junctions for different unique systems of particle accelerators.

Introduction Since 1930 is actively and intensively developed metal to ceramic bonding technologies for electro-magnetic systems and developed technologies give possibility to design and fabrication compact and more effective electromagnetic systems for particle accelerators.

For design and fabrication more effective metal â&#x20AC;&#x201C; ceramic components are necessary to satisfy all requirements, including operational characteristics. Metal to ceramic bonding technologies are combination of different important spheres and topics, including physics, chemistry, mechanics. For effective design and fabrication of metal to ceramic junctions are necessary to satisfy all possible requirements.

For create metal-ceramic junctions with appropriate characteristics are necessary investigate and design special metal to ceramic bonding technology.

In the particle accelerators the one of important metalceramic junctions are RF windows. Fig.1 and Fig.2 present types of RF windows. There are many different types of RF windows (Fig.1:- Pillbox, Fig. 2: - coaxial RF window). The important part of RF windows are dielectric part. The RF window is separated accelerators(UHV side) from RF supply (inert gas) sides.

Metal-Ceramic Components in Particle Accelerators There are many different types of designed and fabricated metal to ceramic junctions in particle accelerators.

Especially metal â&#x20AC;&#x201C; ceramic junctions are widely using in particle accelerators as Ultra High Vacuum (UHV) feedthroughs, insulators, RF windows, vacuum chambers, cathodes, etc. Each system has their special unique characteristics.

a)

Fig. 2: Coaxial RF window [2].

b)

Fig. 1. a) RF window fabricated in Calabazas Creek Research Inc. (700MHz, 1MW, CW window). b) Schematic drawing of the pillbox-type RF window [3].

231 The dielectric part must be satisfy following main parameters - transparent for electro-magnetic fields, thermal stable, good joinability with metals, easy machinability, low outgassing level, etc. As dielectric parts for RF windows are widely using vacuum ceramics like alumina, beryllia, etc. Fig. 3 shows alumina to copper junction as part of Pillobax type vacuum RF window.

ceramic bonding jonts, etc.). The mechanisms which is responsible for an RF window failure has not yet been understand in detail [3]. During design of RF windows are necessary to satisfy all factors thats give possibility to achive effective and reliable RF windows.

Design of RF windows are combination of these topics.

- Mechanical design - materials choosing, mechanical simulations, calculations, etc., - Thermal design - thermal simulations and calculations, thermoregulation system design, etc.

- RF design â&#x20AC;&#x201C; effective electromagnetic filde transporting system, effective geometry of RF window, materials characteristics, etc

Fig. 3. Alumina to copper junction for Pillbox RF window.

Mechanicaly Design of Vacuum RF Window The main requriments of RF windows are â&#x20AC;&#x201C; high mechanical strength, outgassing low level, reliable during long time, appropriate electro-magnetic parameters (including dielectric parameters of ceramic), low gas penetration, dimentional stability, thermal shock resistance. The RF windows are the one of important part at RF systems of particle accelerators.

There are many factors that can failure the RF window (high RF power, surface parameters of ceramic, metal to

Fig. 4. 3D models of Pillbox type RF window.

Fig. 5. Metal to ceramic joint based on molybdenum wire.

232 - Metal to ceramic bonding technology, Mechanically designed the Pillbox type vacuum RF window (Fig. 4,5). The construction materials chosen free oxygen copper (inner box of window), alumina F99.7 as electromagnetic transparent layer, 316SS austenitic stainless steel as flanges and outer box (the stainless steel has copper coated layer).

their characteristics gives possibility to fluently control the impaction force on alumina to copper junction during brazing procedure.

The thickness of the alumina of designed Pillbox RF window is 3 mm, the diameter of molybdenum wire is 0.5 mm.

Precented Methods and Design of Metal to Ceramic Bonding Technology for UHV Systems There are many different methods for metal to ceamic bonding [5,6]. More intensively and effectively using active and moly/manganese brazing methods for metal to ceramics in UHV systems.

Fig. 6. Scheme of diffusion welding method.

The metal-ceramic junction must be electro-magnetic transparent and simultaneously vacuum tight.

The ceramic thickness depends on RF power, electromagnetic length, mechanical strength, etc. For increase electron bombardment during RF window operation the ceramic coated TiN thin layer. Fig. 6 shows diffusion welding method by Gordiev[4]. During bonding the force is created based the molybdenum wire. Molybdenum wire based on

Fig. 7. Roughness and porosity of F99.7 ceramic.

Fig. 8. Vacuum furnace

233 Joined 316LN stainless steel to F99.7 alumina.

Firstly investigated F99.7 alumina surface layer by Zygo â&#x20AC;&#x201C; 3D optical surfae profiler (interferometric profilometer).

Fig. 7 shows the main parameters (roughness, porosity) of F99.7 ceramic.

The F99.7 is high quality vacuum ceramic. After interferometric analize prepared Mn, Mo, Si and Ti mixture with isopropile and obtained mixture is sprayed on ceramic surface (F99.7 and 22XC). The ceramic examples fixed in vacuum furnace (Fig. 8). After that achieved the high vacuum (10-5Torr) in vacuum furnace and increased temperature up to 14000C. The increasing and decreasing of furnace temperature is realizing very slowly (Fig. 10) for reducing surface stresses on ceramic. The one of important problems of metal to ceramic junctions is surface materials joinability and solder wettability including surface stresses.

After high temperature preparation cycle (Fig. 10) in high vacuum environment (10-5Torr) obtained ceramic with Mo/Mn metallized layer (Fig. 9).

The maximum temperature of furnace during Mn/Mo metallization is 14000C (keeping time 20-40min). The thickness of Mn/Mo is 10-30 Îźm. After that prepared mixture Ni with isopropile and sprayed in ceramic surface.The maximum temperature of furnace for Ni plating is 12000C and

Moly/manganes methods are realiable and effective but take more resources [6].

For metal to ceramic bonding is one of important characteristics are Coefficient of Materials Thermal Expansion (CTX). Moly/manganese methods is considering all materials parameters (including materials CTX).

Fig. 11. Scheme of new diffusion brazing methods.

Fig. 9. F99.7 alumina with Mn-Mo metallization layer and joint of 22XC (95% alumina) â&#x20AC;&#x201C; 316SS stainless steel.

Fig. 10: Mn-Mo metallization cycle for F99.7 and 22XC alumina (temperature-time

keeping time 5min,temperature increasing time is app. 10200C/min, decreasing time 3-100C/min. In vacuum environment (10-5Torr) based on 72% silver solder the F99.7 and 22XC alumina brazed with 316SS stainless steel (Fig. 9).

The brazing temperature was 7200C.

For more effective and reliable metal to ceramic bonding is important factor the force equal spread.

Invented new brazing method for different geometry dissimilar itemsand details [7]. This method gives possibility to spread force equally on interlayer zone of metal to

234 ceramic during brazing. The advantages of this method is smooth control of impaction force without considering the geometry of metal and ceramics.

Conclusions Investigated metal to ceramic brazing technologies for accelerators UHV systems (active, moly/manganese methods, etc.)- advantages and disadvantages. Realized experiment – metallized alumina used moly/manganese method, coated Ni layer and brazed with stainless steel and copper.

Investigated RF windows mechanical design, calculation, simulation and fabrication technologies.Investigated the characteristics of materials for RF windows.

Invented new brazing method for difficult geometry dissimilar items and details, for increasing metal to ceramic joining quality.

Investigated metal to ceramic joining technologies based on ceramic adhesive. Mentioned the main advantages and disadvantages as comparison between brazing and adhesive for metal to ceramic bondings for Vacuum RF windows.

Mentioned new ideas and experiments for metal to ceramic bonding without magnetic materials for electromagnetic equipments, for RF windows.

References:

Fig.12. UHV vacuum test stend

1. V.N. Batygin, I.I. Metelkin, A.M. Reshetnikov, ‘’Vacuum ceramics and its joints with metals’’, M.: Energia, 1973,Book, p.410, Russia, 2. R.C.Walton, ‘’A Continuous Wave RF vacuum Window’’, JETR(99)03, JET Joint Undertaking, Abingdon, Oxfordshire, OX14 3EA, UK,

Fig.13. Metal to ceramic junctions with adhesive and copper microstructures.

Fig.12 shows UHV test stend that gives possibility to check metal-ceramic junctions under vacuum environments, high and low temperatures.

Joined metal to ceramic and for that used adhesive based on alumina powders. In Fig.13 shows the microstructures of metal to ceramic junctions (copper to alumina).

Based on experiments this kind of junctions are unstable and ineffective in fast increasing and decreasing of temperature and also mechanical strength is low that brazed junction.

3. A.Jöstingmeier, M. Dohlus, N. Holtkamp,’’Systematic Design of an S-Band Pillbox-type RF Window’’, DESY, D22607 Hamburg, Germany, Report number: DESY-201403353, DESY-M-97-13, 1997, 4. Gordiev , ‘’Metal-alloys cathods and methods their diffusion welding’’, Invention, RF N2041529, Russian Fedaration, 09.08.1995, 5. V.V. Vardanyan, V.Sh. Avagyan, ‘’COMPARING OF METAL-CERAMIC BONDING METHODS FOR ULTRA HIGH VACUUM’’, ISSN 1829-0043, PEOCEEDINGS OF ENGINEERING ACADEMY OF ARMENIA (PEAA), 2015, V.12,N.1, P-192-195, Yerevan

235 6. WALKER AND V. C. HODGES,’’ Comparing Metal-Ceramic Brazing Methods’’, Brazing and Soldering Today, Welding Journal, October 2008, P. 43-50, https://app.aws.org/ad-index 7.VardanShavarshAvagyan, VahagnVanikVardanyan,’’Diffusion brazing methods of difficult geometry dissimilar items and details’’, Patent number – AM201453, Inrellectual Property Agency of the Republic of Armenia, N 2883 A, 25.11.2014

metalebis keramikasTan SemakavSirebeli teqnologiebis kvleva da damuSaveba nawilakebis amaCqarebeli vakuumuri RF sarkmelebisaTvis v. vardaniani, v. avagiani

kandeles sinqrotronuli kvleviTi instituti, axarianis q. 31, erevani, somxeTi, el-fosta: vardanyan.vahagn@gmail.com, vvardanyan@asls.candle.am metal-keramikuli kontaqtebi farTod gamoiyeneba nawilakebis amaCqareblebSi, rogorc Seucvleli kvanZebi, dafuZnebuli maT unikalur maxasiaTeblebze. cnobilia mravali sxvadasxva teqnologia metalis keramikebTan SesakavSireblad da damuSavebulia teqnologiebi specialurad nawilakebis amaCqareblebisaTvis [1]. amJamad sruldeba metal-keramikebis kontaqtebis kvlevebis gaumjobesebisa da proeqtirebis intensiuri samuSaoebi nawilakebis amaCqareblebis sxvadasxva unikaluri sistemebisaTvis.

236

Functionally graded polymer composites with electric and magnetic properties J. Aneli1, L. Nadareishvili2, M. Bolotashvili2 R.Dvali Institute of Machine Mechanics, Mindeli str., 10, 0186, Tbilisi, Georgia V.Chavchanidze Institute of Cybernetics, Tbilisi, Georgia E-mail:jimaneli@yahoo.com 1 2

Abstract. The character of variations of the local electric resistance of film polymer composites on the basis of polyvinyl alcohol with graphite powder from one side and the magnetic susceptibility of the same polymer with nickel nano-particles from another one have been studied. It is established that the changes of these parameters essentially depends on both initial shape of the films and on direction of their orientation. It is concluded that the films of gradiently anisotropic polymer composites may be used in electronics.

Keywords: polymer films, composites, stretching, anisotropy, local electrical resistance, magnetic susceptibility

Introduction It is well known that there are several methods for obtaining of materials with anisotropic properties by chemical methods (copolymerization, polymer-analogous transformation, radiation 窶田hemical modifications, etc.) [1, 2].

At present for obtaining of such structures one of the best methods is the orientation of polymer films in the definite direction and environment conditions. It is known also that at stretching of thermoplastic polymers above glass temperature the material in orientation state is formed. Such polymers are characterized with mono-axis crystal symmetry. In this state the principal direction of macromolecules coincides with the direction of stretching. If the polymer filled with different dispersive fillers, particularly with electric conductive and magnetic materials (graphite, carbon black, metal powders), the particles distribution of lasts interacting with macromolecules transform from chaotic state to orientation one. The change of polymer microstructure significantly defines the material electric and magnetic properties [3, 4].

In the presented work the character of change of electric conductivity and magnetic susceptibility of polymer composite films based on polyvinyl alcohol, graphite and nickel at their mechanical stretching has been investigated.

Basic part

The films were prepared with using of following technology: The water solution of fine grained graphite (average diameter of grains less than 10 micrometers) or nickel (average diameter of grains less than 20 nanometers) suspensions in polyvinyl-alcohol were prepared. The mixture was filtrated and the film was formed on the dryer table.

The specific volumetric electric resistance of the polymer films was changed in the interval 10-50 kOhm.cm. The selection of such interval of the composite resistance was dictated by preliminary selection of conducting composites effectively reacted on the mechanical deformations [4]. The composites contained the magnetic filler are characterized simultaneously both electrical and magnetic properties.

The experiments were carried out on the basis of polymer composite films with rectangle and trapezoidal shape.

The thickness of films was no more than 0.2 mm. The deviation of the values of resistance for any local region of the film was no more than 10%. These films were fixed in special clamps, placed to the heater and were stretched on 50150% at rate 50 cm/min and temperatures 100-120oC. Stretching was conducted for rectangle form sample along big side and for trapezoidal sample in parallel to bases direction (Fig.1 and 2).

Fig.1. Rectangle (A) and trapezoidal (B) shape films before (top) and after (bottom) stretching along big sides

After stretching of the deformed films local ohmic resistances were measured. First of all, it was necessary to mark the film with square grid. In our case the length of square side was equal to 5 mm. The local resistances were measured by using of twin needles after touching them to the film. The measuring of resistance of elementary cages were performed several times and than the average values of resistances were calculated.

Another series of investigations were proceeded on establishment of local magnetic characteristics of gradiently-anisotropic magnetic polymeric composites with magnetic powder fillers like nickel powder.

237 The films from magnetic polymer composites were subjected to the similar stretching procedure as it was previously described.

The resulting distribution of magnetic particles density in polymer composites was recorded by the method of LC-generator similar to the one used by us in work [5] for NMR detection in europium garnet at low temperatures.

It is also interesting to note that a similar method was used for the first precision determination of the magnetic field penetration length in superconductors [6].

Fig.2. Scheme of the measuring of the magnetic characteristics of the polymer films. 1 – Sample, 2 – ferrite tip, 3 – support, 4 – frame

For assessment of magnetic susceptibility distribution over the surface of gradient magnetic films it was used a LC generator of sinusoidal oscillations [5].

The procedure of measurements of the magnetization changes is realized through the sensitive detection of the change of inductance of the LC generator oscillatory contour coil supplied with a tipped ferrite rod core at scanning by it over the investigated surface (Fig. 2). In whole, the susceptibility measurement system consists of the following stages: LC generator, emitter follower for cascade matching, sinusoidal oscillation amplifier and frequency meter.

The frequency of LC generator oscillatory contour is defined by its fixed total capacitance and inductance. The oscillatory contour is an isolated system and tuned on a reference frequency providing its operation on the maximal sensitivity as result of which the slightest contour inductance changes result in the significant changes of its frequency.

Let us note that the induction coil of oscillatory contour was brought away on 30-40 cm from the LC generator by a screened transmission line and the contour inductance with its spurious capacitance enters into contour effective parameters.

The frequency detuning is possible using a 2 mm thick and 15mm long tipped ferrite core put into the coil during its scanning over the film. Namely this principle is used for the definition of the contour quality factor change expressed in the frequency units. During the displacement of coil having a tipped ferrite core near the surface of the gradiently magnetized film surface the change of coil inductance takes place which is followed by the corresponding change of LC generator frequency in a quite significant range giving one possibility to evaluate the change of value of the real part of susceptibility related to frequency.

The experimental set-up is presented in Fig.2. In the inductive coil of the resonance contour of LC-generator it is placed cylindrical tipped ferrite rod used as probe. The investigated rectangular shape magnetic polymer composite

film is displaced relatively the immovable ferrite tip. The scanning of the film surface is realized along the previously marked net contour (Fig.3 ).

Fig.3. Scheme of ferromagnetic film for investigation of the local magnetic susceptibility along directions 1-1, 2-2 and 3-3; dotted line – the middle of the film

Measurements of the dependences F – l were provided with using of the ferromagnetic film, the scheme of which is presented in the Fig. 3.

The change of magnetic particle concentration causes the change of inductance δL of the resonance contour of LC-generator resulting in the frequency displacement of LC-generator df related with dL by relation δf/f =1/2δL/L. This frequency displacement could be precision measured what stipulates the high sensitivity of the method.

At the natural frequency of used LC-generator near ~ 2 MHz the observed range of the frequency change df was about ~ 1000 Hz at the precision of the frequency measurement ~ 1 Hz. As a result of measuring of local resistances of oriented along the parallel to long side of the rectangle shape samples it was established that maximum change of this parameter was noticed along symmetry axes of the rectangle along orientation direction. This change has an extreme character (the maximum is at the central part of the film) and its full shape has Gaussian form. Fig.4 shows that the maximums heights of the local resistances depend on the value of stretching. This result is in good agreement with the known conception on the mechanism of conductivity of conductive polymer composites [3]. Investigation of obtained films using of the metallographic microscope shows that the average optical density of penetrated light through the film nearly exponentially depends on the ordinates of the elementary squares. Therefore it may be proposed that the dependence of concentration of the conducting particles in the local regions of the film has the same character. However the basis of such distribution of the filler particles in the uniaxially stretched polymer composites is not yet clear.

By analogical shape of the same dependence is characterized the one of local resistances in rectangle to stretching directions, although these dependences are somewhat weaker.

It was interesting to establish the character of considered above functional dependences of the local resistances on the concentration of the electric conducting particles.

Fig.4 shows that the increase of filler concentration leads to reduction of the intensity of resistance change at stretching. This phenomenon may be described by following processes. It is known that the filler particles at stretching of polymer composites commit the mutual transition in the polymer matrix initiated by interacting with them macromolecules segments, in result of which the average distances between these particles and consequently the charge transition change accordingly [7]. Here the inverse processes – approach and removing of the particles and consequently the

238 probability of creation of the conducting chains changes respectively. However in case of composites with high concentrations of the conducting particles the probability of arising of new contacts between ones is higher than in opposite case, since the frequency of these elementary processes is higher than in case of composites with relatively low concentrations of these particles. Here the described process is analogical to reserving of the switching conducting chains in the complex electrical engineering schemes.

The obtained results show that the process of displacement of the conducing particles and consequently the change of conductivity take place more intensively in the middle part of the stretched polymer film than in other ones, namely, this change has gradient character with increasing from grips till middle of the film. The amount of this gradient is the higher the lower is filler concentration.

Fig.5. Dependence of local resistances of films on the stretching degree for composites based on PVA containing 30 (1), 40 (2) and 50 (3) mas.% of graphite powder (curves correspond to left half side of central strip of the film

Fig.4. Dependence of local resistances of polymer film on the value of stretching parallel to long side of the rectangle on 50(1), 100(2) and 150%(3). The curves maximums are located on the central line with abscissa coordinate â&#x20AC;&#x153;0â&#x20AC;?

a)

The following series was fulfilled on the trapezium shape conducting films. Here was created the mechanical stretch gradient in perpendicular to base direction, along which the stretching was realized. This gradient was increased from big base and was ended at more stressed small base with maximum.

The experimental data on the definition of character of the dependence of distribution of the local resistances on stretched both rectangle and trapezoidal form films on their coordinates show that the shape of these dependences essentially is defined mainly by two factor: a) the content of electrical conducting fillers in the selected part of the stretched film and b) distribution of conducting particles in the polymer matrix after stretching along selected direcb)

Fig.6. Dependences of local resistances on the film (PVA with 25 mas.% graphite) coordinates in the strips stretched on 150% parallel to bases of trapezoidal shape films in perpendicular to stretching direction from big base to small one (a) and parallel to stretching direction from small base to big one (b). The numbers on the curves indicate the numbers of stripes in perpendicular (a) and parallel (b) to stretching direction. The curve number 5 of Fig.6,b corresponds to central strip of trapezoidal film and others â&#x20AC;&#x201C; to side from it ones (4-3-2-1). The asymmetry of the curves on the Fig.6, a is due to certain inhomogeneous distribution of the filler particles in polymer matrix.

239 tion. Nonlinearity of the dependence of local electrical conductivity both along and perpendicular direction of stretching is explained mainly by the nature of the conductivity of the polymers filled with conducting particles. Namely it is well known that the charge transfer in such systems obey to tunnel mechanism –nonlinear dependence of the conductivity on the distance between neighbor particles.

In the Fig. 7 the results of measurements of generator frequency change along contour lines 1-1, 2-2 and 3-3 are presented. Similar results are obtained at measuring of magnetic susceptibility of film along rectangular to 1-1, 2-2 and 3-3 directions.

3. Gradient distribution of the local resistances in the stretched films along and rectangle to stretching direction is due to gradient of local deformations in the same directions.

4. The gradient distribution of magnetic particles in the stretched direction leads to equivalent change of magnetic properties of these films.

5. The experiments described above open the perspectives in the field of creation of the films with desirable anisotropy of electric conductance and magnetic properties. The perspective is in application of these materials for creation of the so called printed schemes. In electronics these films will be useful for preparing of multifunctional micro-schemes.

References

Fig.7. Dependences of the oscillation frequency of the ferrite sensor on the coordinates of film made from polymer composite along directions 2-2 (1), 1-1 (2), 3-3 (3)

The presented results show that for magnetic polymer composite films with rectangle shape the dependences F – l have similar form, as was obtained for conducting polymer composites (R -l) with same shape. Such resemblance is based on similar character of distribution of the filler particles- conducting ones in rectangle electrical conducting polymer composites and magnetic particles in the magnetic analogues after their uniaxial stretching, because the maximums of curves of dependences of the local resistance on film coordinates correspond to rarefied regions of these films and the maximums of the curves F –l correspond to those regions - frequency increases, when magnetic particle concentration decreases and, consequently, local susceptibility and inductance decrease.

Results of detailed measurements will be published elsewhere.

Conclusions 1. Gradiently anisotropic structures are form after orientation (stretching) in spatial conditions of thin polymer composites based on polyvinyl alcohol, graphite and nickel powders with electrical conducting and magnetic properties. Structure anisotropy leads to anisotropy both electrical conductivity and magnetic properties of these films.

2. After orientation of the rectangle films parallel to it any side forms the film, electrical resistance of which parallel and rectangle directions to orientation axis changes by Gauss low.

1. Lekishvili N. G, Nadareishvili L.I. Polymers and polymeric materials for the fibre and gradient optics / VSP (UtrechtBoston-Köln-Tokyo), 2002, -230 p.(Monograph).

2. Nadareishvili L. GB-optics–a new direction of gradient optics/ /J.Appl.Pol.Sci.2004,v.91,489-493.

3. Aneli. J.N, Khananashvil L.M., Zaikov G.E.. Structuring and conductivity of polymer composites. Nova Sci. Publ. N. – Y.1998, -326 p.

4. Aneli J.N., Khananashvil L.M.., Zaikov G.E.. Effects of mechanical deformations on structurization and electric conductivity of polymer composites.//J.Appl.Pol.Sci. 1999, v.74, p.601-621.

5. Method of NMR recording in magnetoordering materials.

USSR Patent ¹ 279893 (1988).// Pavlov G.D., Chekmarev V.P., Mamniashvili G.I., Gavrilko S.I. 6. Schawlow A.L., Devlin G.E. // Physical Review, v.113, No. 1, 1959, pp. 120-126.

7. Aneli J.N., Zaikov G.E., Mukbaniani O.V: Chemistry and Chemical Technology, 2011, 5,75-82.

funqcionalurad gradientuli polimeruli kompozitebi eleqtruli da magnituri TvisebebiT j. aneli1, l. nadareiSvili2,

m. boloTaSvili2

1 r. dvalis manqana-meqanikis instituti, mindelis q. 10, 0186, Tbilisi, saqarTvelo 2 v. WavWaniZis kibernetikis instituti, s. eulis q. 5, 0186, Tbilisi saqarTvelo el-fosta: jimaneli@yahoo.com

Seswavlilia erTis mxriv polivinilis spirtisa da grafitis nanofxvnilebis bazaze miRebuli firiseburi kompozitebis, xolo meores mxriv amave polimerisa da nikelis nanofxvnilebis bazaze miRebuli kompozitebis magnituri Tvisebebi. dadgenilia, rom am parametrebis cvlileba mniSvnelovnad aris damokidebuli rogorc firebis sawyis formaze, aseve firis orientaciis mimarTulebaze. gamoTqmulia mosazreba gradientulad orientirebuli anizotropuli polimeruli firebis eleqtronikaSi gamoyenebis Sesaxeb.

240

General Overview of Synthesis and Properties of a New Group of Inorganic Polymers - Double Condensed Phosphates M. Avaliani Ivane Javakhishvili Tbilisi State University R. Agladze Institute of Inorganic Chemistry and Electrochemistry E-mail: avaliani21@hotmail.com Abstract. Presented data are the overview of synthesis and investigation of double condensed phosphates and examination of their properties in correlation with advances in the sphere of inorganic polymer’s chemistry.

During last decennary more of 65 new formerly unknown double condensed oligo-, poly- and cyclophosphates have been synthesized by us, including the first representatives of double cyclooctaphosphate and cyclododecaphosphate classes.

These achievements containing the heterocyclic and/or poly- phosphorous anions are distinguished in the important publications in France Germany and in Russia.

Keywords: Polymer’s chemistry, condensation, phosphates, synthesis.

Introduction The significant capacity of condensation of phosphoric anions is recognized approximately two centuries.

By academician I.V. Tananaev the chemistry of inorganic compounds of phosphorous has developed intensively in the last few years for the some major reasons that, first, the phosphate compounds are most suitable for further development of the chemistry of inorganic polymers, and, second, they are finding ever increasing practical application as fertilizers, detergents and as materials used in engineering and construction.

Generally speakingthe increase of condensed crystal chemistry was due to the very rapid development during last 30-40 years of progressive methods of analysis, as well as to the evolution and achievements in this domain of chemistry; numerous cyclophosphates with diverse formula were obtained and described in chemical literature last years; however, usually, the intolerable perplexing classification was used in chemical literature. One of the first necessary endeavour for the progressive classification vas made by AndréDurif and Marie-ThérèseAverbouch-Pouchot.

Condensed phosphates of polyvalent metals, notably double phosphates containing alkali metals possess a number of rather interesting and valuable, appreciable properties, which explains prospects of their application. Actually anions are known for n=3, 4, 5, 6, 8, 9, 10 and 12 [1-8].

High thermal stability, elevated content of phosphorus – these preconditions have caused their application as raw components for manufacture of phosphates glasses, the use of crystalline and non crystallineultraphosphates in quantum electronics are predetermined by specific properties.

It is necessary to observe, that some compounds of cyclophosphates vas primarily synthesized, firstly examined and determined by us, sometimes in collaboration with Dr.

N. Chudinova and academician I. Tananaev[3-6, 1, 8-10].

In fact the achievements obtained by methods and direction of researches, named “Scientific School of Tananaev” in the vast and extensive domain of condensed phosphates isvery remarkable.

It is recognized that sufficient stability of polymeric phosphates in this respect makes it possible to identify and categorize them by the method of paper chromatography. This fact permitted scientists to examine the process of formation and the composition of many normal, basic and/or acid of both simple and double di—, tri—, tetra-, octa and dodecaphosphates of polyvalent metals. This method together with the chemical analysis, IR—spectroscopy, thermogravimetry, X-Ray diffraction, structural analysis was used by us.

The present data is the result of our studies – synthesis, analysis, examination of the experimental records and their comparison and/or correlation which achievements in the domain of inorganic polymer’s chemistry [3-6, 8, 1-2].

Condensed phosphates of polyvalent metals, notably double phosphates containing alkali metals possess a number of rather interesting and valuable, appreciable properties, which explains prospects of their application.

Thus, high thermal stability, elevated content of phosphorus – these preconditions have caused the various applications as raw components for manufacture of phosphates glasses, the use of crystalline and evennoncrystallineultraphosphates in quantum electronics are predetermined by their specific properties.

We synthesized many new double condensed oligoand cyclophosphates, whose general properties we have examined [8, 3-6];It was executedsystematic investigation of MI2O-M2IIIO3-P2O5-H2O at 100!-600!, where MI - are alkali metals and partially – Ag,MIII -Ga, In, Sc and partially Al. In addition exhaustive investigation of systems Ag2O-M2O3 at 100! -600! is on the stage of analysis and examination.

241 Many compounds were wholly examined and the structures are determined by X-ray structural techniques [4-6, 1].

Therefore, presented data are the results of synthesis, analysis, examination of the experimental records, determination/ classification of a new compoundsobtained by us and evaluation of their properties in correspondence with accomplishments and advances in the area of inorganic polymer’s chemistry [3-6, 2, 7].

During last years more of 65 new formerly unknown double condensed phosphates have been obtained, e.g. polyphosphate LiGa(PO 3 ) 4 , cyclotetraphosphate NaGaP4O12 and including the first representatives of double cyclooctaphosphate class K 2 Ga 2 P 8 O 24 and Rb2Ga2P8O24 were obtained by M.Avaliani& N. Chudinova [8,5], crystal structure was examined and described [5-6, 1]. The structure of is presented in figure 2 (in fact it’sreminds slightly the crown-ether).

One of primary synthesized cyclododecaphosphates: Cs 3 Ga 3 P 12 O 36 (fig.3), similarlyCs 3 In 3 P 12 O 36 and Cs3Sc3P12O36 - all compounds have been obtained and determined by us [10-12], (see also detailed and interesting publication/as a references[7]).

These achievements, including the successful synthesis of the first representatives of double cyclooctaphosphateclasss – K2Ga2P8O24 and Rb2Ga2P8O24 are noted, cited and distinguished by many scientists/authors in many important publications [11-2, 6, 9, 5 etc.].

Below some synthesized condensed compounds are presented; In fact they are inorganic oligomers or polymers, sometimes containing the heterocyclic anions; It is also indicated the temperature range of crystallization of condensed compounds during interaction in the various systems.

Study of the reaction in the MI2O-M2IIIO3-P2O5-H2O systems attemperature range 100(120)0C-5500C where M I-are alkaline metals and III M – trivalent metalsGa and In. Molar ratio P/MI/MIII was variable: 15/2,5/1; 15/3,5/1; 15/5,0/1; 15/6,0/1; 15/7,5/1; 15/ 10,0/1. All condensed compounds were identified by roentgen phase analysis and investigates thermogravimetrically, many compounds was wholly examined by X-ray structural techniques [3-6,8, 13].More interesting obtained compounds are presented in the table 1.

In addition it was synthesized some polyphosphates M(PO3)3, e.g. Ga(PO3)3, In(PO3)3 in various forms.

Interactions resulting the reactions in the MI2O- Sc2O2P2O2-H2O - systems at temperature range 100(120) – 550°C. Revealed dependency of compound’s composition from synthesis temperature and molar ratio is presented in schemes (1 and 2) On the scheme (3) is presented dependency of composition and stability of double condensed phosphates of trivalent metals (crystallised in melts of polyphosphoric acids) from ion radius of MIII (the radiuses are determined perBelov-Bokyii for coordination number 6 - for Al-In and for coordination number 8 - for La-Lu, Bi).

Dependency/reliance of composition of synthesized compounds from temperature range of crystallization during interaction in the system Cs2O-Sc2O3-P2O5-H2O and on themolar ratio Cs2O/Sc2O3 (n) is presented in the table 2; The experimental data on primarily synthesized compounds of Cesium-Scandium, notably concerning cyclododecaphosphate Cs2Sc3P12O36,ultraphosphate Na3ScP8O23 and cyclotriphosphates was published by us in works [10-13, 3], the structure and detailed information and references more-

Table 1. Synthesized phosphatesin systems MI2O-M2IIIO3-P2O5-H2O

242 Schemes 1-2. Dependency of compound’s composition VS the temperature and the molar ratio

Scheme 3. General dependency of composition and stability of double condensed phosphates from ion radius of Study of the reactions in the MI2O-Sc2O3-P2O5-H2O systems at temperature range 120(130) – 550°C (MI=Cs)

over data about conditions of cristallization is described in an important and interesting work of scientists Murashova and Chudinova [7].

More remarkable synthesizedcondensed phosphates during investigation of the system MI2O-Sc2O3-P2O5-H2O are presented below (Table 2); Molar ratio for P/MI/MIII was very variable: 15/2,5/1; 15/3,5/1; 15/5,0/1; 15/6,0/1; 15/ 7,5/1; 15/10,0/1; And moreover: 15/2,5/1,5; 15/3,5/1,5; 15/ 5,0/1,5; 15/6,0/1,5; 15/7,5/1,5; 15/10,0/1,5.

Table 2. Synthesized phosphates in the systems MI2O-Sc2O3-P2O5-H2O

243 Table 2. Reliance of composition of condensed phosphates from temperature and on the molar ratio Cs2O/Sc2O3 (n)

Fig.2. Dimer LiGaO6 - Fragment of {LiGa(PO3)4}x polyphosphate’s chain link

In fact the systems, containing Ag-Scneeds to be thoroughly explored in more depth which is the objective of our study at present time.

We will be noted briefly about structures of some cyclophosphates synthesized by us.

The projection of the structure double polyphosphate of Lithium-Gallium {LiGa(PO3)}x along axe Y is presented at the figure 1 and 2[see also publications 8,5].

The structure of synthesized cyctooctaphosphate K2Sc3P8O24 is presented at the figure 3.

The crystals of are monoclinic, space group A2/m, with a 5.138(3), b 12.290(5), c 16.802(13) Å, and ? 101.04(5)°; density (exptl.) = 2.55 for Z = 2. The structure was solved by the heavy-atom and Patterson methods and refined by least-squares to R = 0.041. The structure consists of P8O24 cyclic rings of PO4 tetrahedrons with inversion-centers and mirror plane symmetry elements. The Ga atoms are octahedrally coordinated to 6 O atoms. The K is coordinated to 6 O atoms in a distorted trigonal prism …[8, 13, 5, 1 ].

Fig. 1. Projection of the structure of polyphosphate {LiGa(PO3)}x along axe Y

Fig.3. Projection of the cyctooctaphosphatealong K2Sc2P8O24 axe X

244 On the figure 4 is presented the fragment of cyclooctacycle: the hexamer K2Ca4O30

Fig. 4.The fragment of cycloocta- cycle - the hexamer K2 Ca 4O 30

The structure of synthesized cyclododecaphosphate Cs3Ca3P12O36 [8, 4 ] is presented at the figure 5.

So, by crystallization from melts of polyphosphoric acids at the temperature range of 100(120)-550°C we are obtaining more than 65 double condensed phosphates of monovalent and trivalent metals; all compounds, or practically almost entities were identified by roentgen phase analysis and investigates gravimetrically, thermo gravimetrically, by paper chromatography method, [3-6, 8, 10-13], many compounds was wholly examined by X-ray structural techniques, described in works [8-10, 14, 1].

Fig.5. Projection of thecyclododecaphosphate CS3Ca3P12O36 on the plane xy

The physical and chemical properties of phosphates are evaluated. In addition detailed investigation of system MI2O-MIII2O3-P2O5 -H20 at 1500C -500 !, where MI=Ag is on the stage of definitive examination and analysis of results.

Discussing about the range of M IM III(PO3)4 compoundsâ&#x20AC;&#x2122; structures where isconstantly alkali or any other monovalent metal and where is any trivalent metals such as Gallium, Indium, Scandium and others, even rare earth elements, it can be concluded: While the radius of M+3decreases, the polyphosphate chain identity period increases, due to complication of its form-factors; the cycles slowly appears, the number of structural types increases caused by correlation of average distances between MIII=0) and (MI-O).

Less is the correlation / ratiomore is the probability of big cycle formation. Optimum fulfilment for the realization of the big cyclic anions is parity of big cation of monovalent metal versus trivalent metals with small ion radius.

References 1. I.V.Tananaev , Pure & Appl. Chem., Vol.52, Pergamon Press Ltd. (1980) p.1099-1115.

2. A. Durif, Solid State Sci. Vol.7 ; 2005, p. 760-766.

3. M. A. Avaliani, I.V. Tananaev; Intern.Conf. on Phosphorus chemistry, Talinn.Abst., 39, 1989.

4. Grunze, I.; Palkina, K.K. ;Chudinova, N.N. ; Avaliani, M.A. ; Energy Citations Database; Inorg. Mater. (Engl. Transl.); vol.

23:4, p. 539-544; System Entry Date- 2009 OSTI ID: 5847982.

5. K. Palkina, S. Maksimova, N. Chibiskova, Neorgan. Mater., Vol. 12, N1, 1981, p. 95-100.

6. I.V. Tananaev, X. Grunze, N.N. Chudinova; Neorgan.Mater., vol. 26, N6, 1984, p. 887-900.

7. E.V. Murashova, N.N. Chudinova; Double condensed phosphates of caesium-indium, Neorgan.Mater., vol. 37, N12, 2001, pp. 1521-1524 8. M. Avaliani, Synthesis and investigation of Condensed phosphates of Gallium and Indium, Doct. Thesis, Moscow, N. Kurnakof inst., 1982, p.185.

9. Tananaev, Grunze X, Chudinova ,Neorg. Materialy, T.20, N6, 887-900,1984 10. A. Oudahmane, D. Avignant, D. Zambon, Dipotassiumdialuminiumcyclooctaphosphate, Structure reports online, Vol.2, part 7, 2010, pp. 149-150 11. I .V. Tananev, M. A. Avaliani, N.N. Chudinova, M.K. Gvelesiani, V . N. Gaprindashvili; Condensed phosphates of Scandium, Gallium and Indium. 1. Synthesis and temperature range of crystallisation of solid phases; Proceeding of Georgian Academy of Sciences, Macne, Chem.. Series, vol. 15, N2, 1989, pp. 91-96 12. M. A. Avaliani, M.K. Gvelesiani, V . N. Gaprindashvili; General appropriateness, relevancies and domains of crystallisation of phosphates of Scandium with alkali metals and formation of oligo-, cyclo- and polyphosphates. Proceeding of Georgian Academy of Sciences, Macne, Chem.. Series, vol. 25, N1-2, 1999, pp. 9-15 13. M. Avaliani, M. Gvelesiani, Areas of crystallization of condensed scandium and caesium phosphates and regularities of their formation, Proceeding of the Georgian Academy of sciences, vol. 32, N1-2, 2006, pp. 52-58

245 14. M. Avaliani, M. Gvelesiani, B. Purtseladze, V. Kveselava, P. Nikoleishvili, G.Gorelishvili, R. Chagelishvili, N. Barnovi; Inorganic Polymers: Double Condensed Phosphates of monoand polyvalent Metals - General overview. International Conference of “Innovative Technologies in Metallurgy and Materials Science”, abstr.18; July 16-18, 2015 Tbilisi, Georgia 15. K. K. Palkina, S. I. Maksimova, V. G. Kuznetsov, N. N. Chudinova; Structure of crystals of double octametaphosphate Ga2K2P8O24,”, DokladyAkademiiNauk SSSR, [Crystallogr.] 1979, 245(6), 1386-9

ormagi kondensirebuli fosfatebi, rogorc araorganuli polimerebis axali klasi, maTi sinTezi, kvleva da Tvisebebis zogadi mimoxilva m. avaliani

Tsu, r. aglaZis araorganuli da eleqtroqimiis instituti, mindelis q. 11, 0186, Tbilisi, saqarTvelo el–fosta: avaliani21@hotmail.com samuSao warmoadgens Cvens mier pirvelad sinTezirebuli mono- da polivalenturi metalebis ormagi kondensirebuli fosfatebis sferoSi kvlevebis mimoxilvas, fosfatebis Tvisebebis Seswavlasa da monacemebis analizs araorganuli polimerebis dargSi arsebul miRwevaTa gaTvaliswinebiT da maTTan korelaciaSi. bolo ori aTwleulis manZilze Cvens mier sinTezirebulia 65-ze meti axali, dRemde ucnobi ormagi oligo-, poli- da ciklofosfati, maT Soris msxvili cikluri fosfatebis warmomadgenlebic, iseTebi, rogoricaa ormagi ciklooqtada ciklododekafosfatebi.

Cveni es miRwevebi msxili cikluri da polimeruli fosfatebis miRebis dargSi gaSuqebulia ucxouri mkvlevarebis mier TavianT solidur publikaciebsa Tu monografiebSi safrangeTSi, germaniasa da ruseTSi.

246

Utilization of Scrap Tires by Low-Temperature Pyrolysis and Investigation of Obtained Products P. Tushurashvili, D. Chorgolashvili, T. Khuchua, N. Kobaladze, M. Alelishvili, E. Gelashvili LEPL L. Samkharauli National Forensics Bureau, 84 Chavchavadzeave., Tbilisi Georgia E-mail: NKobaladze@expertiza.gov.ge Abstract. Utilization of scrap tires by low-temperature pyrolysis can be disposed of in an environmentally sound alternative (gaseous, liquid and solid) fuels and metalokordis reception, who have wide application and demand in the market. It is estimated that in order to carry out low-temperature pyrolysis process (temperature, pressure, used raw materials and so on), obtained various products with different chemical composition and properties.

Keywords: Utilization, Pyrolysis, Scrap Tires, Alternative fuels.

Introduction Nowadays the utilization and preservation of scrap tires is a worldwide problem. The scrap tires supply compose 25 million tones across the world and the number increases by 7 million tones annually. Most of the used tires accumulate in landfills, they are bulky and do not degrade. Currently only 23% are consumed in various ways i.e., used tire market, recap market, rubber reclaim market, ground rubber for road surface and sporting square, energetic purpose- scrap tires give more heat than coal (10-16%), in cement industry as a filler and other uses. The other 77% are dumped in landfills or junk yards and cause health, safety, and environmental problems and lack of suitable non-deficient method does not occur utilization.

Utilization of scrap tires by low-temperature (250-3000C) pyrolysis represents environmentally-friendly technology (See device conditional construction). It is based of rubber decomposition by its components. For this purpose, rubber thermal decomposition took place in the inert atmosphere by the hot steam. The tires are loaded in the reactor and pyrolysispasses at 250-3000C, as a result 1) Pyrolysis gases; 2) Char; 3) Metal cord; 4) pyrolysis liquid products, are processed.

Low-temperature pyrolysis process’s advantage is that it does not consume high energetic expanses, pyrolysis products don’t fall into environment, as a result does not form residue, products have wide use and high demand in the market, that’s why it represents an alternative environmentally-friendly processing and at the same time enables you to gain useful products [1-5].

3) Metal cord – elemental and phase composition by the X-Ray spectral and phase analysis (difractogram, Fluorescent spectrum); 4) It is investigated physical and chemical characteristics of liquid products obtained by means of low-temperature pyrolysis process of scrap tires: density at 200C, pour point, flash point in PM cap, distillation range, kinematic viscosity at 200C, water and contaminants content, water soluble acids and bases, ash, carbon residue of 10% remains, acidity, corrosiveness to copper, sulfur content (table 3).

Table 1 Pyrolysis gases composition CH4 C 2H 6 C 3H 8 C4H10 - Isobutan C4H10 C5H12- Isopentan C5H12 C6H14 CO2 N2 H2S

% mol 15.2700 1.4222 2.2679 0.2642 3.0076 0.0776 0.2167 0.0097 7.4852 68.3184 1.6604

Table 2

QHigh QLow WHigh WLow

Specific heat and Wobbe number KJ/M3 Kcal/ M3 13627.1410 3254.7867 12440.7983 2971.4336 28406.0903 6784.6781 25933.1313 6194.0220

Materials and Methods It is investigated physical and chemical characteristics of gaseous, liquid and solid products, obtained by lowtemperature pyrolysis process of scrap tires: 1) Pyrolysis gases –Detailed composition, Specific heat and Wobbe number by the standards “Gost 22667”, “Gost 30319.1” (table 1,2); 2) Technical char – Carbon (83-84%) and Ash content (16-17%);

Hydro-carbonic composition of the above mentioned liquid is examined by 2 dimensional gas chromatograph with time of flight MS-detector (LECO PEGASUS 4D GC×GC -TOFMS). For this study, the primary analytical column was a 50.0 m x 0.2 mm ID x 0.5 μm RTX-DHA-50. The secondary column was a 1.67 m x 0.1 mm ID x 0.1 μm BPX-50.

The temperature program started at 45°C with a 3 minute

247 Device Conditional Construction

ly at 280°C. An injection size of 1.0 μL was used for each analysis. The Well Head Source Oil was analyzed with a split ratio of 200:1 (Chromatogram 1, Contour plot 1).

Results

Difractogram Fluorescent spectrum

hold, and then ramped at 5°C/min to 340°C with a final hold of 15 minutes. The column offset was +5°C with a +20°C modulator offset. Acquired data was saved for a range from 45 to 400 m/z at 200 spectra/sec. Helium was used as the carrier gas at a corrected constant flow of 1.0 mL/min.

A split/splitless inlet, operated in split mode, was used for sample introduction. The inlet was maintained isothermal-

As a rule, during the process receive 1) Pyrolysis gases (5-10%) containing up to 16% methane (combustion heat 3254kcal/m3); 2) Char (25-35%) containing carbon 8384%, ash 16-17%) which is used in a various rubber mixes, metallurgy, varnish, paints and building materials, also patch fuel industry; 3) Metal cord (10-20%), which mainly presents as light doping steel and don’t need extra purify and may be used in metallurgy; 4) pyrolysis liquid prod-

ucts (40-45%), represents complex mix of ~ 5000 compounds, which mainly consists hydrocarbons with the number of carbon atoms C4-C40(alkanes, cycloalkanes, aromatics) and heteroatom organic compounds (oxygen, sulfur, nitrogen, bromine, chlorine), which resembles to crude oil with its properties. Based on this liquid products, using typical oil-refining processes, it is possible to receive valuable

248 Table 3.

fuel for vehicles and boilers.

Conclusions Utilization of scrap tires by low-temperature pyrolysiscan be disposed of in an environmentally sound alternative (gaseous, liquid and solid) fuels and metalokordis reception, who have wide application and demand in the market. It is estimated that in order to carry out low-temperature pyrolysis process (temperature, pressure, used raw materials and so on), obtained various products with different chemical composition and properties.

References: 1. M. Juma, Z. Koreòová, J. Markoš, J. Annus, ¼. Jelemenský.

PYROLYSIS AND COMBUSTION OF SCRAP TIRE.Petroleum & Coal 48(1) 15-26, 2006.ISSN 1337-7027.

2. M. Bajus, N. Olahová. THERMAL CONVERSION OF SCRAP TYRES.Petroleum & Coal 53(2) 98-105, 2011.ISSN 13377027.

3. A. ÈÍ•KOVÁ, D. JUCHELKOVÁ.COMPARISON OF YIELD OF TIRES PYROLYSIS IN LABORATORY AND PILOT SCALES.GeoScience Engineering, Volume LV(2009), No.4 p.

60-65, ISSN 1802-5420.

4. Y. Yongrong, Ch. Jizhong, Zh. Guibin. TECHNICAL ADVANCE ON THE PYROLYSIS OF USED TIRES IN CHINA.ChinaJapan International Academic Symposium Environmental Problem in Chinese Iron-Steelmaking Industries and Effective Technology Transfer Sendai, Japan, 6, March 2000.

5. J. Dodds, W. F. Dornenico,D. R. Evans, L. W. Fish, P. L. Lassahn (Science Applications, Inc.),W. J. Toth. SCRAP TIRES: A RESOURCE AND TECHNOLOGY EVALUATION OF TIRE PYROLYSIS AND OTHER SELECTED ALTERNATE

TECHNOLOGIES. ldaho 83415. 1983.

rezinoteqnikuri nawarmis gacveTili saavtomobilo saburavebis utilizacia da dabaltemperaturuli pirolizis gziT da miRebuli produqtebis kvleva p. TuSuraSvili, d. CorgolaSvili, T. xuWua, n. kobalaZe, m. aleliSvili, e. gelaSvili

ssip levan samxaraulis saxelobis sasamarTlo eqspertizis erovnuli biuro WavWavaZis gamz. 84 ,Tbilisi,saqarTvelo el-fosta: NKobaladze@expertiza.gov.ge rezinoteqnikuri nawarmis - gacveTili saavtomobilo saburavebis dabaltemperaturuli piroliziT SesaZlebelia maTi ekologiurad usafrTxo utilizacia, alternatiuli (airadi, Txevadi da myari) sawvavebis da metalokordis miReba, romlebsac aqvT farTo gamoyeneba da moTxovnileba bazarze. miRebuli produqtebis Sedgeniloba farTo diapazonSi icvleba da damokidebulia pirolizis procesis Catarebis pirobebze (temperatura, wneva da sxva) da gamoyenebul nedleulze.

249

Manganese dioxide (MnO2) – containing composite sorbents S. Hayrapetyan1, E. Alvarenga2, L. Hayrapetyan1, S. Gevorgyan1, G. Pirumyan1 B. Salbu3 Yerevan State University, A. Manoukyan 1, 0025, Yerevan, Armenia NIBIO, Norwegian Institute of Bioeconomy Research, Pb 115, N-1431, Ås, Norway 3 Norwegian University of Life Sciences, Dep. of Environmental Sciences, P.O. Box 5003, N-1432 Ås, Norway E-mail: Scirec@mail.ru 1 2

Abstract. The scanning electron microscopy (SEM), x-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) methods were used for investigation of manganese dioxide (MnO2)–containing composite sorbents and their sorption properties were evaluated as well. A characterization of the sorbents was performed

by SEM and XRF. Diatomite and silicagel were used as the porous carrier for the MnO2 (which provides the functionality of the sorbents). The silica component was prepared by co-precipitation of water glass with manganese dioxide. Potassium permanganate is used as a source of manganese dioxide. Deposition of MnO2 was carried on the pore surfaces of porous materials (silica, diatomite) by means of hydrogen peroxide and formaldehyde. The sorbent prepared under the previously described procedure was tested for compounds containing potassium (K+).

Keywords: Sorbents, manganese dioxide, silica, diatomaceous earth.

Introduction At the beginning MnO2 were used for analytical purposes of sorption of alkali, alkaline earth, actinides and other metals and for nuclear waste systems treatment [1].

Basic research on the sorption of metal ions on manganese dioxide and selectivity, were published in the seventies of the last century [2]. Furthermore, such publications have been used and appeared later in the nineties of last century [3,4]. These studies have shown that the mixed xMnO2.ySiO2 oxide sorbents actively adsorb such cations in synthetic solutions at pH 4 and have an increased sorption capacity for strontium (Sr). The urgent need for the use of MnO2–containing sorbents has not lose its relevance and the research continues for the application of such systems for the adsorption of radionuclides. Composites of manganese - titanium dioxide (MnO2–TiO2) show a high affinity for Sr and uranium (U) at pH 7.0 [5]. Heat treating the mixture of Mn carbonate with the potassium (K) formate and/or Mn carbonate with the K but oxide is prepared α-MnO2–containing sorbent with selective adsorption properties to the K. This is the most acceptable commercial sorbents for separating K+ [6] from water.

Hydrated MnO2 is obtained by precipitation of permanganate by means of H2O2. The reaction is conducted in the presence of silica (SiO2)–containing systems, for example, sodium silicate. After the precipitate was washed deionized water, dewatered by filtration and dried [3] .

Materials and methods Liquid glass - KMnO4 - H2O2 system This reagent was prepared with 200 ml of water glass (390 g/l SiO2, silicate modulus M = 3.0) and 35g KMnO4.

The mixture was diluted to 1200 ml with water and 350 ml H2O2 were added. Afterwards, the pH of the system was adjusted to pH 9.0 by means of phosphoric acid (H3PO4).

The aging of the gel is carried out at room temperature for 40 hours, after which the resulting mixture is dried at 105 oC for 2-3 hours, after drying the dried gel is washed by water and dried again. Calcination was carried out at 500 °C for 1 hour. After that, the material was washed with a nitric acid solution (5-6%) and dried at 150 °C until constant weight.

After grinding and sieving the final product obtained is a sorbent.

Liquid glass - KMnO4 – formaldehyde The liquid glass is prepared from 2 solutions: 1st sol.,200 ml water glass (390g/l, M = 3.0) was diluted with distilled water to 800 ml; 2nd sol., was added 50g KMnO4 were added to 48 ml of sulfuric acid (conc.) and the crystals were dissolved in the water. The final volume was adjusted to 500 ml with water. A colloidal system is obtained because of the mixing of the two solutions (the 1st sol. is added while stirring to the 2nd one). A further gelation of the system occurs when NaOH is added. Further post-treatment of the gel is carried out in accordance with the abovedescribed scheme in sub-section 2.1.

The system SiO2 -MnO2 – diatomite system The sorption process was carried out in dynamic mode configuration in columns with dimensions of 200x1.0 mm at room temperature (20 p C). The substrates taken into account for this study were the following solutions: 1. KOH solution (concentration – 2 g/l); 2. KCl (concentration 2 g/ l, pH 12,5 increased by means of KOH) and 3. CH3COOK (concentration 1g/l and 2 g/l, pH11.5 increased by means of KOH).

Results and Discussion On the figures 1, 3 and 5 and in the tables 1, 2 and 3 are presented the SEM images and the XRF data of the obtained sorbents.

250

(a)

(b)

Fig. 1. (a) SEM image and (b) XRF spectrum of the sorbent SiMnO4.

From these figures and tables, it follows that the resulting sorbents have a uniform structure and these materials contain MnO2 in an amount of 3.34–7.40 wt.% of Mn. This amount of MnO2 in the composition of the sorbent allows this system to be an effective sorbent (See below).

The second type of MnO2–containing sorbent was prepared using formaldehyde (HCOH) instead of hydrogen peroxide (see. Experimental part subsection 2.2). Thus, the MnO2 content in the sorbent is 3.34 wt.% expressed as Mn (See. Table 2). Figure 4 shows the potassium sorption prop-

Table 1. XRF data of the sorbent SiMnO4

Figure 2 shows the sorption curves of K+ sorbent prepared in accordance with the scheme described in subsection 2.1. From Figure 3, it follows that the resulting sorbent has a sorption capacity for K+. In addition, the sorption capacity increases significantly after his regeneration. Regeneration was performed with 10 % nitric acid. The curves in Fig. 2 and in subsequent figures were built on the basis of data obtained by ICP-MS.

Fig. 2. Sorption of K+ on sorbents SiMnO4: 1- Initial, 2- after regeneration. KOH concentration – 2g / l.

erties of the sorbent prepared according to the scheme described in subsection 2.2.

From Figure 3 it follows that the sorbent prepared at relatively low pH values of 9.0 has more sorption capacity than the sorbent prepared at a relatively high pH 11.0.

In the preparation of the sorbent at higher pH values, it appears that partial gelation occurs. Presumably, at higher pH values structuring of silica gel and manganese dioxide fixation on the surface of the silica matrix does not occur. It is known that at high pH in the silica-water system has a silicate character and the solubility of this system is relatively high, than in lower pH values. Hence, the conditions to form a porous structure in a labile state is difficult to control.Gelling of the system does not occur in the preparation of the sorbent in accordance with the known method [3] in which the residue is obtained from water glass and manganese dioxide after the addition of hydrogen peroxide. However, this procedure does not allow adjusting the porous characteristics of the obtained adsorbents.

Therefore, the silica-gel component (in this case water glass) becomes important for the preparation of sorbents. The gelling allows fixing MnO2 in the structure of silica gel.

Furthermore, the use of silica-containing material improves the characteristics of the porous structure of the sorbents.

251

(a)

(b)

Fig. 3. (a) SEM image and (b) XRF spectrum of sorbent SiMnO4–HCOH. Table 2. XRF data of the sorbent MnSiO4–HCOH

It is assumed that if the gelling is carried out in the presence of KMnO4, i.e. KMnO4 completely in intermicellar space, leaching of MnO2 is minimized during the acid treatment (e.g. during the regeneration of the sorbent).

Fig. 4. Sorption of K+ on sorbents SiMnO4–HCOH. KOH concentration - 2 g/l.

In the preparation of the sorbent at higher pH values, it appears that partial gelation occurs. Presumably, at higher pH values structuring of silica gel and manganese dioxide fixation on the surface of the silica matrix does not occur. It is known that at high pH in the silica-water system has a silicate character and the solubility of this system is

relatively high, than in lower pH values. Hence, the conditions to form a porous structure in a labile state is difficult to control.Gelling of the system does not occur in the preparation of the sorbent in accordance with the known method [3] in which the residue is obtained from water glass and manganese dioxide after the addition of hydrogen peroxide. However, this procedure does not allow adjusting the porous characteristics of the obtained adsorbents.

Therefore, the silica-gel component (in this case water glass) becomes important for the preparation of sorbents. The gelling allows fixing MnO2 in the structure of silica gel.

Furthermore, the use of silica-containing material improves the characteristics of the porous structure of the sorbents.

It is assumed that if the gelling is carried out in the presence of KMnO4, i.e. KMnO4 completely in intermicellar space, leaching of MnO2 is minimized during the acid treatment (e.g. during the regeneration of the sorbent).

The third type of MnO2– containing sorbent contains diatomite (Dt) as large porous carrier with the silicagel (see.

Experimental part subsection 2.3) and it showed peculiar results. Figure 6 shows the curves of sorption of K+ on the surface of such sorbent (SiO2–MnO2–Dt).

The content of MnO2 on the surface of the sorbent is most likely the most important factor for the sorption process. However, a uniform distribution on the surface of the porous system has relevance as well due to the availability of functional groups that would influence the sorption capacity of the system.

252

(a)

(b)

Fig. 5. (a) SEM image and (b) XRF spectrum of sorbent SiO2–MnO2–Diatomite Table 3. XRF data of the sorbent SiO2–MnO2–Diatomite

pH of the KOH solution (concentration 2.0 g/l, pH 12.58, 20 p C), passed through a column packed with sorbent MnSiO4. From Figure 8 it follows that after passing of potassium hydroxide solution through the column, it appears a sharp decreasing of pH (to pH 3.0, 20 p C). In the range of 200–600 ml of solution pH does not change and is about pH 6, then with an increase of passed through the column solution to 900 ml pH increases to pH 9.0 in the range of 900–1800 ml to pH 10.

Fig. 6. Sorption of K+ on the sorbent SiO2– MnO2–Dt. Concentration ref. KOH – 2 g/l.

Thus, in the case of SiO2–MnO2–Dt average content of MnO2 is 7.4 wt.% expressed as Mn as shown in Table. 3.

However, the adsorbent has the lowest adsorption capacity (see. Fig. 7).

The mechanism of adsorption: To understand the mechanism of sorption of MnO2 containing sorbent, a solution of K+ was passed through a column filled with the above-mentioned sorbents. Figure 8 shows the change in

Fig. 7. Sorption of K+ to MnO2–containing sorbents.

Concentration ref. KOH – 2 g/l.

253

Fig. 8. Changing the pH of the KOH solution – 2.0 g/l (pH 12.58 at 200C) after passing it through a column packed with the sorbent SiMnO4.

Fig. 10. Changing the pH of the solution KCl (pH 12,5 at 200C increased by KOH) after passing it through a column packed with sorbent MnSiO4–CHOH.

Similar results were obtained in the case of using CH3COOK solutions (Figure 9) and KCl solution (Figure 10). In the latter case, the sorbent used was SiMnO4–HCOH.

Conclusions 1. The gelling of silica-containing component in the preparation of the system SiO2 -MnO2 and controlling the pH of precipitation of MnO2 on the surface of the silica gel is decisive in the production of composite sorbents.

2. The mechanism of adsorption on MnO2 - containing sorbents has ion exchange character.

3. The distribution of the MnO2 on the surface of the sorbent influences the sorption capacity regardless of the MnO2 content of the sorbent.

Acknowledgements The financial support of the Norwegian Research Council Grant # ES 459248/0 is gratefully acknowledged.

References: Fig. 9. Changing the solution pH CH3COOK (pH 11.5 with KOH at 200C) after passing it through a column packed with sorbent SiMnO4. 1–1.5 g /l and 2–1 g /l.

From Figure 9 it follows, as expected, that saturation of the sorbent is faster (2.5 times) by increasing of concentrations of the CH3COOK. If the concentration of potassium acetate solution is 1 g/l, the sorbent saturation (pH of solution passed through the column until the pH reaches the starting solution) occurs when using 1500 ml. Conversely, in the case of a concentration of CH3COOK of 1.5g /l the saturation occurs only after passing through the column 600 ml of the solution.

The similar behaviour appears in case of using KCl solution on the sorbent MnSiO4– HCOH as shown in Fig. 10. Such behaviour of the sorbents indicates that the sorption mechanism has ion-exchange character.

1. B. Amphlett Inorganic ion exchangers, Elsevier 1964, 136p.

2. M. J. Gray, M. A. Malati Adsorption from aqueous solution by ä-manganese dioxide II. Adsorption of some heavy metal cations Issue Journal of Chemical Technology and Biotechnology v. 29, p. 135–144, 1979.

3. D. A. White, R. Labayru Synthesis of a manganese dioxidesilica hydrous composite and its properties as a sorption material for strontium. Ind. Eng. Chem. Res., 1991, 30 (1), pp 207–210.

4. J. Serrano G., O.C. Garcia D. – Ce3+ adsorption on hydrated MnO2. J. of Radioanalytical and Nuclear Chemistry V.230, No1-2 (1998) p.33-37.

5. O.I. Pendelyuk, T.V. Lisnycha, V.V. Strelco, S.A. Kirilov – Amorphous MnO2- TiO2 Composites as Sorbents for Sr2+ and UO22+. Adsorption 11 p. 2005, 799-804.

6. Y. Tanaka, M. Tsuji New synthetic method of producing ámanganese oxide for potassium selective adsorbent. Materials research bulletin ISSN 0025-5408 CODEN MRBUAC 1994, vol. 29, No11, pp. 1183-1191.

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manganumis dioqsidi ((MnO2) kompoziciuri sorbentebis Semcveli s. hairapetiani1, e. alvarenga2, l. hairapetiani1, s. gevorgiani1, g. pirumiani1 b. salbu3 1 erevnis saxelmwifo universiteti, a. manukianis q. 1, 0025, erevani, somxeTi 2 NIBIO, norvegiis bioekonomiuri kvlevebis instituti, Pb 115, N-1431, Ă&#x2026;s, norvegia 3 norvegiis universiteti, garemos Semswavleli mecnierebebis departamenti, P.O. Box 5003, N-1432 Ă&#x2026;s, norvegia el-fosta: Scirec@mail.ru

maskanirebeli eleqtronuli mikroskopiis (SEM), rentgenuli fluorescenciuli(XRF) da induqciurad bmuli plazmuri masspeqtrometriis (ICP-MS) meTodebiT Seswavlilia kompoziciuri sorbentebis Semcveli manganumis dioqsidi (MnO2) da aseve misi sorbciuli Tvisebebi. sorbentebis maxasiaTeblebi dadginda (SEM) da (XRF) meTodebiT. diatomiti da silikageli gamoyenebulia rogorc MnO2-is(romelic uzrunvelyofs sorbentebis funqcionirebas) forovani gadamtani. kvarcis komponenti momzadda manganumis orJangis Semcveli Txevadi minis TandaleqviT. manganumis dioqsidis wyarod gamoyenebulia kaliumis permanganati. MnO2-is daSla ganxorcielda wyalbadis zeJangiTa da formaldehidiT forovani masalebis(kvarci, diatomiti) forovan zedapirebze. zemoTaRniSnuli wesiT momzadebuli sorbenti Semowmda kaliumis ionis (K+) Semcvel naerTebze.

255

Effect of laser radiation on the electric conducting and magnetic properties of polymer materials surfaces J. Aneli1, N. Bakradze2 T. Dumbadze2 R. Dvali Institute of Machine Mechanics, 10, Mindeli str., 0186, Tbilisi, Georgia Georgian Technical University 77, M. Kostava str., 0175, Tbilisi, Georgia E-mail: jimaneli@yahoo.com 1 2

Abstract. Formation of electrical conducting channels with paramagnetic properties on the surface of the polymer composite plates on the basis of phenol-formaldehyde resin, polymethylsilsesqwioxane and fiber glass under influence of CO2 laser irradiation at presence of air have been studied. It is shown that the magnitudes of conductivity and paramagnetic particles of the conducting channels depend on polymer type and irradiation energy. The appearance of electrical conducting regions in the polymer materials is due to laser-chemical transformations of macromolecular physical and chemical structures near the polymer plate surfaces, leading to formation of clusters of double conjugated bonds. These structures are characterized also with paramagnetic properties which may be due to different paramagnetic centers (solvated charges, localized at the chain ends, free radicals, etc.) in the transformed regions of polymers. The obtained results are analogous to ones obtained in such polymers after thermal treatment at high temperatures (pyrolysis), however pyrolysis does not allow the formation of conducting channels with desired conductivity and configuration on the surface of polymer plates in very short time (about several seconds) at present of air.

Keywords: CO2 laser; irradiation; phenol-formaldehyde resin; electrical conductivity; conjugated bonds; paramagnetic centers.

Introduction

Experimental

The studies of chemical modifications of polymer materials under influence of laser radiation have sufficiently spread character [1]. It is known the initiation of photopolymerization after absorption of the light by sensitive molecule [2] or directly –by monomer [3]. The quant output strongly depends on the used photo-sensitive material. It must be existed a possibility of monitoring of the polymer molecular weight by change of the laser irradiated conditions.

The substances under conditions of laser irradiation undergo to double influences of laser beam – effect of electromagnetic waves and thermal heating at rather high temperatures. It is known that high temperature (higher 500-600oC) treatment (pyrolysis) of polymers in vacuum or in the inert atmosphere leads to deep structural transformations of these materials [4]. First of all these changes are expressed in excitation of macromolecules with consequent formation of free radicals and the systems of conjugated double bonds with linear or cyclic structures. At increasing of pyrolysis temperature the degree of conjugation and correspondingly the electrical conductivity increases. However if it is necessary to obtain the polymer plates, only separate parts of which would be electrical conductor on the phone of dielectric environment, method of pyrolysis would not be useful.

In the presented work some local physical and chemical transformations on the surfaces of polymer plates due to laser irradiation at normal physical conditions have been studied.

The composites were prepared using the well known technological method (mixing of components with planned ratio of ones and following heating of mixture up to 240oC under pressure and cooling).The experiments were carried out on the plates with thickness of 4 mm. The irradiation was proceeded at using of CO2 laser generator of type LGI-702 (l = 10.6 mcm, power 800 W). The scheme of irradiation is given on the Fig.1. The laser beam generated from source 1 reflected on the reflector 2, passes through the lens 3 with focus distant 300mm and falls on the sample 4, which is placed on the table 5 automatically movable in three coordinate directions. The diameter of light spot on the polymer plate surface was changed in the interval 1-8mm. Laser irradiation doses were changed in the interval 20-40 J.

Fig. 1. Scheme of irradiation of samples: 1-laser source; 2 – reflector; 3- lens; 4- sample; 5 –table

256 By means of displacement of the table with sample on it at regulated rate there were formed the black paths with different width and configuration. These paths are characterized with electrical conductivity and ESR spectra depending on irradiated energy. Irradiated samples were tested by polarization microscopy technique, electric conductivity – by two-contact method. Paramagnetic properties of the probes took from path materials were measured using of ESR spectrometer of Brukker type. The type and mobility of charge carriers investigated were measured by the Hall effect technique. The structure changes in the macromolecular system was established by infrared spectra (Percin-Elmer type spectrometer).

Results and Discussion On the Fig.2 the electrical conducting channels on the surface of polymer material plate on the basis of phenolformaldehide resin, polymethylsilsesqwioxane and fiber glass are shown. The channels were formed after laser irradiation at energy up to 40 J by means of straight line moving of plate with different rate under focused laser beam.

The lower a rate of moving laser beam the wider and deeper black color of the channels.

Fig. 2. Electrical conducting channels formed on the surface of sample plates after focused laser beam irradiation

Infrared spectra of the alloys of the black material took from path shown the existence of definite amount of conjugated double bonds with linear structure of carbon chain of type ~CH = CH –CH =CH ~. It was established that the concentration of such bonds depends on type of irradiated material, the laser source power, beam intensity, the rate of table displacement of spot diameter of light on the sample surface.

Inclusion of fiber glass into compositions was induced by the following idea. It is known [5] that at high temperatures organosiloxanes react with side hydroxyl groups, disposed on the fiber glass (FG) surface. On the other hand the active chemical groups of phenol-formaldehide and polymethylsilsesqwioxane molecules can introduce to the

chemicalreactions with creation of the intermolecular chemical bonds. In this reaction they form covalent bonds with those side groups according to the following reaction scheme:

where X = H, Na, K; R is a hydrophobic organic residue.

It is known that after high-temperature treatment silsesqwioxanes obtain a structure, close to inorganic glass with spheres of regulation due to formation of three-dimension siloxane cubic structures and selective sorption of one of the composite elements is possible on the filler surface in the hardening composite [5].

We suppose that the reactions between glass surface and the organic molecules of the sample initiated with laser irradiation may be proceeded analogically of described above reactions, in result of which the structures like that shown on the Figure 3 can be formed.

Fig.3. Schematic image of disposition of glassy structures (1), pyrolyzed polymethylsilsesqwioxane (2), polyformaldehide and polyconjugation systems (3) in laserolyzed composite phenoloformaldehide resin + polymethyl-silsesqwioxane + glassy fiber. Big circles mark atoms of silicon, small circles – oxygen atoms

According to Fig. 4, the dependence of electric conductivity the channels on the surface of polymer materials on the laser beam energy grows monotonously. This dependence points out a constant accumulation of polyconjugation systems due to initiated by electromagnetic waves and high temperature photo- and thermochemical complex reactions. As to our point of view formation of polyconjugated systems is rather probable at laserolysis of a compound containing phenoloformaldehyde resin and of polymethylsilsesqwioxane at the glass surface. These conjugated systems are covalently linked to Si-O groups on the glass surface by the skeleton of polymethylsilsesqwuoxane (‘a cube’), schematically shown on Fig.3. Chemical bonds which link organic and inorganic parts of the composite reliably increase stability of polyconjugated struc-

257 tures, responsible for electrically conducting properties of materials. The electrically conducting system of the materials can be considered as a heterogeneous composite material, consisted of highly conducting spheres of polyconjugation and barrier interlayers between them [6,7].

Volumetric part of the polyconjugation spheres is determined by the pyrolysate production technique. It increases gradually with temperature of pyrolysis. Fig. 4 and 5 show that the number of charge carriers and their mobility increases with the energy of laserolysis because of increasing of volume of polyconjugation regiones.

Fig. 4. Dependences of electric conductivity γ of the conducting channels on laserolysis energy

(1) or with formula (2) proposed by N. Mott [9]: (2) where T0 and g0 are parameters of the present model: (3) where a is the radius of localized states, close to the μ) is the density of states at the Fermi level; Fermi level; g(μ e is the electron charge; ν is the phonon frequency; Φ0 = 1 is the constant; β = 21.2 ± 1.2 is the coefficient, determined from the percolation theory [7].

Fig. 6 shows that the temperature dependence of conductivity of the polymer composite irradiated by three energy of the laser beam satisfactorily well described by the Mott formula in the coordinates lgγ - T-1/4 while preliminarily proceeded analogical measurements elucidate essential deviations from data calculated with using formula (1). However, the difference in temperature dependences of conductivity, composed in both coordinates, become so smooth with beam energy rises that they are nearly drawn together for the sample with laser beam energy higher 40 J. On the other hand, the same dependences show that the activation energies (according to the curve slope) decrease with laser beam energy increase. It is explained by intensification of processes promoting increase of the polyconjugation regions (clusters) and their drawing together, which result in continuous decrease of the potential barrier height, and conductivity approximates to the metal type.

Evidently, at very high energies electric conductivity dependences on temperature cannot be described by equations noted above.

Fig. 5. Dependences of the charge carriers mobility μ of the conducting channels on laserolysis energy

The most apparently true model of electric conductivity in materials with the system of double conjugated bonds seems to be the change transfer in the ranges of polyconjugation possessing metal conductivity and jump conductivity between polyconjugation spheres. Such systems are known as the organic semiconductors, conductivity of which is described with formula (1 )[8]:

Fig.6. Temperature dependence of the conductivity of conducting channels irradiated with energies 20 (1), 30(2) and 40J (3) in the coordinates of formula (2).

258 According to [9] the increase of mobility of semiconducting materials with temperature belongs to the growth of carriers mobility m due to the expression:

Temperature dependences of Îź in the lgÎź - T-1/4 coordinates measured for laserolized composites fit straight lines (Fig. 7). Following from this, one can make a conclusion that semiconducting materials formed after laserolysis of polymer materials represent heterogeneous systems, the conductivity of which in the wide temperature range is that with variable jump length r . Temperature dependence of this parameter is described by the following expression:

ated at rather high energies. At more high energies of laserolysis the ESR line width increases due to the following phenomena. Deepening of photochemical and thermochemical reactions in composites leads to formation of local paramagnetic centers with further localization of an unpaired electron in oxygen atom, possessing increased affinity to electron. Due to occurrence of the spin-orbital interaction contribution into the spin-Hamiltonian the time of spin-spin relaxation, responsible for ESR line broadening, decreases. On the other hand, it is probable to increase the contribution of free charges-current carriers into ESR signal, which is characterized by asymmetry and some widening of the line width (so called Dayson line [10]).

Fig. 7. Temperature dependence of charge carriers mobility m for the glass textolyte after laserolysis at energies 20 (1), 30 (2) and 40 J (3), respectively

By method of electron spin resonance (ESR) there were investigated the paramagnetic centers of black materials took from conducting channels. ESR line presents the singlet type signal, which may be due to free radicals or free electrons solvated on the structural defects in the polymer matrix and on silanol groups of the fiber glass after irradiation.

Fig. 9. ESR line width on the laserolysis energy for the polymer composite

Conclusions

Fig.8. Temperature dependence of paramagnetic centers concentration R

The dependence of paramagnetic centers concentration in irradiated polymer composites grows at increasing of the laser beam energy (Fig. 7). Change of the ESR absorption line intensity is accompanied by a definite change of its width. In this case, the form and width of the ESR line changes (at constancy of the g-factor) - lines are broadened at energies higher 30 J and asymmetry of singlet occurs. These changes are more effective for materials, irradi-

1. The irradiation of surfaces of some plate of the glass textolyte containing of carbon chain and polyorganosiloxane polymers with focused laser beam leads to formation of electrical conducting channels, the sizes of which depend on the energy of irradiation.

2. Irradiation of the polymer materials by laser radiation stimulates the processes of formation of the polyconjugated systems, in the frames of which the transport of the electric charges proceeds with a very low activation energy (it has semimetal character).

3. Charge transfer between polyconjugation systems is ruled by the jump conductivity mechanism with variable jump length. In this case, its temperature dependence is described by the Mott formulas.

4. Presence of a glassy fiber and polymethylsilsesquioxane in composites promote formation of covalent bonds between organic and inorganic parts of the composite, at laserolysis of which good contacts between glass surface and conducting clusters is ensured.

Acknowledgements Authors are grateful to Georgian Ministry of Defense for the financial support of this work.

259 References 1. W.W.Duley: Laser processing and analysis of materials, NewYork, Plenum Press, (1983).

2. E.Grunwald, D.Diver, F.Kin: Infrared laser chemistry, NewYork, Plenum Press, (1981).

3. V.S.Letokhov: Uspekhi fizicheskikh nauk (Advances of physical sciences), Vol.125 (1978), p.104 (in Russian).

4. J.N.Aneli, L.M.Khananashvili, and G.E. Zaikov: Structuring and conductivity of polymer composites, New-York, Nova Sci.Publishers, (1998) p.178.

5. Kajiwara T., Inokuchi H., Minomura S., Jap.Plast.Age, 1974,12(1),17-24.

6. Enzel P.,Bein T.//Chem.Materials,1992, 4, 819-824.

7. Shklovskii B.I., Efros A.L., Electronic properties of alloyed semiconductors, Moscow, Nauka, 1979,416.(in Russian).

8. Aviles M.A., Gines J.M., Del Rio J.C., Pascual J.. Perez J.L., Sanchez-Soto P.J. // J.Thermal Analysis and Calorimetry, 2002, V.67,177- 188.

9. Mott N.F., Davis E., Electron Processes in noncrystalline materials, 2nd Ed., oxford, Clarendon Press,1979.

10. Dyson F.J., Phys.Rev.,1955,98,349-358.

lazeruli dasxivebis zemoqmedeba polimeruli masalebis zedapirebis eleqtrogamtar da magnitur Tvisebebze j. aneli1, n. baqraZe2, T. dumbaZe2 1 r. dvalis manqana-meqanikis instituti, mindelis q. 10, 0186, Tbilisi, saqarTvelo 2 saqarTvelos teqnikuri universiteti, kostavas q. 77, 0175, Tbilisi saqarTvelo el-fosta: jimaneli@yahoo.com

Seswavlilia fenolformaldehiduri fisebis, polimeTilsilsesqvioqsanisa da minaboWkos bazaze miRebuli polimeruli kompozitebis zedapirebze maTi lazeÂŹruli dasxivebis Sedegad, haeris garemocvaSi paramagnituri Tvisebebis mqone eleqtrogamtari arxebis warmoqmna. naCvenebia, rom eleqtrogamtari arxebis eleqtrogamtaroba da maTi paramagnetizmi damokidebulia polimeris ti psa da dasxivebis dozaze. eleqtrogamtari arxebis warmoqmna ganpirobebulia polimerul zedapirebTan makromolekulebis lazeroqimiuri gardaqmnebiT, romelTa Sedegad SeuRlebul qimiur bmaTa warmoqmna da maTi klasterizacias aqvs adgili. warmoqmnili sruqturebi xasiaTdeba aseve paramagnituri TvisebebiT (paramagnituri centrebi solvatirebuli eleqtronebis, Tavisufali eleqytonebis da sxvaTa saxiT). miRebuli Sedegebi analogiuria imave polimerebis maRaltemperaturuli TermodamuSavebiT (piroliziT) miRebuli Sedegebisa im gansxvavebiT, rom piroliziT SesaZlebelia mTlianad polimeruli masalis gardaqmna maRal vakuumSi, maSin rodesac lazerolizi saSualebas iZleva Zalian, mcire (wamebi) droSi haeris garemoSi miRebul iqnes sasurveli konfiguraciisa da eleqtrogamtarobis mqone arxebi.

260

Ïåðñïåêòèâíûå ìàòåðèàëû, ïîëó÷åííûå ñåïàðàöèåé óãîëüíîé çîëû Èáðàãèìîâà Ý.Ì.1,2, Ìàëèêîâ Ø.Ð.1, Ïèêóëü Â.Ï.1, Þëäàøåâ Ì.Á.1, Ñàíäàëîâ Â.Í.1, Þñóïîâ Ý.Ê.1, Õàìèäîâ Õ.2 Èíñòèòóò ßäåðíîé Ôèçèêè ÀÍ ÐÓç, Òàøêåíò, Óçáåêèñòàí; Ó÷åáíî-ýêñïåðèìåíòàëüíûé Öåíòð Âûñîêèõ Òåõíîëîãèé, Òàøêåíò, Óçáåêèñòàí

1 2

Ðåçþìå.  Óçáåêèñòàíå íàêîïëåíû áîëüøèå îáúåìû çîëû îò ñæèãàíèÿ óãëÿ, êîòîðûå ïîïàëè â îêðóæàþùóþ ñðåäó ïðè ãðàâèòàöèîííîé ñåïàðàöèè â âèäå çîëû óíîñà è çîëû øëàêà. Çîëà õðàíèòñÿ â áîëüøèõ îòñòîéíûõ áàññåéíàõ íà ó÷àñòêå ÒÝÑ è ÷àñòè÷íî ïðîäàåòñÿ ïî öåíå îòõîäîâ äëÿ äîáàâêè â öåìåíò èëè áåòîí. Íàìè áûëà ïðîâåäåíà äîïîëíèòåëüíàÿ ìàãíèòíàÿ è ñèòîâàÿ ñåïàðàöèÿ çîëû è ïîêàçàíî, ÷òî ìàãíèòíàÿ ôðàêöèÿ ñîñòàâëÿåò äî 5 ìàññ.% çîëû è îáîãàùåíà äî 70% îêñèäàìè æåëåçà, ðåäêèõ çåìåëü è äð.ìåòàëëîâ, êîòîðóþ ìîæíî ïðîäàâàòü ïî öåíå ñûðüÿ. Äîáàâêà íåìàãíèòíîé ôðàêöèè çîëû óíîñà, ñîñòîÿùåé èç ñèëèêàòíûõ ìèêðîñôåð, â àêðèëîâóþ êðàñêó ïðèäàåò èì óñòîé÷èâîñòü ê âîçãîðàíèþ.

Êëþ÷åâûå ñëîâà: çîëà óãëÿ, ìàãíèòíàÿ ñåïàðàöèÿ, ôåððîñôåðû.

Ââåäåíèå Ïðè ýêñïëóàòàöèè óãîëüíûõ ÒÝÖ îáðàçóåòñÿ áîëüøèå îáúåìû çîëû, ãðàâèòàöèîííî ðàçäåëåííûå íà ëåãêóþ (óíîñ) è òÿæåëóþ (øëàê) ôðàêöèè [1]. Ñóùåñòâóþùèå òåõíîëîãèè óòèëèçàöèè çîëû ÒÝÑ âêëþ÷àþò èñïîëüçîâàíèå çîëû øëàêà äëÿ ïðîèçâîäñòâà öåìåíòà, ñòðîèòåëüíûõ øëàêîáëîêîâ è óòÿæåëèòåëåé áóðîâûõ ðàñòâîðîâ, à çîëû óíîñà â êà÷åñòâå íàïîëíèòåëåé êðàñîê [2]. Ôåððîìàãíèòíóþ ôðàêöèþ çîëû èñïîëüçóþò â ìåòàëëóðãèè [3-5]. Óïîìèíàåòñÿ òàêæå òåõíîëîãèÿ äëÿ âûäåëåíèÿ ðåäêîçåìåëüíûõ ýëåìåíòîâ èç çîëû øëàêà. Ïàòåíò Èíñòèòóòà õèìèè è õèìè÷åñêîé òåõíîëîãèè Ñèáèðñêîãî îòäåëåíèÿ ÐÀÍ îïèñûâàåò, êàê ìàãíèòíûå ìèêðîñôåðû âûäåëÿëè èç ìàãíèòíûõ êîíöåíòðàòîâ, ïîëó÷àåìûõ ìàãíèòíîé ñåïàðàöèåé çîëû óëåòà îò ñæèãàíèÿ áóðîãî è êàìåííîãî óãëåé, çàòåì èñïîëüçîâàëè â êà÷åñòâå æåëåçîñîäåðæàùåãî êàòàëèçàòîðà ïðè ïðîâåäåíèè òåðìîëèçà òÿæåëîãî óãëåâîäîðîäíîãî ñûðüÿ, â ðåçóëüòàòå êîòîðîãî ïîëó÷àëè ëåãêóþ íåôòü è âîññòàíîâëåííîå æåëåçî [6]. Îäíàêî, ìàñøòàáû ïðèìåíåíèÿ âûøåóêàçàííûõ òåõíîëîãèé äàëåêî íå äîñòàòî÷íû äëÿ îáåñïå÷åíèÿ óòèëèçàöèè áîëüøèõ îáúåìîâ íàêîïëåííîé çîëû ÒÝÑ. Ïîýòîìó ðàçðàáîòêà ñîâåðøåííûõ ìåòîäîâ óòèëèçàöèè çîëû ñ ïîëó÷åíèåì ïåðåäîâûõ ôóíêöèîíàëüíûõ ìàòåðèàëîâ ñîõðàíÿåò ñâîþ àêòóàëüíîñòü. Ðàíåå íàìè áûëî ïîêàçàíî, ÷òî êàê çîëà óíîñà, òàê è çîëà øëàêà, ñîäåðæàò ïåðåõîäíûå è ðåäêîçåìåëüíûå ýëåìåíòû [7]. Ïðèìåíåíèå êîìáèíàöèè ìàãíèòíîé ñåïàðàöèè è ñèòîâîãî ðàçäåëåíèÿ ïîçâîëèëî âûäåëèòü 3.4 ìàññ.% ìàãíèòíîé ôðàêöèè èç çîëû øëàêà ñ îáîãàùåíèåì 52 ìàññ.% ïî Fe è 0.1 % ðåäêèõ çåìåëü (Ce, Nd, Sm). Ïðè ãîäîâîì îáúåìå ~ 100 òîíí çîëû øëàêà, îáðàçóþùåéñÿ â Àíãðåíñêîé ÒÝÑ, ìàññà íàêîïëåííîé ìàãíèòíîé ôðàêöèè èìååò çíà÷èòåëüíóþ âåëè÷èíó, ÷òî ïðè âûñîêîì îáîãàùåíèè ïîçâîëÿåò

ïîâûñèòü ðåíòàáåëüíîñòü òàêîé òåõíîëîãèè è ðàñøèðèòü îáëàñòü ïðèìåíåíèÿ ïîëó÷åííîãî ìàãíèòíîãî ìàòåðèàëà. Îäíàêî, òåõíîëîãèÿ ñóõîé ìàãíèòíîé ñåïàðàöèè çîëû íå ìîæåò îáåñïå÷èòü ïîëíîå ðàçäåëåíèå ìàãíèòíîé è íåìàãíèòíîé ôðàêöèé. Öåëü äàííîé ðàáîòû ñîñòîÿëà â ðàçðàáîòêå óñîâåðøåíñòâîâàííîé òåõíîëîãèè ìàãíèòíîé ñåïàðàöèè ïóëüïû çîëû øëàêà Àíãðåíñêîé ÒÝÑ, ïîçâîëÿþùåé ïîëíåå ðàçäåëÿòü ìàãíèòíóþ è íåìàãíèòíóþ ôðàêöèè.

Ìàòåðèàëû è ìåòîäû  îòëè÷èå îò ïðåäûäóùåé ðàáîòû, ãäå óòèëèçèðîâàëàñü ñóõàÿ çîëà øëàêà èç îòâàëîâ Àíãðåíñêîé ÒÝÑ, çäåñü èñïîëüçîâàëàñü ìîêðàÿ ïóëüïà çîëû øëàêà íà âûõîäå èç ÒÝÑ. Ìàãíèòíàÿ ñåïàðàöèÿ ïðîâîäèëàñü íà ïîòîêå ïóëüïû, â êîòîðûé áûë ïîãðóæåí ìàãíèòíûé ñåïàðàòîð áàðàáàííîãî òèïà ñ âûñîêî ãðàäèåíòíîé ìàòðèöåé è ñèñòåìîé òðàíñïîðòèðîâêè îòîáðàííîé ìàãíèòíîé ôðàêöèè â íàêîïèòåëüíûé áóíêåð. Ïîñëå ñåïàðàöèè ïîòîê íåìàãíèòíîé ôðàêöèè ïóëüïû íàïðàâëÿëñÿ â îòñòîéíèê. Òàêàÿ ñõåìà íå òðåáóåò äîïîëíèòåëüíîé òðàíñïîðòèðîâêè âñåé ìàññû çîëû øëàêà ê ìåñòó ìàãíèòíîé ñåïàðàöèè è çàòåì îáðàòíîãî âûâîçà >90% íåìàãíèòíîé ôðàêöèè â îòâàëû. Ýëåìåíòíûé ñîñòàâ ìàãíèòíîé è íåìàãíèòíîé ôðàêöèè çîëû øëàêà îïðåäåëÿëñÿ ìåòîäàìè ýêñïðåññíîãî ðåíòãåíî-ôëóîðåñöåíòíîãî (ðàäèîèçîòîïíûå èñòî÷íèêè 109Cd, 241Am) è ÷óâñòâèòåëüíîãî íåéòðîííîãî àêòèâàöèîííîãî àíàëèçîâ ñ èñïîëüçîâàíèåì èññëåäîâàòåëüñêîãî àòîìíîãî ðåàêòîðà ÂÂÐÑÌ è ãàììà-äåòåêòîðîâ Canberra. Êðèñòàëëè÷åñêàÿ ñòðóêòóðà è ôàçîâûé ñîñòàâ çîëû øëàêà, åå ìàãíèòíîé è íåìàãíèòíîé ôðàêöèé îïðåäåëÿëèñü ñ ïîìîùüþ ðåíòãåíîâñêîãî ïîðîøêîâîãî äèôðàêòîìåòðà XRD-6100 (Shimadzu).

261

Ðèñ. 1. Ôîòîãðàôèè çîëû (ñëåâà) è åå ìàãíèòíîé ôðàêöèè (ñïðàâà) â ïîëå 1 1 ìì2.

Äëÿ îïðåäåëåíèÿ ïîòåíöèàëà ïðèìåíåíèÿ ìàãíèòíîé ôðàêöèè çîëû â êà÷åñòâå ôóíêöèîíàëüíîãî ìàòåðèàëà (â õèìè÷åñêîì êàòàëèçå èëè ìàãíèòíûõ óñòðîéñòâàõ) èññëåäîâàëè ýëåêòðîïðîâîäíîñòü íà ïîñòîÿííîì òîêå è ìàãíèòîñîïðîòèâëåíèå â ïðèëîæåíèè ïîñòîÿííîãî ìàãíèòíîãî ïîëÿ.

âåííî ñîãëàñóåòñÿ ñ äàííûìè ïî ôàçîâîìó àíàëèçó ìàãíèòíîé è íåìàãíèòíîé ôðàêöèè çîëû [2-6]. Íà ðèñ. 3 ïîêàçàíà òåìïåðàòóðíàÿ çàâèñèìîñòü îáúåìíîãî òîêà ìàãíèòíîé ïëåíêè, èçãîòîâëåííîé èç ìåëêîé ìàãíèòíîé ôðàêöèè çîëû øëàêà, äîïîëíèòåëüíî ïðîøåäøåé ìàãíèòíóþ è ñèòîâóþ ñåïàðàöèþ (çåðíî

Ðèñ. 2 Ðåíòãåíîãðàììû çîëû øëàêà (à), åå ìàãíèòíîé (á) è íåìàãíèòíîé (â) ôðàêöèè.

Ðåçóëüòàòû Cîãëàñíî ýëåìåíòíîìó àíàëèçó, ìàãíèòíàÿ ôðàêöèÿ çîëû øëàêà, ïîëó÷åííàÿ â ðåçóëüòàòå ìîêðîé ìàãíèòíîé ñåïàðàöèè ïóëüïû ñîñòîèò íà 70 ìàñc.% èç îêñèäà æåëåçà, à îñòàëüíûå - îêñèäû Si (íå îïðåäåëÿþòñÿ), Al (11%), Ca (5%), Mg (1%), K (1%), Zn, Sr, Zr (0,2%) à òàêæå 150 ppm ðåäêîçåìåëüíûõ ýëåìåíòîâ Ce, Nd, Sm. Ðèñ. 1 ïîêàçûâàåò ìèêðîôîòîãðàôèè çîëû øëàêà (ñëåâà) è åå ìàãíèòíîé ôðàêöèè (ñïðàâà), ñíÿòûå íà êàìåðó Samsung L730. Âèäíî, ÷òî ìèêðîñôåðû ÿñíî ðàçëè÷àþòñÿ ïî ñîñòàâó: ÷åðíûå è êîðè÷íåâûå æåëåçíûå, ïðîçðà÷íûå áåñöâåòíûå àëþìîñèëèêàòû, ìîëî÷íûå êàëüöèòû.

Íàìàãíè÷åííûå æåëåçíûå ñôåðû (ñïðàâà) ñòðåìÿòñÿ îáðàçîâàòü êðóãè. Íà ðèñóíêàõ 2 ïðèâåäåíû ðåíòãåíîãðàììû çîëû øëàêà (à), åå ìàãíèòíîé (á) è íåìàãíèòíîé (â) ôðàêöèè, à òàêæå èäåíòèôèöèðîâàíû îñíîâíûå ôàçû: îêñèä êðåìíèÿ, àëþìèíèÿ è æåëåçà. Íåìàãíèòíàÿ ôðàêöèÿ íà 80 % ñîñòîèò èç êâàðöà (aSiO2), 12 % êîðóíäà (-Al2O3) è 8 % ãåìàòèòà. Ìàãíèòíàÿ ôðàêöèÿ ñîäåðæèò 80 % ñîåäèíåíèé æåëåçà (ãåìàòèò, ìàãíåòèò), îñòàëüíîå - êîðóíä, êâàðö è äð. Îáðàùàåò íà ñåáÿ âíèìàíèå øèðîêàÿ äèôôóçíàÿ ïîëîñà ïðè óãëàõ ðàññåÿíèÿ 2θ ~ 20-27 ãðàäóñîâ, óêàçûâàþùàÿ íà ïðèñóòñòâèå íàíî÷àñòèö Ïîëó÷åííûé ðåçóëüòàò êà÷åñò-

262 3. A.S. Shoumkova and V. Stoyanova: Surveying Geology and Mining Ecology Management, Proceed. of the X Ann. Intern.

Geoconf. 2 (2010) 597.

4. L. P. Soloviev, V. V. Bulkin, M. V. Pronina, V. L. Alferov and V. A. Pronin: Review, Ecology & Industry of Russia, 6 (2011), 4.

5. J. M. Kinsella, Sh. Ananda, J. S. Andrew, J. F. Grondek, M.-P. Chien, M. Scandeng, N. C. Gianneschi, E. Ruoslanti and M. J. Sailor: Review, Advanced Materials, 23 (2011), H243.

6. À.Ã. Àíøèö, Í.Ï. Êèðèê, Ò.Ã. Ñîçîíîâà, Î.Ì. Øàðîíîâà. Ïàòåíò ÐÔ, 04.08.2010.

7. Sh. R. Malikov, V. P. Pikul, N. M. Mukhamedshina, V. N. Sandalov, S. Kudiratov and E. M. Ibragimova: Electromagnetic Separation of the Brown Coal Ash of Thermal Power Stations, Journal of Magnetics, 18 (2013), 1-5, doi:104283/ JMAG.2013.18.3. Ðèñ. 3 Òåìïåðàòóðíàÿ çàâèñèìîñòü îáúåìíîãî òîêà ìàãíèòíîé ïëåíêè: 1–3 – íàãðåâ; 2 – îõëàæäåíèå áåç ìàãíèòíîãî ïîëÿ; 4 – îõëàæäåíèå â ìàãíèòíîì ïîëå.

≤100 ìêì), ñìåøàííîé ñ ýïîêñèäíûì ñâÿçóþùèì â ïðîïîðöèè 4:1. Èçìåðåíèÿ ïðîâîäèëèñü áåç ïîëÿ è â ïîñòîÿííîì ìàãíèòíîì ïîëå 0,1 Òåñëà, ïðèëîæåííîì ïåðïåíäèêóëÿðíî ïîâåðõíîñòè ïëåíêè. Íàáëþäàåìûé ãèñòåðåçèñ ýëåêòðîïðîâîäíîñòè îáóñëîâëåí îñòàòî÷íûì ìàãíåòèçìîì ïëåíêè ïîñëå ìàãíèòíîé ñåïàðàöèè (êðèâûå 1-2) è äîïîëíèòåëüíûì íàìàãíè÷èâàíèåì â ïðèëîæåííîì ìàãíèòíîì ïîëå 0.1 Òåñëà (êðèâûå 3-4).

Âûâîäû Ìîêðàÿ òåõíîëîãèÿ ìàãíèòíîãî ñåïàðèðîâàíèÿ ïóëüïû çîëû ÿâëÿåòñÿ áîëåå ðåíòàáåëüíîé, ÷åì ðàíåå ïðèìåíÿâøàÿñÿ ñóõàÿ òåõíîëîãèÿ, ïîòîìó ÷òî ñíèæàåò ýíåðãîçàòðàòû è ïîâûøàåò ýôôåêòèâíîñòü ìàãíèòíîé ñåïàðàöèè. Êîìïîçèòíóþ ìàãíèòíóþ ïëåíêó èç ìàãíèòíîé ôðàêöèè çîëû ìîæíî èñïîëüçîâàòü â êà÷åñòâå ìàãíèòîãðàäèåíòíûõ ïîêðûòèé äëÿ ïëîñêèõ ïîëþñîâ ìàãíèòà, îáåñïå÷èâàþùèõ ýôôåêòèâíóþ ìàãíèòíóþ ñåïàðàöèþ ïóëüïû. Ñôåðè÷åñêàÿ ôîðìà ìàãíèòíûõ ìèêðîñôåð îáåñïå÷èâàåò âûñîêèå êàòàëèòè÷åñêèå ñâîéñòâà, íàïðèìåð, äëÿ ïåðåðàáîòêè òÿæåëîé íåôòè. Êðîìå òîãî ìèêðîñêîïè÷åñêèå ôåððîñôåðû ìîæíî èñïîëüçîâàòü â ìåäèöèíå äëÿ ëå÷åíèÿ ðàêà ïóòåì ëîêàëüíîãî âûñîêî÷àñòîòíîãî ðàçîãðåâà ôåððîñôåð â îïóõîëè äî åå òåðìè÷åñêîãî ðàçðóøåíèÿ. Íåìàãíèòíàÿ ôðàêöèÿ çîëû îáëàäàåò ëó÷øåé òåïëîèçîëÿöèîííîé ñïîñîáíîñòüþ, ÷åì íåñåïàðèðîâàííàÿ çîëà, è ìîæåò ñòàòü áîëåå êà÷åñòâåííûì ñûðüåì äëÿ ñòðîèòåëüíûõ ìàòåðèàëîâ è ïîæàðîñòîéêèõ êðàñîê. Ðàáîòà âûïîëíåíà ïðè ïîääåðæêå ãðàíòà ÔÀ-À13Ô011Ï3-2014 îò ÊÊÐÍÒ Ðåñïóáëèêè Óçáåêèñòàí.

Ëèòåðàòóðà 1. N.L. Rose: Review, Environment Pollution , 91 (1996), 245.

2. A.C. Lua and R.F. Boucher: Review, Intern. J. Coal Preparation and Utilization, 8 (1990), 61.

qvanaxSiris nacris separaciiT miRebuli perspeqtuli masalebi e.m. ibragimova1,2, S.r. malikovi1, v.p. pikuli1, m.b. iuldaSevi1, v.n. sandalovi1, e.k. iusupovi1, x. xamidovi2 1

uzbekeTis respublikis birTvuli fizikis instituti, taSkenti, uzbekeTi 2 maRali teqnologiebis saswavloeqsperimentuli centri, taSkenti, uzbekeTi uzbekeTSi dagrovilia didi moculobiT qvanaxSiris wvis produqti nacari, romelic garemomcvel areSi aris Sereuli gadatanili nacrisa da widis nacris formiT. nacari inaxeba Tboeleqtrosadguris ubanze did sacavebSi da warmoebs misi nawilobrivi gayidva narCenebis RirebulebiT cementisa da betonis danamatad.

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Surface modification of aisi 310 and 440c steels by ion implantation A.I. Guldamashvili, N.M. Kutsia.. Yu.I. Nardaya, Ts.M. Nebieridze, A.V. Sichinava I. Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli st., Tbilisi, Georgia, 0186, E-mail: sipt@sipt.org Abstract. The paper describes changes in mechanical properties of AISI 310 and 440C steel samples, subject to the process of ion implantation. Highly pure polished initial samples were successively implanted with carbon and nitrogen ions with energies of 60 keV, and fluences Ô=1x1016, 1x1017, 1x1018 ion×cm-2. Modified layers of the samples were tested for hardness by micro indentation method, and for wearing by dry friction method, depending on the implantation fluence values. Microhardness and wear resistance of the steel samples increased gradually with the ion irradiation fluence rise, and reached maximal values at fluence 1x1018ion/cm2. Test results of the modified AISI 310 steel showed maximum 2.2-fold hardness increase and 3.5-fold increase of wear resistance. Hardness of modified 440C steel increased 3.8 times, compared to that of the initial sample, while its wear resistance increased 5.7 times. Obtained results show, that successive ion implantation can be used as an effective tool for the improvement of hardness and wear resistance parameters of surface layers of AISI 310 and 440C steels.

Keywords: AISI 310; 440C; Carbon; Nitrogen; Ion Implantation; Microhardness; Wear

Introduction Such radiological process, as ion implantation is one of successfully applied alternative methods for producing novel construction materials with improved physical and mechanical features for further production of various-purpose tools and items with advanced operation parameters.

Radiation technologies are free from the limitations of equilibrium thermodynamics (excess of solubility limit, low temperature of phase nucleation and growth, etc.). Therefore, application of the method of ion implantation, the conditions of which differ substantially from those of equilibrium thermodynamics, enables formation of modified surface layers of metals in equilibrium, non-equilibrium, metastable and nanocrystalline states [1-3]. Modification of surface layers of AISI 310 and 440C stainless steels by ion irradiation is conducted at the final stage of production and does not change the features of the remaining bulk of the material, structure or technology of manufacturing items and tools from the above materials.

The work presents results of microhardness and wear resistance studies in AISI310 and 440C steels, successively irradiated with carbon and nitrogen ions. The work is a logical continuation of long-term investigations, started in Sukhumi city and continued in Tbilisi [4-11].

Materials and Methods Fine-grained, refractory, high purity (99,99%) stainless steels AISI 310 (C 0.25%, Mn 2.%, Si 1.5%, P 0.045%, S 0.03%, Cr 24-26%, Mo 19-22%) and 440C (C 0.95%, Mn 1%, Si 1%, P 0.04%, S 0.o3%, Cr 16-18%, Mn 0.75%) were used as initial materials. Initial samples of the above steels in the form cylindrical plane-parallel disks with the diameter of 19 mm and 1-3 mm thickness were cut from the steel bars, using the machine for automatic cutting, Saw EQSVJ-200. To remove the damaged surface layer and to obtain minimum surface roughness the samples were subject

to mechanical grinding and polishing by machine for precise automatic grinding and polishing, UNIPOL-802. For surface processing we used diamond pastes with 12-0.5 μm grain sizes. Final polishing was made with colloidal silica suspension, 0.25 μm. The plate surface roughness was measured by Alpha-Step 200 profile meter (TENCOR INSTRUMENTS) with accuracy down to 3 nm. Prior to the process of ion implantation measured surface roughness of the samples made 7.5 - 13.2 nm, which met the requirements of ion implantation technology and method of studying physical and mechanical features of modified materials.

Fig. 1 below shows roughness of the initial samples of AISI 310 (a) and 440C (b) steels after final polishing.

SRIM 2012 [12] program was used for the computation of the parameters of profile distribution of the implanted atoms and resulting displacements (vacancies) for proper selection of the modes of AISI 310 and 440C steels implantation with carbon and nitrogen ions with energies 60 keV. Fig.2 shows an example of the computation results of the profile of implanted and displaced atoms in AISI 310, irradiated with nitrogen ions.

Table 1 presents computation results of basic radiation parameters of carbon and nitrogen ions, bombarding AISI 310 and 440C stainless steels.

Table 1. Radiation parameters of carbon and nitrogen ions, bombarding AISI 310 and 440C stainless steels Target AISI 310

440 C

Ion

Ion range, nm

C

81.3

Straggle, nm Displacement/Ion 334

646

N

69.5

29.6

730

C

81.6

32,9

594

N

71,4

30

672

Ion implantation of the polished samples was made by implanter VEZUVII 3M. Carbon dioxide and nitrogen were

264

a

b

Fig.1. AISI 310 and 440C sample surface pattern after grinding and polishing, and before ion implantation

a

b

Fig.2. Range (a) and displacement (b) distribution in AISI 310 as-implanted by N ions with 60 keV energy.

used as working substances in the plasma-arc ion source.

Radiation modification of the steel surfaces by ion implantation was made in two stages. Initially the target was bombarded with carbon ions, and then with nitrogen ones. Implantation of AISI 310 and 440C steels was performed by atomic ions of carbon and nitrogen with energies 60 keV, total fluences Ô=1x1016, 1x1017, 1x1018, ion.cm-2, ion fluxes F=4x1014, ion.cm-2.s-1 at temperatures T=300-350 K.

Results Microindentation under various loadings and constant deformation rate was used for testing mechanical hardness of the modified samples [13]. Microhardness tests were conducted in SHIMADZU Dynamic Ultra Micro Hardness Tester DUN-213S, the load range of which was 0.11996 mN. During testing applied loads onto the diamond indenter varied from 0.1 mN to 1000 mN, which allowed to make microindentation to the depths 50 - 3000 nm. Fig. 2 and Fig. 3 show hardness test results, obtained by microindentation of both initial and modified AISI 310 and 440C steel samples.

It was found that hardness, H, GPa of modified AISI 310 steel layers was substantially (1.8 – 2.2 times) higher than H0,,GPa in initial unmodified steel. Hardness of modi-

fied 440C steel was also (2.5-3.8 times) higher, than that of the unprocessed initial one. Implanted surface roughness measurements (14-29,4 nm) showed two-fold increase, compared with the unirradiated samples, which is explained with selective surface dispersion.

Wear resistance was measured by the method of abrasive wearing of the samples in the process of dry friction, using UNIPOL-802 instrument [14]. Submicron diamond powders were used as the abrasive substances. Ratio of the ion-implanted layer wearing, W to that of the unimplanted one, W0, shows relative wear resistance of the modified layers, W/W0. Thickness of the worn sample layers was determined by measuring the dimensions of the microindenter print, using microscope NIKONE clipse LV 150.

Wear resistance in the implanted samples increased gradually with the ion irradiation fluence increase and reached its maximum at fluence 1õ1018 ion/cm2. In result it was found that wear resistance in the implanted AISI 310 was 2.7 – 3.5 times higher, than in the initial unimplanted samples. Wear resistance of ion implanted 440C steel was 3.7 - 5.7 times higher, than that of the initial one before ion implantation. Table 2 presents results of maximal strengthening and wear resistance values in the surface layers of

265

a

b

Fig.3. Microhardness - H0, GPa depth profile of initial samples of (a) AISI 310 and 440C (b) measured by micro indentation

a

b

Fig. 4. Microhardness - H, GPa dependence in (a) AISI 310 and 440C (b), irradiated with carbon and nitrogen ions on the irradiation fluence (the doze increases from the top down)

266

Fig.5. AISI 310 u 440C sample surface pattern before ion implantation after processing

the steels, successively implanted with carbon and nitrogen ions with fluencies Ô =1x1016, 1x1017, 1x1018, ion cm-2.

.

Table 2. Hardness and wear resistance increase in modified AISI 310 and 440C samples Target

AISI 310

440 C

Ion

Φ, ion⋅cm2,

H/ H0

W/W0

1•1016

1.8

2.7

1•10

17

2.0

3.1

1•1018

2.3

3.5

1•1016

2,5

3.7

1•1017

3.0

4.5

1•1018

3.8

5.7

C+N

C+N

Review of the obtained results shows that wear resistance increase is substantially higher than hardness increase. Wear resistance increase is known to be proportional to that of hardness.

Conclusions Type AISI 310 and 440C stainless steels were successively implanted with carbon and nitrogen ions with energies 60 KeV, total fluences F=1x1016, 1x1017, 1x1018, ion cm2 at temperatures T=300-350 K. After implantation modified surface layers of the samples of implanted materials were subject to hardness testing by microindentation and wear resistance testing by the method of abrasive wearing. The obtained test results were as follows: - Sample hardness increases approximately 1.8 - 2.3 times in AISI 310 steel, and 2.5 - 3.8 times in 440C steel.

- Wear Resistance of the samples increases 2.7 - 3.5 times in AISI 310, and 3.7 – 5.7 times in 440C steel in all the cases.

- Successive, high fluence implantation with ion beams of carbon and nitrogen is an efficient method for improving hardness and wear resistance parameters in such alloys, as stainless steels AISI 310 and 440C.

.

References 1. Material Science Ion Beams./Ed. Harry Bernas. Springer, 2009, - 376 p 2. Gary S. Was. Fundamentals of Radiation Materials Science.

Metals and Alloys. Springer, Chapcher 6, 2007. – 827 p.

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5. G.V. Afanasev, I.G. Gverdtsiteli, A.I. Guldamashvili, E.M. Diasamidze, T.T. Karpenko, N.M. Kutsia. Phase Transformation in Ion Implanted Molybdenum. Items of Atomic Science and Technology. Ser.: Radiation Damage Physics and Radiation Technology (IAST, Ser.: RDP and RT). Kharkiv, KIPT, 1978, iss.1(6), pp. 52-56. (in Russian).

6. A.I. Guldamashvili, E.M. Diasamidze, T.T. Karpenko, N.M. Kutsia. Study of the Composition of Precipitated and IonImplanted Molybdenum Films with Backscattered Protons.

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(March 23-24, 2010, Tbilisi). Tbilisi, UNIVERSAL, p.5665.

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Abstracts. (October 20 – 24, 2014, Tbilisi, Georgia). Tbilisi, Technical University. 2014, p. 47-48.

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B. 2010, v. 268, p.1818-1823.

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soxumis ilia vekuas fizika-teqnikis instituti, mindelis q. 7, Tbilisi, saqarTvelo, 0186, el-fosta: sipt@sipt.org Seswavlilia TanamimdevrobiT naxSirbadis da azotis 60 kev energiis ionebis jamuri Ă&#x201D;=1x1016, 1x1017, 1x1018, ion cm- fluensebiT implantirebuli AISI 310 da 440C ti pis foladebis sisale da cveTamedegoba. nimuSebis sisaleze gamocda ganxorcielebulia dinamiuri ultra mikrosisalis danadgarze SHIMADZU DUN-213S mikroindentirebiT. cveTamedegobis dasadgenad gamoyenebulia abraziuli cveTis meTodi. Sedegad implantirebuli AISI 310 foladis sisale gazrdilia (1.8 2.3) - jer, xolo 440C sisale (2.5 - 3.8) - jer. nimuSebis cveTamedegoba AISI 310 (2.7 - 3.5) - jer da 440C (3.7 - 5,7) - jer metia sawyisi nimuSebis sisaleze. kvlevis Sedegebi gviCvenebs, rom naxSirbadis da azotis ionebis maRali fluensebiT Tanamimdevruli implantacia AISI 310 da 440C foladebis sisalis da cveTamedegobis gaumjobesebis efeqturi meTodia. es samuSao warmoadgens mravalwliani kvlevis logikur gagrZelebas, romelic daiwyo q. soxumSi da grZeldeba q. TbilisSi.

.

268

Êðèîãåííûå âàêóóìíûå òåõíîëîãèè - äîñòèæåíèÿ è ïåðñïåêòèâû Ã. Äãåáóàäçå Ñóõóìñêèé ôèçèêî-òåõíè÷åñêèé èíñòèòóò èì. È.Í. Âåêóà, óë. Ìèíäåëè 7, 0186, Òáèëèñè, Ãðóçèÿ Ýë–ïî÷òà:gdgebua@gmail.com Ðåçþìå.  ðàáîòå ïðåäñòàâëåíû ýòàïû ðàçâèòèÿ êðèîãåííîé òåõíèêè è òåõíîëîãèèâ ñóõóìñêîì ôèçèêî-òåõíè÷åñêîì èíñòèòóòå íà îñíîâå: òåïëîôèçè÷åñêèõ è èíæåíåðíûõ ðàñ÷åòîâ, ðàçðàáîòêè êîíñòðóêöèé è òåõíîëîãèè, ñîçäàíèÿ êðèîñîðáöèîííûõ è êðèîêîíäåíñàöèîííûõ âàêóóìíûõ íàñîñîâ, êðèîñòàòîâ, êðèîïàíåëåé è ðåçóëüòàòîâ èññëåäîâàíèÿ. Ïîêàçàíû ñôåðû ïðèìåíåíèÿ, äîñòèæåíèÿ è ïåðñïåêòèâû.

Êëþ÷åâûå ñëîâà: êðèîãåííûå íàñîñû, ñîðáöèÿ, êîíäåíñàöèÿ, òåìïåðàòóðà, äàâëåíèå

 ñóõóìñêîì ôèçèêî-òåõíè÷åñêîì èíñòèòóòå (ÑÔÒÈ) ðàçâèòèå êðèîãåííîé òåõíèêè è òåõíîëîãèè áûëî îáóñëîâëåíî íåîáõîäèìîñòüþ âûïîëíåíèÿ ïðîãðàìì âîåííî-ïðîìûøëåííîãî êîìïëåêñà ÑÑÑÐ, â ÷àñòíîñòè, ñîçäàíèå ýëåêòðîííûõ è èîííûõ óñêîðèòåëåé, ñâåðõâûñîêî÷àñòîòíûõ è ïëàçìåííûõ ãåíåðàòîðîâ, àïïàðàòóð ðàäèàöèîííî-âàêóóìíîãî è êîñìè÷åñêîãî ìàòåðèàëîâåäåíèÿ, èìèòàòîðîâ êîñìè÷åñêîãî ïðîñòðàíñòâà è îáîðóäîâàíèÿ ñïåöèàëüíîãî íàçíà÷åíèÿ.  öåëîì àêòóàëüíîñòü äàííûõ ðàáîò çàêëþ÷àëñÿ â òîì, ÷òî äëÿ âûÿñíåíèÿ ôèçè÷åñêèõ ÿâëåíèé, ïðîòåêàþùèõ â ìàòåðèàëàõ ïðè âçàèìîäåéñòâèè ñ íèìè ìîùíûõ ïîòîêîâ ýëåêòðîìàãíèòíîé ýíåðãèè, âîçìîæíî ïðîâåäåíèå ìîäåëèðóþùèõ ýêñïåðèìåíòîâ ñ ïðèìåíåíèåì ñèëüíîòî÷íûõ ïó÷êîâ ýëåêòðîíîâ,èîíîâ è äðóãèõ èçëó÷åíèé ðàçëè÷íîé èíòåíñèâíîñòè è ýíåðãèè.Ýêñïåðèìåíòàëüíàÿ áàçà âêëþ÷àëà â ñåáÿ ðÿä óíèêàëüíûõ ïî ñâîèì âûõîäíûì õàðàêòåðèñòèêàì óñòàíîâêè ñ ïëîòíîñòüþ ïîòîêîâ ýíåðãèè â øèðîêîì èíòåðâàëå 10-104Äæ/ñì2 ïðè äëèòåëüíîñòè èìïóëüñîâ 10-7-10-3 ñåê, âîçìîæíîñòü âàðèàöèè ýíåðãèé ýëåêòðîíîâ 103-107 ý è ýëåêòðîííûõ òîêîâ â èìïóëüñå îò 10 äî 105 À. Äëÿ äàííûõ èññëåäîâàòåëüñêèõ óñòàíîâîê îáåñïå÷åíèå íåîáõîäèìîãî ðàçðÿæåíèÿ ïðîñòûìè è íàäåæíûìè êîìïðèìèðóþùèìè ñðåäñòâàìè óñëîæíÿåòñÿ æåñòêèìè óñëîâèÿìè. Áîëüøèå ãàçîâûå íàãðóçêè, èíòåíñèâíûå ìàãíèòíûå è ýëåêòðè÷åñêèå ïîëÿ, âîçäåéñòâèå ìîùíîãî ýëåêòðîìàãíèòíîãî è êîðïóñêóëÿðíîãî èçëó÷åíèÿ, îãðàíè÷åííàÿ àïåðòóðà, ðàçâåëòâëåííîñòü, êîíñòðóêöèîííàÿ ñëîæíîñòü, íåîáõîäèìîñòü âûñîêèõ ñêîðîñòåé îòêà÷êè, ñâåðõ÷èñòîãî âàêóóìà è øèðîêîãî äèàïàçîíà 105÷÷1012 Ïà ðàáî÷åãî äàâëåíèÿ îïðåäåëÿþò òðåáîâàíèÿ, ïðåäúÿâëÿåìûå ê âàêóóìíûì îòêà÷íûì ñðåäñòâàì è ñèñòåìàì. Ïðîâåäåííûå èçûñêàíèÿ, äëÿ ðåøåíèÿ äàííûõ çàäà÷, ïîäòâåðäèëè áåçàëüòåðíàòèâíîñòü

êðèîãåííûõ âàêóóìíûõ îòêà÷íûõ ñðåäñòâ è ñèñòåì. Ïðè ðàçðàáîòêå âûñîêî- è ñâåðõâûñîêîâàêóóìíûõ êðèîãåííûõ ñðåäñòâ îòêà÷êè ñ òðåáóåìûìè õàðàêòåðèñòèêàìè áûëè ðåøåíû òåïëîôèçè÷åñêèå è èíæåíåðíûå çàäà÷û, îïðåäåëåíû îñíîâíûå õàðàêòåðèñòèêè, èññëåäîâàíû êîíñòðóêöèîííûå è ïðèìåíÿåìûå ìàòåðèàëû, ðàçðàáîòàíû ýôôåêòèâíûå êîíñòðóêöèé è âíåäðåíû ïåðåäîâûå òåõíîëîãèè èçãîòîâëåíèÿ. Ýôôåêòèâíîñòü êðèîíàñîñà êàê îòêà÷íîãî ñðåäñòâà íàèáîëåå ïîëíî õàðàêòåðèçóåòñÿ êîýôôèöèåíòîì çàõâàòà à capt – áåçðàçìåðíîé âåëè÷èíîé, ðàâíîé îòíîøåíèþ ÷èñëà îñòàâøèõñÿ â íàñîñå ÷àñòèö ê ïîëíîìó ÷èñëó ÷àñòèö, ïîñòóïèâøèõ â íàñîñ ñî ñòîðîíû îòêà÷èâàåìîé êàìåðû. Çíà÷åíèå êîýôôèöèåíòà çàõâàòà îïðåäåëÿåòñÿ õàðàêòåðîì âçàèìîäåéñòâèÿ ìîëåêóë ãàçà ñ âíóòðåííèìè ïîâåðõíîñòÿìè íàñîñà è ãåîìåòðèåé ýòèõ ïîâåðõíîñòåé. Ñòàòè÷åñêè àêò ñîóäàðåíèÿ õàðàêòåðèçóåòñÿ êîýôôèöèåíòîì êîíäåíñàöèè bcond, îïðåäåëÿþùèì âåðîÿòíîñòü äëèòåëüíîãî (íåìíîãî ïðåâûùàþùåãî ïåðèîäà êîëåáàíèé êðèñòàëëè÷åñêîé ðåøåòêè) óäåðæàíèÿ ïîâåðõíîñòüþ óïàâùåé íà íåå ãàçîâîé ìîëåêóëû. Ñëåäîâàòåëüíî Ν cond =β cond N ÷àñòèö èç óïàâùèõ áóäåò çàäåðæèâàòüñÿ íà ïîâåðõíîñòè, à Νreƒt=(1−βcond)N ÷àñòèö óïðóãî îòðàæàòüñÿ. Êðîìå óêàçàííûõ ïîòîêîâ ñî ñòîðîíû ýëåìåíòà ïîâåðõíîñòè â âàêóóìèðóåìîå ïðîñòðàíñòâî îòõîäèò åùî ïîòîê èñïàðèâùèåñÿ ÷àñòèö Nvap.  ñòàöèîíàðíîì ðåæèìå íà îñíîâå áàëàíñà ïîòîêîâ ìîæíî ñîñòàâèòü óðàâíåíèå Nadh= Νcond - Νvap = βcondN - Νvap (1) ãäå Nvap – ÷èñëî îòêà÷àííûõ ýëåìåíòîâ ïîâåðõíîñòè ÷àñòèö (ñ ó÷åòîì èñïàðåíèÿ). Äëÿ èçîòðîïíûõ óñëîâèé ñîãëàñíî êèíåòè÷åñêîé òåîðèè ãàçîâ

N=

Pg 2πmKTg

,

(2) ;

269 N vap =

Ps 2πmKTs

S (Pg ) = Г capt ( Pg ) S max

, (3)

ãäå Pgè Tg–äàâëåíèå è òåìïåðàòóðà ãàçà â âàêóóìíîé ñèñòåìå (ïàäàþùåì íà ïîâåðõíîñòü ãàçîâîì ïîòîêå) Òs– òåìïåðàòóðà ïîâåðõíîñòè è Ps äàâëåíèå íàñûùåíèÿ îòêà÷èâàåìîãî ãàçà ïðè òåìïåðàòóðå Òs. Åñëè ââåñòè ïîíÿòèå ýôôåêòèâíîãî êîýôôèöèåíòà ïðèëèïàíèÿ ñ ïîìîùþ ðàâåíñòâà Nadh =βeƒƒ Ν, òî ñ ó÷åòîì ñîîòíîøåíèé, (1), (2) è (3) ìîæíî ïîëó÷èòü

⎛

β eff = β cond ⎜1 − ⎜ ⎝

Ps Pg

Tg ⎞ ⎟.

Ts ⎟⎠

(4)

Êàê âèäíî èç ïîëó÷åííîãî ñîîòíîøåíèÿ, ïðè çàäàííîì äàâëåíèè îòêà÷èâàåìîãî ãàçà â âàêóóìíîé ñèñòåìå P g , îòêà÷èâàþùåå äåéñòâèå ýëåìåíòà ñîðáèðóþùåé ïîâåðõíîñòè, õàðàêòåðåçóåìàÿ âåëå÷èíîé βeff, îïðåäåëÿåòñÿ ñ îäíîé ñòîðîíû êîýôôèöèåíòîì êîíäåíñàöèè βcond è ñ äðóãîé òåìïåðàòóðîé äàííîãî ýëåìåíòà ïîâåðõíîñòè Ò, (ó÷òåíî, ÷òî Ps äëÿ äàííîãî ãàçà çàâèñèò òîëüêî îò Òs). Ïîñëåäíåå óñëîâèå ñîäåðæèò çàâèñèìîñòü êîýôôèöèåíòà çàõâàòà íàñîñà à capt îò ðàñïðåäåëåíèÿ òåìïåðàòóðû â îòêà÷èâàþùèõ ýëåìåíòàõ íàñîñà Ãcapt ïðè çàäàííîì Ðg. Îïðåäåëåíèå âåëè÷èíû βcond ñëîæíûì îáðàçîì çàâèñèò îò ïðèðîäû ãàçà, òåìïåðàòóðû ãàçà è êðèîïîâåðõíîñòè, à òàêæå îò ïåðåíàñûùåíèÿ Pg/Ps. Ñîãëàñíî ñîâðåìåííûì ïðåäñòàâëåíèÿì ÷àñòèöû, èìåþùèå íà÷àëüíóþ ýíåðãèþ âûøå íåêîòîðîãî êðèòè÷åñêîãî çíà÷åíèÿ Ecr, íå ìîãóò áûòü çàõâà÷åíû ïîâåðõíîñòüþ. Ýòî çíà÷èò, ÷òî êîýôôèöèåíò βcond áóäåò îïðåäåëÿòüñÿ âåðîÿòíîñòüþ ïðåáûâàíèÿ ÷àñòèöû â ýíåðãåòè÷åñêîì èíòåðâàëå 0-E cr .  ñëó÷àå ìàêñâåëëîâñêîãî ðàñïðåäåëåíèÿ ïî ýíåðãèÿì äëÿ äâóõè òðåõàòîìíûõ ãàçîâ ïîëó÷àåòñÿ

⎞ ⎛ Ecr2 E ⎛ E ⎞ + cr + 1⎟⎟ exp⎜ − cr ⎟.

2 2 RT ⎝ RT ⎠ ⎠ ⎝ 2R T

β cond = 1 − ⎜⎜

(5)

Ïðèâåäåííûå äàííûå óêàçûâàþò, ÷òî äëÿ âñåõ ãàçîâ, êðîìå âîäîðîäà ïðè íå ñëèøêîì âûñîêèõ òåìïåðàòóðàõ ãàçà êîýôôèöèåíò êîíäåíñàöèè ìàëî îòëè÷àåòñÿ îò åäåíèöû. Äëÿ âîäîðîäà áîëåå äîñòîâåðíûì çíà÷åíèåì βcond ñëåäóåò ñ÷èòàòü 0,85. Ïðè èçâåñòíûõ çíà÷åíèÿõ êîýôôèöèåíòà êîíäåíñàöèè βcond ìîæíî ïîäñ÷èòàòü Nads è âû÷èñëèòü êîýôôèöèåíò çàõâàòà Ãcapt äëÿ êðèîíàñîñà ìåòîäîì ÌîíòåÊàðëî [1]. Ñ ïîìîùüþ Ãcapt ìîæíî ðàññ÷èòàòü îäíó èç îñíîâíûõ õàðàêòåðèñòèê âàêóóìíîãî íàñîñà – áûñòðîòó äåéñòâèÿ.  êðèîêîíäåíñàöèîííîì ðåæèìå îòêà÷êè ïðè èçâåñòíîé çàâèñèìîñòè êîýôôèöèåíòà çàõâàòà êðèîíàñîñà îò äàâëåíèÿ â âàêóóìíîé êàìåðå Ãcapt= Ãcapt(Pg) áûñòðîòà äåéñòâèÿ íàñîñà äëÿ äàííîãî çíà÷åíèÿ Pg ìîæåò áûòü îïðåäåëåíà ïî ôîðìóëå

(6)

ãäå S max – ìàêñèìàëüíî âàçìîæíîå çíà÷åíèå áûñòðîòû äåèñòâèÿ, çàâèñÿùåå îò ïëîøàäè âõîäíîãî ñå÷åíèÿ è óñëîâèè ïîäà÷è ãàçà ê íàñîñó.  ñëó÷àå ìàêñâåëëîâñêîãî ðàñïåðäåëåíèÿ ïî ñêîðîñòÿì ÷àñòèö îòêà÷èâàåìîãî ãàçà â âàêóóìíîé êàìåðå áóäåò

S max =

1 8RTg F0 .

4 πμ

(7)

Êðèîñîðáöèîííûå îòêà÷íûå ñðåäñòâà

Íà îñíîâå òåïëîôèçè÷åñêèõ è èíæåíåðíûõ ðàñ÷åòîâ áûëà ñîçäàíû ãàììà êîíñòðóêöèè êðèîñîðáöèîííûõ íàñîñîâ ñåðèè CSP (CSP-0.5D, CSP-1.0D, CSP-2.0D, CSP-8.0D) è CSPS (CSPS-1D) [2] ñ æèäêèì è òâåðäûì àçîòîì â êà÷åñòâå ðàáî÷åãî õëàäàãåíòà ñîîòâåòñòâåííî, â êîòîðûõ ðåàëèçîâàíû òåõíè÷åñêèå ðåøåíèÿ, ïîçâîëÿþùèå óëó÷øèòü ýñïëóàòàöèîííûå õàðàêòåðèñòèêè íàñîñà â øèðîêîì äèàïàçîíå 1.105 - 1.10-9 Ïà ðàáî÷åãî äàâëåíèÿ. Ñðåäè íèõ êðèîêîíäåíñàòîð íîâîé êîíñòðóêöèè äëÿ ýôôåêòèâíîé îòêà÷êè ïàðîâ âîäû è äèîêñèäà óãëåðîäà, êîíôèãóðàöèÿ ïîâåðõíîñòè îòêà÷èâàþùåãî ýëåìåíòà, ñïîñîá òåïëîâîé çàùèòû àäñîðáöèîííûõ ñëîåâ ñ ïîìîùüþ îïòè÷åñêè íåïðîçðà÷íûõ ïîðèñòûõ ìàòåðèàëîâ. Òàêèå ñòðóêòóðû ñïîñîáíû íå òîëüêî íàäåæíî ýêðàíèðîâàòü àäñîðáåíò îò èçëó÷åíèÿ, íî è çàùèùàòü åãî îò çàãðÿçíåíèÿ ëåãêîêîíäåíñèðóåìûìè ïàðàìè, êàê â îáëàñòè âÿçêîñòíîãî, òàê è ìîëåêóëÿðíîãî ðåæèìîâ òå÷åíèÿ. Ïîðèñòûé ýêðàí ïðåäîòâðàùàåò ïîïàäàíèå â îòêà÷èâàåìûé îáúåì ïûëè àäñîðáåíòà, îáðàçóþùåéñÿ â ïðîöåññå ýêñïëóàòàöèè, îáåñïå÷èâàÿ òåì ñàìûì âûñîêóþ ”÷èñòîòó” ñîçäàâàåìîãî âàêóóìà.  êîíå÷íîì ñ÷åòå, áûëî äîñòèãíóòî íèçêîå äàâëåíèå 5.10-5 Ïà îñòàòî÷íîãî ãàçà è, ÷òî ñàìîå ãëàâíîå, ñóùåñòâåííî óâåëè÷åí ðåñóðñ áåñïðåðûâíîé ðàáîòû êðèîñîðáöèîííûõ íàñîñîâ. Íà ðèñ-1 ïðåäñòàâëåí îáùèé âèä êðèîñîðáöèîííûõ íàñîñîâ. Îñíîâíûå õàðàêòåðèñòèêè êðèîñîðáöèîííûõ íàñîñîâ ñâåäåíû â òàáëèöå 1.

Êðèîêîíäåíñàöèîííûå îòêà÷íûå ñðåäñòâà Ïîëó÷åííûå â ðàìêàõ ôèçèêî-ìàòåìàòè÷åñêîé ìîäåëè ðàñ÷åòíûå ñîîòíîùåíèÿ ñîâìåñòíî ñ ïðîãðàììîé ïðîñëåæåâàíèÿ òðàåêòîðèè ÷àñòèö äîñòàòî÷íî ïîëíî îïèñûâàþò ïðîöåññû òåïëî-è ìàññî îáìåíà, ïðîòåêàþùèå â ýëåìåíòàõ êðèîêîíäåíñàöèîííîãî íàñîñà, ïîçâîëÿþò ðàñ÷èòàòü âñå âàæíûå òåõíè÷åñêèå õàðàêòåðèñòèêè íàñîñà è äåòàëüíî èññëåäîâàòü èõ çàâèñèìîñòü îò òåïëîôèçè÷åñêèõ è ðàäèàöèîííûõ ñâîéñòâ èñïîëüçóåìûõ êîíñòðóêöèîí-

270 íûõ ìàòåðèàëîâ è òåõíîëîãè÷åñêèõ ïàðàìåòðîâ ïðîöåññà âàêóóìèðîâàíèÿ. Ñ ýòîé öåëüþ íà îñíîâå ïîëó÷åííûõ ñîîòíîøåíèé áûëà ïðåäñòàâèòåëüíî

ñîñòàâëåíà ïðîãðàììà ðàñ÷åòà íà ÝÂÌ îñíîâíûõ òåõíè÷åñêèõ õàðàêòåðèñòèê êðèîíàñîñà. Ñîãëàñíî ïðîâåäåííûì òåîðåòè÷åñêèì è ýêñïåðè-

Ðèñ.1. îáùèé âèä êðèîñîðáöèîííûõ íàñîñîâ CSP è CSPS ñ æèäêèì è òâåðäûì àçîòîì Òàáëèöà 1

Ðèñ.2. Oáùèé âèä êðèîêîíäåíñàöèîííûõ íàñîñîâ CCP ñ æèäêèì ãåëèåì Òàáëèöà 2

271 ìåíòàëüíûì ðàñ÷åòàì áûëè ñîçäàíû êðèîêåíäåíñàöèîííûå íàñîñû ñåðèè CCP (CCP-8D è CCP-10D).Íà ðèñ-2 ïðåäñòàâëåí îáùèé âèä êðèîêîíäåíñàöèîííûõ íàñîñîâ. Îñíîâíûå õàðàêòåðèñòèêè êðèîêîíäåíñàöèîííûõ íàñîñîâ ñâåäåíû â òàáëèöå 2.

 íàñòîÿùåå âðåìÿ äàííûå òåõíîëîãèè ïðèìåíÿþòñÿ ïðè ðàçðàáîòêå è èçãîòîâëåíèè êðèîñòàòîâ [5] äëÿ èññëåäîâàíèÿ âûñîêîòåìïåðàòóðíûõ ñâåðõïðîâîäíèêîâ. Íà ðèñ. 4 ïðåäñòàâëåí ãåëèåâûé êðèîñòàò ñ óíèêàëüíîé âîçìîæíîñòüþ èññëåäîâàòü ñâåðõïðîâîäíèêè â äèàïàçîíå 2.5 – 300Ê òåìïåðàòóð.

Ðèñ.3. Çàâèñèìîñòü áûñòðîòû äåéñòâèÿ ïî âîäîðîäó îò äàâëåíèÿ ïðè ðàçëè÷íûõ òåìïåðàòóðàõ êðèîïîâåðõíîñòè

Íà ðèñ.3 ïðåäñòàâëåíû ãðàôèêè çàâèñèìîñòè S(P) äëÿ âîäîðîäà ïðè òåìïåðàòóðàõ êðèîïàíåëåé 4,2Ê è 2,5Ê. Ïîíèæåíèå òåìïåðàòóðû êðèîïàíåëåé ïîçâîëÿåò ðàñøèðèòü îáëàñòü êðèîîòêà÷êè âîäîðîäà âïëîòü äî äàâëåíèÿ 10-10Ïà. Ïåðâûé îïûòíûé îáðàçåö, êðèîãåííîãî êîíäåíñàöèîííîãî âàêóóìíîãî íàñîñà ÍÊÑ-10 çàëèâíîãî òèïà ñ ðàáî÷èì õëàäàãåíòîì æèäêèé ãåëèè áûë èçãîòîâëåí ñîâìåñòíî ñ Ëåíèíãðàäñêèì Ïîëèòåõíè÷åñêèì Èíñòèòóòîì (Ì. Ï. Ëàðèí è äð.) è èñïûòàí íà äåéñòâóþùåì óñêîðèòåëå ýëåêòðîíîâ “Âóëêàí”. Íàäåæíîñòü ðàáîòû êðèîíàñîñîâñóùåñòâåííî çàâèñèò îò âûáîðà êîíñòðóêöèîííûõ ìàòåðèàëîâ. Ïðè ýòîì ïðîèçâîäèòñÿ ñîïîñòàâëåíèå ðàçëè÷íûõ ôèçè÷åñêèõ, ìåõàíè÷åñêèõ è òåõíîëîãè÷åñêèõ ñâîéñòâ ñ ó÷åòîì óñëîâèÿ ðàáîòû íàñîñà. Îñîáûå òðåáîâàíèÿ ïðåäúÿâëÿþòñÿ ê òåìïåðàòóðíûì êîýôôèöèåíòàì ëèíåéíîãî è îáúåìíîãî ðàñøèðåíèÿ, òåïëîïðîâîäíîñòè è òåïëîåìêîñòè êîíñòðóêöèîííûõ ìàòåðèàëîâ [4]. ×åì íèæå çíà÷åíèå êîýôôèöèåíòà ëèíåéíîãî ðàñøèðåíèÿ, òåì ëåã÷å îáåñïå÷èòü òåðìè÷åñêóþ êîìïåíñàöèþ êîíñòðóêöèè íàñîñà, à äëÿ îáåñïå÷åíèÿ ìèíèìàëüíûõ òåïëîïðèòîêîâ ê êðèîïîâåðõíîñòÿì ÷åðåç òåïëîâûå ìîñòû ìåòàëë äîëæåí èìåòü ìàëóþ òåïëîïðîâîäíîñòü λ â ñî÷åòàíèè ñ âûñîêîé ïðî÷íîñòüþ σb , ò.å. çíà÷åíèå λ/ σb äîëæíî áûòü íèçêèì. Äàííûì òðåáîâàíèÿì îòâå÷àþò àóñòåíèòíûå õðîìîíèêåëåâûå ñòàëè, òèòàí, ìåäü è àëþìèíèé.  ðàçðàáîòàííûõ êðèîãåííûõ ñðåäñòâàõ îòêà÷êè, ïðè èçãîòîâëåíèè, ðåàëèçîâàíû ñîâðåìåííûå ýôôåêòèâíûå òåõíîëîãèè âàêóóìíîãî íàíåñåíèÿ òîíêèõ 200-300 ìêì ïëåíåê Ag, Al,Cu íà áîëüøåìåðíûå îáúåìû â ñðåäå ãåëèÿ, ïîëèðîâêè àóñòåíèòíîé õðîìîíèêåëåâîé ñòàëè, òèòàíà, ìåäè è àëþìèíèÿ ñ êîýôôèöèåíòîì ÷åðíîòû 0.0006, ÷åðíåíèÿ êðèîêîíäåíñàòîðîâ êðåìíåîðãàíè÷åñêèìè ìàòåðèàëàìè â ñðåäå âîäîðîäà, ïðèìåíåíèÿ òîíêîñòåííûõ òîëùèíîéäî 1.20 ìì êîíñòðóêöèîííûõ ìàòåðèàëîâ è 0.2 ìì òåïëîçàùèòíûõ ýêðàíîâ, ïðèìåíåíèÿ ñïèðàëüíûõ òðóáîê ïîäâåñà òîëùèíîé ñòåíêè 0.3 ìì, èçãîòîâëåíèÿ ðàçáîðíûõ òîíêîñòåííûõ êîíñòðóêöèè è ñâàðêè â ñðåäå ãåëèÿ.

Ðèñ. 4. Îáùèé è ðàçáîðíûé âèä ãåëèåâîãî êðèîñòàòà

Ïåðñïåêòèâíûìè íàïðàâëåíèÿìè ëàáîðàòîðèè êðèîãåííîé òåõíèêè è òåõíîëîãèè ÿâëÿåòñÿ ðàçðàáîòêà è èññëåäîâàíèå: êðèîâàêóóìíîé òåõíîëîãè÷åñêîé óñòàíîâêè äëÿ ïîëó÷åíèÿ, PVD ìåòîäàìè, ÷èñòûõ ìåòàëëè÷åñêèõ è íåìåòàëëè÷åñêèõ íàíîïîðîøêîâ, âûñîêîòåìïåðàòóðíûõ êåðàìè÷åñêèõ è ìåòàëëè÷åñêèõ ñâåðõïðîâîäíèêîâ, â çàäà÷àõ òîíêîïëåíî÷íîé òåõíîëîãèè. Ïðåäëàãàåì ñîòðóäíè÷åñòâî ïî ðàçðàáîòêå êðèîâàêóóìíûõ ñðåäñòâ îòêà÷êè, êðèîêîíäåíñàòîðîâ, êðèîñòàòîâ, âàêóóìíûõ òåõíîëîãè÷åñêèõ îáîðóäîâàíèé è ìàëîãàáàðèòíûõ êðèîñèñòåì äëÿ îòêà÷êè áîëüøîãî

272 ãàçîâîãî ïîòîêà äî 2Ì (Ìàõà) â òåìïåðàòóðíîì äèàïàçîíå 600 – 80Ê, â ÷àñòíîñòè ëàçåð COIL. Ìû âûðàæàåì áëàãîäàðíîñòü Ìåæäóíàðîäíîìó Íàó÷íî-Òåõíè÷åñêîìó Öåíòðó ISTC çà ïîääåðæêó ãðàíòîì G-027, G-401 è Ãðóçèíñêîìó Ôîíäó Øîòà Ðóñòàâåëè - ãðàíò GNF-417.

kriogenuli vakuumuri teqnologiebi miRwevebi da perspeqtivebi

Ëèòåðàòóðà

ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186,Tbilisi, saqarTvelo el–fosta: gdgebua@gmail.com

1. Ñàêñàãàíñêèé Ã.Ë. Ìîëåêóëÿðíûå ïîòîêè â ñëîæíûõ âàêóóìíûõ ñòðóêòóðàõ.-Ì.: Àòîìèçäàò, 1980, 216ñ.

2. Dgebuadze G.N. High Performant Cryosorption Pump. ColdFacts.// The Magazine of the Cryogenic Society of America, Inc., 1999, v.15, No.3, Pages 8,9,28. Summer.

3. Guram N. Dgebuadze. Cryocondensation Pump With Advanced Coefficient Of By H2 And He. GELJ: Physics 2010 | No.2(4), P 38-41.

4. À.Ò. Êîìîâ. Âàêóóìíûå è êðèîãåííûå ñèñòåìû òåðìîÿäåðíûõ óñòàíîâîê è ðåàêòîðîâ. Ìîñêâà, èçäàòåëüñòâîÌÝÈ 2003, 255ñ.

5. Guram Dgebuadze, Ioseb Metskvarishvili, Bezan Bendeliani.

Cryostat for Investigation of Superconductors. Bulletin of the Georgian National Academy of Sciences, vol. 8, no.3, 2014

Cryogenic Vacuum Technologies of Achievement and Prospect G. Dgebuadze Ilia Vekua Sukhumi Institute of Physics and Technology,7 Mindeli str.0186, Tbilisi, Georgia, .

E-mail: gdgebua@gmail.com In work stages of development of cryogenic equipment and technology at the Sukhumi institute of physics and technology are presentedon a basis: heatphysical and engineering calculations, development of designs and technology, creation cryosorption and cryocondensation vacuum pumps, cryostats, cryopanels and results of research. Application spheres, achievements and prospects are shown.

g. dgebuaZe

naSromSi warmodgenilia soxumis fizika-teqnikis institutSi kriogenuli vakuumuri teqnikis da teqnologiebis ganviTarebis etapebi: Tbofizikuri da inJineruli gaTvlebis, konstruqciebis da teqnologiebis damuSavebebis, kriosorbciuli da kriokondensaciuri vakuumuri tumboebis, kriostatebis, kriopanelebis Seqmnis da kvlevebis Sedegebis safuZvlebze. naCvenebia gamoyenebis sferoebi, miRwevebi da perspeqtivebi.

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Animal hair as biological indicator for heavy metal pollution in the two regions of Georgia T. Chelidze, L. Enukidze, M. Chankashvili, T. Loladze R. Agladze Institute of Inorganic Chemistry and Electrochemistry, I. Javakhishvili Tbilisi State University, 11, Mindeli str., 0186, Tbilisi, Georgia E-mail: tamchelidze@yahoo.com Abstract. The increase in pollution is a major and global problem. The work is dedicated to the quantitative determination of the heavy metals in animals hair in the various regions of Georgia. Animal hair is a good bio-monitoring tool for heavy metals assessment and reflects the contents of heavy metals in the forage, ground water and soil, ultimately to the biosphere.

Heavy metals - lead, cadmium, copper and zinc were determined in scalp hair of cows, collected from some different environmental regions of Georgia. These regions are village Kutiri (Khoni municipality, Western Georgia) and villageManglisi (Tetritskaro municipality, Eastern Georgia). The investigations will be performed by differential-pulse polarographic methods. The results of analysis of heavy metals content in scalp hair of cows showed that in Khoni municipality it is necessary to verify the grass on the pasture or ground water, because concentration of zinc is more than permissible norm.

As for the elements - lead, cadmium and copper, their concentration in this region is within the normal range. In case of Manglisi, content of the maintenance elements does not surpass the assumed standards pointing to the ecological purity of this region, in spite of the fact, that it is located near the Bolnisi municipality, where the soil is very polluted with heavy metals. Probably, in this case, the mountainous arrangement of Manglisi plays a significant role.

Keywords: Animal hair, environmental, heavy metal, polarographic method.

Introduction Our environment is affected by a great variety of pollutants. Human activities such as industrial production, mining, agriculture and transportation, release high amount of heavy metals into surface and ground water, soils and ultimately to the biosphere. Because of the potential health hazards of environmental pollution in general and food contaminants in particular, the joint of FAO/WHO Expert Committee recommends the development of internationally coordinated and statistically valid systems for the collection and evaluation of data on contaminants in food from different parts of the world [1]. Although, the basic monitoring systems are set up at the national level, the results of such monitoring should then be assembled at the international level, evaluated and made available to governments.

Bio-monitoring is the major way for ecologically contaminated soil where the cultivated plant and/or corns are used as food. At present, the study of the animal hair is considered as interesting problem to determine the degree of environment contaminated by toxic elements. These animals are in the same living space as men and eat the grass from the pastures. Therefore, bio-monitoring of chemical pollutants becomes more and more important in various countries. In some countries, especially in big cities, such investigations are carried out on dogs, cats, mice, etc [2-5].

The objective of this study is to assess the heavy metals - cadmium, lead, copper and zinc in cows hair from two different environmental regions in Eastern and Western Georgia, and evaluate heavy metal pollution using animal hair as a bio-indicator tool. These regions are village Kutiri

(Khoni municipality, Western Georgia) and village Manglisi (Tetritskaro municipality, Eastern Georgia).

There are several ways for penetration of microelements in living organism. The heavy metals toxicity in domestic animals can occur from drinking-water contamination, high ambient air concentration near emission sources, or by eating contaminated food. The heavy metals and some of their organic derivatives are cumulative and may attain equilibrium within the body only after prolonged exposure, selective localization of such materials in susceptible organs and tissues of the body may cause injury when high levels are attained. It is well known that, as the compounds circulate in living organism by means of blood, their content in the internals (heart, liver, kidney, nail, etc) are different and the scalp hair of human or animals gives an average picture. It should be noted that sample collection through cutting hair is absolutely harmless for animal and does not injure them, reducing the risk of possible contamination, low cost, easy collection and storage. Hair of animal reflects the accumulation and concentration of heavy metals of the previous months and years. Recently, the hair analysis technology has been developing rapidly.

The village Kutiri islocated in Western Georgia at an altitude of 62 meters above sea level. Mainly subtropical podzols (stagnicacrisols) in this village are characterized with acid, neutral or weak alkalin pH [6]. This region is characterized by damp climate â&#x20AC;&#x201C; warm winter and hot summer.

Manglisi is located in the eastern part of Georgia at an altitude of 700 - 900 meters above sea level. There, basically, brown calcareous soils with alkaline or neutral pH [6] are found. This region is characterized by dry, subtropical

284 climate – warm, almost dry winters and hot, dry summers.

The municipality is bounded by the municipality of Bolnisi, where the mining activities and the soil is contaminated with toxic microelements.

Materials and Methods The investigation will be performed through differential-pulse polarographic methods with a dropping mercury electrode (t=3.5 sec, m=2.6 mg/sec) by a three-electrode cell. The scalp hair of the cattle was selected as a sample of investigation to determine the degree of ecosystem contamination by heavy metals. The analytical procedure included: a careful washing technique by acetone and rinsing many times with redistilled water, drying at the 100ºC for an hour, weighing and burning at the 450 ºC for 5 hours in the quartz vessel. The receipted ash was treated by 1N HNO3 and evaporated. After this 1N HCI was added and evaporated again. The ashobtained in result of the mineralization of hair was dissolved in 10 ml of 0.1N HCI. After this, the solution is placed into the thermostatic cell (t=25ºC) and polarographic curves recorded. The value of potential was taken towards the saturated calomel electrode potential.

Results On the basis of our investigation it was established that the toxic metal content in the eight cows scalp hair from village Kutiri, that concentration of lead, cadmium and copper was recorded from 0.64 to 1.56 mg/kg, from 0 to 0.46 mg/kg, from 2.94 to 12.42 mg/kg respectively. Therefore, the obtained value does not exceed the limits allowed by international standards. Concentration of zinc in the samples of scalp hair of cow ranged between 206.54 - 307.80 mg/kg. The content of zinc is usually high in hair due to its physiological function. In wool of sheep from Greece, Mexico, Poland and Syria it is observed that values were from 73.62 to 244.73 mg/kg [7,8] The concentration of zinc in horses ranged from 19.56 to 86.00 mg/kg [9,10] and in cattle in an industrialized region from 98.5 to 333.9 mg/kg [11]. In our opinion, it is certain that the high value of zinc requires additional investigations, as Kutiri is not in an industrialized region. Therefore, for the establishment of the reasons of this fact, it is necessary to study the heavy metal content in soil. The uptake of heavy metals by plants depending upon the soil type, plant growth stages and plant species on the pasture in this region is also increasing. Zinc is one of the important trace elements that play a vital role in the physiological and metabolic process of many organism, it is an essential component of a large number of enzymes participating in the synthesis and degradation of carbohydrates, lipids, proteins and nucleic acids, but despite of this fact, excessive dose of it will damage the health of animals as well as of human [12,13].

In case of Manglisi, content of the maintenance elements does not surpass the assumed standards: lead - from 0.7 mg/kg to 1.82 mg/kg, cadmium - from 0.008 mg/kg to

0.03 mg/kg, zinc - from 45.25 mg/kg to 91.7 mg/kg, copper from 5.55 mg/kg to 9.73 mg/kg, pointing to the ecological purity of this region, in spite of the fact that it is located near the Bolnisi municipality, where the soil is very polluted with heavy metals. Probably, in this case, the mountainous arrangement of Manglisi plays a significant role.

Conclusions On the basis of our investigation it was established that the toxic metal content in the cows scalp hair from village Kutiri (Khoni municipality, Western Georgia) of lead, cadmium and copper does not exceed the limits allowed by international standards. In case of zinc, this concentration is very high, therefore, for establishment of the reason of this fact it is necessary to study plants on the pasture in this region. In case of Manglisi, content of the maintenance elements do not surpass the assumed standards pointing to the ecological purity of this region, in spite of the fact that it is arranged near the Bolnisi municipality, where the soil is very polluted with heavy metals. Probably, in this case, the mountainous arrangement of village Manglisi plays a significant role.

References: 1. Seventy-seventh Meeting of the Joint FAO/WHO Expert Committee on Food Additives, Rome, 2013.

2. E. Kalu, J.A. Nwantaand A.O. Anaga: Determination of the Presence and Concentration of Heavy Metal in Cattle Hides Singed in Nsukka Abattoir, Journal of Veterinary Medicine and Animal Health, 7(1) (2015), 9-17.

3. S. Morais, F. Garcia e Costa and M. de Lourdes Pereira: Heavy Metals and Human Health,Universidade de Aveiro, Portugal, (2012), 152-154.

4. K. Chojnacka, A. Saeid , I. Michalak, M. Mikulewicz: Effects of Local Industry on Heavy Metals in Human Hair, Environ.

Toxicol. Pharmac, 34 (2012), 1563-1570.

5. M. Pourjafar, K.Badiei:Cattle Hair as a Biomarker of Lead Pollution in the Region of the Shiraz Oil and Petrochemical Industries in Iran, International Journal of Veterinary Research, 4 (2010), 141-145.

6. T. Urushadze, Z. Seperteladze, E. Davitaya, B. Kalandadze, T. Alexidze: Natural Resource Potential of Western Georgia and Territorial Management of Agrolandscapes. Bulletinof the Georgian National Academy of Sciences, 4(1) (2010), 74-79.

7. B. Patkowska-Sokola, Z. Dobrzanski, K. Osman, R. Bodkowski, K. Zygadlik: The Content of Chosen Chemical Elements in Wool of Sheep of Different Origins and Breeds, Arch. Tierzucht, 52 (2009), 410-418.

8. A. Ramirez-Perez, S. Buntinx, R. Rosiles: Effect of Breed and Age on Voluntary Intake and the Micromineral Status of Nonpregnant Sheep, Small Ruminant Res., 37 (2000), 231-242.

9. J. Janiszewska, K. Betlejewska-Kadela: Effects of Season Feeding on the Content of Mg, Zn, Cu, Mn and Co in Horse Hairs, Med. Weter., 49 (1993), 522-523.

10. R. Asano, K. Suzuki, T. Otsuka, M. Otsuka, H. Sakurai: Concentrations of Toxic Metals and Essential Minerals in the Mane Hair of Healthy Racing Horses and their Relation to Age, J. Vet. Med. Sci.,64 (2002), 607-610.

11. K. Rogowska, J. Monkiewicz, A. Grosicki: Lead, Cadmium, Arsenic, Copper and Zinc Contents in the Hair of Cattle

285 Living in the Area Contaminated by a Copper Smelter in 2006-2008, Bull. Vet. Inst. Pulawy, 53 (2009), 703-706.

12. K. Chojnacka, H. Gorecka: The Influence of Living Habits and Family Relationships on Element Concentrations in Human Hair, Sci. Total Environ.,36 (2006), 612-620.

13. O. Senofonte, N. Violante, S. Caroli: Assessment of Reference Values for Elements in Human Hair of Urban Schoolboys, J.Trace Elem. Med. Biol., 14 (2000), 6-13.

cxovelis bewvi rogorc mZime liTonebiT dabinZurebis biologiuri indikatori saqarTvelos or regionSi T. WeliZe, l. enuqiZe, m. CankaSvili, T. lolaZe iv. javaxiSvilissaxelobis Tbilisis saxelmwifo universiteti, r. aglaZis araorganuli qimiisa da eleqtroqimiis instituti, mindelis q., 11, 0186, Tbilisi, saqarTvelo el-fosta: tamchelidze@yahoo.com samuSao eZRvneba cxovelis bewvSi mZime liTonebis Semcvelobis gansazRvras saqarTvelos sxvadasxva regionSi. cxovelis bewvi warmoadgens bio-monitoringis karg saSualebas toqsikuri elementebis Semcvelobis dasadgenad sakvebSi, sasmel wyalSi, niadagsa da saerTod mTlianad biosferoSi. samuSaoSi gamokvleulia mZime liTonebi - tyvia, kadmiumi, spilenZi da TuTia Zroxis bewvSi, romelic aRebuli iqna saqarTvelos or regionSi - dasavleT saqarTveloSi sofel qutirSi (xonis munici paliteti) da aRmosavleT saqarTveloSi sofel manglisSi (TeTri wyaros munici paliteti). kvlevebi Catarebuli iqna diferencialur-impulsuri polarografiis meTodiT. samuSaoSi dadgenili iqna, rom sofel qutirSi zemo aRniSnuli liTonebidan mxolod TuTiis koncentraciaa normaze maRali. es Tavis mxriv, saWiroebs am regionSi saZovrebis rogorc mwvane safaris, aseve miwisqveSa wylebis Semdgom kvlevebs. rac Seexeba sofel mangliss, oTxive elementis koncentracia ar aRemateba saerTaSoriso normebs, rac erTmniSvnelovnad miuTiTebs am regionis ekologiur sisufTaveze, miuxedavad imisa, rom is mdebareobs ekologiurad dabinZurebul bolnisis munici palitetis mezoblad.

286

Ðîëü ìîðñêèõ õëîðèäîâ â ôîðìèðîâàíèè îáëà÷íûõ ÷àñòèö ðàçëè÷íîé ôàçîâîé ñòðóêòóðûïðè èñêóññòâåííîì óâåëè÷åíèè îñàäêîâè âîçäåéñòâèè íà ãðàäîâûå ïðîöåññû Ì. Âàòèàøâèëè, Ó. Äçîäçóàøâèëè, È. Äæàíåëèäçå Ãîñóäàðñòâåííûé Âîåííûé Íàó÷íî-Òåõíè÷åñêèé Öåíòð “Äåëüòà” ã. Òáèëèñè, Ðåñïóáëèêà Ãðóçèÿ Ýë-ïî÷òà: mivv123@mail.ru Ðåçþìå. Öåëüþ ïðåäñòàâëåííîé ðàáîòû ÿâëÿåòñÿ èññëåäîâàíèå ôèçèêî-õèìè÷åñêèõ ñâîéñòâ òâåðäûõ ÷àñòèö è êàïåëü ìîðñêèõ õëîðèäîâ íàòðèÿ (NaCl), êàëèÿ (ÊÑl), ìàãíèÿ (MgCl2) è êàëüöèÿ (ÑàÑl2) äëÿ âûÿâëåíèÿ íàèáîëåå ýôôåêòèâíûõ â êà÷åñòâå ãèãðîñêîïè÷åñêîãî ðåàãåíòà â ðàáîòàõ ïî èñêóññòâåííî óâåëè÷åíèþ îñàäêîâ (ÈÓÎ) è âîçäåéñòâèþ íà ãðàäîâûå ïðîöåññû.

Êëþ÷åâûå ñëîâà: ìîðñêèå õëîðèäû, ÷àñòèöû ãèãðîñêîïè÷åñêèõ ðåàãåíòîâ, èñêóññòâåííîå óâåëè÷åíèå îñàäêîâ, âîçäåéñòâèå íà ãðàäîâûå ïðîöåññû, ôèçè÷åñêàÿ è ýêîíîìè÷åñêàÿ ýôôåêòèâíîñòü.

Ìàòåðèàëû èññëåäîâàíèÿ Ïðèâëåêàëèñü äàííûå ôèçèêî-õèìè÷åñêèõ ñâîéñòâ ÷àñòèö ãèãðîñêîïè÷åñêîãî ðåàãåíòà (×ÃÐ), ïîëó÷åííûõ ýêñïåðèìåíòàëüíûì ïóòåìè âçÿòûõ èç ëèòåðàòóðíûõ èñòî÷íèêîâ [1 -15].

Ôèçè÷åñêèå îñíîâû çàñåâà ÎÎÑ ×ÃÐ Ñ ïîìîùüþ òåõíè÷åñêèõ ñðåäñòâ àêòèâíûõ âîçäåéñòâèé òâåðäûå ÷àñòèöû ×ÃÐ ñ äèàìåòðàìè îò 1 äî 10 ìêì äèñïåðãèðóþòñÿ: â òåïëóþ ÷àñòü ïîäîáëà÷íîãî ñëîÿ â òåìïåðàòóðíîì èíòåðâàëå ïëþñ 20 - ïëþñ 10°Ñ, ãäå îíè àêòèâíî âïèòûâàþò âëàãó èç îêðóæàþùåé ñðåäû; â òåïëóþ ÷àñòü îáëàêîâ è îáëà÷íûõ ñèñòåì (ÎÎÑ) â òåìïåðàòóðíîì èíòåðâàëå ïëþñ 10 - 0°Ñ, ãäå îíè îñå-äàþò íà åñòåñòâåííûå îáëà÷íûå êàïëè è àêòèâíî âïèòûâàþò âëàãó èç îêðóæàþùåé ñðåäû; â íèæíþþ ïåðåîõëàæäåííóþ ÷àñòü ÎÎÑ â òåìïåðàòóðíîì èíòåðâàëå ìèíóñ 1 – ìèíóñ 10°Ñ, ãäå îíè îñåäàþò íà îáëà÷íûå ÷àñòèöû (êàïëè, ñíåæèíêè è ëåäÿíûå êðèñòàëëû) è àêòèâíî âïèòûâàþò âëàãó èç îêðóæàþùåé ñðåäû. Âî âñåõ òðåõ ñëó÷àÿõ, â ðåçóëüòàòå îáâîäíåíèÿ è ðàñòâîðåíèÿ òâåðäûõ õëîðèäîâ, îáðàçóþòñÿ æèäêèå ×ÃÐ. Äîñòèãíóâ êðèòè÷åñêèõ ðàçìåðîâ êàïëè íàñûùåííûõ ðàñòâîðîâ õëîðèäîâ ðàçáðûçãèâàþòñÿ íà íåñêîëüêî êðóïíûõ (äî 4) è ìíîæåñòâî ìåëêèõ(äî 90) êàïåëü. Äàëåå îíè çà ñ÷åò êîàëåñöåíöèè íà÷èíÿþò çàíîâî ðàñòè äî ÷àñòèö îñàäêîâ, òî åñòü ïðîñìàòðèâàåòñÿ öåïíàÿ ðåàêöèÿ Ëåíãìþðà [11]. Âðåìÿ è ñêîðîñòü ðîñòà æèäêèõ ×ÃÐ áóäåò çàâèñåòü îò ðàçíîñòè ìåæäó íàñûùàþùåé óïðóãîñòè âîäÿíîãî ïàðà è óïðóãîñòüþ íàñûùåíèÿ íàä ïîâåðõíîñòüþ ÷àñòèö õëîðèäîâ, íàõîäÿùèõñÿ â ðàçëè÷íûõ ôàçîâûõ ñîñòîÿíèÿõ [4,5]. Çàðîæäåíèå êðóïíûõ èñêóññòâåííûõ æèäêèõ ×ÃÐ â òåïëîé ÷àñòè ïîäîáëà÷íîãî ñëîÿ, óâåëè÷åíèå èõ ðàçìåðà è êîëè÷åñòâà â òåïëîé è íèæíåé ïåðåîõëàæäåííîé ÷àñòÿõ ÎÎÑ ñïîñîáñòâóåò:

ïðåæäåâðåìåííîìó ïîäàâëåíèþ ñëàáûõ âîñõîäÿùèõ ïîòîêîâ (<4 ì/ñ) â çîíå ôîðìèðîâàíèÿ îñàäêîâ è óñêîðåíèþ ïðîöåññà îñàäêîîáðàçîâàíèÿ â íèõ [3, 7]; ïåðåðàñïðåäåëåíèþ âîäíîñòè ìåæäó òåïëîé è ïåðåîõëàæäåííîé ÷àñòÿìè ÎÎÑ â ïîëüçó èõ òåïëîé ÷àñòè [1]. Íåêîòîðîå êîëè÷åñòâî èñêóññòâåííûõ æèäêèõ ×ÃÐ ñ ïîìîùüþ âåðòèêàëüíûõ âîçäóøíûõ ïîòîêîâ èç òåïëîé ÷àñòè ïîäîáëà÷íîãî è îáëà÷íîãî ñëîåâ, òåïëîé è íèæíåé ïåðåîõëàæäåííîé ÷àñòåé ÎÎÑ ïîïàäàåò â ñðåäíþþ è âåðõíþþ ïåðåîõëàæäåííóþ ÷àñòè ÎÎÑ â èíòåðâàëå âûñîò 6-7 êì, ãäå â òåïëûé ïåðèîä ãîäà òåìïåðàòóðà îêðóæàþùåãî âîçäóõà äîñòèãàåò ìèíóñ 20 – ìèíóñ 35°Ñ [3]. Ïðîöåññ êàïëåîáðàçîâàíèÿ è ðîñòà êàïåëü áóäåò ïðîäîëæàòüñÿ äî òåõ ïîð ïîêà òåìïåðàòóðà çàìåðçàíèÿ æèäêèõ ×ÃÐ, çàâèñÿùàÿ îò êîíöåíòðàöèé (Ñ) è ýâòåêòè÷åñêîé òåìïåðàòóðû (tý)ÊÑ1, NaCl, MgCl2è ÑàÑ12 íå ñòàíåò íèæå òåìïåðàòóðû çàìåðçàíèÿ âîäû. Ôîðìèðîâàíèå è ðîñò ãðàäà íà çàìåðçøèõ êàïëÿõ ìîæåò íàáëþäàòüñÿ ïðè âûñîêî ãèãðîñêîïè÷åñêèõ è èìåþùèõ íèçêóþ ýâòåêòè÷åñêóþ òåìïåðàòóðó ìîðñêèõ õëîðèäàõ [3]. Óâåëè÷åíèå êîí-öåíòðàöèè «ïîòåíöèàëüíûõ» èñêóññòâåííûõ çàðîäûøåé ãðàäèí â èíòåðâàëå òåìïåðàòóð ìèíóñ 20 – ìèíóñ 35°Ñ è óìåíüøåíèå äåôèöèòà åñòåñòâåííûõ ëåäÿíûõ ÷àñòèö â çîíå ôîðìèðîâàíèÿ îñàäêîâ (ÇÔÎ) ñïîñîáñòâóåò èíòåíñèâíîìó ïðîòåêàíèþ ïðîöåññà îáëàêî è îñàäêîîáðàçîâàíèÿ

Óñëîâèÿ êàïëåîáðàçîâàíèÿ íà òâåðäûõ ×ÃÐ Òâåðäûå õëîðèäû (òàáë.1, [4–6, 10]) õàðàêòåðèçóþòñÿ ôîðìîé è öâåòîì êðèñòàëëîâ, ìîëåêóëÿðíûì âåñîì (Ì) è ïëîòíîñòüþ (ðê), òåìïåðàòóðàìè ïëàâëåíèÿ (t„)è êèïåíèÿ (tê), ðàñòâîðèìîñòüþ (S) è ãèãðîñêîïè÷íîñòüþ (Ã), õàðàêòåðèçóþùåéñÿ îòíîñèòåëüíîé âëàæíîñòüþ îêðóæàþùåãî âîçäóõà (U). ÑÈç òàáë. 1 âèäíî, ÷òî ñ óìåíüøåíèåì òåì-ïåðàòóðû îêðóæàþùåé ñðåäû îò 20

287 äî 0 °Ñ óìåíüøàþòñÿ ðàñòâîðèìîñòè ÊÑ1 - îò 34,4 äî 28,1 %; NaCl- îò 35,9 äî 35,7 %; MgCl2- îò 54,8 äî 52,9 %; ÑàÑ12 - îò 74,5 äî 59,5 % è óâåëè÷èâàþòñÿ çíà÷åíèÿ ãèãðîñêîïè÷åñêîé òî÷êè (Ã) ÊÑ1 - îò 84 äî 85%; NaÑ1 –îò75,3 äî76,5 %;MgCl2- îò 33 äî 42 %; ÑàÑ12 - îò 22 äî 42 %. Ðàñòâîðèìîñòè MgCl2è ÑàÑ12 áîëåå, ÷åì â 1,5 ðàçà ïðåâûøàþò ðàñòâîðèìîñòè ÊÑ1 è NaCl. Âûÿâëåííûå îñîáåííîñòè ôèçèêî-õèìè÷åñêèõ ñâîéñòâ òâåðäûõ õëîðèäîâ èãðàþò âàæíåéøóþ ðîëü â ïðîöåññàõ êàïëåîáëàêî-è îñàäêîîáðàçîâàíèÿ, ïðîèñõîäÿùèõ â àòìîñôåðå. Òàáëèöà 1. Ôèçèêî-õèìè÷åñêèå ñâîéñòâà òâåðäûõ õëîðèäîâ

Параметры

Твердые хлориды KCI

NaCl

Мg С12

СаС12

Молекулярный вес, М

74.6

58.4

95.2

111

Рт(кг/'М ’) при t=0 °С

1989

2165

2316

2510

Температура, Плавлен (°С) ия

768

800,8

713

772

1407

1465

1412

1935

t=0 0C

28,1

35,7

52,9

59,5

t=100C

31,3

35,7

53,8

65,0

t=200C

34,4

35,9

54,8

74,5 42

Кипения Растворимос ть, S (%) при

Гигроскопич ность, Г (%), при:

0

t=0 C

85

76,5

42

t=100C

-

-

-

-

t=200C

84

75,3

33

24

Примечание: знак (-) - отсутствуют данные

Âðåìÿ è ñêîðîñòü ðîñòà êàïåëü æèäêèõ ×ÃÐ Âîäíûå ðàñòâîðû õëîðèäîâ (òàáë. 2, [4 - 6, 10]) õàðàêòåðèçóþòñÿ òåìïåðàòóðàìè çàìåðçàíèÿ (tç,) è êèïåíèÿ (t ê), ïðîöåíòíîé êîíöåíòðàöèåé (Ñ), ïëîòíîñòüþ (ð ∝ ), âÿçêîñòüþ (ç), ìîëåêóëÿðíîé äèôôóçèåé (Ä), óïðóãîñòüþ íàñûùåíèÿ âîäÿíîãî ïàðà (å), ýâòåêòè÷åñêîé òåìïåðàòóðîé (t,) è êîýôôèöèåíòîì ïîâåðõíîñòíîãî íàòÿæåíèÿ (ó). Èç òàáë. 2 âèäíî, ÷òî ó õëîðèäîâ MgCl 2è ÑàÑ1 2 çíà÷åíèÿ C, ρ ∝,η, e è σ ñóùåñòâåííî âûøå, à çíà÷åíèÿ Ä, têè tñóùåñòâåííî íèæå,÷åì ó ÊÑ1 è NaC1.  òåïëîé ÷àñòè ïîäîáëà÷íîãî è îáëà÷íîãî ñëîåâ â ñîîòâåòñòâèè òàáë. 2 [5]ïðè t = 0 0Ñ è ρ∝ = 5,372 êã/ì3 ñ óâåëè÷åíèåì çíà÷åíèé Ñ â êàïëÿõ NaCl îò 6,5 äî 26% âðåìÿ ðîñòà êàïåëü îò 2 äî 200 ìêì óìåíüøàåòñÿ îò 2,46 äî 1,29 ìèí.Ïðè Ñ =13 % =(const), ñ óâåëè÷åíèåì tîò 0 - 10 0Ñ è ñ” îò5, 372 äî 10,428 êã/ì 3, âðåìÿ ðîñòà êàïåëü îò 2 äî 200 ìêì óìåíüøàåòñÿ îò 1,9 äî 0,96 ìèí., à âðåìÿ ðîñòà êàïåëü îò 2 äî 500 ìêì –îò11,89 äî 6,01 ìèí. Ñêîðîñòè ðîñòà êàïåëü NaCl (âîäû) â òåïëîé ÷àñòè ïîäîáëà÷íîãî è îáëà÷íîãî ñëîåâ â ñîîòâåòñòâèè ðèñóíêà [5], ïðè Ñ =25 % (0%), t = 10 0C è ρ∝ = 5,37 êã/ì3, óìåíüøàþòñÿ ñ óâåëè÷åíèåì èõ ðàçìåðîâ è ïðèáëèæàþòñÿ ê íóëþ, êîãäà d→∝. Ïðè d = 20ìêì ñêîðîñòè ðîñòà êàïåëü NaCl (âîäû) ðàâíû 35(8) ìêì/

ñ, à ïðè d = 40 ìêì óìåíüøàþòñÿ äî 18(5) ìêì/ñ. Ïðåäâàðèòåëüíûå îöåíêè ïîêàçûâàþò, ÷òî ïðè d = const ñêîðîñòè ðîñòà êàïåëü KCl è NaCl è âîäû ñóùåñòâåííî ìåíüøå ñêîðîñòè ðîñòà êàïåëü MgCl 2 è ÑàÑ1 2. Ïîñëåäíèå ìîãóò ïðèâåñòè ê áîëåå èíòåíñèâíîìó ïðîöåññó îñàäêîîáðàçîâàíèÿ è óâåëè÷åíèþ èñêóññòâåííûõ îñàäêîâ ïðè èõ äèñïåðãèðîâàíèè â ÎÎÑ.

Âðåìÿ ðîñòà ðàçìåðà è ìàññû ãðàäèí, çàìåðçøèõ íà êàïëÿõ ×ÃÐ Õëîðèäû ÿâëÿþòñÿ âûñîêîãèãðîñêîïè÷åñêèìè âåùåñòâàìè è õàðàêòåðèçóþòñÿ çíà÷åíèÿìè íèçêîé ýâòåêòè÷åñêîé òåìïåðàòóðû [4 - 7, 12- 15], ïîýòîìó îíè ìîãóò ñûãðàòü îïðåäåëåííóþ ðîëü â ôîðìèðîâàíèè îñàäêîâ ñ ðàçëè÷íîé ôàçîâîé ñòðóêòóðîé, â òîì ÷èñëå è ãðàäà. Äëÿ îöåíêè âëèÿíèÿ ôèçèêî-õèìè÷åñêèõ ñâîéñòâ ÊÑ1, NaCl, MgCl 2 è ÑàÑ1 2íà ïðîäîëæèòåëüíîñòü çàìåðçàíèÿ êàïåëü â ã. Ñòàâðîïîëå (550 ì íàä óðîâíåì ìîðÿ) â ôåâðàëå 1998 ã. áûëè ïðîâåäåíû 8 íàòóðíûõ ýêñïåðèìåíòîâ [3].  äíè ïðîâåäåíèÿ ýêñïåðèìåíòîâ òåìïåðàòóðà îêðóæàþùåãî âîçäóõà èçìåíÿëàñü îò ìèíóñ 1 äî ìèíóñ 140Ñ, à îòíîñèòåëüíàÿ âëàæíîñòü – îò 80 – äî 93%. Àíàëèç ïîëó÷åííûõ ðåçóëüòàòîâ ïîêàçàë ñëåäóþùåå [3, 15]. Ïðè ðàâíûõ êîíöåíòðàöèÿõ ðàñòâîðîâ, ÷åì íèæå t ý òåì ïðîäîëæèòåëüíåå ïðîöåññ çàìåðçàíèÿ êàïåëü ýòèõ ðàñòâîðîâ (ó êàïåëü ÊÑ1 ïðè tý = - 10,60Ñ ïðîäîëæèòåëüíîñòü çàìåðçàíèÿ ñîñòàâëÿåò 4 – 30 ìèí., à ó MgCl2 ïðè tý = -33,5 0Ñ - 4 – 57 ìèí). Îòìå÷åí ôàêò çàìåðçàíèÿ êàïåëü íàñûùåííûõ ðàñòâîðîâ MgCl2 (tý = -33,5 0Ñ) ïðè áîëåå âûñîêîé òåìïåðàòóðå (-8 0Ñ), ÷òî îáúÿñíÿåòñÿ ðàçáàâëåíèåì ñîäåðæèìîãî êàïåëü âñëåäñòâèå êîíäåíñàöèîííûõ ïðîöåññîâ, ñîïðîâîæäàþùèõ çàìåðçàíèå.Óêàçàííàÿ çàêîíîìåðíîñòü õàðàêòåðíà è äëÿ êàïåëü, ñîäåðæàùèõ íàñûùåííûå ðàñòâîðû NaCl (tý= -21,2 0Ñ) è ÑàÑ12(tý= -51,2 0Ñ) [3].  ãðàäîâûõ îáëàêàõ êàïëè íàñûùåííûõ ðàñòâîðîâ ñ ïîìîùüþ âîñõîäÿùèõ ïîòîêîâ äîñòèãàþò ðàçëè÷íûõ âûñîò è ñîîòâåòñòâóþùèõ óðîâíåé t ý [3], ãäå âåðîÿòíîñòüèõ çàìåðçàíèÿ äîñòàòî÷íîâûñîêàÿ (tç <tý). Îáðàçîâàííûå íà çàìåðçøèõ êàïëÿõ ãðàäèíû çà êîðîòêèé ïðîìåæóòîê âðåìåíè ïîä äåéñòâèåì ãðàâèòàöèîííîé êîàãóëÿöèè, ìîãóò äîñòè÷ü êàòàñòðîôè÷åñêèõ ðàçìåðîâ (2 – 5 ñì). Ñ ó÷åòîì ôèçèêîõèìè÷åñêèõ ñâîéñòâ êàïåëü ×ÃÐ â [3] áûëè ïðîâåäåíû ÷èñëåííûå ðàñ÷åòû ðîñòà ìàññû (mí ) è ðàçìåðà ãðàäèí (Rê) ñ íà÷àëüíûìè ðàäèóñàìè (Rí), ðàâíûìè 0,1,0,2, è 0,3 ñì. Ðàñ÷åòû ïðîâîäèëèñü ïðè ïëîòíîñòè ñ =700 êã/ ì3, ñêîðîñòè ãðàâèòàöèîííîãî ïàäåíèÿ ãðàäèí Vã = 20ì/ ñ , ñêîðîñòè âîñõîäÿùèõ ïîòîêîâ W = 5ì/ñ, âîäíîñòÿõ â èíòåðâàëå çíà÷åíèé q = 2 – 14 ã/ì 3, ìîùíîñòÿõ ïåðåîõëàæäåííîé ÷àñòè îáëàêà â èíòåðâàëå çíà÷åíèé ΔÍ = 2 -6 êì, ýâòåêòè÷åñêèõ òåìïåðàòóðàõ â èíòåðâàëå çíà÷åíèé tý = -10,6 - -51,2 0Ñ. Íèæíèå ãðàíèöû ΔÍ îãðàíè÷åíû âûñîòîé ðàñïîëîæåíèÿ çíà÷åíèé íóëåâîé èçîòåðìû Í 0, à âåðõíèå ãðàíèöû ΔÍ - âûñîòîé

288 Òàáëèöà 2. Ôèçèêî-õèìè÷åñêèå ñâîéñòâà âîäíûõ ðàñòâîðîâ õëîðèäîâ ïðè Ò = 20° Ñ Параметры

Вода

Водные растворы хлоридов КС1 6 12 18 1036,9 1076,2 1185 0,996 0,998 1,012

С (%) Ρр (кг, м3) Η (103Пас)

998,2 1, 002

0,5 1001,4 -

Д (м2/с) Е (мм. рт. tэ(0С) Σ (103-Н/м)

0 72,8

0,196 -0,3 73,8

С (%) Ρр (кг, м3) Η (103Пас) Д (м2/с) Е (мм. рт. tэ(0С) Σ (103-Н/м)

998,23 1,002 0 72,8

0,5 1001,8 — - 0.4 73.8

С (%) Ρр (кг, м3) Η (103Пас) Д (м2/с) Е (мм. рт. tэ(0С) Σ (103-Н/м)

998,23 1, 002 0 72,8

0,5 1002,2 -0,4 73,8

С (%) Ρр (кг, м3)

998,23

0,5 1002,4

0,187 ' -2,8 75,6 NaCl 6,5 1045.0 1,113 0,123 -41 76,2 MgС1г 8,5 1069.4 1,32 0, 138 -6 78,8 СаС1г 10 1083,5

Η (103Пас) Д (м2/с) Е (мм. рт. tэ(0С) Σ (103-Н/м)

1, 002 0 72,8

73,8

1,27 0,12 -7 79,8

24 1162,3 1,036

0,197 -5,9 78,5

0,209 -9.6 81,5

15,4 - 10,6* 84,7

13 1093.2 1.337 0,152 -8,9 79,7

19,5 1143,8 1,598 0,158 — -15,6 83,4

26 1197,2 1,943 0,162 13,6 -21,2* 87,3

17 1146,2 2,34 0,144 -20 84,4

25,5 1225,3 4,32 0,136 <-20 89,4

34 .

1317,9 9,61 -33,5* 96,1

20 1177,5

30 1281,6

40 1395,7

1,89 0,129 -20 86.7

3,6 0,129 -48 94,4

6,6 0,123 6,15 -51,2* 102,8

Примечание: (*) - концентрации и температуры, соответствующие точке эвтектики для каждой соли; (-) - отсутствуют данные.

ðàñïîëîæåíèÿ çíà÷åíèé tý ñîîòâåòñòâóþùèõ õëîðèäîâ. Êðóïíûå ãðàäèíû (R ê >1ñì), ïðèâîäÿùèå ê êàòàñòðîôè÷åñêèì ãðàäîáèòèÿì, ìîãóò ôîðìèðîâàòüñÿ íà íàñûùåííûõ çàìåðçøèõ êàïëÿõ: ÊÑ1 ïðèRí >0,1 ñì,tç <tý=-10,6 0Ñ, ΔÍ = 2 êì è q = 14 ã/ì3;NaCl ïðèRí >0,1 ñì, tç <tý= -21,2 0Ñ, ΔÍ = 4 êì è q e”8 ã/ì3; MgCl2 ïðè Rí >0,1 ñì, tç <tý = -33,5 0Ñ, ΔÍ = 6 êì è q e”6 ã/ì3; CaCl2, ïðè Rí >0,1 ñì, tç <tý = -51,2 0Ñ, ΔÍ = 8 êì è q e”4 ã/ì3.

Çàêëþ÷åíèå 1. Ñ óìåíüøåíèåì òåìïåðàòóðû óìåíüøàþòñÿ ðàñòâîðèìîñòè òâåðäûõ ×ÃÐ è óâåëè÷èâàþòñÿ çíà÷åíèÿ èõ ãèãðîñêîïè÷åñêèõ òî÷åê.Ðàñòâîðèìîñòè MgCl2 è ÑàÑ12 áîëåå, ÷åì â 1,5 ðàçà ïðåâûøàþò ðàñòâîðèìîñòè ÊÑ1 è NaCl. Ñ óìåíüøåíèåì t ý óâåëè÷èâàåòñÿ âåðîÿòíîñòü êàïëåîáðàçîâàíèÿ íà òâåðäûõ ×ÃÐ.

2. Âðåìÿ ðîñòà ðàçìåðîâ êàïåëü NaCl âòåïëîé ÷àñòè ïîäîáëà÷íîãî è îáëà÷íîãî ñëîåâ îò 2 äî 200 ìêì ïðè t = 0 0 Ñ è ñðåäíåì çíà÷åíèé ñ ” =5,3728 êã/ì 3 ñ óâåëè÷åíèåì Ñ îò 6,5 äî 26% óìåíüøàåòñÿ îò 2,46 äî 1,29 ìèí. Ïðè Ñ = 13 % = (const), ñ óâåëè÷åíèåì t îò 0 -

10 0Ñ è ρ∝ îò 5, 372 äî 10,428 êã/ì3, âðåìÿ ðîñòà êàïåëü îò 2 äî 200 ìêì óìåíüøàåòñÿ îò 1,9 äî 0,96 ìèí., à îò 2 äî 500 ìêì – îò 11,89 äî 6,01 ìèí.

3. Ñêîðîñòè ðîñòà êàïåëü NaCl (âîäû) ïðè Ñ = 25 % (0%), t = 10 0C è ρ ∝ =5,37 êã/ì 3, óìåíüøàþòñÿ ñ óâåëè÷åíèåì èõ ðàçìåðîâ è ïðèáëèæàþòñÿ ê íóëþ, êîãäà d→∝. Ïðè d = 20 ìêì ñêîðîñòè ðîñòà êàïåëü NaCl (âîäû) ðàâíû 35 (8) ìêì/ñ, à ïðè d = 40 ìêì óìåíüøàþòñÿ äî 18 (5) ìêì/ñ.

4. Çàìåðçàíèå êàïåëü ×ÃÐ ïðîèñõîäèò òåì áûñòðåå, ÷åì âûøå çíà÷åíèå tý. Ïðîäîëæèòåëüíîñòü çàìåðçàíèÿ êàïåëü×ÃÐ óìåíüøàåòñÿ ñ óìåíüøåíèåì C è óâåëè÷èâàåòñÿ ñ óâåëè÷åíèåì èõ äèàìåòðà è ìàññû. Êðóïíûå ãðàäèíû îòìå÷àþòñÿ ïðè âûñîêèõ çíà÷åíèÿõ q,ΔÍ è íèçêèõ çíà÷åíèÿõ tý.

5. Êàïëè MgCl2 è ÑàÑ12 ïî ñðàâíåíèþ ñ êàïëÿìè ÊÑ1, NaClè âîäûîáëàäàþò áîëåå âûñîêîé S è σ, áîëåå íèçêîé Ãè tý. Ïîýòîìó îíè ìîãóò áûòü ïðèâëå÷åíû êà÷åñòâå ×ÃÐ â ðàáîòàõ ïî ÈÓÎ è âîçäåéñòâèþ íà ãðàäîâûå ïðîöåññû.

289 Ëèòåðàòóðà: 1. Áàðòèøâèëè È.Ò. è äð. Ðåçóëüòàòû ïðîòèâîãðàäîâûõ ðàáîò, ïðîâîäèìûõ ïî ìåòîäó Çàê ÍÈÃÌÈ. Òðóäû VIII Âñåñîþçíîé êîíôåðåíöèè ïî ôèçèêå îáëàêîâ è àêòèâíîãî âîçäåéñòâèÿ. Ë: Ãèäðîìåòåîèçäàò, 1969.

2. Áåêðÿåâ Â. È. Íåêîòîðûå âîïðîñû ôèçèêè îáëàêîâ è àêòèâíûõ âîçäåéñòâèé íà íèõ. – ÑÏá. ÐÃÃÌÓ, 2007, 337 ñ.

3. Âàòèàøâèëè Ì. Ð. Êàëîâ Õ.Ì. Èññëåäîâàíèå âëèÿíèÿ ôèçèêî - õèìè÷åñêèõ ñâîéñòâ àòìîñôåðíûõ àýðîçîëåé íà ôîðìèðîâàíèå è ðîñò êàïåëüíûõ çàðîäûøåé ãðàäà. Ìàòåðèàëû XLIIIíàó÷íî - ìåòîäè÷åñêîé êîíôåðåíöèè ïðåïîäàâàòåëåé è ñòóäåíòîâ. «Óíèâåðñèòåòñêàÿ íàóêà ðåãèîíó». Ñòàâðîïîëü, Èçä. ÑÃÓ, 1998.

4.Âàòèàøâèëè Ì.Ð, Ìàêóàøåâ.Ì.Ê. Ðàçðàáîòêà ìåòîäèêè èñêóññòâåííîãî óâåëè÷åíèèÿ îñàäêîâ èç îáëàêîâ è îáëà÷íûõ ñèñòåì ñ ïðèìåíåíèåì ëåãêîìîòîðíûõ ñàìîëåòîâ. //Öèêëû ïðèðîäû è îáùåñòâà. Ìàòåðèàëû XVII Ìåæäóíàðîäíîé íàó÷íîé êîíôåðåíöèè 26 íîÿáðÿ 2009, ñ. 215-234.

5. Âàòèàøâèëè Ì.Ð, Ìàêóàøåâ.Ì.Ê. Îöåíêà âðåìåíè è ñêîðîñòè ðîñòà êàïåëü NaCl â ïîäîáëà÷íîé è îáëà÷íîé àòìîñôåðå ðàçëè÷íîé ôàçîâîé ñòðóêòóðû. //Öèêëû ïðèðîäû è îáùåñòâà. Ìàòåðèàëû XIX Ìåæäóíàðîäíîé íàó÷íîé êîíôåðåíöèè 15 - 16 äåêàáðÿ 2011, ñ. 187 – 194.

6. Âàòèàøâèëè Ì.Ð. Èññëåäîâàíèå ôèçèêî-õèìè÷åñêèõ ñâîéñòâ õëîðèäîâ è ïðèâëå÷åíèå íàèáîëåå ýôôåêòèâíûõ â ðàáîòàõ ïî èñêóññòâåííîìó ðåãóëèðîâàíèþ îñàäêîâ. // Öèêëû ïðèðîäû è îáùåñòâà. Ìàòåðèàëû XIX Ìåæäóíàðîäíîé íàó÷íîé êîíôåðåíöèè 15 - 16 äåêàáðÿ 2011, ñ. 199 – 206.

7. Äåêòÿðåâ Â.Í. Ãèäðîìåõàíè÷åñêèå ïðîöåññû îáðàáîòêè ãèäðîáèîíòîâ. – Ïåòðîïàâëîâñê Êàì÷àòñêèé: Êàì÷àò ÃÒÓ, 2008. -173 ñ.

8. Äðîôà À.Ñ., Åðàíüêîâ Â.Ã., Èâàíîâ Â.Í., Ùèëèí À.Ã., ßñêåâè÷ Ã.Ô. Ýêñïåðèìåíòàëüíûå èññëåäîâàíèÿ ýôôåêòà âîçäåéñòâèÿ ñîëåâûìè ïîðîøêàìè íà îáëà÷íóþ ñðåäó// Èçâ. ÐÀÍ. Ôèçèêà àòìîñôåðû è îêåàíà. 2012. Ò. 49, 3ñ. 327 – 335.

9. Èíñòðóêöèÿ ïî áîðüáå ñ çèìíåé ñêîëüçêîñòüþ íà àâòîìîáèëüíûõ äîðîãàõ, Ìèíàâòîäîð ÐÑÔÑÐ, ÂÑÍ 2087, 45 ñ.

10. Ìàêóàøåâ Ì. Ê. Èñïàðåíèå ìàëûõ ÷àñòèö. – Íàëü÷èê: Ýëü - ÔÀ, 2001. – 80 ñ 11. Ìåéñîí Á.ÄÆ. Ôèçèêà îáëàêîâ. Ë.: Ãèäðîìåòåîèçäàò.

1961.

12. Ïðåéñ È.Ð., Ñõèðòëàäçå Ã.È. Îá îòíîñèòåëüíîé âëàæíîñòè âîçäóõà íàä íàñûùåííûìè ðàñòâîðàìè ñîëåé. // Ôèçè÷åñêàÿ õèìèÿ. Ì.: 1978.

13. Ðîäæåðñ Ð.Ð. Êðàòêèé êóðñ ôèçèêè îáëàêîâ. – Ë. Ãèäðîìåòåîèçäàò. 1961.

14. Ñïðàâî÷íèê õèìèêà. Õèìè÷åñêîå ðàâíîâåñèå è êèíåòèêà, ñâîéñòâà ðàñòâîðîâ, ýëåêòðîäíûå ïðîöåññû: ò. 3, èçäàíèå âòîðîå. Èçäàòåëüñòâî. «Õèìèÿ»; Ì; 1965, 1008 ñ.

15. Vatiashvili M.R., Preis I. R., Kalov Y.M. Coming into the guestion of aerosols chemical –and - phyicals properties influense upon disastrous hail forming. 12-th international Conference on Cloud and Presipitation. Zurich, Switzerland. 1996.

V 2.

The role of marine chloride in the cloud particles formation for the different phase structures with artificial increasing of precipitation and impact on the hail processes M. Vateishvili, U. Dzodzuashvili, I. Janelidze Georgian State Military Technical Centre “DELTA” , Georgia, Tbilisi E-mail: mivv123@ mail.ru The Physical-chemical properties of the marine chloride of the different phase structures are being investigated. There were revealed more perspective from them for applying as hygroscopic reagents in activities for artificial increasing of precipitation and impact on the hail processes. The obtained results after verification in the field conditions on the independent material give the opportunity to improve the physical and economic efficiency of these activities.

zRvis qloridebis roli sxvadasxva fazuri struqturis Rrublebis nawilakebis formirebaSi naleqebis xelovnuri zrdisas da misi zemoqmedeba setyvis procesebze m. vaTiaSvili, u. ZoZuaSvili, i. janeliZe

saxelmwifo samxedro samecniero teqnikuri centri „delta“, saqarTvelo, Tbilisi el-fosta: mivv123@ mail.ru aRniSnul SemTxvevaSi Cven vikvlevT sxvadasxva fazuri struqturis zRvis qloridebis Tvisebebs. naleqebis xelovnurad gasazrdelad da setyvaze gavlenis mosaxdenad gamovlenil iqna yvelaze perspeqtiuli, raTa higroskopul reagentad yofiliyvnen gamoyenebuli. savele pirobebSi Semowmebis Semdeg miRebuli SedegebiT naTeli gaxda, rom aRniSnuli midgomiT gaizrdeba samuSaoebis fizikuri da ekonomikuri efeqturoba.

290

Ðàäèàöèîííàÿ ýêîëîãèÿ òåððèòîðèè çàïàäíîé Ãðóçèè Ä. Ïàòàðèäçå, Ì. Êâèíèêàäçå, Ä. Êóïàðàäçå, Â. Êèðàêîñÿí, Í. Õóíäàäçå Òáèëèññêèé ãîñóäàðñòâåííûé óíèâåðñèòåò èì. Èâ. Äæàâàõèøâèëè, Êàâêàçñêèé èíñòèòóò ìèíåðàëüíîãî ñûðüÿ èì. À.À. Òâàë÷ðåëèäçå Óë. Ìèíäåëè N 11, Òáèëèñè, 0186 Ýë–ïî÷òà: m_kvinikadze@mail.ru Ðåçþìå. Ðàññìîòðåíû ðåçóëüòàòû ðàäèîýêîëîãè÷åñêèõ ðàáîò, ïðîâåäåííûõ íà òåððèòîðèè çàïàäíîé Ãðóçèè 20082010 ãîäàõ. Îõàðàêòåðèçîâàíû ïðè÷èíû ïðèðîäíûõ è òåõíîãåííûõ àíîìàëèé. Ñóùåñòâîâàíèå ïðèðîäíûõ àíîìàëèé â îñíîâíîì ñâÿçàíî ñ ðàçíîîáðàçèåì ïîñëåäíèõ ôàç êàëèåâûõ ãðàíèòîâ Äçèðóëû, à òàêæå, ñ ìåëêèìè êèñëîòíûìè äàåêîâûìè îáðàçîâàíèÿìè. Òåõíîãåííûå àíîìàëèè ÿâëÿþòñÿ ñëåäñòâèåì àâàðèè íà ×åðíîáûëüñêîé ÀÝÑ è àíòðîïîãåííîãî âîçäåéñòâèÿ ÷åëîâåêà íà îêðóæàþùóþ ñðåäó.

Êëþ÷åâûå ñëîâà: ðàäèîýêîëîãèÿ, òåõíîãåííîå çàãðÿçíåíèå, ãðàíèòîèäû, ñëàíöû, òåøåíèò, ôîíîëèò.

Ýêîëîãè÷åñêîå ñîñòîÿíèå íàøåé ïëàíåòû - îäíà èç ñàìûõ îáñóæäàåìûõ òåì ñîâðåìåííîãî ìèðà. Ñðåäè ìíîãî÷èñëåííûõ ïðîáëåì ýòîãî õàðàêòåðà îñîáîå âíèìàíèå óäåëÿåòñÿ âîïðîñàì ãëîáàëüíîãî ïîòåïëåíèÿ, ïðîáëåìàì òåõíîãåííûõ îòõîäîâ, è, ÷òî îñîáåííî âîëíóåò ÷åëîâå÷åñòâî - ðàäèàöèîííîå çàãðÿçíåíèå îêðóæàþùåé ñðåäû.  ïîñëåäíèå äåñÿòèëåòèÿ îñîáóþ àêòóàëüíîñòü ïðèîáðåëà ïðîáëåìà òåõíîãåííîãî ðàäèàöèîííîãî çàãðÿçíåíèÿ, âûçâàííîãî, â ÷àñòíîñòè, êàòàñòðîôàìè ×åðíîáûëüñêîé (1986 ã.) è Ôóêóñèìñêîé ÀÝÑ (2011 ã.). Âñå èñòî÷íèêè ðàäèàöèè íà ïëàíåòå ìîæíî ðàçäåëèòü íà åñòåñòâåííûå (êîñìè÷åñêîå èçëó÷åíèå, ãàçû, ðàäèîèçîòîïû) è àíòðîïîãåííûå (ñâÿçàííûå ñ äåÿòåëüíîñòüþ ÷åëîâåêà). Åñëè ñ òåõíîãåííûìè èñòî÷íèêàìè çàãðÿçíåíèÿ ìîæíî áîðîòüñÿ è ñâîäèòü èõ äåéñòâèÿ ê ìèíèìóìó, òî îò ïðèðîäíûõ ìîæíî çàùèòèòüñÿ ëèøü ÷àñòè÷íî. Ðàäèîàêòèâíî âñå, ÷òî íàñ îêðóæàåò: ïî÷âà, âîäà, âîçäóõ, ðàñòåíèÿ è æèâîòíûå.  çàâèñèìîñòè îò ðåãèîíà ïëàíåòû óðîâåíü åñòåñòâåííîé ðàäèîàêòèâíîñòè ìîæåò êîëåáàòüñÿ îò 5 äî 20 ìèêðîðåíòãåí â ÷àñ (MR/h), ÷òî íå îïàñíî äëÿ ÷åëîâåêà è æèâîòíûõ. Õîòÿ, ìíîãèå ó÷åíûå íå ðàçäåëÿþò ýòîãî ìíåíèÿ è óòâåðæäàþò, ÷òî ðàäèàöèÿ, äàæå â ìàëûõ äîçàõ ïðèâîäèò ê ðàçâèòèþ ðàêîâûõ êëåòîê è ìóòàöèÿì [1]. Îñîáûé èíòåðåñ äëÿ ðàäèîýêîëîãèè ïðåäñòàâëÿåò ðàäèîàêòèâíîñòü êàê êîðåííûõ ïîðîä, òàê è ïî÷âåííîãî ïîêðîâà, íåïîñðåäñòâåííî âëèÿþùåãî íà ðàñòèòåëüíîñòü è æèâîòíûé ìèð [2]. Èñòî÷íèêîì ýòîé ðàäèîàêòèâíîñòè ÿâëÿþòñÿ ïîäñòèëàþùèå ïîðîäû, îáðàçóþùèå ïî÷âåííûé ïîêðîâ. Óðîâåíü ðàäèîàêòèâíîñòè ïîâåðõíîñòíûõ âîä îïðåäåëÿåòñÿ ðàäèîàêòèâíîñòüþ âåðõíèõ ãåîëîãè÷åñêèõ ãîðèçîíòîâ, â îñíîâíîì êîðåííûõ ïîðîä è ïî÷â, êîòîðûå ýòè âîäû ðàçìûâàþò. Êðîìå òîãî, óðîâåíü ðàäèîàêòèâíîñòè áèîìà (ò.å. ñîâîêóïíîñòè ýêîñèñòåì îäíîé ïðèðîäíî-

êëèìàòè÷åñêîé çîíû) è ïðèçåìíîãî ñëîÿ âîçäóõà íàõîäèòñÿ â ïðÿìîé çàâèñèìîñòè îò ñîäåðæàíèÿ ðàäèîíóêëèäîâ â ïî÷âàõ è ò.ä. Ñ äðóãîé ñòîðîíû, ïîñëå ãèáåëè ðàñòåíèé áîëüøàÿ ÷àñòü ðàäèîíóêëèäîâ ïåðåõîäèò (âîçâðàùàåòñÿ) â ïî÷âó (ðèñ. 1).

Ðèñ. 1. «Êðóãîâîðîò» ðàäèîíóêëèäîâ â ïðèðîäå

Ïî÷âà - íàèáîëåå ðàñïðîñòðàíåííûé íà ïîâåðõíîñòè Çåìëè ïðèðîäíûé èîííîîáìåííûé ìàòåðèàë. Ñêàïëèâàþùèåñÿ íà ãðàíèöå ëèòîñôåðû è àòìîñôåðû åñòåñòâåííûå ðàäèîíóêëèäû ïîïàäàþò â ïî÷âó èç ðàçðóøàþùèõñÿ êîðåííûõ ïîðîä. Çàòåì ÷àñòü ðàäèîíóêëèäîâ ñ ãàçàìè ýìàíèðóåò â àòìîñôåðó, ÷àñòü êîíöåíòðèðóåòñÿ â íàçåìíûõ ðàñòåíèÿõ, à ÷àñòü ñ ãðóíòîâûìè âîäàìè è îñàäêàìè âûíîñèòñÿ â ãèäðîñôåðó. Ïðîñòðàíñòâåííîå ðàñïðåäåëåíèå åñòåñòâåííûõ ðàäèîíóêëèäîâ â ïî÷âàõ ñâÿçàíî ñ ëàíäøàôòíûì è ãåîëîãè÷åñêèì ñòðîåíèåì çåìíîé êîðû.

291 Ðàäèîãåîõèìè÷åñêèå îñîáåííîñòè ïîäñòèëàþùèõ ïîðîä, ëàíäøàôò è èíòåíñèâíîñòü ïîòîêà ñîëíå÷íîé ðàäèàöèè íà çåìíóþ ïîâåðõíîñòü – ýòî ãëàâíûå ôàêòîðû, îïðåäåëÿþùèå èõ ñîäåðæàíèå â ïî÷âå. Îñíîâûâàÿñü íà ïðèâåäåííûõ îáùåèçâåñòíûõ ôàêòàõ ðàññìîòðèì, ïðèðîäíîå è òåõíîãåííîå çàãðÿçíåíèå òåððèòîðèè Çàïàäíîé Ãðóçèè. Ïî äàííûì èññëåäîâàòåëåé ïðîøëûõ ëåò ïðèðîäíûå àíîìàëèè ñâÿçàíû, â îñíîâíîì, ñ ãðàíèòîèäàìè Äçèðóëüñêîãî êðèñòàëëè÷åñêîãî ìàññèâà, òîãäà êàê òåõíîãåííûå, â îñíîâíîì, ðåçóëüòàò àâàðèè ×åðíîáûëüñêîé ÀÝÑ è àíòðîïîãåííîãî âîçäåéñòâèÿ ÷åëîâåêà íà îêðóæàþùóþ ñðåäó.  60-õ ãîäàõ ïðîøëîãî ñòîëåòèÿ íà Äçèðóëüñêîì êðèñòàëëè÷åñêîì ìàññèâå Êàâêàçñêîé ïàðòèåé Êîëüöîâñêîé ýêñïåäèöèè (Åññåíòóêè) áûëà ïðîâåäåíà ãàììà-ñúåìêà, öåëüþ êîòîðîé ÿâëÿëîñü èçó÷åíèå è îöåíêà óðàíîíîñíîñòè ðåãèîíà, äëÿ ïðèìåíåíèÿ ýòîãî ñûðüÿ â âîåííîé ïðîìûøëåííîñòè. Ïîçäíåå àíàëîãè÷íûå ðàáîòû áûëè ïðîâåäåíû ãðóçèíñêèìè

- ýòè àíîìàëèè, â íàñòîÿùåå âðåìÿ, íå ïðåäñòàâëÿþò èíòåðåñ äëÿ ïðîìûøëåííîé ðàçðàáîòêè.  ðàáîòàõ ïðåäûäóùèõ ëåò îòñóòñòâóåò îöåíêà ýêîëîãè÷åñêîãî âëèÿíèÿ ðàäèîàêòèâíîñòè, êàê íà ìåñòíîå íàñåëåíèå, òàê è íà îêðóæàþùóþ ñðåäó. Èç òåõíîãåííûõ ðàäèîàêòèâíûõ çàãðÿçíåíèé òåððèòîðèè Ãðóçèè, íàèáîëåå çíà÷èòåëüíûì áûëà àâàðèÿ ×åðíîáûëüñêîé ÀÝÑ. Îñîáåííî áîëüøàÿ äîçà ðàäèàöèè áûëà çàôèêñèðîâàíà íà ÷åðíîìîðñêîì ïîáåðåæüå Ãðóçèè. Ïî ðàáîòàì 1987-1989 ãîäîâ, â âûøå íàçâàííîì ðåãèîíå óðîâåíü ðàäèàöèè ñîñòàâëÿë 90-225 ìêð/÷àñ, ïðè ïðåäåëüíî äîïóñòèìîé êîíöåíðàöèè (ÏÄÊ) - 9-10 ìêð/÷àñ.  1995 ãîäó, ïðîâåäåííûå èññëåäîâàíèÿ ïîêàçàëè, ÷òî ðàäèàöèîííîå çàãðÿçíåíèå íàìíîãî íèæå, ÷åì â ïåðâûå ãîäû ïîñëå àâàðèè [4].  îñíîâíîì, ýòî áûëî ñâÿçàíî ñ ýëåìåíòàìè êîðîòêîãî ïîëóðàñïàäà (íàïðèìåð ïîëóðàñïàä èçîòîïà éîäà 131, ðàâåí 8,04 ñóòîê).  2008-2012 ã.ã., íàìè áûëè ïðîâåäåíû ãåîýêîëîãè÷åñêèå è ãåîõèìè÷åñêèå èññëå-äîâàíèÿ â Çàïàäíîé Ãðóçèè, â ÷àñòíîñòè, âäîëü ïîáåðåæüÿ

Ðèñ. 2. Êàðòà ôàêòè÷åñêîãî ìàòåðèàëà èçìåðåíèé ðàäèàöèîííîãî ôîíà òåððèòîðèè áàññåéíà ðåêè Ðèîíè (Êðàñíûå òî÷êè - ôîí âûøå íîðìû, çåëåíûå - íèæå íîðìû)

ãåîëîãàìè [3]. Ïî ðåçóëüòàòàì ýòèõ ðàáîò áûëî âûñêàçàíî ñëåäóþùåå ìíåíèå: - ïîâûøåííûé ôîí ïðèðîäíîé ðàäèîàêòèâíîñòè, â îñíîâíîì ñâÿçàí ñ ïîñëåäíåé ôàçîé âíåäðåíèÿ ïåãìàòèòîâûõ ïîðîä ãðàíèòîèäîâ Äçèðóëüñêîãî êðèñòàëëè÷åñêîãî ìàññèâà è íå èìååò øèðîêîå ðàñïðîñòðàíåíèÿ; - íîñèòåëÿìè è êîíöåíòðàòîðàìè óðàíà è òîðèÿ â íèõ ÿâëÿþòñÿ ìèíåðàëû: áèîòèò, àïàòèò, îðòèò, ñôåí è öèðêîí;

×åðíîãî ìîðÿ [5] è áàññåéíà ðåêè Ðèîíè [6]. Öåëüþ íàøèõ ðàáîò, ïîìèìî ýêîëîãî-ãåîõèìè÷åñêèõ, ÿâëÿëîñü îïðåäåëåíèå ñòåïåíè ïðèðîäíîãî è òåõíîãåííîãî ðàäèàöèîííîãî çàãðÿçíåíèÿ òåððèòîðèè Çàïàäíîé Ãðóçèè. Èçìåðåíèÿ åñòåñòâåííîãî ðàäèàöèîííîãî ôîíà ïðîâîäèëèñü â òî÷êàõ îòáîðà ãåîõèìè÷åñêèõ ïðîá. Ðåçóëüòàòû èçìåðåíèé â áàññéíå ðåêè Ðèîíè áûëè íàíåñåíû íà îñíîâó Google Earth (ðèñ. 2), à ïðèáðåæíîé ïîëîñû ïîáåðåæüÿ ×åðíîãî ìîðÿ íà êàðòó ðàéîíà èññëåäîâàíèé (ðèñ. 3). Ïî äàííûìè Ìèíèñòåðñòâà

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Ðèñ. 3. Êàðòà ôàêòè÷åñêîãî ìàòåðèàëà èçìåðåíèé ðàäèàöèîííîãî ôîíà ïðèáðåæíîé ïîëîñû ïîáåðåæüÿ ×åðíîãî ìîðÿ (ó÷àñòîê Ñàðïè-Ïîòè)

îõðàíû îêðóæàþùåé ñðåäû è ïðèðîäíûõ ðåñóðñîâ Ãðóçèè, â íàñòîÿùåå âðåìÿ, çà âåëè÷èíó ÏÄÊ, ïðèíÿò èíòåðâàë 10-12 ìêð/÷àñ. Èññëåäîâàíèÿ ïðîâîäèëèñü â ïîðîäàõ ðàçëè÷íîãî âîçðàñòà - ïàëåîçîéñêèõ, ìåçîçîéñêèõ è êàéíîçîéñêèõ. Ïî ðåçóëüòàòàì èçìåðåíèé åñòåñòâåííîãî

ðàäèàöèîííîãî ôîíà ïîñòðîåí áëîê-ãðàôèê ðàñïðåäåëåíèÿ âåëè÷èí åñòåñòâåííîãî ðàäèàöèîííîãî ôîíà ïî âîçðàñòàì ïîäñòèëàþùèõ (êîðåííûõ) ïîðîä (ðèñ. 4) Íà îñíîâàíèè àíàëèçà ðåçóëüòàòîâ ïîëåâûõ ðàáîò è ðàñøèôðîâêè âûøåïðèâåäåííîãî ãðàôèêà, ÿâíî âèäíî

Ðèñ. 4. Ðàñïðåäåëåíèå âåëè÷èí åñòåñòâåííîãî ðàäèàöèîííîãî ôîíà ïî âîçðàñòó ïîäñòèëàþùèõ ïîðîä (öâåòà òî÷åê ñîîòâåòñòâóþò öâåòàì íà ðèñ. 3; öèôðû ñïðàâà – âåëè÷èíà åñòåñòâåííîãî ðàäèàöèîííîãî ôîíà â MR/h; ÷èñëî â ñêîáêàõ – êîëè÷åñòâî èçìåðåíèé).

293

Ðèñ. 5. Âîðîíêà îò âçðûâà áîìáû (ñ. Íèãâçíàðà, Îíñêèé Ìóíèöèïàëèòåò)

ïîâûøåíèå ðàäèàöèîííîãî ôîíà â ñëåäóþùèõ ïîðîäàõ: - âî âñåõ ïàëåîçîéñêèõ ãðàíèòîèäàõ, â êîòîðûõ åñòåñòâåííûé ðàäèàöèîííûé ôîí ÷àñòî âäâîå âûøå äîïóñòèìîé íîðìû (Äçèðóëüñêèé êðèñòàëëè÷åñêèé ìàññèâ, þæíûé ñêëîí Áîëüøîãî Êàâêàçà); - ïðàêòè÷åñêè âî âñåõ íèæíåþðñêèõ êðèñòàëëè÷åñêèõ ñëàíöàõ, ò.í. «ëåéàññêèå ñëàíöû», â êîòîðûõ äîçà ïðèðîäíîé ðàäèàöèè, òàêæå êàê è â ãðàíèòîèäàõ, äîñòèãàåò 20 MR/h (þæíûé ñêëîí Áîëüøîãî Êàâêàçà); - â ñðåäíåþðñêèõ ùåëî÷íûõ ãàááðîèäàõ-òåøåíèòàõ (Îêðåñòíîñòè ã. Êóòàèñè) - â êàéíîçîéñêèõ òðàõèòîâûõ ôîíîëèòàõ è ñèåíèòàõ (Ãóðèÿ). Îñòàëüíûå ñðåäíåþðñêèå âóëêàíîãåííûå ïîðîäû (îñíîâíîãî ñîñòàâà), à òàêæå âåðõíåþðñêèå è ìåëîâûå èçâåñòíÿêè è êàéíîçîéñêèå ïîðîäû ñîõðàíÿþò åñòåñòâåííûé ðàäèàöèîííûé ôîí â ïðåäåëàõ íîðìû. Ìíîãî÷èñëåííûå èçìåðåíèÿ ðàäèàöèîííîãî ôîíà ïî÷âåííîãî ñëîÿ òåððèòîðèè ×åðíîìîðñêîãî ïîáåðåæüÿ Ãðóçèè è áàññåéíà ðåêè Ðèîíè, ïîêàçàëè, ÷òî àíîìàëüíûå çíà÷åíèÿ èìåþò òåõíîãåííîå ïðîèñõîæäåíèå, íîñÿò èçáèðàòåëüíûé õàðàêòåð è çàâèñÿò îò ìèíåðàëüíîãî ñîñòàâà ïî÷âû. Íàïðèìåð, ïðè ïðîâåäåíèè ðàáîò â óùåëüå ðåêè Ðèîíè (íà òåððèòîðèè Îíñêîãî ìóíèöèïàëèòåòà), ñåëåíèÿ Íèãâçíàðà èçìåðåíèÿ ïîêàçàëè ïîâûøåííûå çíà÷åíèÿ ðàäèàöèîííîãî ôîíà.  ðåçóëüòàòå îïðîñà ìåñòíîãî íàñåëåíèÿ áûëî óñòàíîâëåíî, ÷òî â ýòîì ìåñòå, âî âðåìÿ âîåííûõ äåéñòâèé 2008 ãîäà, ðîññèéñêèì âîåííûì ñàìîëåòîì áûëà ñáðîøåíà áîìáà, âîðîíêà îò êîòîðîé ïîêàçàíà íà ðèñ. 5. Ìû ïðèâîäèì òîëüêî ôàêò, òàê êàê íå ìîæåì óñòàíîâèòü òî÷íóþ çàâèñèìîñòü ýòîé

àíîìàëèè îò äåéñòâèÿ ðîññèéñêèõ âîåííûõ. Íà ïîáåðåæüè ×åðíîãî ìîðÿ âûäåëÿþòñÿ îòäåëüíûå íåáîëüøèå ó÷àñòêè ñ âûñîêèì ðàäèàöèîííûì ôîíîì (15-20 ìêð/÷), ÷òî õàðàêòåðíî â îñíîâíîì äëÿ ãëèíèñòûõ ïîðîä. Ïî íàøåìó ìíåíèþ, ýòî îòãîëîñêè ×åðíîáûëüñêîé êàòàñòðîôû.  ïðåäåëàõ òåððèòîðèè ã. Êóòàèñè, â ïî÷âåííûõ ñëîÿõ ðåêè Ðèîíè, çàôèêñèðîâàí ïîâûøåííûé ôîí ðàäèàöèè, ÷òî, î÷åâèäíî, ñâÿçàíî ñ ïðîìûøëåííûìè îòõîäàìè Êóòàèññêèõ ïðåäïðèÿòèé.

Çàêëþ÷åíèå 1. Ïîâûøåííûé ðàäèàöèîííûé ôîí (20-25 ìêð/÷) õàðàêòåðåí äëÿ Äçèðóëüñêèõ âûñîêîêàëèåâûõ êðàñíûõ ãðàíèòîèäîâ, â áîëüøèíñòâå ñëó÷àåâ óäàëåíûõ îò íàñåëåííûõ ïóíêòîâ. Ñ ýêîëîãè÷åñêîé òî÷êè çðåíèÿ îíè íå îêàçûâàþò çíà÷èòåëüíîãî âîçäåéñòâèÿ íà ìåñòíîå íàñåëåíèå.

2. Ïîâûøåííûé ðàäèàöèîííûé ôîí ïî÷âåííîãî ñëîÿ íåêîòîðûõ ëîêàöèé áàññåéíà ðåêè Ðèîíè ñâÿçàí ñ àíòðîïîãåííîé äåÿòåëüíîñòüþ ÷åëîâåêà.

Ëèòåðàòóðà 1. Õîëë Ý. Äæ. Ðàäèàöèÿ è æèçíü. Ì.: Ìåäèöèíà, 1989, 256 ñòð.

2. Äàâûäîâ Ì.Ã., Áóðàåâà Å.À., Çîðèíà Ë.Â. Èçä-âî Ôåíèêñ. Ðàäèîýêîëîãèÿ. 2013, 635 ñòð.

3. ×èõåëèäçå Ê. Âàðäçåëàøâèëè Í., Íåêîòîðûå çàêîíîìåðíîñòè ðàñïðåäåëåíèÿ óðàíà è òîðèÿ â êðèñòàëëè÷åñêèõ ïîðîäàõ Äçèðóëüñêîãî âûñòóïà. Ñîîáùåíèÿ Àêàäåìèè Íàóê Ãðóçèíñêîé ÑÑÐ, 139, 3, 1990, ñòð. 533-536 (íà ãðóçèíñêîì ÿçûêå) 4. Èíôîðìàöèîííûé áþëåòåíü èçó÷åíèÿ è ïðîãíîçèðîâàíèÿ ýêîëîãè÷åñêîãî ñîñòîÿíèÿ ïîäçåìíîé ãèäðîñôåðû è îïàñíûõ ãåîëîãè÷åñêèõ ïðîöåññîâ. Òáèëèñè, 2000, 87 ñòð. (íà ãðóçèíñêîì ÿçûêå)

294 5. Êâèíèêàäçå Ì., Ïàòàðèäçå Ä., Êóïàðàäçå Ä., Òóìàíèøâèëè Ã., Êîÿâà Ê. Êîìïëåêñíàÿ ãåîýêîëîãè÷åñêàÿ îöåíêà ïðèáðåæíîé ïîëîñû ïîáåðåæüÿ ×åðíîãî ìîðÿ (Ó÷àñòîê Ñàðïè-Ïîòè). Îò÷åò ïî äîãîâîðó 215. Íàöèîíàëüíûé íàó÷íûé ôîíä èì. Øîòà Ðóñòàâåëè, 2010, 116 ñòð. (íà ãðóçèíñêîì ÿçûêå).

6. Êâèíèêàäçå Ì., Êóïàðàäçå Ä., Ïàòàðèäçå Ä., Òóìàíèøâèëè Ã., Êèðàêîñÿí Â. Êîìïëåêñíàÿ ãåîýêîëîãè÷åñêàÿ îöåíêà áàññåéíà ðåêè Ðèîíè. Îò÷åò ïî äîãîâîðó 5-24. Íàöèîíàëüíûé íàó÷íûé ôîíä èì. Øîòà Ðóñòàâåëè, 2012, 129 ñòð. (íà ãðóçèíñêîì ÿçûêå).

Radiation ecology in western Georgia D. Pataridze, M. Kvinikadze, D. Kufaradze, V. Kirakosian, N. Khundadze I. Javakhishvili Tbilisi State University, Alexandre Tvalchrelidze Radiation ecology of the Western Georgia.

Caucasian Institute of Mineral Resources. Department of the Geo-Ecology and Applied Geochemistry. 11 Mindeli Str., 0186 Tbilisi, Georgia. e-mail: m_kvinikadze@mal.ru In 2008-2012, comprehensive geo-ecological studies of the Black Sea coast and Rioni River Basin (Western Georgia) were carried out. The aim of the investigations was to determine the degree of pollution of: near-shore and inflowing stream waters; bottom sediments; soils; greens; natural and technogenic background radiation.

Studies have shown that in the Western Georgia are occurred: natural background radiation anomalies (U - Ra - Th - K), associated with Paleozoic granitoids and Middle Jurassic coal sediments; technogenic pollution is associated with the Chernobyl accident and was selective; in the major cities radiation anomalies are associated with anthropogenic activity.

dasavleT saqarTvelos teritoriis radiaciuli ekologia d. patariZe, m. kvinikaZe, d. yufaraZe, v. kirakosiani, n. xundaZe

ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti kavkasiis aleqsandre TvalWreliZis mineraluri nedleulis instituti mindelis q. 11, 0186, Tbilisi, saqarTvelo el-fosta: m_kvinikadze@mail.ru statiaSi ganxilulia dasavleT saqarTvelos teritoriis farglebSi 2008-2010 wlebSi, Catarebuli radioekologiuri samuSaoebis Sedegebi. daxasiaTebulia, rogorc bunebrivi, aseve teqnogenuri anomaliebis gamomwvevi mizezebi. bunebrivi anomaliebis arseboba ZiriTadad dakavSirebulia Zirulis granitebis bolo fazis kaliumian saxesxvaobebTan, aseve calkeul patar-patara mJave daikur warmonaqmbebTan teqnogenuri saxis anomaliebi esaa Cernobilis atomuri eleqtrosadguris afeTqebis Sedegad, jer kidev SemorCenili, calkeuli mcire zomis kerebi da samrewvelo qalaqebisaTvis damaxasiaTebeli antropogenuli zemoqmedebiT gamowveuli mcire gamovlinebebi.

295

Arsenic-Containing Ore Production Waste Monitoring and Possibilities of Remediation in Racha-Svaneti Regions of Georgia Sh. Japaridze, R. Gigauri, N. Bichiashvili TSU Rafael Agladze Institute of Inorganic Chemistry and Electrochemistry, 11, Mindeli str., Tbilisi, 0186, Georgia E-mail: nini.bichiashvili@mail.ru Abstract. The implemented work represents a significant report for Racha-Svaneti safety. Five amortized sarcophaguses have been investigated for their content of total arsenic. According to the international standards (TCLP, WET), their forms, valence, solubility coefficient, toxicity level and spread have been established. A complete picture of how to select a new sarcophagus, which implies disposal and burial of arsenic wastes given their solubility and toxicity, has been obtained.We are aware that this problem can be coped in the near future in Racha. Our report will greatly assist managers in taking account of all the advices and studies in connection with the landfills.

Keywords: arsenic, solubility, toxicity, Racha.

Introduction

Fig 1. Incomplete scheme of compounds synthesized from arsenic-containing wastes Table 1. Results of initial and final leaching of arsenic from arsenic-containing wastes

Acid water precipitator (Uravi) Preparations precipitator (Uravi) Old plant sarcophagus (Uravi) Sarcophagus burnt (Tsana)

Yield of arsenic as compared with the initial %

3+

As % Leached 5+ As %

Leached

Total As %

Results obtained by WETstandard**

Yield of arsenic as compared with the initial % Leached 3+ As % Leached 5+ As %

Results obtained by TCLPstandard*

Initial data, determination of As% and pH Location of landfills

Arsenic is found in nature as a chalcophile element –in the form of sulfides, thiosulfates, oxides, oxothiosalts, arsenides and arsenates. In Georgia, the Racha-Uravi deposit is realgar-orpiment, while that of Svaneti-Tsana – arsenopyrite.

Today, the both deposits are conserved and no arsenic is produced there. The problem is the arsenic-containing wastes and the adjoining arable soils.

Ecotoxicology has its clearly defined task – to reveal the mechanisms of toxic impact of man-made factors on the environment and living organisms. Nature protection is one of the main indicators of the quality of life. Particularly urgent is this issue for such land-poor country as Georgia.

In spite of its toxicity, arsenic is one of the microelements necessaryfor human and animal and plant growth and development; some plants and mollusks are capable ofaccumulating up to 1% of arsenic in the organism without damaging themselves.

Out of arsenic-containing wastes, where the content of arsenic makes 4% and over, remediation of physiologically active substances is possible. At first the basic product “white arsenic” (As2O2) is obtained. It is the physiologically most active product, 20 times surpassing orpiment in toxicity, which is caused by the cause-and-effect relation characteristic of the white arsenic.

The scope of use of arsenic-containing wastes is wide: semiconductor systems, laser systems, pharmacy, zoo veterinary, nanotechnologies, nanomaterials, etc.

Initially, the wastes of four main sarcophaguses were studied in Racha, and of one – in Svaneti.To study the wastes toxicity, the modern, international test methods – Toxicity Characteristic Leaching Procedure (TCLP) and Waste Extraction Test (WET) were used. Out of the buffer systems, the acid-base equilibrium was selected, where the scope of pH is within 3.8-5.8.

7.36 0.022 0.012

0.46

0.01

0.005

0.2

14.7

trace 0.018

0.13

trace 0.046

0.31

1.2

0.41

_

34.16

0.18

_

15.58

0.007 3

2.045

0.005

_

0.56

0.88 0.011

According to TCLP, 25g of average air-dry arsenic residue sample were taken to be added with a 500 mL buffer

296 standard (1:10), pH=5;T=300C; the process took place under conditions of continuous agitation in a magnet stirrer during 24 hours.

According to WET, again 25 g of average air-dry arsenic residue sample were taken to be added with a 250 g buffer standard (1:10), pH=5; ; the process took place under conditions of continuous agitation in a magnet stirrer during 48 hours.

Behavior of calcium arsenate and white arsenic on the derivatograph obtained by the thermogravimetric method

Fig. 1. Thermogram of calcium arsenate (curve 1) and arsenic oxide (curve 2). 1. The thermogram shows the arsenic arsenate mass reduction to 5.8%at 50-1000C. Heat evolution and thawing take place. At 100 0C, reduction makes 23.9%.

2. The thermogram shows the arsenic (III) oxide mass reduction to 41.4% at 200-275 0C. At 550 0C, evaporation occurs or reduction makes 97.7%.

It can be concluded that most arsenides are thermally stable, as against arsenates and oxides.

In addition to arsenic leaching, the above-mentioned test methods were used to identify the content of other heavy metalsyielded in liquid.

Sample N 3 (preparations precipitator) in dry residue of leached liquid is analyzed for the content of heavy metals by the quantitative-spectral analysis.

Table 2. Results of quantitative-spectral analysis of heavy metals

The topicality of the subject consists in the implementation of the set task using the test methods equaled with the international European standards, which enable to consider the situation in approximation with natural conditions,when landfills are amortized and the arseniccontaining wastes are in the open ground, subjected to rain and snow, and can be studied during 24 and 48 hours for solubility, forms, toxicity level and spread of both arsenic and other heavy metals.

The arsenic-containing wastes, where the content of arsenic makes 4 to 17%, have been studied.The types of arsenic compounds to be produced by their utilization have been identified.

As a result of study of five amortized landfills, the quality, forms, valence, pH, solubility and toxicity level of the arsenic-containing wastes have been established. The modern test methodsâ&#x20AC;&#x201C; Toxicity Characteristic Leaching Procedure (TCLP) and Waste Extraction Test (WET) have been applied for solving the problem.

Results of the quantitative-spectral analysis have found arsenic to contain together with arsenic other heavy metals as well.

The thermogravimetric analysis was conducted to arsenite and arsenate. The difference between them is that arsenite, or wascompletely evaporated at the temperature of 550 0C, while the reduction of the mass of arsenate at the temperature of 1000 0C constituted 24%.

The necessity of construction of two additional sarcophaguses for soluble and insoluble residues/wastes has been established. In case only one sarcophagus is constructed, it will locate first the insoluble residues and then the soluble ones, so that the safety is better ensured.

saqarTvelos regionebis raWasvaneTis dariSxanSemcveli madnebis warmoebis narCenebis monitoringi da remediaciis SesaZleblobebi S. jafariZe, r. gigauri, n. biWiaSvili

ivane javaxiSvilis sax. Tbilsis saxelmwifo universiteti, r. aglaZis araorganuli qimiisa da eleqtroqimiis instituti, mindelis q. 11, 0186, Tbilisi, saqarTvelo el-fosta: nini.bichiashvili@mail.ru Catarebuli kvleviTi samuSaoebi warmoadgens mniSvnelovan angariSs raWa-svaneTis usafrTxoebisaTvis. xuTi amortizebuli sarkofagisaTvis Seswavlilia dariSxanis saerTo Semcvelobebi. saerTaSoriso standartebis mixedviT (TCLP, WET) dadgenilia maTi formebi, valentoba, xsnadobis koeficienti, toqsikurobis xarisxi da gavrcelebis areali. sruli suraTia warmodgenili, Tu rogor unda ganxorcieldes axali sarkofagis SerCeva, rac gulisxmobs dariSxanis narCenebis damarxvas xsnadobisa toqsikurobis gaTvaliswinebiT.

297

Geopolitical changes and new environmental challenges in the context of management of the industrial and municipal waste in the post soviet space.

Prospective of “green” utilization of agricultural waste in georgia O. Kutsnashvili1, O. Tsiklauri2, A. Chirakadze3, L. Ghurchumelia2, K. Chigogidze4, G. Chiradze5 Georgian Engineering Academy, 29 Rustaveli Avenue, 008, Tbilisi, Georgia Iv. Javakhishvili Tbilisi State University, R. Agladze Institute of Inorganic Chemistry and Electrochemistry, 11 E. Mindeli Street, 0186,Tbilisi, Georgia 3 Georgian Technical University, Department of Engineering Physics, 77 M. Kostava Street 77, 0175, Tbilisi, Georgia 4 D. Uznadze Association of Psychologists of Georgia,22 P. Iashvili Street, Tbilisi, Georgia 5 Akaki Tsereteli Kutaisi State University,59, King Tamar Street, 4600 Kutaisi, Georgia E-mail: omar.kutsnashvili@gmail.com 1 2

Abstract. After the split of Soviet Union the integral centralized system of monitoring, transporting and processing of industrial and municipal waste was destroyed. All the Post- Soviet States have been faced with the new environmental challenges conditioning the necessity of working out of a national conception and compiling of a scientifically grounded program for guarantying environmental security. This task is given a special attention in the new variant of the strategy of development of Georgia being prepared for publishing by the numerous groups of authors. The detailed study and reevaluation of these issues within the frames of the integral ecosystem of the South Caucasus is a must, which requires cooperation of the scientists of different spheres (Physics, Chemistry, Biology, Geology, Geophysics, Ecology, Healthcare, Economics, Social Sciences, Psychology,etc). The present work concerns the quantitative indicators of the problem of solid, toxic waste and the most significant principles of this kind of organization. Methods and the prospective of “green” synthesis of nanoparticles are consideredand the socio-psychological aspects of the possible involvement of population are discussed.

Keywords: Geopolitical changes, industrial and municipal waste, “green” synthesis, nano-particles

Introduction Designing of the national programs of the individual South Caucasian States is expedient only within the integral frame of concept of the ecosystem of the region[1].

Geographical, geological and climatic specificity of the South Caucasus causes its oversensitivity towards the violation of the environmental balance. Imbalance can retroact heavily the ecosystems of the whole region. Direct application of the internationally approbated methods in the sphere of management of solid waste is quite prospectless for the “small” republics of the Post Soviet space. [2,3].

The above mentioned circumstances are conditioned by the small quantities of the raw material and (in case of introducing of existing technologies) automatically require importing of the corresponding raw materials. All this enhance the likelihood of polluting of the environment equally at the both stages: of its transportation and utilization.

The existing widely used technologies are designed for the large-tonnage manufacturing and are expensive and often pose ecological threatson the territory of manufactures and on the surrounding territory as well. Based on the above stated, it is a must to focus the utilization technologies on the small tonnage manufacturing using the local raw material (waste), and at the same time to provide

the environmental safety. The maximum environmental effectiveness should be the main criteria for the manufacturing with the adequate economic profit. The prospect of the above mentioned approach in the sphere of management of solid wastes is obvious when from the recycled material within the small manufacture scale it becomes possible to produce demanded and competitive environmentally safe goods [3,4]. The necessity of establishment of the new scientific-technological institutes for the safety of the recycled resources and environment, that will work out by the order of the State institutions the innovation technologies for management of the environmental problems, create the corresponding data base and help elaborating of the new methods for safe utilization of the solid toxic wastes and support their implementation is obvious.

Materials and Methods Principlees of creating of a full-pledged modern system of waste management and its implementation.One of the most actual and current issues is creating of a fullpledged modern system of waste management and its implementation in Georgia, not to say anything about its priority. Working out of an adequate to European standards system of recording, storing and processing of residue

298 waste is of a paramount importance. Arising out of experience we can say, that system of waste management is directly connected with the policy of environment protection, readiness of the society for accepting the fundamental requirementsof that policy and be actively involved in implementing of that latter. It is widely known, that environmental problems of new member states are different from those of the “traditional” European Union countries, but modernization of legislation and establishment of the modern system of waste management enabled them to improve their practice gradually. We have to study the experience of emergence, recording, processing and storing of waste and other appropriate indicators of that countries thoroughly well. This will help us to avoid mistakes and accelerate establishment and development of the modern system of waste management in Georgia.

Environmental Problems Connected with the Residue Waste. In the environmental security conception worked out by the National Academy of Sciences in 2010 -2011 the notion of the so-called “ecological disaster zone” has been introduced for characterizing the soil and water extreme pollution as a result of the exploitation of Madneuli copper mine. The environmental problems of Zestafoni and Chiatura regions are no less in significance. The scientists know, that tens of thousands of tons of manganese containing products thrown in the open air and those lying on the ground are very dangerous and have greater impact on the soil and water and through them affect health of the population.Contamination of Rachaand LowerSvaneti with the arsenic is also a heaviest current problem. In this (one of the most beautiful_areas of Georgia approximately 120 000 tons of deadly toxic arsenic containing waste is scattered in the open air without any control. All his causes heavy contamination of the soil and primarily affects health of the local population. That latter looses thousands of hectares of the agricultural lands, pastures and forest-parks.

Lead containing residue waste is no less dangerous. There are great risks connected with its utilization, as the tendency of opening the large-tonnage manufactures and implementation of the appropriate technologies are obvious.

Soon (in a few years time) it will cause importing the toxic raw material into Georgia for “loading” that type of manufacture. Urgent task is to work out of the environmentally secure technologies of processing the lead containing waste designed for the small-tonnage manufactures and their implementation in new factories and plants. The technologies should be elaborated basing on the novel researches of the Georgian and foreign scientists.

Involvement ofpsychological methods in solving of environmental problems. The complex approach of solving of environmental al problems means involvement of psychology and psychological methods of diagnostics, especially in heavily contaminated areas and regions where we have cases of mental retardation in children and other

psychosomatic diseases and psychological deviations, such as criminal behavior tendency etc., also general social attitudes rooted in the mentality of population and causing sometimes irreparable harm to the environment.

Nowadays Eco-psychology seeks to reshape modern psychology by showing that it cannot stand apart from an intimate human connection with the natural environment.

We are following the coverage of modern Eco-psychology that includes: Physical and mental health benefits of interacting with nature; Bio-philia; Eco-therapy; Psychology of environmental destruction; Science, technology, and the depth of experience with nature; The rediscovery of the wild; Urban sustainability; Indigenous cultures; Responsibility for protecting natural places and other species;Human-animal interaction. All this means, that our aim is to study the psychological conditions of formation of ecological mentality and impact of environmentally unfavorable environment on the mentality and intellectual development of children and adolescents, and population of the country in general. We are working on training modules for changing social attitudes and creating the environment friendly attitudes on the social and dispositional attitude levels. Our goal is also to elaborate the optimal psycho-diagnostic computerized test battery for identifying the mental and psychological status according to“hot spots” and “red flags”. Our task covers creating of direct and indirect propaganda or PR-means for attitude alterations and changes of the population into the environmentally literate and friendly ones, where it is needed by means of working out and creating special video clips, educational films and programs.

Results Utilization of Agricultural Wastes and Synthesis of the Metal Nano Particles Through Biosynthesis of the Vegetative Wastes. Gold and other metal nanomaterials are increasingly popular in medicine, special optoelectronic and magnetic devices; in electrochemical and microelectronic apparatus; nano- and micro-sensor instruments and systems. Nowadays it is one of the most dynamic and rapidly developing fields of high-technology manufacturing.

In 2015-2016 the market (including the product made of using nanotechnologies and nano-materials) according to the authoritative scientific evaluations (and among them USA Agency of Environment Protection) is to go beyond 1 trillion US dollars. As for the gold nano- particles the total amount of their production in 2013 comprised only 3 tons, but by 2015 it is to increase to 100-150 tons with the total cost of 10-15 billion US dollars [5,6]. Existing methods are mostly based on the chemical reactions in the electrolithe solutions and are very expensive, technologically sophisticated and contain environment threats. Sharp increase of the nanoparticle production will be associated with serious environmental challenges, being stressed by a num-

299 ber of leading scientists of the world. Thus, elaborating of the environmentally clean and cheap methods for producing metal nano-particles is an actual and current problem.

Nowadays, the most environment-friendly method of creating nano-particles is the method of biosynthesis. As it is widely known, vegetations contain a great amount of carbohydrates, cellulose and proteins rich in OH, COOH and NH groups. Separate groups actively participate in reduction reactions having place in solutions and restore ions of the metal, others participate in stabilization and formation of nano particles [7-8]. Thus, in the biosynthetic methods vegetaions perform the function of bioreactor and do not need addition of the expansive reagents. Consequently, biosynthesis (in respect with the convenient physical and chemical methods)are much more cheap, environmentally safer and technologically simpler. For achieving the high economic effectiveness, it is expedient before the process of biosynthesis to extract from the vegetation waste the valuable (mainly in medicine, perfumery and food industry) materials and biologically active substances, not taking part in biosynthesis of nano-particles. Novelty of the research having started in Georgia is the complex usage of the methods (and devices) being highly effective, environmentally safe and providing a high quality of the derived products.These methods are: super critical CO2 fluidextraction, microwave drying/extraction, and combineduse of the methods. For obtaining gold nano- particles by processing vegetations, waste of grapes, tea leaves, citruses, fruits and vegetable, etc. were chosen. The latter is determined by the cheapness of the material, which is rich with various complexes and can be effectively used for obtaining the high-quality extracts, as well as for elaborating of thelow-cost,environmentally clean, simple and highly productive technology, as well as creating the experimental device model. All this materials are widely spread in the world and can be regarded as the inexhaustible raw material(e.g., in 2013 the world production of grapes comprised 68-70 million tons and almost 15 million tons of processing waste was generated);they are widely spread in Georgia and pose quite a significant environmental problem. The gold nanoparticles were obtained through the biosynthesis of aurum chloride (AuCl3) solution using the grapewaste, tea leaf extract and other materials listed above,in conditions of supercritical extraction and microwaveradiation impact. Materials were dried in the microwave device at 30-400C temperature within the wide range of the microwave power, turned into the granulated powder and processed via the supercritical fluid extraction, microwave extraction and combined extraction. The derived material, being enriched with proteins, is crumbled and mixed into the AuCl3 solution with the certain weight ratio.The mixture is placed in the microwave device. Synthesis was performed with the different weight ratio, within wide range of thepower and duration of microwave radi-

ation, the maximally possible interval of the supercritical extracting parameters and in conditions of different pH .

After completing of the process the mixture was filtered.

Nano-particles were purified and cleaned by means of centrifugation. The obtained highly dispersive powder was washed in the ionized water, then dried and prepared for the analyses. The purified nano-particles are investigated by the X-ray diffractometry, X-ray fluorescent analysis, Atom-absorption spectrophotometry, Scanning electric microscopy, Scanning tunnel microscopy; Ultraviolet, visible, near and far infrared spectroscopy, Optical spectrum-fluorometry, etc.

Conclusions Waste-causedenvironmental pollution is one of the most serious sources having a negative influence on the human health. Annualgeneration of waste is disproportional to the present level of the manufacturing production and economic conditions of the population. We do not have a service of recording of the emergence and storage of residue waste and its classification system. Most of the residual wasteis put into the garbage pitswithout any preliminary sorting and processing, or is thrown uncontrolled.

There is practically no reliable information about the recording, classifying, processing, storage and utilization procedures on the waste. The required financing for solving the problemsis so great, that budget and international funding are not enough for fixing the problem. Thus, implementation of the high-technological methods of industrial processing of the residue waste (or the “Green Industry”) is the most realistic and promising way of solving the heaviest environmental problems In Georgia.

References 1. O. Tsiklauri, A. Sarukhanishvili, V. Kveselava, M. Manafov, F. Sadikhov, M. Alosmanov, N. Kniazyan, N. Arutyunyan, G. Pirumyan. The South Caucasus Region: Concept of Unified Metastable Ecosystem. Monitoring of Anthropogenic and Technogenic Waste and the Opportunity of Ecologically Safe Utilization. Georgia Chemical Journal, 12 (2012), No1. 7786, 2012.

2. O. Tsiklauri, R. Kokilashvili, T. Chakhunashvili, N. Dvali, L. Baghaturia, J. Chachanidze. An environmentally safe technology of recycling of used lead accumulators, Georgia Chemical Journal,11 (2014), ¹4, 450–455(in Georgian).

3. O. Tsiklauri, T. Marsagishvili, T. Chakhunashvili.An optimal technology of recycling of used accumulators, Proceedings of the International Scientific-Technical Conference Tbilisi2010, Publishing House of Tbilisi State University, 2010, 123–129(in Georgian).

4. O. Tsiklauri, A, Chirakadze, Sh.Sidamonidze,N. Sagharadze, L. Arabuli. Main aspects of national concept of the efficient management of production and municipal waste.Georgia Chemical Journal, 14 (2014), ¹1, 174–177 (in Georgian).

300 5. A. Kovalev. Trends of the Nanomaterial Market. Mediterranean Journal of Social Sciences, 4 (2013), No 9, 655-659.

6. F. Piccino, F. Gottschalk, S. Seeger, B. Nowack. Industrial production quantities and uses of ten engineered nanomaterials in Europe and the world. J. Nanopart. Res.,(2012), 14:1109. DOI 10.1007/s11051-012-1109-9,available at: http:/ /publicationslist.org/data/nowack/ref-128/ Piccinno(2012).pdf.

7. P. Gorelkin, N. Kalinina, A. Lav, V. Makarov, M. Talyanski, I. Yaminski. Synthesis of nano-particles by use of vegetation.

Nano-industry:Science&Technical Journal, 7 (2012), 132-137 (in Russian).

8. V. Makarov, O. Sinitsina. “Green” nanotechnologies: synthesis of metallic nano-particles by use of vegetation. Acta Naturae,1 (2014), 23-29 (inRussian).

geopolitikuri cvlilebebi da axali ekologiuri gamowvevebi postsabWoTa sivrceSi myari toqsikuri narCenebis marTvasTan dakavSirebiT o. qucnaSvili1, o. wiklauri2, a. WiraqaZe3, l. RurWumelia2, q. CigogiZe4, g. CiraZe5 1 saqarTvelos inJineriis akademia,rusTavelis prosp. 29, , 008, Tbilisi, saqarTvelo 2 Tsu, r. aglaZis araorganuli da eleqtroqimiis instituti, mindelis q. 11, 0186, Tbilisi, saqarTvelo 3 saqarTvelos teqnikuri universiteti, kostavas q. 77, 0175, Tbilisi, saqarTvelo 4 d. uzanZis saqarTvelos fsiqologiis asociacia, p. iaSvilis q. 22, Tbilisi, saqarTvelo 4 akaki wereTlis quTaisis saxelmwifo universiteti, Tamar mefis q. 59, 4600, quTaisi, saqarTvelo el–fosta: omar.kutsnashvili@gmail.com

ssrk daSlis Semdeg moiSala sawarmo da sayofacxovrebo narCenebis marTvis erTiani centralizebuli sistema, yvela postsabWoTa saxelmwifo aRmoCnda ekologiuri usafrTxoebis uzrunvelyofis axali mecnierulad dasabuTebuli nacionaluri programis SemuSavebis aucileblobis winaSe, rasac mniSvnelovani adgili eTmoba saqarTvelos ganviTarebis strategiaSi, romelic gamosacemad moamzada avtorTa mravalricxovanma jgufma. saWiroa am sakiTxebis detaluri ganxilva da gaazreba amierkavkasiis erTiani ekosistemis koncepciis CarCoebSi, rac moiTxovs sxvadasxva dargis mecnierTa erTobliv muSaobas. naSromi eZRvneba agreTve nanonawilakebis „mwvane“ sinTezis kvlevasa da garemosdacviT saqmiqnobaSi mosaxleobis aqtiuri Cabmis socio– fsiqologiur aspeqtebs.

301

Detection of the source of radioactive contamination in the NPP region M. Kozhevnikova, V. Levenets, I. Rolik, V. Voyevodin National Science Center â&#x20AC;&#x153;Kharkov Institute of Physics & Technologyâ&#x20AC;?, Akademichna str. 1, Kharkiv, 61108, Ukraine; E-mail: levenets@kipt.kharkov.ua Abstract. Analysis of the Chernobyl accident impact on the environmental situation in the Zaporozhskaya NPP (ZNPP) location area has been performed. Data processing technique is proposed for pollution source detection in the NPP region.

Analysis has been made for the motion of air masses inside the ZNPP 30-km zone. Maps of air-mass trajectories have been drawn, and the distribution of radionuclide particles in air over the territory under study in 1986 has been determined.

Keywords: Chernobyl accident, Zaporozhskaya NPP, environmental situation, source identification

Introduction

Methods of pollution source identification

The aims of ecological monitoring around the NPP are to determine and to prevent possible detrimental effects of NPP operation on the atmosphere, terrestrial and aquatic ecosystems, and also, to provide ecological safety of NPP. The monitoring task in this case is to detect deviation from the norm, to clear up the deviation reason, to eliminate the cause of trouble and to forestall its further occurrence.

The main NPP monitoring objects include the atmosphere, terrestrial and aquatic ecosystems being within the NPP observation area. Among the main harmful influencing factors, we should mention radiation discharges and release, release and spill of chemical due to NPP operating activities, thermal pollution of the atmosphere and the adjacent water area of the hydrologic systems [1].

The problem of the NPP environmental impact should be considered comprehensively, taking into account the NPP location and also other man-made sources of pollution, both local and regional.

In connection with the necessity for ecological monitoring of NPP pollutant emissions into the atmosphere, the central problem is currently to develop methods for determining the location of a probable source of pollution from the ratio of pollutants contained in air samples taken over the area of interest. To determine the pollution sources, mathematical methods are used, which are based on the solution of the inverse problem of impurity transport. With the use of a certain number of measuring points, these methods make it possible to reconstruct the parameters of pollution sources and also, to clarify the spatial location of aerosol pollution. For simulation of the processes of air pollution spread, one of the methods of factor analysis, viz., the method of receptor modeling (MRM), is applied.

The method uses chemical and physical characteristics of gases and particles created on the source and the receptor to identify their presence and to determine the source contribution to the concentration on the receptor [2].

The aim of this work has been to validate the method of pollutants source identification [3-4] using the air measurement values obtained in the area adjacent to the ZNPP in the first days after the Chernobyl accident.

To identify the principal factors that affect the atmosphere in the ZNPP location area, the method of factor analysis (MFA) has been used [5].

Concentrations of substances or elements contained in the samples under investigation were used as initial data for performing calculations. A more detailed description of the MFA can be found in [6, 7]. The MFA makes it possible to determine both the characteristics of the pollution sources and the contributions of individual sources to specific samples. The question about location of the pollutant sources themselves is solved by analyzing air-mass trajectories, by which the pollutants are transferred.

To determine the spatial distribution of pollutants, the HYSPLIT-4 program [8] was used. The program simulates the processes of formation and propagation of a pollutantloaded air cloud from the given source.

The input meteorological data necessary for HYSPLIT4 were taken from the meteorological model calculations based on in-situ measurement results.

Characterization of the subject of research The ZNPP location area is a part of the Donetsk-TransDnieper economic region belonging to the zones that experience a heavy anthropogenic impact. Among regional pollution sources one should mention, first of all, industrial complexes of towns Krivoy Rog and Zaporozhe as the closest to the ZNPP observation area, where more than 31 thousand fixed sources of environmental pollution can be counted, most of them representing the faultiest technologies of heavy industry. The Chernobyl NPP may also be referred to regional pollution sources. The local pollution sources include, apart from the ZNPP, a large-scale industry of the Nikopol-Marganets industrial zone, and also, the Zaporozhskaya thermal power plant (ZTPP) which is the largest suppliers of a variety of pollutants to the natural environment of the region [9].

The territorial structure of the working group on the left riverside in the region includes the Enerhodar industri-

302 al hub that stands out. Its basis is formed by ZTPP and ZNPP power productions.

The major sources forming the radiation burden on the population living in the ZNPP 30-km zone comprise natural radionuclides, including those present in the ZTPP releases, and artificial radionuclides: 90Sr and 137Cs of global fallouts, 90Sr and 137Cs of ChNPP accident release, as well as a wide range of radionuclides comprised in the ZNPP emissions and discharges.

In the aerial effluents, the main part of activity falls on artificial radioactive gases (ARG): 133Xe, 135Xe, 41Ar; whereas the aerosols are dominated by short-lived nuclides (SLN) with the half-life less than 24 hours: 88Rb and 138Cs. Among the long-lived nuclides (LLN) with the half-life more than 24 hours, 60Co, 54Mn, 24Na, 51Cr, etc. are the main pollutants. Iodine radioisotopes are present in the effluent in both the gas and aerosol forms. The quantity of 137Cs and 89 Sr, 90Sr in the effluents is insignificant. However, considering their high biological hazard, continuous monitoring of their entry into the environment is carried out. The releases of radionuclides to the atmosphere are presented in Table 1.

The radionuclides content in free air of the ZNPP location area during entire operating time, with the exception of the period of ChNPP accident impact, was found to be at the level of average annual background concentrations.

A higher level of radiation survived approximately to the middle of the next year (1987), following which it again became close to the natural background of the area. No radionuclides, being ZNPP release products, were observed in free-air aerosols of the region, except the aerosols taken over the NPP site Table 1 [9]. Radionuclides releases to the atmosphere for the ZNPP operating period in 1985-1987, as a percentage of the allowable emission for NPP

1985

1986

1987

ARG

1.6

3.0

1.4

SLN LLN

0.0005 0.0005

0.001 0.0043

0.0073 0.0032

131

0.1

1.9

1.0

I

Results Studies have been made into the relationship between the Chernobyl NPP accident and a sharp aggravation of radiation situation in the ZNPP location area over a period of 1986-1987.

The explosion of the Chernobyl NPP unit 4 on 26 April 1986 was the largest disaster in the industrial history as regards both the magnitude and the consequences for the mankind and the wildlife. It appeared that about 3 % of radionuclides accumulated in Chernobyl NPP unit 4 by the moment of the disaster were released into the environment.

It amounted to ~ 30 MCi or 1.3x1019 Bq of radionuclides [10]. The Chernobyl cloud toured twice round the earth and left its radioactive trail over a considerable part of the

Northern hemisphere. Nearly 200 of radioactive isotopes in different phase and chemical forms drifted in the atmosphere along complex trajectories over distances of thousands of kilometers from the ChNPP. In May 1986, many of them were detected in all the countries of the Northern hemisphere, on water areas of the Pacific, Atlantic and Arctic Oceans. The most notable among them were 131I and 137 Cs radionuclides. The longest distances from the ChNPP were covered by 103Rb, 106Rb, 131I, 133I, 132Te, 134Cs, 137Cs, and also, by radioactive inert gases present in vapor-aerosol mixtures, and submicrometer particles. That just determined the formation of rather great-in-area radioactive “spots” on the territories of the majority of European countries. In the first hours and days of the Chernobyl NPP accident, after release of radionuclides, of paramount importance were primarily the radionuclides 131I, 133I, 135I, and also, 140La, 239Np, 132Te, 133Xe and 140Ba. In a few months, the pollution level was determined by 141Cs, 103Rb, 95Zr and 89 Sr. Two years after the disaster, the radiation pollution of the environment was mainly due to 144Cs, 144La and 106Rb, and also, due to 134Cs and 137Cs. At the present time, the pollution is determined by 90Sr, Pu and Am [11].

To assess the ecological situation in the ZNPP location area, we have used the air test values taken at eight monitoring points around the NPP in 1985-1987 (Table 2). The data were processed with the PMF v3.0.2.2. code [12]. The procedure resulted in the identification of two principal factors observed in the area of studies: 1) the dominating element is 90Sr and 2) dominating elements are 134Cs and 137 Cs. At the time of active release from the reactor (from 26 April to 5 May 1986), the wind around Chernobyl spun full 360 degrees with the result that radiation releases (of different radionuclide compositions in different days) covered a great area.

To make sure that the observed high radionuclide content in ground air is due to the ChNPP accident discharges, a 3D modeling of 134Cs, 137Cs and 90Sr distribution in the airshed over the 30-km ZNPP location area was performed.

The area is specified by the coordinates 47.27-47.76 north latitude and 34.23-35.00 east longitude. Initially, the airmass trajectory in the first week after the accident was obtained (Fig. 1).

Then, the air-mass trajectories were calculated for a certain period of time when the east wind first gave way to west wind (27-28 April), and then to north wind (29 April – 6 May), with the result that the southern regions of Ukraine, as well as Moldova and Rumania were exposed to pollution (Fig. 2).

The back propagation path (Fig. 3), which was defined from the ZNPP for a period from 3.05.86 till 27.04.86 (6 days) at heights of 20 m, 500 m and 1000 m, clearly shows that the pollution propagation originated from the ChNPP. The radiation situation at the Z NPP aggravated on 30 April 1986, when the wind took a stable southerly direction, and the pollution plume from the ChNPP damaged unit 4 began passing the south of Ukraine (Fig. 4). The basic calculations of this situation have been made for the period from 29.04.86 to 2 May 1986.

303

Fig. 1. Trajectories of air-mass motion from the ChNPP at heights of 20 m (red curve), 1000 m (blue curve) and 10000 m (green curve) from 26.04.86 till 8.05.86

Fig. 2. Direct propagation path from the ChNPP from 29.04.86 till 1.05.86, at heights of 20 m (red line), 500 m (blue line) and 1000 m (green line). At a level of 500 m, prevalence of pollution from Chernobyl is observed; the releases are directed toward S-E to the ZNPP, reaching the ZNPP location area at heights of 500 and 1000 m on 1May

As a result of information processing for the period from 26 April to 8 May 1986, we have obtained the data on the concentration and deposition particles of 134Cs, 137Cs and 90Sr in this period. For the ZNPP, the main release of these radionuclides fell on 1 â&#x20AC;&#x201C; 2 May 1986, this being con-

firmed by the radiological environment monitoring data of the ZNPP survey points (Fig. 5) Thus, direct and back paths of air-mass motion in the ZNPP 30-km area have been obtained; maps of 134Cs, 1374Cs and 90Sr distribution within Ukraine after the Chernobyl

304

Fig. 3. Back propagation path from the ZNPP at heights of 20 m (red line), 500 m (blue line) and 100 m (green line) (coordinates 47.51 N and 34.6 E) for 6 days from 3.05.86 till 27.04.86

Fig. 4.

137

Cs particle deposition from 29 April to 1 May; the source height is 20 m

accident in 1986 have been drawn. The map processing suggests that the radionuclide content in the free air of the ZNPP location area had drastically increased after the ChNPP accident and led to a substantial environmental degradation.

Conclusions The distribution of pollutants within Ukraine during the first week after the Chernobyl accident and its environmental impact in the ZNPP location area have been analyzed.

305

Fig. 5. 137Cs concentration within Ukraine. Time of emission - 29.04.1986. Noon. Duration – 72 hours (till 2.05.1986. Noon.). The source height is 50 m

Three-dimensional distribution of pollutants within the 30-km ZNPP zone in 1986 has been determined, and confirmatory evidence has been provided that it was the Chernobyl accident that caused a several-fold increase in the content of radionuclides in the open air, water and soil of the given region.

References: 1. S.V. Barbashev, The concept and principles of ecological monitoring organization and conduction in NPP location areas // Radiation and ecological safety of nuclear fuel cycle enterprises, 2(1997), 80-88 2. M.F. Kozhevnikova, V.V. Levenets, I.L. Rolik, Identification of pollution sources: computation methods, PAST , 6 (2011),149-156 3. M.F. Kozhevnikova, V.V. Levenets, K.A. Mets, I.L. Rolik, Analysis of pollutants distribution for the zirconium cycle enterprise, PAST, 5 (2013), 95 - 99 4. M.F. Kozhevnikova, V.V. Levenets, K.A. Mets, I.M. Neklyudov, I.L. Rolik, Identification of the emission source using the simulation of the pollutants propagation process and the factor analysis, Zbirnyk naukovykh prats SNUYaEmaP, 3(2013), 71 - 77 5. P.K. Hopke, Recent developments in receptor modelling, Journal of Chemometrics,17 (2003), 255 - 265 6. P.K. Hopke, Receptor Modeling in Environmental Chemistry, Wiley, 1985 7. P.K. Hopke, Receptor Modeling for Air Quality Management, Elsevier,1991 8. Draxler Ronald R., G.D. Hess, Description of the HYSPLIT-4 Modeling System, Air resources Laboratory, NOAA Technical Memorandum ERL ARL-224, 1997

9. V.K. Bronnikov, N.A.Verkhovetsky Zaporozhskaya NPP and the environment, Kharkov, 1994 10. 20 years of the Chernobyl disaster. Looking into the future.

National report of Ukraine, Kiev, 2006 11. A.V. Yablokov, Myth of insignificant Chernobyl disaster consequences, Moscow, 2001 12. P. Paatero, Least squares formulation of robust, nonnegative factor analysis, Chemom. Intell. Lab. Syst, 37(1997), 23 – 35

radiaqtiuri dabinZurebis deteqtireba atomuri eleqtrosadguris regionSi m. koJevnikova, v. voevodini

leveneci, i. roliki, v.

erovnuli samecniero centri „xarkovis fizikateqnikis instituti“, akademiCnas q.1, xarkovi, 61108, ukraina; el-fosta: levenets@kipt.kharkov.ua gaanalizebulia Cernobilis avariis Sedegebis gavlena ekologiur mdgomareobaze zaporoJies atomuri eleqtrosadguris (aes) raionSi. SemoTavazebulia aes-is raionSi dabinZurebis wyaros deteqtirebis monacemebis damuSavebis meTodi. analizi Catarda haeris masebis moZraobisaTvis zaporoJies aes-is 30 km-ian zonaSi. Sedgenilia haeris masebis moZraobis traeqtoriis rukebi da gansazRvrulia radionuklidebis nawilakebis haerSi ganawileba mTels teritoriaze 1986 wlis monacemebiT.

306

An Assessment of Trace Heavy Metal Contamination of Some Edible Oils Regularly Marketed in BenueandTaraba States of Nigeria R. Odoh1, O.J. Oko1, M.S. Dauda2, Department of Chemical Sciences, Federal University Wukari, PMB 1020, Taraba State, Nigeria Department of Chemistry, University of Abuja, P.M.B 117, Abuja E-mail:odohraf@gmail.com 1 2

Abstract. The determination of Cd, Cr, Cu, Fe,Mn, Ni, Pb and Zn contents in edible oils (palm oil, ground-nut oil and soyabean oil) bought from various markets of Benue and Taraba state were carried out with Flame Atomic Absorption spectrophotometric technique. The method 3031 developed acid digestion of Oils for metal analysis by Atomic Absorption or ICP spectrometry was used in the preparation of the edible oil samples for the determination of total metal content in this study. The overall results (μg/g) in palm oil sample ranged from 0.028-0.076, 0.035-0.092, 1.011-1.955, 2.101-4.892, 0.666-0.922, 0.054-0.095, 0.031-0.068 and 1.987-2.971 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively, while In ground-nut oil the overall results ranged from 0.011-0.042, 0.011-0.052, 0.133-0.788, 1.789-2.511, 0.078-0.765, 0.0450.092, 0.011-0.028 and 1.098-1.997 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively. Of the heavy metals considered Cd and Ni showed the highest contamination in the soya bean oil sample. The overall results in soya bean oil samples ranged from 0.011-0.015, 0.017-0.032, 0.453-0.987, 1.789-2.511, 0.089-0.321, 0.011-0.016, 0.012-0.065 and 1.011-1.997 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively. The concentration of Pb was the highest. The degree of contamination by each metal was estimated by the transfer factor. The transfer factors obtained for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in edible oils (palm oil, ground-nut oil and soyabean oil) were 10.800,16.500,16.000,18.813,15.115,14.230,23.000 and 9.418 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in palm oil, and 7.000, 12.500, 8.880, 11.333, 7.708, 10.833, 15.00 and 6.608 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn in ground-nut oil while for soya bean oil the transfer factors were 13.000, 11.000, 7.642, 11.578, 4.486, 13.00, 12.333 and 4.412 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively. The inter-element correlation was found among metals in edible oil samples using Pearson’s correlation co-efficient. There were positive and negative correlations among the metals determined. All Metals determined showed degree of contamination but concentrations lower than the USP specification.

Keywords: Heavy Metals; Edible oils; Contamination; Benue and Taraba State markets.

Introduction

The presence of small amounts of trace metals in oils and fats is known to produce deleterious effects on quality. The strongest and most notable proxidants are copper and iron, which produce a noticeable oxidative effect at concentrations as low as 0.005ppm and 0.03 ppm respectively [1,2,3]. Some metals e.g., nickel, zinc, copper, cadmium and lead are important from a health and safety stand point, as linked either directly or indirectly via cholesterol levels to coronary heart disease [4,5].Heavy metal poisoning is a medical condition caused by increased levels of the heavy metals such as Pb, Cd, Cr, Cu, Mn, Ni, and Zn in the body. Although some metals are essential for life, all metals are toxic at sufficiently high concentrations. Generally the gap between what could be described as essential and toxic is very narrow. This is because many biological systems exist naturally on the margin of metal toxicity while the physical and geochemical redistribution of toxic metals in environments or food items by human activities has a strong potential to disrupt ecosystem and food chains [6].

The determination of the inorganic profile of edible oils is important because of the metabolic role of some elements in the human organism. On the one hand there is knowledge of the food’s nutritional value which refers to major and minor elements. On the other hand, there is the concern to verify that the food does not contain some minerals

in quantities toxic for the health of the consumers, regardless whether this presence of minerals is naturally occurring or is due to contamination during the production processes [7]. Oil characterization is the basis for further nutritional and food technological investigations such as adulteration detection. Edible oil is rich in antioxidant vitamins, trace elements and supplies fatty acids essential for proper growth, development and for general well-being [8,9]. It has been reported that contamination of diets including edible oil with heavy metals could result from different sources such as drinking water, high ambient air concentrations, industrial waste, acidic rain breaking down soils and food chain [10, 11]. Contamination of the food chain with heavy metals could pose potential health risk to humans and animals because these heavy metals have the ability to “bio-accumulate”. Reports from previous research have shown that compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted) [10]. Although edible oil remain vital in human nutrition and medicinal treatment, there is concern about its contamination by toxic elements and the potential risk such contamination could pose to the consumers in our locality [12].This contamination could have access to the oils during planting, harvesting, processing, packaging, storage or sale of the product.

Furthermore, studies have indicated that edible oils are

307 often adulterated to mask their colors and properties hence the need to assess the extent of adulteration [13, 14]. It has been shown that edible oil obtained from the fruit of the oil palm tree, ground-nut seed and soya bean seed are the most widely produced edible oils in the country today and are the common cooking ingredient in Africa, South East Asia and parts of Brazil and other parts of the world [15].To the best of our knowledge no study has been conducted in our environment to evaluate the concentration of heavy metals present in edible oil and the potential hazards such contamination may pose to human health although studies on heavy metals have mostly been carried out on soil, water, paint and food [16]. This study thus aims at investigating the levels of the heavy metals Cd, Cr,Cu,Fe,Ni, Pb and Zn in edible oils sold in different markets in Benue and Taraba state, Nigeria.

Materials and methods

The edible oil samples (palm oil, ground-nut oil and soya bean oil) were purchased from different markets in Benue (located in Otukpa, Makurdi, Katsina-Ala) andTaraba (located in Wukari, Ibi, Takum) states while the control edible oil (palm oil, ground-nut oil and soya bean oil) were bought from local producers in selected villages from each state where there is no industrial activity . A total of 90 edible oil samples (palm oil, ground-nut oil and soya bean oil) each were purchased for the two states studied.

15composite samples were then analysed.

The method 3031 developed acid digestion of Oils for metal analysis by Atomic Absorption or ICP spectrometry was used in the preparation of the edible oil samples for the determination of total metal content in this study [17].

0.5 g of the representative sample was mixed with 0.5 g of finely ground potassium permanganate and then 1.0 ml of concentrated sulphuric acid was added while stirring. A strong exothermic reaction was observed. The sample was then treated with 2 ml concentrated nitric acid. 10 ml of concentrated HCl was added and the sample heated until the reaction was complete. It was then filtered. The filter was washed with hot concentrated HCl. The filter paper was transferred to a digestion flask and treated with 5 ml of concentrated hydrochloric acid. To remove the manganese, the digestate was neutralized with concentrated ammonium hydroxide. Water and ammonium phosphate were added and the digestate stirred while a precipitate of manganese ammonium phosphate was formed. When the precipitation was complete, the digestate was filtered. The ammonia was then boiled off. The sample is brought to volume and analyzed on FAAS. Standards were prepared with serial dilution techniques within the range of each metal determined. The standards used were Analar grade; the instrument was first calibrated with stock solutions of the prepared standards before being analyzed using Flame Atomic Absorption Spectrophotometer. After every five sample analyzed using FAAS, the first sample was repeated for quality check. Only when the result was within 10% of earlier readings did the analysis proceed further. The data obtained in the study were analyzed using Pearson correlation analysis.

Result and discussion

The results of heavy metal concentrations in the edible oil (palm oil, ground-nut oil and soya bean oil) samples are presented in Tables (1, 2, 3 ) and summaries of the results are presented in Table(4 ). The edible oil samples bought from different markets in the two states revealed elevated levels of the heavy metals Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn . The mean concentrations of heavy metals obtained in edible oils from the control area were much lower than those obtained from the edible oil (palm oil, ground-nut oil and soya bean oil) bought from the different market places under consideration. This reflects heavy metal contamination of edible oils (palm oil, ground-nut oil and soyabean oil) bought from these market places. For palm oil and ground-nut oil samples, out of the heavy metals considered, lead showed the highest level of contamination. The overall results (Îźg/g) in palm oil sample ranged from 0.0280.076, 0.035-0.092, 1.011-1.955, 2.101-4.892, 0.666-0.922, 0.054-0.095, 0.031-0.068 and 1.987-2.971 for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively, while for the ground-nut oil sample the overall results ranged from 0.011-0.042, 0.0110.052, 0.133-0.788, 1.789-2.511, 0.078-0.765, 0.045-0.092, 0.011-0.028 and 1.098-1.997Îźg/g for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively. For the soya bean oil samples, out of the heavy metals considered Cd and Ni showed the highest level of contamination, the overall results in soya bean oil samples ranged from 0.011-0.015, 0.017-0.032, 0.4530.987, 1.789-2.511, 0.089-0.321, 0.011-0.016, 0.012-0.065 and 1.011-1.997Îźg/g for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn respectively.

Generally, in the three edible oils (palm oil, ground-nut oil and soyabean oil) studied, the concentration of the heavy metals were high compared to the concentration of the heavy metals in the edible oils (palm oil, ground-nut oil and soyabean oil) obtained as control . This is an indication that these heavy metals are the primary contaminants in the edible oils (palm oil, ground-nut oil and soyabean oil) bought from these various markets place. This was reflected in the low level of these heavy metals obtained as control areas in comparison with those obtained from the market place. Also, the degree of heavy metal contamination of the edible oils (palm oil, ground-nut oil and soyabean oil) which were determined by its transfer factor was also high. From the mean results and transfer factor, there is a clear indication that the heavy metals determined (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) are the most contaminants of the edible oils (palm oil, ground-nut oil and soyabean oil) bought from these various markets place in Benue and Taraba state. All the samples (palm oil, ground-nut oil and soyabean oil) contained detectable amounts of these heavy metals of interest which were determined in the study. Lead, a ubiquitous and versatile metal was also detected in the edible oils examined. It has become widely distributed and mobilized in the environment and human exposure to and uptake of this non-essential element has consequently increased [10]. At high levels of human exposure, there is damage to almost all organs and systems, most importantly the central nervous system, kidneys and blood, culminating in death at excessive levels. At low levels, haem synthesis and other biochemical processes have been re-

308 ported to be affected by lead contamination [18, 19, 20].

Lead continues to be a significant public health problem in developing countries where there are considerable variations in the sources and pathways of exposure, therefore there need for caution in the processing and handling of edible oils in order to reduce contamination of this metal from the environment. Chromium can irritate the skin and cause ulceration at low exposures while long term exposure can cause kidney and liver damage. It can also cause damage to circulatory and nerve tissues. Copper is the strongest pro-oxidant for oils and for the best stability, the content of copper should be below 0.02 ppm μg/g [21,22].

The contamination of copper may be due to the degradation and deterioration of some metal alloys of iron equipment, being utilized for the treatment, storage and purification of the oils. High doses of copper can cause anaemia, liver and kidney damage, and stomach and intestinal irritation. People with Wilson’s disease are at greater risk for health effects from over exposure to copper. Long term exposure to cadmium is associated with renal dysfunction. Cadmium is bio persistent and once absorbed remains resident for many years. High exposure can lead to obstructive lung diseases and has been linked to lung cancer.

Cadmium may also cause bone defects in humans and animals. The average daily intake for humans is estimated to be 0.15μg from air and 1μg from water [23]. Manganese is known to block calcium channels and with chronic exposure results in CNS dopamine depletion. This duplicates almost all of the symptomology of Parkinson’s disease.

Excessive amounts of nickel can be mildly toxic. Long term exposure can cause decreased body weight, heart and liver damage and skin irritation; the symptoms of exposure to some poisonous nickel compounds include nausea, vomiting, headaches and sleeplessness. The symptoms get worse later on from 12 to 24 hours after exposure and include palpitation, difficulty in breathing, chest pains and extreme fatigue. Nickel is rarely poisonous, but certain nickel compounds are extremely dangerous. The most common is nickel carbonyl in refineries, nickel mines and plating factories [24, 25, 26]. Correlations were established among the various metals under consideration as shown in Table5. Generally the correlations among the metals were very poor, there was negative correlation between the pair of Pb /Zn in palm oil sample, in ground-nut oil there were positive correlation between the pair of Cd/Cu, Cd/Mn and negative correlation between pair of Cd/Ni while in soyabean oil there was positive correlation between the pair of Cd/Fe,this correlation between Cd and these metals may probably indicate that they emerged from the same origin or anthropogenic sources.

For safety of human health, various regulatory organizations such as USP, BP, EPA, WHO, USEPA have set up parameters to limit the presence of heavy metals in edible oils. Parameters such as permissible daily exposure (PDE), rationale for reference doses (RFD’s), oral component limit (OCL) and parenteral component limits (PCL) are guidelines set to regulate elemental contaminations in different products of edible oils[17].

Factors influencing the toxicity of metals include interactions with essential metals, formation of metal-protein

complexes, age and stage of development, lifestyle factors, chemical form or speciation and immune status of host [27].It is known that significant percentage of Nigerian population consume edible oils both as nutritional and medicinal agents. It is good news that the edible oil samples analysed contained these toxic metals of interest at concentrations lower than the USP specification but if accumulated in the body over time may pose a risk to the health of consumers after many years.

Conclusion The results obtained from the analysis of the edible oils (palm oil, ground-nut oil and soyabean oil) bought from various markets of Benue and Taraba state in Nigeria indicated that the concentrations of the heavy metals determined (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were higher than those found in the control samples. The degree of contamination of Pb was the highest. Cd, Cr, Cu, Fe, Mn, Ni and Zn also showed high degree of contamination in edible oils. From this reason, it could be predicted that the contaminations of these heavy metals determined; Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn are probably from anthropogenic sources. The observed contaminants were Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn and their concentrations and factors of accumulations were high in all the edible oils studied.

Edible oils have been part of human diet from the beginning of human life. For generations, it has been recognised as both a nutritious food and a valuable medicine. However, care should be taken to evaluate the purity and safety of this nutritional and medicinal agent to the human system.

In as much as the edible oil samples (palm oil, ground-nut oil and soyabean oil) analysed contained these toxic metals of interest at concentrations lower than the USP specification if allowed to accumulate in the body over time it may pose risk to the health of consumers after many years.

Hence, there is a need for closer monitoring of heavy metals in the other edible oils sold in the Nigeria markets and also enlightenment campaigns to consumers on likely ways to avoid contamination of edible oils such as the containers in which they are kept.

Table1. Heavy Metal Contents(μg/g) of Palm Oil sold in local market in Benue and Taraba State of Nigeria Sites 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Cd 0.076 0.063 0.042 0.035 0.045 0.065 0.075 0.054 0.048 0.053 0.063 0.028 0.067 0.057 0.033

Cr 0.057 0.059 0.049 0.035 0.056 0.088 0.045 0.075 0.067 0.073 0.092 0.088 0.075 0.077 0.054

Cu 1.112 1.955 1.856 1.788 1.678 1.835 1.699 1.589 1.023 1.011 1.955 1.654 1.896 1.105 1.786

Fe 3.511 2.521 2.975 2.245 2.331 2.859 2.222 2.789 2.208 2.156 3.999 2.115 2.101 4.892 3.401

Mn 0.922 0.831 0.701 0.744 0.875 0.666 0.698 0.844 0.689 0.801 0.788 0.732 0.841 0.887 0.771

Ni 0.095 0.065 0.075 0.067 0.061 0.087 0.092 0.077 0.054 0.071 0.055 0.085 0.065 0.081 0.075

Pb 0.041 0.031 0.032 0.044 0.043 0.065 0.055 0.052 0.032 0.041 0.033 0.055 0.061 0.041 0.068

Zn 2.123 2.971 2.554 2.065 2.876 1.997 2.543 2.234 2.543 2.675 2.654 2.098 2.012 2.122 1.987

Mean S.D MIN MAX

0.054 0.015 0.028 0.076

0.066 0.017 0.035 0.092

1.596 0.350 1.011 1.955

2.822 0.818 2.101 4.892

0.786 0.079 0.666 0.922

0.074 0.013 0.054 0.095

0.046 0.012 0.031 0.068

2.364 0.339 1.987 2.971

309 Table 2. Heavy Metal Contents (μg/g) of Ground nut Oil sold in local market in Benue and Taraba State of Nigeria Sites 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Cd 0.023 0.012 0.042 0.035 0.025 0.011 0.013 0.015 0.017 0.021 0.023 0.028 0.012 0.019 0.023

Cr 0.056 0.042 0.022 0.011 0.012 0.028 0.017 0.021 0.025 0.029 0.026 0.019 0.018 0.029 0.023

Cu 0.432 0.231 0.653 0.788 0.678 0.133 0.699 0.589 0.321 0.431 0.444 0.333 0.237 0.387 0.298

Fe 2.511 2.321 1.975 2.245 2.331 1.859 2.222 1.789 2.208 2.156 1.999 2.115 2.101 1.892 2.401

Mn 0.122 0.131 0.765 0.144 0.175 0.166 0.098 0.144 0.089 0.201 0.078 0.132 0.141 0.211 0.171

Ni 0.045 0.065 0.055 0.067 0.061 0.087 0.092 0.077 0.054 0.071 0.055 0.045 0.065 0.081 0.055

Pb 0.012 0.017 0.012 0.011 0.013 0.018 0.021 0.016 0.011 0.019 0.014 0.012 0.013 0.011 0.028

Zn 1.231 1.971 1.554 1.767 1.876 1.997 1.543 1.234 1.543 1.675 1.654 1.098 1.123 1.543 1.987

Mean S.D MIN MAX

0.021 0.009 0.011 0.042

0.025 0.011 0.011 0.056

0.444 0.196 0.133 0.788

2.142 0.185 0.209 0.165013 1.789 0.078 2.511 0.765

0.065 0.014 0.045 0.092

0.015 0.005 0.011 0.028

1.586 0.307 1.098 1.997

Table 3. Heavy Metal Contents (μg/g) of Soybean Oil sold in local market in Benue and Taraba State of Nigeria sites 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Cd 0.013 0.015 0.012 0.014 0.012 0.011 0.012 0.011 0.013 0.015 0.012 0.014 0.011 0.012 0.015

Cr 0.019 0.026 0.017 0.018 0.022 0.021 0.032 0.021 0.023 0.018 0.025 0.023 0.024 0.019 0.023

Cu 0.987 0.897 0.856 0.788 0.678 0.835 0.699 0.589 0.543 0.453 0.555 0.567 0.896 0.762 0.786

Fe 2.511 2.321 1.975 2.245 2.331 1.859 2.222 1.789 2.208 2.156 1.999 2.115 2.101 1.892 2.401

Mn 0.122 0.131 0.201 0.144 0.175 0.166 0.098 0.144 0.089 0.201 0.321 0.132 0.141 0.122 0.171

Ni 0.016 0.013 0.012 0.011 0.012 0.014 0.011 0.015 0.012 0.011 0.012 0.014 0.016 0.012 0.015

Pb 0.021 0.031 0.012 0.044 0.043 0.065 0.055 0.022 0.032 0.041 0.033 0.025 0.061 0.041 0.028

Zn 1.123 1.971 1.554 1.011 1.876 1.997 1.543 1.234 1.543 1.675 1.654 1.098 1.133 1.098 1.987

Mean S.D MIN MAX

0.013 0.001 0.011 0.015

0.022 0.004 0.017 0.032

0.726 0.158 0.453 0.987

2.142 0.157 0.209 0.0559 1.789 0.089 2.511 0.321

0.013 0.002 0.011 0.016

0.037 0.015 0.012 0.065

1.499 0.360 1.011 1.997

Table 4. Summaries of results of Heavy Metal contents (μg/g) of some edible oils sold in some selected local markets in Benue and Taraba state of Nigeria

Metals

Cd

Cr

Cu

Mean S.D

0.054 0.015 0.0280.076

0.066 0.017 0.0350.092

Range Contro l T.F Mean S.D Range Contro l T.F Mean S.D Range Contro l T.F

Mn

Ni

Pb

Zn

1.596 0.350 1.0111.955

Fe Palm Oil 2.822 0.818 2.1014.892

0.786 0.080 0.6660.922

0.074 0.013 0.0540.095

0.046 0.013 0.0310.068

2.364 0.339 1.9872.971

0.150

0.005

0.004

0.100

0.052

0.005

0.002

0.251

10.800

16.500

14.230

23.000

9.418

0.021 0.009 0.0110.042

0.025 0.011 0.0110.052

16.000 18.813 15.115 Ground-nut Oil 0.444 2.142 0.185 0.196 0.209 0.165 0.133- 1.789- 0.0780.788 2.511 0.765

0.065 0.014 0.0450.092

0.015 0.005 0.0110.028

1.586 0.307 1.0981.997

0.003

0.002

0.050

0.024

0.006

0.001

0.240

7.000

12.500

10.833

15.000

6.608

0.013 0.001 0.0110.015

0.022 0.004 0.0170.032

8.880 11.333 7.708 Soya bean Oil 0.726 2.142 0.157 0.158 0.209 0.056 0.453- 1.789- 0.0890.987 2.511 0.321

0.189

0.013 0.002 0.0110.016

0.037 0.015 0.0120.065

1.500 0.360 1.0111.997

0.001

0.002

0.095

0.185

0.035

0.001

0.003

0.340

13.000

11.000

7.642

11.578

4.486

13.000

12.333

4.412

Table 5. Inter-elemental correlation of heavy metals in edible oils (palm oil,ground-nut oil and soya-bean oil) Cd

Cr 0.133

Cu -0.081 -0.064

Fe 0.186 0.248 -0.151

Mn 0.274 0.037 -0.261 0.377

Ni 0.258 -0.056 -0.152 0.158 -0.004

Pb -0.060 0.132 0.266 -0.151 -0.167 0.449

-0.235

0.560 -0.441

0.107 0.294 0.067

0.644 -0.090 0.268 -0.250

-0.513 -0.237 0.094 -0.471 -0.120

-0.323 -0.008 -0.198 0.194 -0.143 0.285

-0.072

-0.118 -0.083

0.609 0.172 0.282

-0.056 -0.146 -0.258 -0.239

-0.183 -0.031 0.455 0.075 -0.166

-0.320 0.329 0.072 -0.131 -0.124 -0.110

Zn 0.133 -0.141 0.027 -0.198 0.056 -0.475 -0.686 -0.022 -0.042 -0.054 0.174 0.029 0.254 0.463 0.191 0.269 -0.044 0.141 0.314 -0.152 0.121

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310 13. Park, J.R and Lee,D (2003) Detection of adulteration in olive oils using triacylglycerols compositions by high temperature Gas Chromatography. Bull Korean Chem.Soc.24(4):527-530.

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nigeriis benuasa da tarabas StatebSi gayidvaSi arsebuli zogierTi saWmeli zeTis mZime metalebis narCenebiT dabinZurebis Sefaseba r. odo1, o. jon oko1, m. dauda2 1

qimiur mecnierebaTa departamenti, federaluri universiteti vukari, 1020, Stati taraba, nigeria 2 qimiis departamenti, abujas universiteti, P.M.B 117, abuja el–fosta: odohraf@gmail.com atomuri absorbciis speqtrofotometruli meTodiT ganxorcielda Cd, Cr, Cu, Fe,Mn, Ni, Pb da Zn Semcvelobis gansazRvra benuasa da tarabas Statebis zogierT marketSi gayidvaSi arsebul saWmel(palmis, miwis Txilisa da soios) zeTebSi. atomuri absorbciuli an ICP speqtrometriis meTodiT metalis Semcvelobis gansazRvrisaTvis gamoyenebulia zeTebis mJavebiT damuSavebis standartuli meTodi 3031, romlis mixedviTac momzadda zeTis nimuSebi zemoTaRniSnuli metalebis gansasazRvrad. palmis zeTis nimuSebSi Cd, Cr, Cu, Fe, Mn, Ni, Pb da Zn saerTo Semcveloba (μg/g)-Si, meryeobda Sesabamisad 0.028-0.076, 0.0350.092, 1.011-1.955, 2.101-4.892, 0.666-0.922, 0.054-0.095, 0.031-0.068 da 1.987-2.971 farglebSi, maSin roca miwis Txilis zeTSi saerTo Semcveloba (μg/g)-Si, icvleboda 0.011-0.042, 0.011-0.052, 0.133-0.788, 1.789-2.511, 0.078-0.765, 0.045-0.092, 0.011-0.028 da 1.098-1.997-s Soris, Sesabamisad Cd, Cr, Cu, Fe, Mn, Ni, Pb da Zn-isaTvis. ganxiluli mZime metalebidan Cd da Ni-iT metad dabinZurebulia miwis Txilis zeTi. soios zeTSi Cd, Cr, Cu, Fe, Mn, Ni, Pb da Zn-is saerTo Semcveloba (μg/g)-Si, 0.011-0.015, 0.017-0.032, 0.453-0.987, 1.789-2.511, 0.089-0.321, 0.011-0.016, 0.012-0.065 da 1.011-1.997 farglebSia Sesabamisad. yvelaze maRalia Pb-is Semcveloba. TiToeuli metaliT dabinZurebis xarisxi gansazRvrulia gadatanis faqtoriT. saWmel zeTebSi(palmis zeTi, miwis Txilis zeTi, soios zeTi) gadatanis faqtori dadgenilia Cd, Cr, Cu, Fe, Mn, Ni, Pb da Zn-isaTvis. palmis zeTSi dadginda Sesabamisad 10.800,16.500,16.000,18.813,15.115,14.230,23.000 da 9.418,da 7.000, 12.500, 8.880, 11.333, 7.708, 10.833, 15.00 da 6.608 miwis TxilSi Cd, Cr, Cu, Fe, Mn, Ni, Pb da ZnTvis,maSin rocasoios zeTisaTvisgadatanis faqtori aRmoCnda 13.000, 11.000, 7.642, 11.578, 4.486, 13.00, 12.333 da 4.412 Sesabamisad Cd, Cr, Cu, Fe, Mn, Ni, Pb da Zn-isaTvis. pirsonis korelaciuri koeficientis gamoyenebiT dadginda saWmel zeTebSi metalebs Soris arsebuli korelacia. gansazRvrulia dadebiTi da uaryofiTi korelaciebi arsebul metalebSi metalebSi. yvela gansazRvruli metali aCvenebs dabinZurebis xarisxs, magram USP instruqciiT gansazRvrulze naklebi koncentraciiT.

311

Design & fabrication of the experimental diffusion welding machine A.A. Gevorgyan, V.Sh. Avagyan, A.S. Simonyan, V.S. Dekhtiarov, V.A. Danielyan, T.H. Mkrtchyan, V.V. Vardanyan CANDLE Synchrotron Research Institute, Acharyan 31, Yerevan 0040, Armenia, www.candle.am Abstract.Vacuum brazing and diffusion welding as compared to other conventional methods of joining are specialized bonding processes. There are a lot of different techniques of brazing and diffusion welding, for example torch, induction heat, furnace with different gases and etc.In this paper we are indicating what we have researched and developed on the technological process for vacuum induction brazing and diffusion welding of nonferrous metals. We have designed and fabricated vacuum brazing equipment taking into account vacuum level, physical-mechanical properties of materials, sample geometry and etc.

In this topic various aspects of vacuum induction brazinghavealso been researched,such as material selection, basic parameters and steps required for brazing, operation and maintenanceof vacuum brazing systems, safety aspects and construction of vacuum diffusion welding equipment.Assessment of joint quality of brazed joints and results are shown.

Keywords: diffusion welding equipment, diffusion brazing equipment, vacuum linear motion mechanism

Introduction There are many spheres (accelerator technologies, synchrotron radiation devices, medical instrumentation, aerospace engineering, RF systems and etc.) where complex assemblies and high quality components considered to join by using vacuum brazing or diffusion welding techniques. The vacuum induction brazing and diffusion welding are used when componentsâ&#x20AC;&#x2122; joining becomes difficult by using the conventional methods like welding or torch brazing. Using vacuum brazing we can bond complex components from different materials like metals and non-metals (ceramic) which are very difficult to weld or sometimes even impossible to join.Scientists tend to use vacuum induction brazing and diffusion welding processes to make quality joints and achieve high targets as the most effective joining techniques.

For developinghigh quality vacuum brazing and diffusion welding system at first we chose the material, researchedphysical-mechanical properties of it, designed and fabricated vacuum diffusion equipment with induction heating system, and wealso designed new vacuum linear motion mechanism.

Materials and Methods There are a lot of different vacuum diffusion welding machines with various vacuum systems, heating systems, capabilities and etc [1]. Basically, diffusion welding machines should consist of the following main parts: 1. Main frame, 2. Vacuum chamber (fabricated from stainless steel), 3. Vacuum system, 4. Heating system, 5. Cooling system, 6. Pneumatic system, and 7. Measuring tools (vacuum gauge and dynamometer). Before using the vacuum diffusion welding machine, the maincomponents of it should be checked and cleaned, mainly temperature accuracy, leak

rate, chamber condition, all electrical connections, cooling system, and etc. The experimental diffusion welding machine can be used to accomplish a lot of different experimental tasks, particularly diffusion welding of different metal components to each other, brazing, outgassing and annealing or other heating processes. Moreover, it has several windows, which can give opportunities to realize some technological modifications[2]. All these aforementioned processes are actual in accelerator technology.

The diffusion welding machine, shown in fig.2, consists of the vacuum chamber, the dimensions of which are: 500mm diameter, 480mm depth. There are two types of heaters, one of them is induction heating system the maximum temperature of which is about 1500OC and the second one is tungsten helix heater which can reach up to 2000OC temperature at a vacuum of 1.2x10-5Torr. These two opportunities make it easy to work both with metals and composites.

This welding machine was designed with two pumps: for vacuum pump and diffusion oil one. Recently, instead of these two pumps a turbomolecular vacuum pumping system with 270l/s pumping speedwas installed (which includes a turbomolecular pump and a dry scroll pump).

The design of vacuum diffusion welding machine shown in fig.1 also includes vacuum linear motion mechanism (patented design [2]) which is designed to fabricate E-beam windows.This vacuum diffusion welding machine can also be used in the field of accelerators. The electron-beam windows have crucial role in accelerator technologies. Joint types of e-beam windows can be sectional and welded.

The sectional windows are applied when the energy of ebeam is low. Working with high energy e-beams the abovementioned windows should be brazed and as a result they should have vacuum tight joints. The vacuum linear motion mechanism indicated in fig.3 is specially designed for

312 the vacuum diffusion welding machine to move thin foils into the heating area. For the thin foils being in the heating area during the whole process can cause some problems, such as deformation and even melting of foil (which is 40Âľm). This mechanism is designed to work in high temperature up to 1500OC and corresponds to all requirements to work with experiments connected with e-beam windows.This mechanism was designed to transport thin foil or some samples to heating area.

Results Aforementioned vacuum diffusion welding machine has been successfully designed and fabricated. All systems: vacuum system, heating system, pressing system, are satisfied to all requirement.

Fig. 1. Design of Welding Machine

Fig.3. Vacuum Linear Motion Mechanism Results

Fig. 2. Diffusion Welding Machine Fabricated

313 Conclusion Vacuum system was compatible to all requirements of vacuum brazing and diffusion welding. The above-illustrated processes of joining will be highly useful for developing UHV compatible accelerator components in future.

References 1. I.F.Kazakov, “Diffusion Welding of Materials”, 1976,Russia.

2. AvagyanVardan, ArturGevorgyan, “Diffusion welding method of part copper to steel patent”,¹2882A, AM20140054, 17.04.2014.

3. VaheDanielyan, VardanAvagyan, “Manipulator for UHV Chamber”, Patent number–AM20140161, Intellectual Property Agency (Yerevan, Armenia)25.03.2015.

difuzuri SeduRebis eqsperimentuli danadgaris damuSaveba da Seqmna a.a. gevorqiani, v.S. avagiani, a.s. simoniani, v.s. deqtiarovi, v.a. danieliani, t.p. mkrtCiani, v.v. vardaniani

kandles sinqrotronuli kvleviTi instituti, aCariani 31, erevani, 004, somxeTi el-fosta: www.candle.am vakuumuri rCilva da difuzuri SeduReba sxva meTodebTan SedarebiT warmoadgenen SekavSirebis specializebul procesebs. cnobilia rCilvisa da difuzuri SeduRebis sxvadasxva meTodi, magaliTad, aalebis, induqciuri gaxurebis, Rumelebi gazisa da sxva sawvaviT da a.S. warmodgenil naSromSi naCvenebia feradi metalebis vakuumuri induqciuri rCilvisa da difuzuri SeduRebis teqnologiuri procesebis kvleva da damuSaveba. damuSavebulia da Seqmnilia vakuumuri rCilvis mowyobiloba, romelSic gaTvaliswinebulia vakuumis done, masalebis fizikur-meqanikuri Tvisebebi, nimuSebis geometria da sxv.

314

Powdery composites for matrix ceramics T. Kuchukhidze1, N. Jalabadze3, G. Kvartskhava3, O. Lekashvili2, N. Jalagonia1, R. Chedia1,2 Ilia Vekua Sukhumi Institute of Physics and Technology, 7 Mindeli Str., 0186, Tbilisi, Georgia Iv. Javakhishvili Tbilisi State University, P. Melikhishvili Institute of Physical and Organic Chemistry, Tbilisi, Georgia 3 GeorgianTechnical University, Tbilisi, Georgia E-mail:sipt@sipt.org 1 2

Abstract. Present study deals with theoxide (Al2O3, ZrO2) matrix powdery composites obtaining method, containing various reinforced (oxides, carbides, oxynitrides and etc.) components. Powdery composites have been obtained by fellowing methods: Sol-gel, co-precipitation combustion reaction, simultaneous synthesis of components and mechanicchemical method. Obtained pressing powdery composites containing graphene oxide (0.5–2%) are based on alumina. It is established, low temperature transformation of metastable aluminum oxyhydroxides with different dopants and reinforced components.

Keywords: α-Al2O3, powdery composites, transformation, seeds, granulation.

Introduction Ceramic obtained on the base of aluminum oxide has wide application range, accounted for the unique properties, for example, wear-resistance, dielectric characteristics, and exploitation ability at high temperatures and in corrosive atmosphere. Currently great attention is paid to the use of nanotechnology, α-Al2O3 powdery and obtaining nanostructural matrix ceramics based on it. Many methods, such as sol-gel process, precipitation, chemical decomposition, plasma-chemical, electrochemical, microemulsion, high temperature oxidation and etc, have been usedfor the obtaining of matrix α-Al2O3. Heating of aluminum hydrates has obtained various type alumina such as α,χ,η,κ,θ,γ,ρ. Gradually heating of aluminum oxyhydroxides or unstable interim phases of alumina results in forming only α-Al2O3 (~1200oC) [1-7].

Matrix ceramics based on Al2O3 and ZrO2 are widely used in various fields of technology because it is characterized with high physical-mechanical properties, electrophysical features and chemical resistance. Cutting tools have been fabricated for machining steel based alloys, because they are characterized bya longer tool life able to cut difficult to machine such as hardened steel nickel alloys upon inclusion into alumina of ZrO2 micro-cracks are formed, which effectively absorbs energy, as a result of which ceramics acquire fracture toughness. Fibers of different types of compounds of aligned structure (SiC) improve resilience of ceramic matrix composites.Patent and scientific literature describe obtaining methods of matrix ceramic composites, which includes two basic processes: preparation of powdery composites and high temperature consolidation in various furnaces. Methods of preparation of powdery composites (Al2O3-Y2O3-ZrO2, Al2O3-SiCMgO, Al2O3-B4C-Y2O3, ZrO2-ZrN-Al2O3, Al2O3-WC-Co) have been described in the cited literature.Recently grinding of powders mixture till nano size widely use dry and wet methods in nano mills. For example, Al2O3–ZrO2 com-

posite is obtained by co-precipitation of aluminum nitrite and zirconium (IV) oxychloride presence of ammonia. Suspensions homogenization of the obtained matrix materials and second dissolved components are widely used. For example, homogenization of powdery Al2O3 or solution ZrOCl2 have beencarried out by magnetic stirring. Nanosize Al2O3-TiC powders can be obtained through high-energy reactive milling of mixtures of TiO2, Al and graphite powders. Powdery composite ZrO2-ZrN-Al2O3 have been obtained by grinding of premade powders. Zirconia toughness alumina is obtained analogously, which contains Y2O3 for stabilization of zirconium oxide. Various carbides are fabricatedby containing composites based on matrix oxide such as Al2O3-SiC-MgO, Al2O3-B4C-Y2O3, Al2O3-WC and etc [8-13].

Given the unique physical-mechanical properties of graphene, the production of graphene-based ceramic matrix composites has been given much attention during the last decade. Many examples of graphene-based oxide and non-oxide ceramic materials are currently known, from which it can be concluded that the incorporation of graphene into a material leads to a dramatic change in its physicalmechanical properties. Many research centers of developed countries are currently occupied with the production of graphene-based ceramic matrix composites [15-16].

Materials and Methods 1.1 Materials and reagents α-Al2O3, aluminum isopropoxide, silicon carbide, ammonium paratungstate, magnesium nitrite, alcohols, amines, carbohydrates, oligomers, polymers.

1.2 Obtaining of α-Al2O3 powdery Sol of unstable aluminum oxohydroxide has been obtained by hydrolysis of Al(OC3H7)3. Aluminum isopropoxide has been dissolved in water and heated at 80-85oC with constant stirring about 6-8 hrs. Water was removed

315 from the obtained sol and xerogel was dried at ~120oC. Obtaining ultrafine α-Al2O3 from xerogel has been conducted by its annealing from the room temperature up to 1200oC in high temperature furnace.

1.3 Obtaining of Al2O3-SiC-MgO Powdery composite was obtained by adding silicon carbide (10-30% mass) and magnesium nitrate in a sol of aluminum isopropoxide. Obtained suspension was dried and heated at 700oC, further obtained powdery was grinding in a nano mill during 8 hrs. Other carbide containing powdery composites were obtained analogously.

1.4 Obtaining of Al2O3-WC-Y2O3 Mixture of metal nitrates, ammonium paratungstate and organic compounds (alcohol, amines, carbohydrates, oligomers, polymers and etc) have been mixed in a porcelain.

Mixture was placed in a quartz tube and was heated at 250300oC in an argon atmosphere during 1 hrs. Swelled black masses have been grinded in a nano mill, powder was placed in the quartz tube and was heated at 900oC in a hydrogen atmosphere (120 min). When carbidization is finished, powder is cooled in an argon atmosphere.

1.5 Obtaining of Al2O3-graphene oxide composite Graphene oxide has been obtained by modificated Hummers’method. Graphene oxide suspension was added a α-Al2O3 nanopowder (70-130 nm), aluminum isopropylate and further the mixture was mixed in a nano mill. Obtained sticky suspension was dried at 1100C and then grinded by using corundum glass and balls.

1.6 Granulation of powdery composites Pregranulation of ultrafine powdery was carried out by a granulator SD-1000 to obtain granules with size 10-300 mcm.

Fig. 1. Laboratory granulator SD-1000

Granulation was conducted atthe initial stage, 30 g polyvinyl alcohol was dissolved in 1 L water with constant stirring at 800C condition. 300 g powdery composite and 3 g dispersant- modified polyacrylic acid (Sokalan-CP 10S) was added in the solution. Obtained suspension was mixed with magnetic stirring and then delivered by speed 10-20 mL/min in a granulation zone by a peristaltic pump. Granulation zone was regulated by the temperature range within 40-1500C. Suspension emission has been carried out with a compressed air till 3 atmosphere. Obtained granules are collected in a recipient and are dried in a furnace if necessary.

Powders have been obtained by components dry and wet homogenization methods in nano mills (FRITCH, planetary mill Pulverisette 7 premium line and RETCH PM 100).

Annealing have been in high temperature furnaces (OXYGON, Model ¹ FR210-30T-A-200-EVC) and furnace JINYU1700°C. Granulometric analysis of synthezed powdery carried out to laser nanosizer (Analysette 12 Dyna sizer). Structural-morphological research of obtained powders and ceramic products were studied by optical and electronic scanning microscopes (Nikon ECLIPSE LV 150,NMM-800RF/ TF, JEOL JSM-6510LV). Phase analysis of samples was conducted on the difractometer ÄÐÎÍ-3 (Cu-Ká, Ni, filter, 2o/min). Thermal analysis (DSC) carried out fellow device– DSC 200 F3–NETZSCH.

Results Powdery composites such as Al2O3-SiC-MgO, Al2O3B4C-MxOy, Al2O3-WC-Y2O3, Al2O3-ZrO2(5-20%)-Y2O3, ZrO 2 -Al 2 O 3 (10-30%)-Y 2 O 3 ,Al 2 O 3 -MgAl 2 O 4, Al 2 O 3 graphene oxide, etc, have been discussed in the present study.Various methods have been used to obtain composites (Sol-gel,co-precipitation, combustion reaction, simultaneous synthesis of components and mechanicchemical method). Mixture of aluminum oxohydroxides (Al2O3.xH2O) is obtained in result of hydrolyze aluminum isopropoxide. Nitrates of holmium, thorium, gadolinium, dysprosium, lanthanum and neodymiumare added to sol (0.1-0.2% mas.) calculated on metal.Drying of dopant-added gel is conducted at 1200C. Thermal treatment of obtained xerogel was conducted at 120oC, 500oC and at 800 o C (c) for 2 hrs.It is shown from IF spectra, that in all three samples in area of 3429-1635 cm-1absorption sols of O-H are revealed, andin area of 476-758 cm-1 -Al-O coordination bonds are observed. In particular, intensive maxima of AlO6tetrahedral and AlO4 octahedral groups are revealed: 476-738 cm-1 , 547-758 cm-1, 549 cm-1. Absorption maxima -827 cm-1points on presence of γ- Al2O3. Influence of lanthanum, cerium, neodymium, gadolinium, dysprosium, holmium and thorium ions on the transformation of unstable aluminum compounds into in alpha-alumina were studied. It is established from X-ray-phase analysis, that in a presence of holmium, formation of á-Al2O3 begins at temperature lower than 1000oCand at 1100oC temperature it transfers in á-Al2O3.

316 Mixture of aluminum oxohydroxides (Al2O3.xH2O) containing second reinforced component was carried out in hydolize process by adding of other phase (premade powders). Water was removed by typical method or with emission in a quartz tube has heated at 300oC Pressing powdery composites based on á-Al2O3 have been obtained in an argon flow.The method has been used for obtaining of carbides containing powders, namely á-Al2O3-B4C-Y2O3, Al2O3-ZrO2(5-20%)-Y2O3, ZrO2-Al2O3(10-30%)-Y2O3 powders have been obtained by co-precipitation method of aluminum isopropoxide, yttrium acetate and zirconium acetate.

Easy method for the obtaining of oxide powdery composites is often used in the laboratory practice that is based on the interaction between metal nitrates andorganic compounds (Solution Combustion Synthesis) [11].

Initiation temperature of reaction is 450-500oC. The reaction is exothermic and temperature of reaction mixture reaches 800-1500oC. Temperature of reaction mixture changes according to oxidizers/reducers ratio. Reaction speed is rather high 2-4 cm/sec. Pellets are easily fragmented and

composites interlinked by C-O-Al bonds will be formed on the surface of each particle. A graphene layer will function as growth inhibitor of Al2O3 particles and will dramatically impede the matrix particles growth process.

Powders of graphene oxide-alumina have been obtained with wet grinding method of that components by nano mills. In the first way have been obtained graphene oxide

by Hummers’ modified method. Pictures shows, main obtaining methods of graphene oxide.

Powdery composite [Al2O3]–[graphene oxide], containing 0.5-1.5 % (vol) graphene oxide has been obtained by homogenization of components in a nano mill presence connecting component 2% (mas) Al(i-C3H7O)3.

Conclusions Pressing powdery composites have been obtained for the matrix ceramics with physical-chemical process. Obtaining methods of thefollowing powders have been studied: Al2O3-SiC-MgO, Al2O3-B4C-MxOy, Al2O3-WC-Y2O3, á-Al2O3-ZrO2(5-20%)-Y2O3, ZrO2-á-Al2O3(10-30%)-Y2O3, áAl2O3-MgAl2O4,Al2O3-graphene oxide and etc. Obtained

Fig. 2. Reaction mixture: synthetic graphite-NaNO3-KMnO4-H2SO4 system (a);Suspension of graphite oxide (b); Obtained graphene oxide gel by sonification of graphite oxide (c).

nano-sized particles are generated [10]. By Solution Combustion Synthesisoxide powdery composites á-Al2O3ZrO2(5-20%)-Y2O3, ZrO2-á-Al2O3(10-30%)-Y2O3, á-Al2O3MgAl 2O 4and others were synthesized. MgO, Y 2 O 3 , ZrO2were included in reaction mixture in different compounds. It is established by SEM microscopes that sizes of primary crystals of powders are within 50-300 nm and they generate large sized easily breakable agglomerates.

An intensive research in the production of graphenereinforced composites is currently under way. A singlelayer carbon atom (2D structure, sp2 hybridization) consisting of six-member cycles is the strongest and lightest in comparison with all the currently known materials, has an enormous tensile strength ∼1000 GPa. By combining the unique properties of fragile ceramics and graphene, the production of promising engineering material is possible. The graphite, graphene and reduced graphene oxide functional groups (-OH, -COOH, -O-O-, etc.) and the alumina surface OH groups will easily react with trialkylaluminumor aluminum isopropoxide these two components being linked by-O-Al–O- bonds. Thus, in producing a compacted powder composite, organic-inorganic hybrid

powdery composite [Al2O3]–[grapheneoxide] based on alumina and graphene oxide, which were connected with chemical -C-O-Al- bonds.Three-component powdery composite á-Al2O3-WC-Y2O3 has obtained by a combustion reaction and grinding in nano mills.

Acknowledgements The financial support of Shota Rustaveli National Science foundation Grant ¹30/36 is gratefully acknowledged.

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fxvnilovani kompozitebi matriculi keramikebisaTvis T. kuWuxiZe1, n. jalabaZe3, g. qvarcxava3, o. lekaSvili2, n. jalaRonia1, r. Wedia1,2 1

ilia vekuas soxumis fizika–teqnikis instituti, mindelis q. 7, 0186, Tbilisi, saqarTvelo 2 ivane javaxiSvilis saxelobis Tbilisis saxelmwifo universiteti, p. meliqiSvilis fizikuri da organuli qimiis instituti, jiqias q. 5, 0186, Tbilisi, saqarTvelo 3 saqarTvelos teqnikuri universiteti, kostavas q. 77, 0175, Tbilisi saqarTvelo el–fosta: sipt@sipt.org mocemul naSromSi Seswavlilia oqsiduri matriculi (Al2O3, ZrO2) fxvnilovani kompozitebis miReba, romlebic Seicaven sxvadasxva tipis gamaZlierebel komponentebs, rogorcaa oqsidebi, karbidebi, oqsinitridebi da sxv. fxvnilovani kompozitebis misaRebad gamoyenebul iqna zol–gel meTodi, TviTganviTarebadi Jangva–aRdgenis, komponentebis erTdrouli sinTezisa da meqanoqimiuri meTodebi. miRebulia grafenis oqsidis (0.5– 2%) Semcveli dasawnexi fxvnilovani kompozitebi aluminis oqsidis fuZeze. Seswavlilia aluminis metastabiluri oqsohidroqsidebis dabaltemperaturuli transformacia sxvadasxva dopantebisa da gamaZlierebeli komponentebis Tanaobisas.

CONTENTS – ÑÎÄÅÐÆÀÍÈÅ À. Ãóëäàìàøâèëè - Îñíîâíûå ýòàïû ðàçâèòèÿ èîííîé èìïëàíòàöèè â Ñóõóìñêîì ôèçèêî-òåõíè÷åñêîì èíñòèòóòå èì. È. Âåêóà .............................................................……………………………......................……………………......... 5 L. Anatychuk - Historical aspects, state of the art and trends of further development of thermoelectricity ……...... 10 F. Marquis, G. Bokuchava - The Physics of Carbon Nanotube Nanofluids and Nanostructured Materials for Multifunctional Applications ......................................................................................................………………………….......... 19 M. Torikachvili - High-pressure studies of novel superconducting and magnetic materials ….......................…........... 24 I. Kurashvili, G. Darsavelidze - Mechanical relaxation processes in monocrystalline Si-Ge alloys .……………............ 28 E. Sanaia, G. Bokuchava, R. Chedia - Synthesis and Consolidation of Superconductor Magnesium Diboride ....... 31 Z. Guguchia, R. Khasanov, Z. Bukowski, A. Shengelaya, H. Keller, A. Amato, E. Morenzoni - Hydrostatic Pressure Effects on the Superconducting Gap Symmetry in the Iron-based Superconductor Ba1-xRbxFe2As2 ……… 36 L. Chkhartishvili, R. Becker, R. Avci - Relative stability of quasi-planar boron clusters …............................................. 42 Ç. Äæèáóòè, Ä. Äàðàñåëèÿ, Ä. Äæàïàðèäçå , À. Øåíãåëàÿ - Îðèãèíàëüíàÿ òåõíîëîãèÿ áûñòðîãî ñèíòåçà ñïîìîùüþ ôîòîííîãî îáëó÷åíèÿ äëÿ ñîâðåìåííûõ ìàòåðèàëîâ ………………………………………………………............ 47 E. Kutelia, G. Kvinikadze, E. Sanaia, T. Dzigrashvili - Efficiency of application of super-pure gallium (≥7N+) obtained by membrane technology for production of high quality GaAs single crystals ……...................................... 52 I. Metskhvarishvili, G. Dgebuadze, B. Bendeliani, V. Gabunia - Influence of fifth group elements on superconductive properties of high temperature superconductors ……………….............................................................. 55 V. Kulikauskas, V. Zatekin, V. Privezentsev, V. Zinenko, Yu. Agafonov, V. Egorov, E. Steinman, A. Tereshchenko - Investigation of SiO2/Si Structure Combine Implanted by Zn+ and O+ Ion .................……………………………………...... 60 Í. Äîëèäçå, Ç. Äæèáóòè, Ì. Òèãèøâèëè, Í. Õó÷óà, Ð. Ìåëêàäçå, Í. Ãàïèøâèëè - Âëèÿíèå ñïåêòðàëüíîãî ñîñòàâà ñâåòà íà ôîòîýëåêòðè÷åñêèå ñâîéñòâà èîííîëåãèðîâàííîãî Êðåìíèÿ ………………………….................... 63 Í. Êåêåëèäçå, Ä. Êåêåëèäçå, Å. Õóöèøâèëè, Á. Êâèðêâåëèÿ, Ë. Íàäèðàäçå, È. Àìáîêàäçå, Ã. Êåêåëèäçå Òåõíîëîãèÿ ñîçäàíèÿ ðàäèàöèîííî-ñòîéêèõ ìàòåðèàëîâ ………................................................................………...... 68 T. Paghava, M. Metskhvarishvili, M. Beridze, I. Kalandadze, M. Kvirikashvili - Investigation of n-Si crystals irradiated by high-energy protons through the Photo-Hall method ……………............................................................... 71 T. Paghava, M. Metskhvarishvili, M. Beridze, I. Kalandadze, M. Kvirikashvili - Growth Defects Radiation Annealing in n-Si crystals received by the zone meltingmethod …………….................................................................... 75 À. Òóòóíäæÿí - Ïîëóïðîâîäíèêîâûå ñòðóêòóðû äëÿ íèçêîòåìïåðàòóðíûõ ïåðåêëþ÷àòåëåé íà îñíîâå ãåðìàíèÿ, ëåãèðîâàííîãî ìíîãîçàðÿäíîé ïðèìåñüþ çîëîòà è ñóðüìîé …………................................................... 79 È. Òàáàòàäçå, Ì. Êàäàðèÿ, Ã. ×óáèíèäçå, Ë. Ãàïèøâèëè, Ò. Ìåëàøâèëè, Ê. Êîìàõèäçå - Âëèÿíèå îáëó÷åíèÿ èîíàìè àðãîíà íà ýëåêòðîôèçè÷åñêèå õàðàêòåðèñòèêè ïîäëîæåê Si-Ge …………………………………………….......... 83 E. Khutsishvili, N. Khutsishvili, L. Gabrichidze, N. Kobulashvili, N. Kekelidze - Removal of Impurities from Metallurgical Silicon ……………………………………………………………........................................................................................ 86 Ø. Ìàõìóäîâ, Ø. Ìàõêàìîâ, À. Ñóëàéìàíîâ, À. Ðàôèêîâ, Ê. Áåêìàòîâ, Õ. Ýðãàøåâ - Âëèÿíèå êîíöåíòðàöèè áîðà íà âðåìÿ æèçíèíîñèòåëåé çàðÿäà âíåéòðîííî-ëåãèðîâàííîì êðåìíèè ..…………….......... 90 Ò. Ïàâëèàøâèëè, À. Òóòóíäæÿí, Ã. Öåðöâàäçå - Îñàæäåíèå ïîðèñòûõ ïëåíîê äèîêñèäà êðåìíèÿ çîëü-ãåëü ìåòîäîì ……………………..........................................................................................……………………………………………… ....... 93 A. Bibilashvili, S. Sikharulidze, Z. Kushitashvili, L. Jangidze, L. Jibuti - Development of technology receiving thin dielectric layers for micro and nanoelectronics ……………….......................................................................……….... 96 À. Ñè÷èíàâà, Þ. Íàðäàÿ, Í. Ãàïèøâèëè, Ã. Àð÷óàäçå, Ö. Íåáèåðèäçå, Î. Êàøèÿ - Èññëåäîâàíèå ìåõàíè÷åñêèõ ñâîéñòâ ìîíîêðèñòàëëè÷åñêèõ ñïëàâîâ Si1-õGeõ(õd”0,02) ……....................................................... 101 Ë. Íàäèðàäçå, Á. Êâèðêâåëèÿ, Å. Õóöèøâèëè, Ä. Êåêåëèäçå, Ã. Êåêåëèäçå, Í. Êåêåëèäçå - Èññëåäîâàíèå îïòè÷åñêîãî ïîãëîùåíèÿâ ñîåäèíåíèÿõ III-V …………………………............................................................................... 106 Ê. Áàðáàêàäçå, Ì. Áèëèñåèøâèëè, Ç. Èñàêàäçå, ß.Òàáàòàäçå, Â. Ãàáóíèÿ, À. Êóöèÿ, Ì. Áàðáàêàäçå, Ì. Ðåõâèàøâèëè - Ðàçðàáîòêà òåðìîýëåêòðè÷åñêèõ ñïëàâîâ Si0,95Ge0,05 n-è p-òèïà è ñîçäàíèå íà èõ îñíîâå òåðìîýëåêòðè÷åñêîé áàòàðåé, ðàáîòàþùåé íà âîçäóõå äî òåìïåðàòóðû 10000C ..............………………………...... 110

À. Æóðàâëåâ, Á. Øèðîêîâ, À. Øèÿí, Ã. Áîêó÷àâà, Ã. Äàðñàâåëèäçå - Ãàçîôàçíûå ìåòîäû â ðàçðàáîòêàõ òåðìîýëåêòðè÷åñêèõ ïðåîáðàçîâàòåëåé è ãåòåðîýïèòàêñèàëüíûõ ñòðóêòóð ...............…………………………........... 115 V. Lysko - Metrology of thermoelectric materials ……………………………………………………………………………...................... 120 M. Nadareishvili, T. Gegechkori, G. Mamniashvili, T. Zedginidze, T. Petriashvili - Study on the Possibilities for Changing the Absorption Spectra of Photocatalytic TiO2 Nanopowders with the Aim of Improving Their Efficiency ……………………………….........................................................................................................………………............... 125 Ô. Áàñàðèÿ, È. Òàáàòàäçå, Ì. Ðåõâèàøâèëè - Ïîëó÷åíèå è èññëåäîâàíèå ìàòåðèàëîâ àíòèñóáëèìàöèîííîé çàùèòû ñðåäíåòåìïåðàòóðíûõ âåòâåé òåðìîýëåìåíòîâ è òåðìîáàòàðåéíà îñíîâå ñïëàâîâ PbTe è GeTe …………………………………………………................................................................................................. 128 Ã. Áîêó÷àâà, À. Ñè÷èíàâà, È. Êóðàøâèëè, Í. Ãàïèøâèëè, Ã. Äàðñàâåëèäçå, Á. Øèðîêîâ, Í. Ñåì íîâ Èññëåäîâàíèå ñïåêòðîâ ôîòîýëåêòðè÷åñêîé ÷óâñòâèòåëüíîñòè â áëèæíåì äèàïàçîíå èíôðàêðàñíîãî èçëó÷åíèÿ p-n ñòðóêòóð, ñôîðìèðîâàííûõ íà ïîäëîæêàõ Si-Ge .................…………………………………………............ 132 K. Saritas, K. Thiessen - Photovoltaics - Research and Application at the Science and Technology Park Berlin Adlershof ………………………………………………………………………………….................................................................................. 135 Z. Vardosanidze, G. Bokuchava, T. Sulaberidze, V. Kuchukhidze, D. Berishvili - For holographic raster concentrator photodiode matrix …………………………………………………………...................................................................... 139 V. Lysenko, S. Kondratenko, Ye. Melnichuk, V. Lobanov, M. Terebinska, Yu. Kozyrev - Photoelectric properties of Si/Geheterostructures with nanoscale objects ................................................................…………………………………...... 143 Ê. Êîáàõèäçå, Í. ×õåíêåëè - Ðàçâèòèå íàïðàâëåíèÿ ïðåîáðàçîâàòåëåé ýíåðãèé íà áàçå ïîëóïðîâîäíèêîâûõ p-n ïåðåõîäîâ ………………………………………………....................................................................... 148 N. Chikhradze, G. Abashidze, M. Chikhradze - Bulk nanocomposites by adiabatic explosion consolidation of powders ………………………………………………………………......................................................................................................... 153 P. Kervalishvili, V. Labunov, E. Hristoforou, M. Mostafavi, P. Oliveira, P. Yannakopoulos - Boron isotope enriched graphene based neutron sensors …………………………………................................................................................. 158 A. Gerasimenko, L. Ichkitidze, V. Podgaetsky, S. Selishchev - Mechanical Properties of the Bulk Nanobiomaterial ................................................................................................................................................................. 163 È. Ñàäûêîâ, Ó. Ñàëèõáàåâ - Íåéòðîííî-àêòèâàöèîííûé àíàëèç îñîáî ÷èñòûõ ìàòåðèàëîâ â èíñòèòóòå ÿäåðíîé ôèçèêè ÀÍ Ðóç ……………………........................................................……………………………………......................... 167 A. Ugulava, S. Chkhaidze, Sh. Kekutia, M. Verulashvili - Determination of the magnetic anisotropy constant of nanoparticles using measurements of the low-temperature heat capacity ………………………………………....................... 171 Ð. Ìåëêàäçå, À. Äèäåáàøâèëè, Ã. Êàëàíäàäçå, Ã. Ïåðàäçå, Ò. Ìàêàëàòèÿ, Ç. ×àõíàêèÿ, Ê.×èòàÿ Íàíîãåòåðîñòðóêòóðû äëÿ ðåíòãåíîâñêèõ ñåíñîðîâ ……………………………………....................................................... 176 L. Gurchumelia, F. Bejanov, M. Tsarakhov, Z. Khutsishvili, D. Nadareishvili - Development of technology for production of new types, eco-safe, composite fire-extinguishing and fire-protective materials …………..................... 180 Ts. Gagnidze, R. Chagelishvili, N. Chavtasi - Nontraditional methods of recovery of gold from antimony ores and contrates ………………………................................................................................................................................... 184 M. Mostafavi, A. Tadjeddine,Ch. Humbert, P. Kervalishvili, T. Bzhalava, V.Kvintradze, M. Tsirekidze, G. Kakabadze, T. Berberashvili - Studying Physical Characteristics of Nano-Bio-Materials for Sensory Application ....... 188 À. Ñàòòèåâ, Ø. Ìàõêàìîâ, Ì. Êàëàíîâ,Ì. Ýðäîíîâ, Â. Ðóñòàìîâà, Ñ. Áàêèåâ, Õ. Õîëìåäîâ – Ìåäüêèñëîðîäíûå ïðåöèïèòàòû â íåéòðîííî-òðàíñìóòàöèîííîì êðåìíèè …….......................................................... 193 Ó. Êóðáàíîâ, Ç. Õóäàéáåðäèåâ, Ý. Êàðèìáàåâ, Ñ. Äæóìàíîâ - Âîçìîæíûå ìåòàëë-äèýëåêòðèê ïåðåõîäû è íàíîðàçìåðíîå ðàçäåëåíèå ôàç â äûðî÷íî-ëåãèðîâàííûõ êóïðàòàõ …................................................................. 195 À. Áèáèëàøâèëè, Ð. Ãóëÿåâ, Í. Äîëèäçå, Ã. Ñõèëàäçå, Ç. Äæèáóòè - Íèçêîòåìïåðàòóðíûé ìåòîä ïîëó÷åíèÿ íàíîïë íîê GaN ……………………………………………............................................................................................................. 200 D. Kakulia, A. Tavkhelidze, V. Gogoberidze, M. Mebonia - Physical properties of nanograiting layers ….................. 204 R. Chedia, T. Kuchukhidze, G. Bokuchava, A. Khvadagiani, V. Gabunia, N. Jalagonia - Fabrication and Study of Alumina Based Matrix Composite Ceramics ……………………............................................................................................ 208 T. Marsagishvili, G. Mamniashvili,G. Tatishvili, N. Ananiashvili, M. Gachechiladze, J. Metreveli - Study of temperature dependence of some physical characteristics of electrolytic nickel coatings on copper ……................ 212

N. Jalagonia, Ts. Ramishvili, I. Jinikhashvili, Q. Sarajishvili, T. Korkia, Z. Amiridze, R. Chedia - Impregnation of Iron (II, III) Compounds in Wood and Their Reduction till Nano Zero-valent Iron ………………................................. 216 Ç. Äæàáóà, À. Ãèãèíåèøâèëè - Ïðèãîòîâëåíèå è ìåõàíè÷åñêàÿ ïðî÷íîñòü ïë íîê íåêîòîðûõ ñîåäèíåíèé ðåäêîçåìåëüíûõ ýëåìåíòîâ ………………………………………................................................................................................ 221 A. Peikrishvili, G. Mamniashvili, T. Gegechkori, B. Godibadze, E. Chagelishvili, M. Tsiklauri, A. Dgebuadze Liquid-phase explosivefabrication of superconducting MgB2 composites ................................................................... 225 V. Vardanyan, V. Avagyan - Investigation and Design of Metal to Ceramic Bonding Technologies for Particle Accelerator’s Vacuum RF Window …………………………………………………........................................................................... 230 J. Aneli, L. Nadareishvili, M. Bolotashvili - Functionally graded polymer composites with electric and magnetic properties …………………………………………………………………………........................................................................................... 236 M. Avaliani - General Overview of Synthesis and Properties of a New Group of Inorganic Polymers Double Condensed Phosphates ………………………………………………………........................................................................................ 240 R. Tushurashvili, D. Chorgolashvili, T. Khuchua, N. Kobaladze, M. Alelishvili, E. Gelashvili - Utilization of scrap tires by low-temperature pyrolysis and investigation of obtained Products …………………….......................................... 246 S. Hayrapetyan, E. Alvarenga, L. Hayrapetyan, S. Gevorgyan, G. Pirumyan, B. Salbu – Manganese Dioxide (MnO2) – Containing Composite Sorbents ……………………………….................................................................................. 249 J. Aneli, N. Bakradze, T. Dumbadze - Effect of Laser Radiation on the Electric Conducting and Magnetic Properties of Polymer Materials Surfaces ………………………………………….......................................................................... 725 Ý. Èáðàãèìîâà, Ø. Ìàëèêîâ, Â. Ïèêóëü, Ì. Þëäàøåâ, Â. Ñàíäàëîâ, Ý. Þñóïîâ, Õ. Õàìèäîâ Ïåðñïåêòèâíûå Ìàòåðèàëû, Ïîëó÷åííûå Ñåïàðàöèåé Óãîëüíîé Çîëû ……………............................................... 260 A. Guldamashvili, N. Kutsia, Yu.Nardaya, Ts. Nebieridze, A. Sichinava - Surface Modification of AISI 310 and 440C Steels by Ion Implantation ………………………............................................................................................................ 263 Ã. Äãåáóàäçå - Êðèîãåííûå âàêóóìíûå òåõíîëîãèè - äîñòèæåíèÿ è ïåðñïåêòèâû ……......................................... 268 R. Shamugia - Estimator Model for Time Redundancy Influence on Task Feasibility in a Technical System with Subsystems for Detection of Servicer Failures and Their Recovery ……………………………….......................................... 273 V. Kirtskhalia - Influence of Earth’s gravitational field on the thermodynamic characteristics of ideal gases ......... 277 T. Chelidze, L. Enukidze, M. Chankashvili, T. Loladze - Animal hair as biological indicator for heavy metal pollution in the two regions of Georgia ……………………………………................................................................................... 283 Ì. Âàòèàøâèëè, Ó. Äçîäçóàøâèëè, È. Äæàíåëèäçå - Ðîëü ìîðñêèõ õëîðèäîâ â ôîðìèðîâàíèè îáëà÷íûõ ÷àñòèö ðàçëè÷íîé ôàçîâîé ñòðóêòóðû ïðè èñêóññòâåííîì óâåëè÷åíèè îñàäêîâ è âîçäåéñòâèè íà ãðàäîâûå ïðîöåññû ………………………………....................................................................................................................... 286 Ä. Ïàòàðèäçå, Ì. Êâèíèêàäçå, Ä. Êóïàðàäçå, Â. Êèðàêîñÿí, Í. Õóíäàäçå - Ðàäèàöèîííàÿ ýêîëîãèÿ òåððèòîðèè çàïàäíîé Ãðóçèè ………………………………………............................................................................................. 290 Sh. Jafaridze, R. Gigauri, N. Bichiashvili - Arsenic-Containing Ore Production Waste Monitoring and Possibilities of Remediation in Racha-Svaneti Regions of Georgia ........................................................................ 295 O. Kutsnashvili, O. Tsiklauri, A. Chirakadze, L. Ghurchumelia, K. Chigogidze, G. Chiradze - Geopolitical Changes and New Ecological Challenges in the Context of Management of the Industrial and Municipal Waste in the Post Soviet Space. Prospective of “green” utilization of agricultural waste in Georgia ……………………........... 297 M. Kozhevnikova, V. Levenets, I. Rolik, V. Voyevodin - Detection of the source of radioactive contamination in the NPP region …………………………………………………............................................................................................................ 301 R. Odoh, O. Oko, M. Dauda - An Assessment of Trace Heavy Metal Contamination of Some Edible Oils Regularly Marketed in Benue and Taraba States of Nigeria ………………………….............................................................. 306 A. Gevorgyan, V. Avagyan, A.Simonyan, V. Dekhtiarov, V. Danielyan, T. Mkrtchyan, V. Vardanyan - Design & fabrication of the experimental diffusion welding machine ……………............................................................................. 311 T. Kuchukhidze, N. Jalabadze, G. Kvartskhava, O. Lekashvili, N. Jalagonia, R. Chedia - Powdery composites for matrix ceramics ………………………………………………………...................................................................................................... 314