狭バンドギャップ3元混晶半導体鉛錫テルル単結晶の無重力下における結晶成長

• 資料種別: 規格・テクニカルリポート類
• タイトル: 狭バンドギャップ3元混晶半導体鉛錫テルル単結晶の無重力下における結晶成長
• 著者・編者: 山田, 智秋; 木下, 恭一; Yamada, Tomoaki; Kinoshita, Kyoichi
• 著者標目: 山田, 智秋; 木下, 恭一; Yamada, Tomoaki; Kinoshita, Kyoichi
• 出版事項: 宇宙開発事業団
• 出版年月日等: 1994-10-20
• 出版年（W3CDTF）: 1994-10-20
• 並列タイトル等: Crystal growth of narrow band gap ternary mixed semiconductor PbSnTe single crystal in space
• タイトル（掲載誌）: 宇宙開発事業団技術報告
• 掲載ページ: 431-467
• ISSN（掲載誌）: ISSN : 1345-7888
• 本文の言語コード: jpn
• 件名標目: 狭バンドギャップ半導体; 3元混晶半導体; PbSnTe単結晶; 微小重力環境; 結晶成長; 温度勾配; 1方向凝固法; マランゴニ対流; 熱輸送; 気泡内在; 介在物; 組成均一性; モル分率; 転位密度; 電気伝導度; narrow band gap semiconductor; ternary mixed crystal semiconductor; PbSnTe single crystal; microgravity environment; crystal growth; temperature gradient; unidirectional solidification; Marangoni convection; heat transport; bubble internals; inclusion; composition homogeneity; mole fraction; dislocation density; electrical conductivity
• 対象利用者: 一般
• 一般注記: Crystal growth of Pb(1-x)Sn(x)Te was conducted by unidirectional solidification technique using temperature gradient furnace under microgravity environment in space shattle. Single crystal was made by using a seed crystal maintaining temperature more than 40 C/cm and 5.5 mm/h of solidification speed. Diminishing free surface of melts by pressing melts to seed crystal with a spring made of graphite and a push-plate made of boron nitride, suppression of Marangoni convection was attempted. 15 mm in diameter and 58 mm in length of cylindrical crystal was obtained from the experiment. In this crystal, position of solid-liquid interface at initiation of crystal growth moved to high temperature side by about 10 mm compared to ground crystal growth, and a small amount of seed crystal was fused. It is suggested from the results that suppression of heat transport due to convection is made under microgravity environment. Crystal grown under microgravity has locally ununiform composition. That is, some big bubbles internally presents, and linear vacancies or Sn surplus inclusions are observed around the bubbles. At location where no bubbles present, however, composition homogeneity of space grown crystal was remarkably improved compared with ground grown crystal. That is, beside composition homogeneity along growth axis was improved, 0.16 of constant region of SnTe mole fraction was obtained over about 10 mm ranging from 33 mm to 43 mm in length. Further, dislocation density decreased from 3x10(exp 6) per sq cm of mean value of ground grown crystals to 5x10(exp 5) /sq cm. Moreover, on electrical properties, homogeneous composition area of space grown crystal showed high electron mobility more than two times of ground grown crystal. These phenomena suggest that thermal convection suppression is effective under microgravity. In this flight experiment, it was found that several tens of spherical crystals having 0.5 - 11 mm in diameter had grown on springs or among gap of springs. It is because the springs provided space for growth of spherical crystal and place for nucleation. It is guessed that raw material of spherical crystal was carried from reservoir of melts to spring chamber through small gap (approximately 0.1 mm) between BN crucible and push-plate. Further, it is guessed from the experimental procedures that these spherical crystals grew during cooling after end of unidirectional solidification and growth rate was rapid. And, it is high growth rate why enough crystal habit did not develop and Sn surplus inclusions were partially observed. However, dislocation density of some small crystals is order of 10(exp 4) /sq cm, and it is as low as factor of two compared to ground grown crystal. It is considered as reason that spherical crystal did not suffer mechanical stresses from container wall because of growth without contact of spherical crystal to container wall.; 資料番号: AA0004116001; レポート番号: NASDA-TMR-940002 V.2
• オンライン閲覧公開範囲: インターネット公開
• 掲載誌（NCID）: AN00364784; https://ci.nii.ac.jp/ncid/AN00364784
• 連携機関・データベース: 国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）; https://irdb.nii.ac.jp
• 提供元機関・データベース: 宇宙航空研究開発機構 : 宇宙航空研究開発機構リポジトリ

• 要約等: スペースシャトル内の微小重力環境下において、Pb(1-x)Sn(x)Te結晶を温度勾配炉を用いた1方向凝固法により育成した。温度勾配は40度C/cm以上、固化速度は5.5mm/hで、種子結晶を使用し、単結晶化を図った。グラファイト製のバネと窒化ホウ素製の押圧板により融液を種子結晶側に押し付け、融液の...