| Project/Area Number |
13450355
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
無機工業化学
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| Research Institution | Tohoku University |
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Principal Investigator |
YAMANE Hisanori Tohoku University, Center for Interdisciplinary Research, Professor, 学際科学国際高等研究センター, 教授 (20191364)
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| Co-Investigator(Kenkyū-buntansha) |
SARAYAMA Seiji Ricoh Company, Ltd., R & D Center, Research and Development Group, Chief Researcher, 応用電子研究所・オプトデバイス開発センター, 主席係長研究員
KUBOTA Shunichi Tohoku University, Institute for Multidisciplinary Research for Advanced Materials, Research Associate, 多元物質科学研究所, 助手 (10271975)
SHIMADA Masahiko Tohoku University, Institute for Multidisciplinary Research for Advanced Materials, Professor, 多元物質科学研究所, 教授 (80029701)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥13,700,000 (Direct Cost: ¥13,700,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2002: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 2001: ¥9,100,000 (Direct Cost: ¥9,100,000)
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| Keywords | Gallium nitride / zinc-blende-type structure / Flux method / K melt / Cathodoluminescence / Crystal growth / Solution growth / Crystal morphology / 金属ナトリウム融液 / 立方晶閃亜鉛鉱型 / 反応容器 / 立方晶窒化ガリウム / 金属カリウム融液法 |
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| Research Abstract |
Gallium nitride, having the hexagonal wurtzite-type structure (h-GaN), has attracted an interest as a material for blue-light emitting diodes and short-wavelength laser diodes. GaN has a polymorph of the cubic zinc-blende-type structure (c-GaN), hut the detail properties on the c-GaN have not been clarified due to the lack at bulk c-GaN single crystals.
In the present study, granular and platelet GaN crystals were prepared at 700℃ for 24 h and 7 MPa of N_2 by using a K flux. The platelet crystals of h-GaN with a size of about 1 mm were obtained at the vapor-liquid interface. The granular crystals with a size of 50 μm were characterized as a mixture of c-GaN and h-GaN. Rietveld analysis revealed that granular crystals contain 40% of c-GaN. The granular crystals of 30 μm containing 95% of c-GaN were obtained at 600℃,24 h and 7 MPa of N_2. The size of the granular crystals of 70% c-GaN, prepared at 700℃, 24 h and 4 MPa of N_2 was about 60 μm. The formation of c-GaN increased with decreasin
… More
g temperature and N_2 pressure.
The granular crystals having the maximum size of 200 μm was obtained at 700℃, 96 h and 4 MPa of N_2. A colorless transparent c-GaN crystal with a size of 80 μm was picked up in the sample synthesized at 650℃,96 h and 4 MPa of N_2. Square facets of (100) phase and steps of equilateral triangle shape of (111) phase, reflecting the threefold-axis symmetry of cubic structure, were observed. A peak from near band-edge emission of c-GaN at 3.209eV observed in the cathodoluminescence spectrum of the c-GaN crystal was consistent with the results reported for c-GaN thin films. The half-value width of the peek was 76 meV.
Granular and platelet GaN crystals were also synthesized by using a K-Na flux. However, the ratio of c-GaN is the granular or plates prepared with the K-Na flux was smaller than that prepared with the K flux. No crystal was obtained from K-Ga melt in a W crucible at 650 -680℃ and 4 -7 MPa of N_2. Granular crystals with a size of 40 μm were obtained from partial melt of K-Ga intermetallic compounds at 610 -630℃. Less
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