1999 Fiscal Year Final Research Report Summary
Low temperature growth of GaN single crystals using a Na metal flux
| Project/Area Number |
09555274
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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 | 展開研究 |
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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 Institute for Advanced Materials Processing, Tohoku University, Associate Professor, 素材工学研究所, 助教授 (20191364)
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| Co-Investigator(Kenkyū-buntansha) |
OKABE Toru Institute for Advanced Materials Processing, Tohoku University, Research Associate, 素材工学研究所, 助手 (00280884)
KUBOTA Shun-ichi Institute for Advanced Materials Processing, Tohoku University, Research Associate, 素材工学研究所, 助手 (10271975)
ENDO Tadashi Graduate School of Engineering, Tohoku University, Professor, 工学部, 教授 (30176797)
SOMENO Yoshihiro Tohoku Alps Co. Ltd., Researcher, 電子部品事業本部, 研究開発職
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| Project Period (FY) |
1997 – 1999
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| Keywords | gallium nitride / single crystals / flux growth / crystal growth / crystal structure / X-ray diffraction / cathodoluminescence / sodium melt |
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| Research Abstract |
Wurtzite-type hexagonal GaN single crystals were obtained at 650 - 840℃ for 72 - 300 h in a sealed stainless-steel tube container, using Ga, NaNィイD23ィエD2 and Na as starting materials. GaN formation finished within 24 h at 840℃. In the samples heated at lower temperatures for 24 h, Ga-Na intermetallic compound, GaィイD239ィエD2NaィイD222ィエD2, covered with a GaN layer, precipitated at the bottom of the stainless-steel tube. Longer reaction time was needed to accomplish the nitridation of Ga at these conditions.
The GaN single crystals were deposited in the region of 2 cm from the bottom of the stainless-steel tube container. The GaN single crystals grown in the upper half part of the region were platelet with amber color or colorless. The maximum size of the crystals is about 2 mm. They grew perpendicular to the tube wall. In the lower part, the crystals were dark yellow and pyramidal or prismatic, having a size of 0.4 - 0.7 mm. The pressure of NィイD22ィエD2 in the sealed stainless-steel tube container decreased during the formation of GaN. The morphology change suggested that the NィイD22ィエD2 pressure approached an equilibrium partial pressure of NィイD22ィエD2 for GaN formation.
Electron microprobe analysis did not detect any impurity elements in the crystals. The near band-edge emission of GaN was observed at 363 mm by cathodoluminescence spectroscopy. The colorless transparent platelet single crystals prepared at 650℃ for 300 h exhibited the sharpest peak with strongest intensity. This revealed that the crystals with a good quality grew at lower temperature and at a slow growth rate.
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Research Products
(17 results)
