| Project/Area Number |
18560308
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Electronic materials/Electric materials
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| Research Institution | The University of Tokushima |
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Principal Investigator |
NISHINO Katsushi The University of Tokushima, Institute of Technology and Science, Graduate School, Associate Professor (70284312)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Shiro The University of Tokushima, Institute of Technology and Science, Graduate School, Professor (20135411)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,940,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥540,000)
Fiscal Year 2007: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | AlGaN / GaN / Direct Synthesis Method / Bulk growth / MOCVD / UV-LED / バルク / 基板 |
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| Research Abstract |
In this research project, we tried to grow thick AlGaN, which can be used as substrates for epitaxy of AlGaN. If AlGaN substrates are obtained, AlGaN epitaxial growth in lattice-matched system becomes possible and light absorption in the substrate is much reduced for UV-light emitters.
The growth method is the direct synthesis method(DSM).In DSM, metal Ga and NH_3 is used as sources. Trymethylaluminum (TMA) was added for AlGaN growth. GaN template grown by MOCVD on c-plane sapphire was used as a substrate.
As the result of growth, AlGaN of about 20 μm thick with a few percent of Al content was obtained in 1-hour growth. The surface was smooth. At higher growth temperature, AlGaN with about 20% of Al content was obtained, but the surface was very rough and the crystallinity was not good for the use as a substrate.
At the same time, some investigations for UV-LEDs were carried out on MOCVD-grown AlGaN on sapphire. We found that edge dislocations and mixed dislocations with edge component affect the light intensity of the UV-LEDs more than the other dislocations. Also, we confirmed that the AlGaN-based UV-LEDs had higher light intensity than the GaN-based LEDs for the same crystallinity.This is because GaN absorbs UV-light but AlGaN does not absorb.
Configuration of the p-type electrodes was investigated. In some configurations, light intensity was reduced due to the generation of heat. The radiation of heat is important.
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