1996 Fiscal Year Final Research Report Summary
A research on full-color LED using UV light emitting devices
| Project/Area Number |
07555102
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 試験 |
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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 |
SAKAI Shiro The Univ.of Tokushima, Faculty of Eng.Professor, 工学部, 教授 (20135411)
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| Co-Investigator(Kenkyū-buntansha) |
YUASA Takayuki Sharp Cent.Res.Lab., Senior Researcher, 第一研究部, 副主任
NAOI Yoshiki The Univ.of Tokushima, Faculty of Eng.Lecture, 工学部, 講師 (90253228)
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| Project Period (FY) |
1995 – 1996
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| Keywords | GaN / InGaN / Bulk GaN / MOCVD / LED / Semiconductor lasers / Homoepitaxy / Dislocation |
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| Research Abstract |
Although a blue-to UV nitride light emitting devices are realized, many problems still remain unsolved. The LED is most commonly fabricated by growing InGaN/AlGaN double-heterostructure on sapphire substrate by MOCVD technique. However, the growth critically depends on the substrate annealing prior to the growth and the deposition conditions of the low-temperature buffer layrs making the growth extremely difficult. In addition, the misfit dislocation was recently shown to work as a non-radiative recombination center. Therefore, the elimination of the dislocation can substantially improve LED efficiency and lower the threshold current of the lasers. In this research, the growth of bulk GaN and a homoepitaxy by MOCVD were tried and investigated in detail. The following topics were investigated.
1.Growth of thick GaN and bulk GaN by sublimation method : A GaN with a thickness of several tens of mum to several hundred of mum on sapphire and a bulk GaN with the size of several hundreds of mum to several mm were obtained. A technique to grow bulk GaN in the selective area on the substrate was developed, and the device processing of the bulk GaN became possible.
2.Growth of InGaN on sapphire : GaN and InGaN films were grown on sapphire by MOCVD,and the layrs were characterized. Especially, the formation mechanism of the inhomogeneity in InGaN was investigated in detail.
3.Homoepitaxial growth : GaN and GaN/InGaN double-heterostructure were grown on bulk GaN by MOCVD and the grown layrs were characterized. It wasfound that the growth mode on the bulk substrate was very different of that on the sapphire substrate.
Above research results provided the basis for fabricating super-high-efficiency-LED and nitride lasers on a bulk GaN substrate.
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