Study of the Optical Processes in Nitride Alloy Semiconductors
| Project/Area Number |
18540320
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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 |
Condensed matter physics I
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| Research Institution | Wakayama University |
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Principal Investigator |
SHINOZUKA Yuzo Wakayama University, Faculty of Systems Engineering, Professor (30144918)
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| Co-Investigator(Kenkyū-buntansha) |
UNO Kazuyuki Wakayama University, Faculty of Systems Engineering, Associate Professor (90294305)
KAN'NO Ken'ichi Wakayama University, Faculty of Systems Engineering, Professor (80024339)
秋元 郁子 和歌山大学, システム工学部, 講師 (00314055)
越野 和樹 和歌山大学, システム工学部, 助手 (90332311)
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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 |
¥3,890,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥390,000)
Fiscal Year 2007: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2006: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | alloy semiconductor / superlattice / quantum well / III-V compound / CPA / ESR / exciton / nitride / 超格子半導体 |
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| Research Abstract |
1. The optical absorption spectrum of a binary alloy semiconductor A_<1-x>B_x were studied by coherent potential approximation (CPA) . A tight binding model is used for a Frenkel exciton in the presence of the diagonal and off-diagonal randomness. The effects of the randomness are respectively included as the potential part Σ (E) and the amplitude part Γ(E), which are shown to relate to the coherent locator L (E) by Shiba (Prog. Theor. Phys. 46, 1971, 77) as L(E) = (E-Σ(E)) /Γ(E) . The average Green's function with Σ (E) and Γ (E) , is self-consistently determined. The obtained CPA equations were applied to a 3dim. bulk system with a simple band structure and also to quantum well systems.
2. Local atomic configurations of GaInNAsSb alloys has been investigated using extended X-ray absorption fine structure spectroscopy. Due to its small composition of Sb, there was a difficulty in the analysis of the experimental data. Upgrading the background removable technique, the difficulty has been successfully solved. A first trial of a prediction of Raman scattering simulation has been also investigated using ab initio calculations. The results quantatively agree well with the experimental results.
3. Luminescence properties of In_xGa_<1-x> multiple quantum wells with [0001], <11-2-2>, <11-20> orientation were studied for the variety of indium composition x and photo excitation intensity. For a sample with relatively large composition x, besides a characteristic red emission from the well structures, an additional emission band appeared remarkably around blue region under intensive excitation with ns-pulses into GaN band-to-band transition. The emission was tentatively attributed to the emission from defects in GaN layer induced by excess photo-carriers. It was also confirmed that both emissions decayed by a few microseconds after pulses, however, no transient ESR signal had been found.
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Report
(3 results)
Research Products
(5 results)
