1995 Fiscal Year Final Research Report Summary
Study of Quantum Effect in Amorphous Semiconductors of Nanometer Sized Structure
| Project/Area Number |
06640448
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | Yamaguchi University |
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Principal Investigator |
OGIHARA Chisato Yamaguchi University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90233444)
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| Co-Investigator(Kenkyū-buntansha) |
SHINOZUKA Yuzo Yamaguchi University, Faculty of Engineering, Professor, 工学部, 教授 (30144918)
SUEOKA Osamu Yamaguchi University, Faculty of Engineering, Professor, 工学部, 教授 (00012378)
MORIGAKI Kazuo Hiroshima Institute Technology, Faculty of Engineering, Professor, 工学部, 教授 (60013471)
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| Project Period (FY) |
1994 – 1995
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| Keywords | amorphous semicondutor / luminescence / nanometer sized structure / superlattice |
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| Research Abstract |
Quantum effects on the electronic states and recombination processes has been studied by means of measuring lifetime distribution of photoluminescence for band edge modulated (BM) a-Si_<1-x>N_x : H films and a-Si : H/a-Si_<1-x>N_x : H superlattices having artificial nanometer sized structure. We have observed two different types of generation rate dependence of the lifetime distribution at 11 K :
1.The lifettime distribution shifts toward shorter lifetime with increasing generation rate. This is behavior of non-geminate recombination.
2.The lifetime distribution has a peak at 1 ms and is independent of generation rate. The emission is considered to be due to triplet excitons.
The type 1 has been observed for bulk a-Si : H and a-Si : H/a-Si_<1-x>N_x : H superlattices of large well layr thickness, L_W. The type 2 has been observed for bulk a-Si_<1-x>N_x : H,BM a-Si_<1-x>N_x : H and a-Si : H/a-Si_<1-x>N_x : H superlattices of small L_W. The peak at 1 ms is still seen at 100 K in the bulk a-Si_<1-x>N_x : H which contains more nitrogen, BM a-Si_<1-x>N_x : H of short modulation period, , and a-Si : H/a-Si_<1-x>N_x : H superlattices of small L_W. These results indicate that the excitons are stable since the dielectric constant is small and Coulomb interaction is strong for a-Si_<1-x>N_x : H of more nitrogen and that excitons become two dimensional and stable where confinement effect is expected.
Our results show the existence of emission from triplet excitons and the two dimensional feature of them in the amorphous silicon based semiconductors of nanometer sized structure.
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