| Project/Area Number |
60540196
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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
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| Research Institution | The Institute for Solid State Physics, The University of Tokyo |
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Principal Investigator |
MORIGAKI Kazuo The Institute for Solid State Physics, The University of Tokyo, Professor, 物性研究所, 教授 (60013471)
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| Co-Investigator(Kenkyū-buntansha) |
TAKENAKA Hisashi The Institute for Solid State Physics, The University of Tokyo, Research Associa, 物性研究所, 助手 (20013542)
HIRABAYASHI Izumi The Institute for Solid State Physics, The University of Tokyo, Research Associa, 物性研究所, 助手 (80126151)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1986: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1985: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Keywords | Optically detected magnetic resonance / Amorphous silicon / Superlattices / Recombination processes / A centres |
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| Research Abstract |
We have set up the apparatus for time-resolved optically detected magnetic resonance (TRODMR) measurements operating at 9.6 GHz and 2 K. A dye laser pumped by either a pulsed <N_2> laser of 5 ns or a pulsed excimer laser of 10 ns was used as a pulsed excitation source. Using such equipment, we have carried out TRODMR experiments on a-Si:H, a- <Si_(1-x)N_x> :H and a-Si:H/a- <Si_(1-x)N_x> :H superlattices. The following results and conclusions have been obtained:
1. The ODMR signal due to tail electrons in a-Si:H was observed for the first time. Thus, radiative recombination of tail electrons with trapped holes at the A centres and/or the valence band tail was clarified as a function of delay time of the microwave pulse and the gate pulse for the measurement, <t_d> , after a pulsed excitation.
2. For a-Si:H/a- <Si_(1-x)N_x> :H superlattices, the confinement effect of electrons and holes in the well layer (a-Si:H) was inferred from the results of relative change in the luminescence intensity at the A centre resonance as a function of <t_d> . For superlattices not containing a number of defects at the interfaces, nonradiative recombination through dangling bonds in thin well layers was found to be suppressed compared to that for a-Si:H bulk films.
3. Triplet exciton recombination was investigated by observing the g <Similar or Equal> 4 ODMR signal and the broad g <Similar or Equal> 2 ODMR signal in a-Si:H, a- <Si_(1-x)C_x> :H and a- <Si_(1-x)N_x> :H. From TRODMR experiments, it was concluded that triptet excitons decay with a time constant of <about> 1 ms in a-Si:H. From these investigations, we conclude that TRODMR technique provides a powerful means for elucidating recombination processes and nature of recombination centres in semiconductors.
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