1999 Fiscal Year Final Research Report Summary
Photocalorimetric Spectroscopy of Excitons in Semiconductor-Energy Dissipation Processes of Photo-excited States-
| Project/Area Number |
10640308
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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 |
固体物性Ⅰ(光物性・半導体・誘電体)
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
ARIMOTO Osamu Okayama University, Faculty of Science, Associate Professor, 理学部, 助教授 (70193092)
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| Co-Investigator(Kenkyū-buntansha) |
KONDO Yasuhiro Tohoku University, Graduate School of Engineering, Associate Professor, 大学院・工学研究科, 助教授 (20013534)
NAKAMURA Kaizo Okayama University, Faculty of Science, Professor, 理学部, 教授 (40025359)
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| Project Period (FY) |
1998 – 1999
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| Keywords | exciton / zinc diphosphide / photocalorimetric spectroscopy / phonon / nonradiative relaxation process / excitation spectrum / luminescence / exciton-phonon scattering |
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| Research Abstract |
In order to clarify nonradiative relaxation processes of excitons due to exciton-phonon scattering, simultaneous measurements of photocalorimetric (PC) spectra and excitation spectra of exciton luminescence have been performed in a semiconductor crystal β-ZnP_2, which is one of the most suitable materials for the exciton study. The main results obtained are as follows :
1. For singlet excitons, power of the light absorbed by the crystal is converted to that of the thermal heating of the crystal almost at an equal rate, which amounts to nearly 80%, in the energy range from the 1s longitudinal exciton energy E_L to the band gap energy E_g.
2. The amounts of both singlet exciton luminescence and heat generation decrease in the 1s reflection band, which suggests the presence of other optical process such as resonant Rayleigh scattering in this energy region.
3. The ratio of the PC signal to the luminescence intensity is enhanced at the exciton resonances n=1 to 4. This fact indicates that the rate of the nonradiative decay of excitons relative to the emission of the luminescence is large at the exciton resonances.
4. The PC spectrum under excitation into the triplet exciton resonance region with E//b resembles fairly well the absorption spectrum of the triplet exciton besides unknown background. This fact indicates that, if the background is neglected, the absorbed light to create the triplet excitons is converted to the heat generation almost at a constant rate.
The results mentioned above were presented at the International Conference on Luminescence and Optical Spectroscopy of Condensed Matter held in the last summer and also at meetings of the Physical Society of Japan.
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Research Products
(32 results)
