Quantum-Statistics Behavior of the Exciton-Biexciton System In GaAs/AlAs Type-II Superlattices |
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Authors: | M Nakayama H Ichida |
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Institution: | Department of Applied Physics, Faculty of Engineering , Osaka City University , 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka , 558-8585 , Japan |
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Abstract: | We have investigated the quantum-statistics behavior of the exciton-biexciton system from the photoluminescence properties in (GaAs) m /(AlAs) m type-II superlattices with m = 12 and 13 monolayers, where the lowest-energy type-II exciton consists of the n = 1 X electron of AlAs and n = 1 o heavy hole of GaAs. The long exciton lifetime of the order of w s due to the indirect transition nature enables us to obtain precisely the density relation between the exciton and biexciton from the line-shape analysis of time-resolved photoluminescence spectra. In a relatively low exciton-density region, the biexciton density obeys a well-known square law. At an exciton density around 1 2 10 10 cm m 2 , the biexciton density suddenly increases with a threshold-like nature. This behavior, which is realized at a bath temperature up to 8 K under an excitation power of the order of 100 mW/cm 2 , results from the characteristics of Bose-Einstein statistics of the exciton-biexciton system. |
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Keywords: | Exciton Biexciton Bose-Einstein Statistics Photoluminescence Gaas/AlAs Type-II Superlattice |
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