| Summary: | 碩士 === 長庚大學 === 光電工程研究所 === 98 === We investigate the carrier dynamics of the self-assembled InAs/GaAs quantum-dot (QD) heterostructures experimentally and theoretically. Theoretical discussions that take into account the dot size distribution, the random population of density of states, and the important carrier transferring mechanisms of a QD system, are proposed. The carrier capturing and relaxing, radiative and nonradiative recombination, thermal emission and retrapping, and the thermal induced electron-phonon scattering, are all considered. Mechanisms of carrier dynamics in QD system related to the thermal redistribution and lateral transition of excitons, and the filling effect on density of states, are discussed in detail. The temperature and incident-power dependent photoluminescence spectra from QD samples with different dot size distributions are measured and studied. In addition, the phonon-assisted activations of excitons in the QD system are analyzed. Quantitative discussion of the correlation between thermal redistribution and electron-phonon scattering effects on QD system provides distinct explanation for the different behaviors with increasing temperature that observed in the photoluminescence spectra from QD heterostructures.
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