Temperature dependence of photoluminescence from single and ensemble InAs/GaAs quantum dots

We investigate the temperature dependence of photoluminescence from single and ensemble InAs/GaAs quantum dots systematically. As temperature increases, the exciton emission peak for single quantum dot shows broadening and redshift. For ensemble quantum dots, however, the exciton emission peak shows narrowing and fast redshift. We use a simple steady-state rate equation model to simulate the experimental data of photoluminescence spectra. It is confirmed that carrier-phonon scattering gives the broadening of the exciton emission peak in single quantum dots while the effects of carrier thermal escape and retrapping play an important role in the narrowing and fast redshift of the exciton emission peak in ensemble quantum dots.

National Natural Science Foundation of China 60676054 Knowledge Innovation Project of Chinese Academy of Sciences KJCX2.YW.W09-3 National Basic Research Programme of China 2007CB924904 Supported by the National Natural Science Foundation of China under Grant No 60676054, the Knowledge Innovation Project of Chinese Academy of Sciences (KJCX2.YW.W09-3), and the National Basic Research Programme of China under Grant No 2007CB924904