Carrier interaction in self-assembled quantum dots studied by single dot spectroscopy

Summary from only given. In recent years, many studies of the electronic states in self-assembled quantum dots (SAQDs) using single dot spectroscopy have been reported. PL spectra measured by single dot spectroscopy show discrete and sharp peaks which indicate 0D confinement of carriers. At higher excitation powers, PL spectra show the interesting phenomena where we see many peaks to be emerged. Delkel et al. (1998) calculated the excited states due to exciton interactions and the results corresponded well to PL spectra measured at different excitation powers. Landin et al. (1998) also reported the similar phenomena. However, these reports assume the ideal density of stares in SAQDs, and more precise measurements are still needed. In the paper, we performed single dot PL and PLE spectroscopy at various excitation powers. These results clearly demonstrate carrier interaction in SAQDs. We show the excitation power dependence of non-resonant PL spectra from InGaAs/GaAs SAQDs. This sample is island-etched, therefore the number of QDs excited is limited to about ten.