Dephasing And Energy Relaxation Processes In Self-Assembled In(Ga)As/Gaas Quantum Dots

Time-resolved two-beam experiments were performed on self-assembled In(Ga)As/GaAs quantum dots (QD's). In contrast to previous two-beam transmission experiments on stacked QD's we investigated the photoluminescence properties of single QD layers. The dynamics of the ground state saturation and the state filling processes of the excited states were found to depend on the excitation intensity. As a result the exciton life-times of several hundred ps for the ground state: and the excited states were determined. Under resonant excitation a short decay of about 25 ps was observed for specific circular polarization.