Carrier capture and escape in InxGa1-xAs/GaAs quantum dots:: Effects of intermixing

We have investigated photoexcited carrier dynamics in as-grown and intermixed InxGa1-xAs/GaAs quantum dots and quantum wells by time-resolved photoluminescence with subpicosecond temporal resolution. Experiments were performed at high excitation in the temperature range 60-300 K. At lower temperatures, carrier lifetime in the dots is determined by radiative recombination, while at temperatures over 150 K carrier thermal emission becomes dominant. Carrier capture into the dots was found to be fast and governed by carrier-carrier scattering. In particular, at room temperature and high-excitation intensity, the carrier capture time of 0.72 ps was observed for the intermixed dots.