Carrier capture and emission in self-assembled InGaAs/GaAs quantum dots

We have investigated photoexcited carrier dynamics in as-grown and intermixed InGaAs/GaAs quantum dots and quantum wells by time-resolved photoluminescence with subpicosecond temporal resolution. Experiments were performed in the high excitation regime in the temperature range 60-300 K. At low temperatures, carrier lifetime in the dots is determined by the 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 the carrier-carrier scattering. In particular, the carrier capture time of 0.72 ps has been observed at room temperature and high excitation intensity for the intermixed dots.