Materials Science Forum, Vol.384-3, 31-34, 2002
Carrier dynamics in small InAs/GaAs quantum dots
Photo-excited carrier dynamics in small InAs/GaAs quantum dots was investigated in the temperature range from 80 up to 230 K by time-resolved photoluminescence. Very long lifetimes (up to 10 ns) are observed in this system at low temperatures and excitation intensities. At low excitation intensity the luminescence peak exhibits a red shift at later times after the excitation. At higher excitation intensities the luminescence peak is blue-shifted, the spectrum broadens and a faster decay is obtained. Photo-excited carrier dynamics is discussed considering different processes related to trapping and thermal escape of the carriers as well as their relaxation and recombination, taking into account confinement effects and the wetting layer as a possible channel for carrier exchange.