Photoexcited carrier transfer in InGaAs quantum dot structures: Dependence on the dot density

Carrier dynamics has been measured by time-resolved photoluminescence in self-assembled InGaAs/GaAs quantum-dot structures with dot density of the order of 10(8)-10(10) cm(-2). The time of carrier transfer into a dot, which ranges from 2 to 20 ps, has been found to decrease with increasing quantum dot density. The temperature and photoexcited carrier density dependencies of the carrier transfer times suggest that potential barriers at wetting layer and quantum-dot interfaces hinder carrier capture in low-density quantum-dot structures. (C) 2000 American Institute of Physics. [S0003-6951(00)05017-8].