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) to 10(10) cm(2). The time of carrier transfer into a dot, which is in the region 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 the barrier, wetting layer and quantum dot interfaces hinder carrier capture in low-density quantum dot structures.