Experimental determination of Auger capture coefficients in self-assembled quantum dots

Time-resolved studies of the wetting layer photoluminescence are combined with state-filling spectroscopy of the quantum dot and wetting layer emission to obtain carrier transfer rates from the wetting layer to the quantum dot states. With this method, capture rates can be measured for constant carrier concentrations in the wetting layer. The results show that the capture efficiency increases with the carrier concentration in the wetting layer, indicating the important role of Auger processes in the capture dynamics. In the analysis, the concept of capture cross section per unit time is introduced, and this is used to determine the single dot Auger capture coefficient in self-assembled dots. The value obtained can in principle be used as an input to model carrier capture in all self-assembled dot devices with similar dot layers.