Photoluminescence fatigue in three-dimensional silicon/silicon-germanium nanostructures

We find fatigue of low temperature photoluminescence (PL) in Si/SiGe three-dimensional island morphology nanostructures under continuous excitation. Initially, the PL intensity slowly decreases by less than 15%, and after ~10 min it decreases rapidly by more than 80%. After the PL intensity stabilizes, a complete recovery requires heating the sample to nearly room temperature. We propose that accumulation of charge within SiGe islands is responsible for the enhancement of Auger recombination and hence the observed PL fatigue.