Optical control of the exciton charge states of single quantum dots via impurity levels

Abstract

The impact of residual impurities on neutral and charged exciton complexes in single InGaAs quantum dots (QDs) grown by metalorganic chemical vapor deposition were investigated by microphotoluminescence combined with photon correlation measurements. We show that the formation of a charged exciton can be controlled by using resonant excitation to the residual impurity level. This optical excitation scheme is useful for the selective generation of only charged excitons in initially neutral QDs without sophisticated sample designs.