Surface photovoltage spectroscopy and photoluminescence study of vertically stacked self-assembled InAs/GaAs quantum dots

We present a study of two 30-layer stacks of self-assembled InAs/GaAs quantum dots with different spacer layer (SL) thickness using surface photovoltage spectroscopy (SPS) and photoluminescence (PL) at room temperature. Both PL and SPS spectra of stacked QDs structure with a thinner spacer layer in comparison to other structures show additional feature. QD features are more clearly visible in SPS spectra and show more features in comparison to PL ones. This study demonstrates the considerable potential of SPS and PL for the contactless and nondestructive characterization of QDs structures at room temperature.