Barrier thickness dependence of the photoscreening of the piezoelectric field in (111) orientated GaAs–InxGa1−xAs double quantum wells

Abstract

In this article we present low temperature photoluminescence spectra from a series of (111) orientated GaAs–InxGa1−xAs double quantum well structures with differing barrier thicknesses. We demonstrate an enhancement in the carrier screening of the strain induced internal piezoelectric field by photocreated electrons and holes as the barrier thickness is increased. The enhanced screening arises from an increase in the spatial separation of the electron and hole populations. Additionally, we observed a photoinduced spatial transfer of the second lowest lying heavy hole level. This spatial transfer is a strong function of the electron and hole separation and limits the amount of the optically pumped “blue” shift of the lowest energy intersubband transition.