Moving photoluminescence bands in GaAs1−xSbx layers grown by molecular beam epitaxy on InP substrates

Abstract

We report the excitation intensity dependent photoluminescence properties of GaAs_1−xSb_x layers grown by molecular beam epitaxy on InP substrates. Photoluminescence consists of the bound exciton and the quasi‐donor‐acceptor pair transitions for the layers in the range of 0.26≤x≤0.94. The concentration modulation produced by the relaxation of the misfit strain between the epitaxial GaAs_1−xSb_x layer and InP substrate is responsible for the quasi‐donor‐acceptor pair transition. A large Stokes shift between the photoluminescence transition of the bound exciton and the band gap determined by the optical absorption measurements is also consistent with our model of concentration modulation.