Photoreflectance Spectra from GaAs Buffer Layer of GaAs/AlAs Multiple Quantum Well/GaAs Buffer/GaAs Substrate

Abstract

We have measured photoreflectance spectra from a GaAs buffer of a GaAs/AlAs multiple quantum well (MQW)/GaAs buffer/GaAs substrate. In order to interpret our experimental results, we have tried to modify Aspnes's low field limit theory for electroreflectance. From this treatment, the built-in electric field at the interface between the MQW layer and the GaAs buffer layer is estimated to be 35 kV/cm. It has been shown that PR spectra at various points on the sample surface resolve the question on the homogeneity of the MQW layer thickness.