Field inhomogeneity effects on photoreflectance spectra of ZnSe/GaAs

Abstract

Photoreflectance measurements from ZnSe epilayers of different thicknesses were carried out. In photoreflectance spectra, the exciton line shape “rotation” is observed to be much slower than that in the reflectance spectra by increasing the epilayer thicknesses. To analyze the exciton line shape rotation quantitatively, the photoreflectance spectra were calculated considering the built-in electric field inhomogeneity effects near the interface as well as the interference effects. Calculated line shapes of the photoreflectance spectra show a good agreement with the observations. Our results imply that inhomogeneity effects of the interface built-in electric field plays an important role in the spectral rotation in photoreflectance.