Polarization anisotropy in room temperature contactless electroreflectance spectrum of self-organized lateral compositional superlattices

Abstract

We report the results of room temperature contactless electroreflectance measurements on (GaP)2(InP)2superlattices grown on GaAs (001) substrates which show lateral composition modulation along the [110] direction in the (001) plane. The strong polarization anisotropy of some features in the spectrum has been explained by identifying them as arising from transitions in the lateral superlattice formed due to the composition modulation. The measured optical transition energies are considerably lower than theoretical estimates based on the random alloy model, suggesting the need for a better model to describe the electronic band structure of this system.