Influence of exciton impact ionization and illumination intensity on the exciton-polariton reflectance of GaAs

Abstract

External electric fields cause impact ionization of excitons in GaAs. We investigated the influence of impact ionization on exciton-polariton reflectance spectra. The change in the reflectance spectra due to the external field is similar to the change obtained by reducing the illumination intensity to very small values. This joint behavior is explained in terms of band bending near the crystal surface and related damping of the exciton polariton.