Effect of an electric field on the scattering of excitons by free carriers in semiconducting quantum-well structures

Abstract

We have calculated the effect of an electric field applied along the direction of carrier confinement on the scattering of excitons by free carriers in semiconducting quantum-well structures. We find that although the application of the electric field does not change the functional form of the dependence of the differential cross section on the scattering angle or the dependence of the total cross section on the incident wave vector of the free carrier, it does change the magnitude of the total cross section. For scattering of heavy hole excitons by electrons, the peak value of the total elastic cross section decreases with increasing electric field while when the exciton is scattered by heavy holes, the peak value of this cross section increases with electric field. This reduction or enhancement is negligible for narrow wells or for weak fields but there is an appreciable change in the total elastic scattering cross section for wider wells and stronger fields. We also find that the electric field also enhances the ionization cross section for the scattering of excitons by both electrons and heavy holes.