Effects of impurity induced disorder on the index of refraction in GaAsAlGaAs quantum wells

Abstract

A theoretical model for the refractive index in impurity induced disordered (IID) GaAsAlGaAs quantum wells is presented. The electron and hole dispersion is obtained from the Luttinger-Kohn Hamiltonian and a bulk conduction band Hamiltonian which includes the effects of nonparabolicity. We solve the Hamiltonians using a finite difference method which is flexible enough to accommodate the potential profile in disordered quantum wells. Both TE and TM refractive indices are calculated, and our results are in excellent agreement with the published experimental data available. The inter-diffusion coefficient of Al and Ga is obtained by comparing our calculated subband level results, including the effects of excitons, to the published experimental data. The theoretical model allows accurate calculation of the index of refraction, allowing the refractive properties of impurity induced disordered wells to be accurately tailored experimentally.