Heavy and light exciton states in c-AlGaN/GaN asymmetric double quantum wells

Abstract

This work presents a theoretical study of the lowest heavy- and light-exciton energy states in a c-AlGaN/GaN asymmetric double quantum well. It makes use of the variational method to determine the eigenstates of the corresponding Schrödinger equation, within the effective mass and parabolic band approximations. We studied the behavior of the exciton energy, the corresponding binding energy as well as the photoluminescence energy peak as a function of the left quantum well width and the central barrier height. Direct and indirect exciton states can be obtained depending on the quantum well configuration. The motivation for this study comes from the experimental reports by T. Wecker et al., in which they measure the photoluminescence energy peak in similar systems with different aluminum concentrations. The comparison of our results with the experimental outputs shows good agreement.