Effect of Dielectric Mismatch on Exciton Binding Energy in ZnS/MgxZn1-xS Quantum Wells

Abstract

We calculate the binding energies of heavy- and light-hole excitons in ZnS/MgxZn1-xS single quantum wells (SQWs) as functions of the well width by using a variational method. We take into account the effect of the mismatch between the dielectric constants of the well and the barriers (dielectric mismatch effect) in our calculation. The increases in the heavy- and light-hole exciton binding energies in ZnS/MgxZn1-xS SQWs for a Mg content (x) of 1.0 are 58.9 meV and 60.2 meV, respectively. In the case of narrow wells, the heavy- and light-hole exciton binding energies calculated by considering the dielectric mismatch effect exceed the longitudinal optical phonon energy of ZnS when x ≥ 0.3. [DOI: 10.1380/ejssnt.2010.145]