Exciton binding energy inInxGa1−xAs/GaAs strained quantum wells

Abstract

In this paper we present experimental and theoretical studies of the exciton binding energy in ${\mathrm{In}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As strained quantum wells confined within GaAs layers, as functions of the well width and the barrier height. Photoluminescence excitation measurements are performed under a steady magnetic field of up to 6 T and a temperature of 10 K. The Landau-level-related transitions have been identified. By extrapolating the photon energies of the transitions to zero magnetic field, the binding energy of the heavy-hole exciton is obtained for samples with well widths ranging from 65 to 100 Å and values of x from 0.07 to 0.13. A model calculation is carried out in a framework of the variation method. A good agreement between the experimental and calculated results is achieved. The exciton binding energy is found to decrease with increasing well width and decreasing barrier height, which is accounted for in terms of the exciton spatial confinement.