Center-of-mass quantization of excitons in CdTe/Cd1−xZnxTe quantum wells

Abstract

Photoluminescence excitation spectra are obtained for a large set of strained CdTe/${\mathrm{Cd}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Zn}}_{\mathit{x}}$Te single-quantum-well samples, as a function of well thickness. The experimental spectra are reproduced by an accurate variational exciton envelope function, expanded in products of electron and hole subbands. An analytical approximation for the exciton envelope function, well suited for thin films with finite confinement potentials, is also given. The good agreement obtained between theory and experiment for both methods strongly supports the concept of center-of-mass quantization for this quantum-well system in the thickness range from 180 to 1000 Å.