Binding energies of excitons in semiconductor quantum wells: Quantum subband interference effect.

Abstract

The set of eigenequations for determining the energy levels and wave functions of Wannier excitons in a semiconductor quantum well is derived by use of Green's-function theory. These equations form a matrix labeled by the quantum-well subband index of the exciton. The coupling between excitons of different subband indices is included for the first time through the nondiagonal elements of the electron-hole Coulomb interaction. We found that this quantum interference effect represents a significant modification to calculated values of exciton binding energies.