LO-phonon-assisted emission edge of free excitons in GaAs and GaAs/GaxAl1−xAs quantum wells

Abstract

Photoluminescence data and theoretical calculations are given for the LO-phonon-assisted free-exciton emission edge in bulk GaAs and in GaAs/${\mathrm{Ga}}_{\mathrm{x}}$ ${\mathrm{Al}}_{1\mathrm{-}\mathrm{x}}$As quantum wells for temperatures up to 90 K. The observed temperature dependence of the emission edge and the change of the intensity between the bulk case and the quantum-well case is in accord with theory. Evidence also is given for the observation of the two LO-phonon-assisted free-exciton emission edge in the quantum-well system.