Effect of electric field on the sharp photoluminescence spectra of undoped GaAs–Al0.25Ga0.75As multiple quantum well structures

Effects of an electric field on the low temperature (4.2 K) photoluminescence spectra from undoped GaAs–Al0.25Ga0.75As multiple quantum well samples grown by molecular beam epitaxy have been investigated. The photoluminescence in the semitransparent Schottky‐barrier configuration is dominated by the transitions of the n=1 light‐hole free exciton, the heavy‐hole free exciton, the light and heavy hole excitons bound to a neutral donor, and the heavy hole‐to‐neutral donor. As the electric field is increased the photoluminescence intensity is shifted from the neutral donor bound heavy‐hole exciton peak to the heavy hole‐to‐neutral donor peak and to the n=1 electron‐to‐neutral acceptor peak. More than two orders of magnitude change in intensity of the neutral donor bound heavy‐hole exciton peak is observed in the electric field range studied. No discernible shift in the energy of any of the intrinsic and near‐intrinsic emission is observed. However, some shift is observed for the n=1 electron‐to‐neutral accept...