Effect of the insertion of an ultrathin AlP layer on the optical properties of GaAsP/GaP quantum wells

Abstract

We have systematically investigated the correlation between electronic states and optical properties in indirect GaAsP/GaP quantum wells (QW’s) which have an ultrathin AlP layer inserted during fabrication. The insertion of 1 monolayer (ML) of AlP at the center of a 60-Å GaAsP QW drastically increased the photoluminescence intensity, and in particular the efficiency of the no-phonon (NP) transition. The NP intensity relative to its TO phonon replica was found to be greatly dependent on the structural parameters and was drastically reduced when the arsenic composition of the well region exceeded 15%. The relative NP intensity was found to increase sharply as the width of the AlP layer was increased above 2 ML’s. These results suggest that the efficiency of the NP transition is improved when the $X_z$ electrons are involved in radiative recombination rather than the $X_{\mathrm{xy}}$ electrons.