Lineshape changes on photoluminescence spectra of GaAs/AlGaAs multiple quantum well with number of wells and barrier width

Abstract

We investigate the effects of barrier thinning on the photoluminescence (PL) spectra of GaAs/AlGaAs based quantum well system. By employing the transfer matrix method, we numerically determine the allowed energy states for the well system. For the case of a multiple quantum well, we observe sets of localized energy levels or "minibands," in the valence and conduction bands. We then delineate the PL spectra based from a statistical model of free carrier recombination and possible transitions. Because the minibands provide many recombination paths, it effectively broadens the PL spectra. Another important observation is the diminishing of the energy difference between between the light hole and the heavy hole ground state energy levels diminishes as the barrier width decreases. This results to an apparent disappearance of the shoulder of the PL spectra.