Acceptor-related photoluminescence study in GaAs/Ga1−xAlxAs quantum wells

A theoretical study of the photoluminescence spectrum associated with shallow acceptors in GaAs-(Ga,Al)As quantum wells is performed. As a general feature, there are two special structures in the acceptor-related spectrum: an edge associated with transitions involving acceptors at the center of the well, and a peak associated with transitions related to on-edge acceptors. The photoluminescence line shape depends on the temperature, the quasi-Fermi energy of the conduction-subband electron gas, and on the acceptor distribution along the quantum well. It is suggested that an analysis of the acceptor-photoluminescence line shape could allow an experimental determination of the quasi-Fermi-energy level of the conduction-subband electron gas as well as of the on-edge-acceptor binding energy. Experimental results of unintentionally doped multiple-quantum-well GaAs-${\mathrm{Ga}}_{0.7}$ ${\mathrm{Al}}_{0.3}$As samples by Miller et al. [Phys. Rev. B 25, 3871 (1982)] and of single quantum wells of GaAs-${\mathrm{Ga}}_{0.85}$ ${\mathrm{Al}}_{0.15}$As by Meynadier et al. [J. Appl. Phys. 58, 4307 (1985)] are in excellent agreement with theoretical results obtained with a homogeneous distribution of acceptor impurities along the GaAs layer and a convenient choice of the quasi-Fermi-energy level.