Photoluminescence from carriers confined at an AlxGa1−xAs/GaAs heterojunction interface

Abstract The optical transition known as the H-band is investigated by means of low-temperature photoluminescence on Al x Ga 1− x As/GaAs single heterojunctions grown by metalorganic chemical vapor deposition. The strong, broad, and asymmetric band occurs in the GaAs spectrum at energies ranging between the shallow bound exciton region and the carbon-related free-to-bound transition. The peak energy of this band is observed to increase roughly linearly with the logarithm of the excitation intensity. Our study addresses the possible interface-defect-related nature of this band. We examine two models which qualitatively explain our observations. We attribute this band to holes tunneling from the notch at the Al x Ga 1− x As/GaAs interface and recombining with electrons from the GaAs conduction band, as opposed to a donor-interface- acceptor recombination mechanism.