The nature of the deep levels responsible for photoelectric memory in GaAs/AlGaAs multilayer quantum-well structures

Abstract

The electron capture parameters and photoionization cross section of the unintentional deep levels, which are responsible for photoelectrical memory in GaAs/AlGaAs multilayer quantum-well structures, have been found from an analysis of the kinetics of the excess current during and after optical illumination of these structures. The dependence of the photoionization cross section on the photon energy, the capture cross section, and the energy barrier for capture of an electron from the bottom of the conduction band indicate that the unintentional deep levels are DX centers formed by the silicon impurity. These DX centers probably appear during growth of the structures as a result of silicon diffusion from the quantum wells along as-grown defects.