The influence of saturation of electron drift velocity on photorefractive effect in GaAs/AlGaAs quantum wells structures

Abstract The structures of the semi-insulating quantum wells based on GaAs/AlGaAs material composition are photorefractive materials of high sensitivity and short time of response. An important factor affecting the course of the photorefractive phenomenon in these materials is the nonlinear relationship between the velocity of electrons and the intensity of the electric field. The article compares two most frequently used models of nonlinear transport of electrons in GaAs: a classic two-valley model and an empirical model accounting for the saturation of the dependence of electron velocity on electric field intensity. It has been shown how the selection of the model influences the predicted distribution of space-charge field during the photorefractive two-wave mixing, which allows evaluating the correctness of the use of these models.