Abstract

We have analyzed the influence of shallow traps on the effect of non-steady-state photo- EMF. The general expression for amplitude of the photocurrent for apparent filling degrees of deep and shallow levels is derived. We analyze the photocurrent behavior with respect to temporal and spatial frequencies and discuss the case of high illumination levels. We present a possible way to determine real photoelectric parameters (the lifetime of carriers, their mobility, and average diffusion length). The general calculations were performed for crystal parameters typical for photorefractive Bi₁₂SiO₂₀. We believe that the influence of shallow traps is not restricted to the considered cases. The effect of nonsteady-state photo-EMF in other photoconductive crystals (e.g., semi-insulating GaAs) with different material constants, may reveal peculiarities at other characteristic temporal and spatial frequencies.

© 2001 Optical Society of America