Analysis of the influence of nonlinear carrier transport on the photorefractive response in GaAs with applied alternating electric field

• The photorefractive grating in GaAs:Cr with an applied AC electric field is studied.
• The hot-electron and field-enhanced capture cross section effects are included.
• Analytical solutions are given.
• Influence of the nonlinear electron transport in two-wave mixing is examined.
• Results are compared with the available experimental data from earlier works.

The photorefractive response in semi-insulating GaAs:Cr is theoretically studied when an alternating electric field is applied to a crystal. The calculations are based on material equations including electron and hole currents, nonlinear hot-electron transport and field-enhanced recombination rates. The generalized solutions for the fundamental amplitude of the space-charge field are given. It is shown that for an AC sine-wave field the hot-electron effect reveals in a very small degree. A comparison of the obtained solutions with available experimental data indicates recombination coefficient values of the order of 10−6–10−5 cm3/s which can be attributed to the field-enhanced capture cross section effect.