Investigation of transient transport and recombination phenomena in semiinsulating GaAs

Photoconductivity and Hall voltage kinetics were measured simultaneously in SI GaAs monocrystals, using the pulsed neodimium laser excitation. The scattering and recombination centres were found to have a different influence at different time intervals of the transients (from 10 ns to some seconds). It is shown that in GaAs the photoconductivity relaxation in some time intervals can be interpreted correctly only by taking into account the mobility changes. The obtained resuls are explained in terms of recharging of the scattering centres and variations of the capture cross-section of charge carries on the local centres.