Space-charge limited free carrier transport in semi-insulating III-V compounds

We demonstrate a novel way to analyse carrier recombination and transport processes in photorefractive semiconductors via kinetics and exposure characteristics of light induced diffraction. The results of a picosecond degenerate four-wave mixing on free carrier gratings in semi-insulating GaAs and InP bulk crystals are discussed. The role of a deep trap recharging in carrier diffusion and recombination is sensitively revealed through a feedback effect of a space-charge field to nonequilibrium carrier transport or directly through linear electrooptic effect.