Deep-trap governed carrier dynamics in semi-insulating crystals analyzed by time-resolved four-wave mixing technique

Abstract

We demonstrate versatile applications of a nonlinear, four wave mixing (FWM) technique to study deep-impurity governed carrier generation. transport and recombination by monitoring subnanosecond dynamics of light difraction onfree carrier grating. Role of transport-created space chargefield to carrier dynamics is analyzed numerically and studied experimentally in semi-insulating CdTe: K CdTetCe, and GaAs:EL2. We present a novel way to determine the conductivi@ type of a photorefractive cryrtal doped by deep and codoped by shallow impurities. FWM technique is extended to monitor transient photoquenching of EL2 in GaAs at 300 K, control the compensation ratio of deep trap. map the spatial distribution of defects in GaAs w+-s , and study ultrafast recombination in vicinity ofdislocotions.