Ambipolar diffusion measurements in semiconductors using nonlinear transient gratings

Abstract

The theory of self-diffraction of light by transient free-carrier gratings in semiconductors has been expanded to the case in which nonlinear absorption of light creates the grating. Its application to the experiments performed allowed determination of the free-carrier ambipolar diffusion coefficients in CdS, CdSe, and ZnSe crystals, and the mechanism of free-carrier recombination and carrier lifetime in CdS at low temperatures.