THEORETICAL STUDIES OF TRANSIENT RAMAN SCATTERING OF NON-EQUILIBRIUM CARRIERS IN SEMICONDUCTORS — EFFECTS OF CARRIER COLLISIONS

Abstract

We present a comprehensive theory for time-resolved Raman scattering from non-equilibrium electrons in direct bandgap semiconductors. Specifically, we include (1) the effects of probing with ultrashort laser pulse: (2) the effects of finite carrier collision time; (3) the effects of band structure; and (4) the effects of damping in the optical transition, in the calculations of Raman scattering cross section. Both elastic and inelastic scattering processes are taken into account in formulating the effects of carrier collision time. The effects of damping in the optical transitions have to be considered for the experimental condition of probing with above-bandgap laser excitations even if under some circumstances they do not drastically change the lineshape of the single-particle-scattering spectrum due to spin-density fluctuations.