Abstract

Recently, several authers [1-3] have investigated the dynamics of electron-hole plasma generated by picosecond and sub-picosecond laser pulses in GaAs. In one of these experiments El 3 the electron-LO phonon dynamics was directly observed at 77 K by means of a pump-probe Raman scattering experiment using a 600 fs, 588nm laser pulse. They observed an increase in the LO phonon population at 2 ps, which was attributed to the phonons emitted during the cascade of electrons to edge of the band. We have investigated the cooling of carriers excited by a 588nm laser pulse using ensemble Monte Carlo approach. The model takes into account the carrier-carrier and carrier-phonon interactions using a band model which consists of three nonparabolic valleys for the conduction band and two parabolic valance bands. Since the excitation levels used in the above experiment were less or equal to 10¹⁷ cm^–3 and the holes were neglected in their theoretical model, we have investigated first a simple model, where only carrier-phonon interactions were active and the presence of the heavy holes was considered, to account for the energy gained by the holes.

© 1987 Optical Society of America