Monte Carlo Investigation of Hot Photoexcited Electron Relaxation in GaAs

Abstract

Recently, several authors [1–3] have investigated the dynamics of electron-hole plasma generated by picosecond and sub-picosecond laser pulses in GaAs. These measurements have indicated the importance of electron-hole interaction in the cooling process (especially in the presence of a cold hole plasma) and the existence of non-equilibrium phonon distributions as a result of cooling of photoexcited electrons and holes. Previous theoretical studies of the cooling process have ignored the presence of the upper valleys even when the energy of the excited electrons exceeds the energy separation between the central and the upper valley. Additionally, assumptions had to be imposed on the form of the distribution function of the electrons and phonons. Ensemble Monte Carlo (EMC) techniques avoid these assumptions and have been used to investigate the effects of electron-hole (e-h) interaction [4] and non-equilibrium phonons [5] on the relaxation rate of photoexcited electrons. In this study we present the first EMC calculation to account for both the e-h interaction and hot phonon effect.

Supported by the Office of Naval Research.