Hot-phonon and electron-hole scattering effects on the transient transport of photogenerated electrons in GaAs

We investigate the transient response of photogenerated carriers to an external electric field in bulk GaAs. The results of our Monte Carlo simulations indicate that the initial velocity rise times are a strong function of the carrier density. This is caused by a combination of the hot-phonon effect and the enhanced electron-hole scattering within the plasma. Contrary to some previous suggestions, the hot-phonon effect alone is insufficient to explain the initial velocity behavior seen experimentally. The steady-state velocity is limited by the electron-hole scattering.