Dynamical response of electrons in GaAs in a high electric field

Abstract

The dynamical behaviour of hot electrons in GaAs at 300 and 77 K is studied by a Monte‐Carlo technique. The three valley Γ‐L‐X model is used. The transient response of electrons is calculated both, for instantaneously switched on and periodically time‐varying electric fields. The results critically depend on the intervalley coupling constants. Due to the accepted weak ΓT‐L coupling the relaxation phenomena appear already at frequencies of the order of 10 GHz. The relaxation effects are most significant at amplitudes of 2.5 to 6 kV/cm due to the electron transfer from Γ to L valleys.

Enhanced drift velocity of photoelectrons in a semiconductor with ultrafast carrier recombination

“…The electron drift velocity becomes larger when the lifetime becomes shorter and the excess energy becomes smaller. This enhancement of the drift velocity corresponds to the electric field region at which the transient electron response is characterized by the velocity overshoot phenomenon [7][8][9]. The momentum of an electron subjected to a high electric field relaxes much faster than its energy; therefore, during the initial moments of its temporal evolution, the electron drift velocity can reach values several times larger than the steadystate drift velocity.…”