Session Z18 - Semiconductors X: Transport and High Electric Field Properties.
MIXED session, Friday morning, March 24
206AB, MCC
Collective impact ionization has been used by Hjalmarson et al.(H. Hjalmarson, F. Zutavern, G. Loubriel, A. Baca, and D. Wake, Sandia Report SAND93-3972(1996).) to explain the lock-on effect observed in GaAs photconducting semiconductor switches. We have used this theory to study some of the steady state properties of the lock-on current filaments which accompany this effect. In steady state, the energy gained from the electric field is exactly the same as the energy lost due to the phonon cooling of the hot carriers. In the simplest approximation, the carrier distribution function approaches a quasi-equilibrium Maxwell-Boltzmann distribution. In this presentation we report preliminary results on the validity of this quasi-equilibrium approximation. We have found that this approximation leads to a filament carrier density which is much lower than the density needed to achieve a quasi-equilibrium distribution. Further work is in progress.