Nonequilibrium macroscopic models of carrier dynamics in a semiconductor

Abstract

A nonequilibrium macroscopic description of carrier dynamics in a semiconductor under the influence of space-time varying fields is discussed. The description is obtained by interpolating between the Boltzmann transport and moment formulations. The resulting model is used to simulate the response of electrons in GaAs to a step change in the applied electric field. In this illustration, the nonequilibrium model is implemented using a single-valley model for GaAs. The results for average velocity and mean energy obtained with this model are compared to those obtained from a Monte Carlo simulation using a three-valley model for GaAs. The results are in reasonably good agreement. The differences between them arise primarily from the limitations of the single-valley model for GaAs for fields at which the intervalley scattering of electrons is dominant.