10.1 Introduction

In this chapter, we present numerical results for the transport of electrons in bulk GaAs, in a GaAs n ⁺ - n _i - n ⁺ diode and in a GaAs-MESFET obtained by means of our multigroup approach (8.17). All of these calculations are performed for the lattice temperature T _L = 300 K. We approximate the conduction band of GaAs by taking into account the ?-valley in the center of the first Brillouin zone and four equivalent L-valleys along the crystallographic directions ?1, 1, 1 ?. The zero energy level is set to the energy of the bottom of the ?-valley, in other words, ? _0? = 0. In our transport model for GaAs, we regard the acoustic deformation potential scattering (ADP) with the transition rate

(10.1)

and the ionized impurity scattering (IMP)

(10.2)

with the screening parameter = e ² N _I/ ? _st ? ₀ k _B T _L. The most important intravalley scattering mechanism for GaAs is the polar optical interaction (POP) with the transition rate

(10.3)