Relative influence of relaxation times on the frequency behaviour of GaAs

Abstract

Within the frame of the drifted Maxwellian approach, the Gunn effect in GaAs at 300 °K can be sufficiently described by only three balance equations describing carrier, momentum, and energy exchange between central and upper valleys if an ohmic damping is taken into account, representing the satellite valleys. The approximation holds for fields up to 20kV/cm and frequencies up to 200 GHz. The limiting frequency increases with the rate of particle transfer between nonequivalent valleys and is reduced by the upper valley ohmic damping and by the relative amount of energy scattered back from the upper to the central valley.