Minority electron transport across p+ doped submicron layers of GaAs

Abstract

The dynamics of transient transport of minority electrons injected into p+ doped submicron layers of GaAs have been investigated using ensemble Monte Carlo method. It is found that the transit times of electrons across these layers are longer or shorter depending on the electric field strength, injection energy, and the width of the layers. The transit time across a 0.4 μm p+ doped GaAs layer increased from 1.0 to 2.0 ps at 10 kV/cm, while it decreased from about 3.0 to 2.0 ps at 50 kV/cm when the inelastic scattering of the minority electrons by the hole plasma is taken into account. Also, the calculated transit times across a 0.4 μm wide layer do not show any significant dependence on the injection energy when electron–hole (e–h) interaction is accounted for. The average drift velocity across the 0.4 μm layer doped p = 2 × 1018 cm−3 is 2 × 107 cm/s which is more than twice the saturation velocity in GaAs. This is attributed to the role of the e–h interaction which leads to reducing both the mobility of electrons and their transfer rates to the upper valleys in GaAs, and the rapid thermalization of the energy and momentum distributions of the electrons.