Hot hole effects in uniaxially stressedp-type germanium under E∥P∥ [1 1 1]

Abstract

High field behaviour of holes in uniaxially stressedp-type germanium for stressP and the electric fieldE along the [1 1 1] axis is studied. The field dependence of the drift velocity, the frequency dependence of the longitudinal differential mobility and the spectral dependence of the sub-band population for direct hole transitions between the upper and lower splitted sub-bands are calculated by the Monte-Carlo method. A Gunn-type negative differential mobility is demonstrated to appear atP ⩾ 7 to 8 kbar,E ≈ 0.15 to 4 kV cm⁻¹ in a frequency rangev ≈ 0 to 100 GHz. It is shown, that the stimulated emission and current increase observed by I. V. Altuhovet al. [1] cannot be ascribed to the direct hole transitions between the sub-bands because the population inversion of the transitions is absent.