Two mechanisms of the negative-effective-mass instability in p-type quantum well-based ballistic p+pp+-diodes: Simulations with a load

There exist two regimes of the negative-effective-mass (NEM) instability in ballistic $p^{+}{\mathrm{pp}}^{+}-\mathrm{diodes}$ with two-dimensional hole gas in the p-base: the instability of homogeneous NEM-hole distribution in a quasineutral plasma region, and the instability of a thin accumulation layer, which forms inside a depletion region and contains NEM holes. Both instabilities lead to the development of terahertz oscillatory regimes. The regimes’ simulation in the inductance-loaded diodes with base lengths 0.05–0.15 $\mu \mathrm{m}$ demonstrates that such loads substantially enlarge the voltage range of the second regime and give rise to oscillatory regimes, which do not appear in unloaded diodes at all. Efficiencies of different oscillatory regimes are estimated.