Evidence For Heavy Hole and Light Hole Current Separation in P-Type   Resonant Tunneling Diodes With Prewells
  We investigate the transport of holes through $AlAs/In_{.10}Ga_{.90}As$ resonant tunneling diodes which utilize $In_xGa_{1-x}As$ prewells in the emitter with $x=0,.10,$ and $.20$. The data show an increase in peak current and bias at resonance and a concurrent increase in the peak-to-valley ratio with increasing x. We explain this enhancement in tunneling as due to confinement (or localiz- ation) of charges in the prewell and the formation of direct heavy(light) hole to heavy(light) hole conduction channels as a consequence. 
R. M. Lewis, H. P. Wei, S. Y. Lin, and J. F. Klem