Tunneling of x-point electrons in triple barrier diodes

Abstract

Tunnelings of X-point electrons are observed in MBE grown AlAs-well, Al 0.5Ga 0.5As-barrier triple barrier diodes. In this structure, X-point minima are the lowest conduction band. At 85 K, tunneling peaks are observed both in the thicker and the thinner barrier diode. Although there is a large difference in current density, bias voltages for respective current peaks are very similar for these two diodes. This rules out the possibility of resonant tunnelings through a parasitic Γ-point quantum well in a Al 0.5Ga 0.5As barrier. Five current peaks are identified and these are assigned as the tunnelings from the ground subband in one well to the ground, the first excited, and the second excited subband in the other well. Comparison with a Γ-point resonant tunneling diode shows that the electron mass which defines the subband energy levels in the well is the X-point transverse mass.