Three-dimensional numerical analysis of multi-mode quantum transport in zero-dimensional resonant tunnelling diodes

Abstract

Lateral-mode non-conserving resonant tunnelling through a zero-dimensional AlGaAs/InGaAs/AlGaAs resonant tunnelling diode (0D RTD) has been analysed by numerically solving the three-dimensional Schrodinger equation with scattering boundary conditions. The authors report on the effect of lateral-mode mixing, caused by elastic scattering due to an hour-glass-shaped confinement potential, on the multi-mode transmission properties and current-voltage characteristics of the device. The calculated S-matrix clearly shows both new transmission peaks in the off-diagonal components which measure the lateral-mode-non-conserving resonant tunnelling and the related Fano-resonance-type structures in the diagonal components which represent an interference between the second-order resonant tunnelling process and the conventional tunnelling process for the off-resonant condition. The difference between the energy separations of the lateral modes in the cathode region and in the quantum box leads to observable fine current peaks in the current-voltage characteristics due to the lateral-mode-conserving tunnelling.