Theoretical study of tunneling phenomena in double-barrier quantum-well heterostructures

Abstract
The resonant tunneling phenomenon through quantum-well states in one-dimensional double-barrier single-quantum-well heterostructures is studied with use of the nonequilibrium tunneling theory of Caroli et al. and a scattering-theoretic Green’s-function technique with a simple model Hamiltonian. The effect of external bias is found exactly in the calculation of the Green’s function for the junction within this model, obviating any restriction on the magnitude of the external bias. The density of states of the junction, its dependence on the external bias, and the formation of bound states in the quantum-well region are discussed. Our results for the tunneling current yield resonance peak-to-valley ratios in reasonably good agreement with experiment, indicating that this treatment of the tunnel junction, when applied to real materials, can more accurately describe existing experimental results.