Coherence of resonant tunneling in heterostructures

A simple argument is put forward to substantiate the rule that either coherent resonant tunneling or sequential tunneling will occur according to whether the natural energy width for the former (in frequency units) is large compared to or small compared to the scattering frequency for an electron in the quantum-well two-dimensional subband based on the resonant quasilevel. © 1987 The American Physical Society.