A model for resonant and sequential tunneling in the presence of scattering

In this paper we present a model to calculate the coherent and the sequential tunneling (or incoherent) transmission probabilities across a double-barrier heterojunction in the presence of scattering centers. The model, based on the previously reported transmission-line technique, provides a simple, yet powerful method to integrate these two different tunneling mechanisms. It is shown that if the scattering processes are taken into account, the coherent tunneling mechanism is strongly affected near the resonant peaks. On the other hand, the incoherent tunneling process, which arises due to the presence of scattering centers, dominates as the scattering lifetime is decreased. Effects of the scattering process on the current-voltage characteristics are investigated.