Random Impurity And Phonon-Scattering Processes In Multibarrier Structures

In mesoscopic devices, in addition to the tunnel barriers, the electrons interact with a random configuration of impurities as well as with phonons. The scattering processes are usually modeled using (a) Matthiessen's rule with (b) phenomenological parameters. In this paper, we investigate the validity of such scattering models and propose an alternative approach based on the Keldysh formulation and the diagrammatic analysis. Consequently, the scattering rates depend on the strength of the disorder, the temperature, the electron energy as well as on the spatial coordinates. However, we show that the semiclassical Matthiessen rule can be used to combine the two scattering rates in quantum effect devices assuming large electron mean free paths and within the scope of self-consistent Born approximation. The assumption of a large mean-free path remains valid for moderately strong disorder even at room temperature, which makes our model suitable for practical simulation of electron transport.