Accuracy of equivalent model in band-to-band tunneling simulation of semiconductor nanowires

Abstract

The accuracy of the equivalent model (EM) in the band-to-band tunneling simulation of semiconductor nanowires is investigated by constructing EMs for various semiconductor nanowires and calculating the tunneling characteristics with the non-equilibrium Green’s function method. As the target window is widened, the EM accurately reproduces not only the traveling states but also the evanescent states. The relative error of the maximum tunnel current is shown to decrease exponentially with the transport window size. It is also shown that semiconductor nanowires can be classified into two types (D-type and I-type) according to the dispersion of the evanescent mode connecting the valence and the conduction band edges, and that the D-type nanowires can be represented with a smaller EM basis size or high accuracy compared to the I-type nanowires.