Surface roughness and electron backscattering in high aspect ratio silicon nanowires

Four contact current voltage characteristics of high aspect ratio, moderately doped silicon nanowires will be presented and discussed. A nonlinear behavior of the current as a function of the voltage drop has been detected, at room temperature, in small silicon nanowires: the current increases quadratically with respect to the voltage drop increasing. The dependency of this nonlinear behavior with temperature is reported. In this work it will be shown that a possible explanation of this effect can be given taking in account the silicon nanowire surface roughness, that drives the carrier backscattering. This hypothesis is supported by Monte Carlo simulations based on a simple model. The simulation results are in qualitative agreement with the experimental data.