Simplified model for ballistic current–voltage characteristic in cylindrical nanowires

The ballistic regime gives the upper limit of an electron device performance. This paper proposes a fast and efficient model for calculating the current–voltage characteristic of a cylindrical nanowire within the framework of the non-equilibrium Green's function. Under certain assumptions, the calculation is simplified to a one-dimensional problem and the modes due to the radial confinement are given by an analytical equation. We further derive an analytical expression for the current–voltage characteristic at temperature approaching 0 K. The relationship between the radius of the nanowire and the electrical current is clearly shown in this expression. The effects of the radius on the current–voltage characteristic curve are also studied. Furthermore, we plot the trend of the saturation current as the radius is increased as predicted by both the numerical result and our analytical model. Our proposed model can be further used to include electron–photon interaction in the calculation of nanoscale optoelectronic devices.