Threshold voltage dispersion and impurity scattering limited mobility in carbon nanotube field effect transistors with randomly doped reservoirs

This paper have investigated the threshold voltage dispersion and the impurity scattering limited mobility in carbon nanotube field effect transistors with randomly doped source and drain extensions. Accurate transport simulations have been performed solving the self-consistent 3D Poisson-Schrodinger equation, within the non-equilibrium Green's function formalism. In particular, non-ballistic transport has been taken into account, due to elastic scattering with ionized impurities in doped source and drain extensions. The authors show that even if the channel is undoped, impurity scattering in the source and drain extensions can significantly reduce the effective mobility, intrinsically inhibiting ballistic transport, while the effect of random dopants on the dispersion of the threshold voltage is limited