An extended model for carbon nanotube field-effect transistors

In this paper, we present an extended Schottky barrier model that includes two new crucial aspects: i) current injection from the metal contacts into the channel does not occur directly but is mediated by the segment of the nanotube underneath the metal contacts whose density of states (DOS) is altered through the proximity of the metal (referred to in the following as "metal-modified" nanotube segment); and ii) the energy gap of carbon nanotubes with an average diameter of ∼1.4 nm seems to be rather ∼1.2 eV than ∼0.7 eV as typically assumed for these type of tubes. Our simulation allows us for the first time to quantitatively describe subthreshold characteristics of CNFETs over the entire gate voltage range.