A simple drain current model for Schottky-barrier carbon nanotube field effect transistors

Abstract

We report on a new computational model to efficiently simulate carbon\nnanotubebased field effect transistors (CNT-FET). In the model, a central\nregion is formed by a semiconducting nanotube that acts as the conducting\nchannel, surrounded by a thin oxide layer and a metal gate electrode. At both\nends of the semiconducting channel, two semi-infinite metallic reservoirs act\nas source and drain contacts. The current-voltage characteristics are computed\nusing the Landauer formalism, including the effect of the Schottky barrier\nphysics. The main operational regimes of the CNT-FET are described, including\nthermionic and tunnel current components, capturing ambipolar conduction,\nmultichannel ballistic transport and electrostatics dominated by the nanotube\ncapacitance. The calculations are successfully compared to results given by\nmore sophisticated methods based on non-equilibrium Green's function formalism\n(NEGF).\n