Pressure-dependent Schottky barrier at the metal-nanotube contact

We carry out first-principles density-functional calculations to investigate the electronic structure of the gold-carbon nanotube contact. It is found that a pressure applied on the gold-nanotube contact shifts the Fermi level from the valence edge to the conduction edge of the carbon nanotube. This can explain the n-type transport behavior frequently observed in the nanotube field-effect transistor using the gold as electrodes. An atomistic model is proposed for a possible origin of the pressure when the nanotube is embedded in the gold electrode.