Ab initio investigation of charge transfer technique for control of Schottky contacts in CNTs

Abstract

The mechanism of charge transfer for doping p-type Palladium-contacted Carbon Nanotube Field Effect Transistors (CNTFETs) using SbCl6 is investigated via ab initio Density Functional Theory (DFT). The interaction of SbCl6 with a (100)-Pd surface leads to an adsorption of a Chlorine atom, which peels off from a rehybridized SbCl5, lowering the workfunction of Pd. The interaction of SbCl6 with carbon nanotube having different diameters shows that the molecule is repulsed from the surface of the nanotube, after acquiring an electron from the CNT for neutralization. The band structure calculation reveals that this exchange of charge enables the nanotube to be doped p-type. Hence both interactions serve to enhance injection of holes from Pd to the CNT.