▎ 摘　　要

Investigation of the conductance properties of metal-graphene contacts is essential for the future nano-electronics technology. In this study, we focus on the conductance mechanism and the voltage-dependent transport properties of both p-type and n-type graphene-metal contacts. Copper and gold are chosen as the contact metal for n-type and p-type doped graphene-metal interface, respectively. Utilizing first principles quantum mechanical calculations with density functional theory in conjunction with Green's function formalism, transmission spectra of graphene-metal contacts and the voltage-dependent variations of the current and the resistance are obtained. Finally, it is shown that obtained resistance-voltage behaviours of graphene-metal contacts are in consistent with the results reported in the literature and the voltage-dependency of the contact resistance has to be taken into consideration for the nanoscale circuit design process. (C) 2013 Elsevier B. V. All rights reserved.