Improved understanding of metal–graphene contacts

Metal–graphene (M–G) contact resistance (RC) is studied through extensive experimental characterization, Monte–Carlo transport simulations and Density Functional Theory (DFT) analysis. We show that the back–gate voltage dependence of RC cannot be explained only in terms of the resistance of the junction at the edge between contact and channel region. Experiments and DFT calculations indicate a consistent picture where both Ni and Au contacts have a M–G distance larger than the minimum energy distance, and where the M–G distance is crucial in determining the RC value.