First-principles investigation on potential profile induced in graphene by surface and edge metal contacts

Abstract

Abstract To utilize graphene as an electronic device graphene has to be brought into contact with a metal electrode and the metal contact has a significant impact on the characteristics of the device. We have investigated the potential profile induced in graphene layer by metal contacts, which describes how charges are redistributed between metal and graphene in order to eliminate the difference in work function between them, by using first-principles calculations. It is found that the potential profiles are much different between surface and edge contact metal/graphene junctions. For surface contacts the potential profile is significantly influenced by Pauli exclusion interactions and bond formation between metal and graphene. On the other hand, the edge contacts lack Pauli exclusion interactions and the non-graphene-like metallic states of C atoms near the metal edges, which are induced by bond formation, are suggested to have a major effect on eliminating the work function difference.