Temperature and face dependent copper-graphene interactions

The interaction between graphene and metals represents an important issue for the large-area preparation of graphene, graphene transfer and the contact quality in graphene devices. We demonstrate a simple method for estimating and manipulating the level of interaction between graphene and copper single crystals through heat treatment, at temperatures from 298 K to 1073 K. We performed in-situ Raman spectroscopy showing Cu face-specific behavior of the overlying graphene during the heat treatment. On Cu(1 1 1) the interaction is consistent with theoretical predictions and remains stable, whereas on Cu(1 0 0) and Cu(1 1 0), the initially very weak interaction and charge transfer can be tuned by heating. Our results also suggest that graphene grown on Cu(1 0 0) and Cu(1 1 0) is detached from the copper substrate, thereby possibly enabling an easier graphene transfer process as compared to Cu(1 1 1).