Long distance distortions in the graphene near the edge of planar metal contacts

Abstract

The properties of the planar junction between graphene layer and thin film metal structures are important for formation of the electronic devices integrating the structures of the two-dimensional materials. However, the properties of the graphene-metal contacts are still weakly controlled in the large area device fabrication. In this report we demonstrated an approach acceptable to characterize the long distance distortion area produced by the metal contact edges in the graphene monolayer. The systematic analysis of the Raman maps of the graphene is performed aiming to describe the changes in the graphene monolayer produced by the technology dependent parameters in the planar structures used for the measurements by the circular transmission line method. It was proved that Au contacts produce the compressive strain in the graphene layer in the distances up to about 2–4 μm from the contact edges. The transition between the n- and p-type of the doping is combined with the compression strain in the long distance graphene distortion area close to the Ni-contact edges. An equivalent electrical circuit is proposed for description of the graphene distortion area near the contact edges.