All-graphene edge contacts: Electrical resistance of graphene T-junctions

Using ab-initio methods we investigate the possibility of three-terminal graphene “T-junction” devices and show that these all-graphene edge contacts are energetically feasible when the 1D interface itself is free from foreign atoms. We examine the energetics of various junction structures as a function of the atomic scale geometry. Three-terminal equilibrium Green's functions are used to determine the transmission spectrum and contact resistance of the system. We find that the most symmetric structures have a significant binding energy, and we determine the contact resistances in the junction to be in the range of 1–10 kΩ μm which is comparable to the best contact resistance reported for edge-contacted graphene-metal contacts [1,2]. We conclude that conducting all-carbon T-junctions should be feasible.