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

TL;DR

This study uses ab-initio calculations to explore the feasibility and electrical properties of all-graphene T-junctions, demonstrating that such structures can have low contact resistance comparable to metal contacts.

Contribution

It introduces the concept of all-graphene T-junctions, analyzing their energetics and electrical resistance, showing their potential as feasible all-carbon electronic contacts.

Findings

Symmetric structures have high binding energy.

Contact resistance ranges from 1-10 kOhm.

All-graphene T-junctions are energetically feasible.

Abstract

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 kOhm which is comparable to the best contact resistance reported for edge-contacted graphene-metal contacts. We conclude that conducting all-carbon T-junctions should be feasible.