Electrical transport across metal/two-dimensional carbon junctions: Edge versus side contacts

TL;DR

This study compares electrical transport properties of metal/2D carbon junctions with edge versus side contacts, revealing geometry-dependent differences in conductance behavior confirmed by theoretical calculations.

Contribution

It provides the first detailed comparison of edge and side contact effects on electrical conductance in 2D carbon materials, emphasizing contact geometry's role.

Findings

Edge contacts show linear dI/dV versus V dependence.

Side contacts exhibit nonlinear dI/dV proportional to V^{3/2}.

Theoretical models support experimental observations.

Abstract

Metal/two-dimensional carbon junctions are characterized by using a nanoprobe in an ultrahigh vacuum environment. Significant differences were found in bias voltage (V) dependence of differential conductance (dI/dV) between edge- and side-contact; the former exhibits a clear linear relationship (i.e., dI/dV \propto V), whereas the latter is characterized by a nonlinear dependence, dI/dV \propto V3/2. Theoretical calculations confirm the experimental results, which are due to the robust two-dimensional nature of the carbon materials under study. Our work demonstrates the importance of contact geometry in graphene-based electronic devices.