A Physical Model of Contact Resistance in Ti-Contacted Graphene-Based Field Effect Transistors

Abstract

The effect of device fabrication processing conditions is often overlooked in the evaluation of the contact resistance in metal–graphene contact. In this work, we investigate the Ti–graphene contact resistance theoretically and experimentally. A compact model has been proposed to reveal and evaluate the role of different factors in controlling the value of contact resistance. A layer of oxidized Ti or polymer residues at the Ti–graphene interface has been considered to explain the reduced carrier transmission probability through the interface. Experimental results report a low contact resistance as small as 271.45 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega ~\cdot \mu \text{m}$ </tex-math></inline-formula> and our model agrees with the measured values. The proposed model explains the large variation of the contact resistance reported in the literature up to date and help to improve metal–graphene contact for future applications.