UV/Ozone treatment to reduce metal-graphene contact resistance

TL;DR

This paper demonstrates that ultraviolet ozone treatment at the contact interface of graphene devices significantly reduces contact resistance without damaging the graphene, improving device performance.

Contribution

The study introduces a UVO treatment method to effectively lower metal-graphene contact resistance by reducing interface contamination, with minimal impact on graphene quality.

Findings

Contact resistance reduced to less than 200 Ω·μm.

UVO treatment does not significantly damage graphene.

Effective removal of interface contaminants demonstrated.

Abstract

We report reduced contact resistance of single-layer graphene devices by using ultraviolet ozone (UVO) treatment to modify the metal/graphene contact interface. The devices were fabricated from mechanically transferred, chemical vapor deposition (CVD) grown, single layer graphene. UVO treatment of graphene in the contact regions as defined by photolithography and prior to metal deposition was found to reduce interface contamination originating from incomplete removal of poly(methyl methacrylate) (PMMA) and photoresist. Our control experiment shows that exposure times up to 10 minutes did not introduce significant disorder in the graphene as characterized by Raman spectroscopy. By using the described approach, contact resistance of less than 200 {\Omega} {\mu}m was achieved, while not significantly altering the electrical properties of the graphene channel region of devices.