Low-Contact-Resistance Graphene Devices with Nickel-Etched-Graphene Contacts

The performance of graphene-based transistors is often limited by the large electrical resistance across the metal-graphene contact. We report an approach to achieve ultra-low resistance metal contacts to graphene transistors. Through a process of metal-catalyzed etching in hydrogen, multiple nano-sized pits with zigzag edges are created in the graphene that form strong chemical bonds with deposited nickel metallization for source-drain contacts without the need for further annealing. This facile contact treatment prior to electrode metallization results in contact resistance as low as 100 ohm-um in single-layer graphene field-effect transistors, and 11 ohm-um in bilayer graphene transistors. The treatment is compatible with complementary metal-oxide-semiconductor fabrication processes, and holds great promise to meet the contact performance required for the integration of graphene in future integrated circuits.