Vacancy Assisted Bilayer Graphene Contact for Monolayer Graphene Channel Devices

Contact engineering of monolayer graphene channel FETs has been a fundamental limiting factor hindering its intrinsic benefits for applications such as THz electronics, quantum sensing, quantum computing/communication devices, etc. This experimental work presents a unique technique to achieve record low contact resistance using carbon vacancy-assisted bilayer graphene contact. The bilayer graphene contact with engineered carbon vacancies lowered the metal-graphene interfacial distance and enhanced the atomic orbital overlap, eventually lowering the contact resistance. The interfacial properties and orbital interactions are investigated using density functional theory and non equilibrium Green’s function based transport computations. The reduction in contact resistance is then experimentally validated using unique Kelvin probe structures with monolayer and bilayer contacts. The captured contact resistance is as low as $\sim 36~\Omega $ . $\mu \text{m}$ , which is a record low contact resistance value reported to date.