Ultralow Specific Contact Resistivity in Metal-Graphene Junctions via Contact Engineering

A systematic investigation of graphene edge contacts is provided. Intentionally patterning monolayer graphene at the contact region creates well-defined edge contacts that lead to a 67% enhancement in current injection from a gold contact. Specific contact resistivity is reduced from 1372 ? µm for a device with surface contacts to 456 ? µm when contacts are patterned with holes. Electrostatic doping of the graphene further reduces contact resistivity from 519 to 45 ? µm, a substantial decrease of 91%. The experimental results are supported and understood via a multiscale numerical model, based on density functional theory calculations and transport simulations. The data are analyzed with regards to the edge perimeter and hole-to-graphene ratio, which provides insights into optimized contact geometries. The current work thus indicates a reliable and reproducible approach for fabricating low resistance contacts in graphene devices. A simple guideline for contact design that can be exploited to guide graphene and 2D material contact engineering is provided.