Impact of Contact Configuration on Contact Resistance in Ultranarrow Graphene Nanoribbon Devices

Contact resistance strongly deteriorates the performance of devices based on 2-D materials and their nanostructures, masking their exceptional electronic and transport properties. This work explores the dependence of contact resistance (
${R}_{C}$
) of graphene nanoribbon (GNR) devices on contact geometry using atomistic quantum transport simulations. The influence and contributions of edge and top contacts and GNR width scaling on
${R}_{C}$
is studied in detail. Metallization effects on the density of states, transmission, and GNR field-effect transistor (GNR FET) driving current are investigated. We show that wider GNRs (~4 nm) exhibit edge-dominated transport and lower
${R}_{C}$
than the ultranarrow GNRs (~0.4 nm) that exhibit much higher contact resistance which is also dependent on the contact area.