Anomalous length scaling of carbon nanotube-metal contact resistance: An ab initio study

Employing open-ended carbon nanotubes (CNTs) with and without hydrogen termination, we study the length scaling of metal-CNT contact resistance and its correlation with chemical bonding from first principles. Both models similarly show a transition from the fast-growing short-length scaling to the slow-growing long-length scaling. However, while the hydrogenated CNTs have much lower short-length resistances than H-free CNTs, Schottky barrier of the former is almost twice thicker and its eventual long-length-limit resistance becomes significantly higher. This demonstrates the critical role of atomistic details in metal-CNT contacts and localized CNT edge states for the Schottky barrier shape and metal-induced gap states.