▎ 摘　　要

We study graphene-metal static contacts by fabricating the transmission line model (TLM) pattern on a graphene nanoribbon (GNR) and dynamic contacts by GNR nano-electromechanical (GNEM) switches with and without periodic concave patterns on the suspended top electrode. A negative contact resistance extracted from the results of TLM analysis is attributable to the inhomogeneity of GNRs owing to the doping from the metal and the substrate. All the dynamic contacts in GNEM switches show clear pull-in operations, which are not reversible. GNEM switches with periodic arrays of concave contacts show global pull-in onto the bottom surface of the concave and then exhibit local pull-in onto the slanted sidewall surfaces of the concave, which is confirmed by finite element method simulation. In addition, plastic deformation at the contact is observed as a result of the local pull-in failure mode, which completely hinders the GNRs from pulling out from the contact surface. (C) 2017 The Japan Society of Applied Physics