▎ 摘　　要

A new double-contact geometry for graphene devices is studied and compared to traditional top contacts. Double contacts consist of metal below and above the graphene in a sandwich-type configuration. Four-probe structures were tested for both single-layer [chemical-vapor-deposition (CVD)-grown] graphene and bilayer (mechanically exfoliated) graphene, with both showing a decrease in contact resistance of at least 40% and an increase in transconductance greater than 20%. CVD-grown single-layer graphene transistors exhibited contact resistance as low as 260 Omega . mu m, with an average of 320 Omega . mu m. This new geometry can help minimize the impact of contacts on graphene device performance.