Subthreshold slope below 60 mV/decade in graphene transistors induced by channel geometry at the wafer-scale

Abstract In this paper, we demonstrate experimentally that field-effect transistors with nanoconstricted graphene monolayer channels have a subthreshold swing (SS) below 60 mV/dec, which is slightly dependent on temperature. Two shapes of nanoconstricted graphene monolayers are considered: (i) a bow-tie shape, representative for a symmetric channel, and (ii) a trapezoidal shape, which illustrates an asymmetric channel. While both types of nonuniform channels are opening a bandgap in graphene, thus showing an on/off ratio of 10 5 , the SS in the graphene bow-tie channel is below 60 mV/dec in the temperature range 25 °C–44 °C.