Sub-10 nm graphene nano-ribbon tunnel field-effect transistor

We report a temperature independent subthreshold slope (SS) of ∼47 mV/dec at low temperature in a triple top gate graphene tunnel field-effect transistor (TFET). The outer gates are used to define the p and n-doped regions of the ∼9.4 nm wide graphene nanoribbon, while the middle gate is used to switch the device between the ON and OFF states. Due to the flexibility of electrostatic doping, the device characteristics are compared in different configurations, specifically, field-effect transistor (FET) mode and TFET mode. A minimum SS of ∼47 mV/dec along with a saturation current density of ∼8.51 μA/μm is realized in the case of TFET mode at 5 K. This low SS is found to be temperature independent up to 40 K, after which an exponential increase is observed with a slope of 8.4 V/dec at 300 K. In clear contrast, linear temperature dependence of the SS is found in the case of FET mode.