Room temperature on-wafer ballistic graphene field-effect-transistor with oblique double-gate

Abstract

We have fabricated and measured ballistic graphene transistors with two oblique gates that can be independently biased. The gates, with lengths of about 30 nm and separated by a distance of about 40 nm, are tilted at 45° with respect to the source and drain electrodes, which are distanced at 190 nm. Electric measurements reveal specific properties of ballistic carrier transport, i.e., nonlinear drain voltage-drain current dependences with saturation regions and negative differential resistance at certain bias voltages. Tens of ballistic transistors with very large transconductances were fabricated on a chip cut from a 4 in. graphene wafer. Such double-gate transistor configurations can be used also as extremely efficient, state-of-the-art photodetectors.