Improve the transconductance of a graphene field-effect transistor by folding graphene into a wedge

Abstract

The transport property of a graphene wedge channel is studied theoretically and its leakage current through field emission is estimated when considering the effect of the internal electric field. The transconductance of the graphene transistor is improved from 0.016 to 0.321 μS μm−1 when the graphene is folded into a wedge (with angle of wedge π/6 and radius curvature 2.7 nm at the tip), while the wedge height is much smaller than the space between the top-gate and the channel. The improved transconductance is due to the locally enhanced electric field, which results in a potential well and causes electron accumulation at the wedge tip. The leakage current through field emission JFE shows a super-linear increase with the channel conductive current JDS, where overall the electron supply for the field emission at the wedge tip is improved by the channel bias voltage VDS.