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

TL;DR

This paper reports the fabrication and measurement of ballistic graphene transistors with oblique double gates, demonstrating unique transport properties and potential applications in high-performance photodetectors.

Contribution

It introduces a novel double-gate graphene transistor design with oblique gates, revealing ballistic transport phenomena and high transconductance on a wafer scale.

Findings

Observation of nonlinear drain current dependence and negative differential resistance.

Successful fabrication of multiple ballistic transistors on a 4-inch wafer.

Potential use as highly efficient photodetectors.

Abstract

We have fabricated and measured ballistic graphene transistors with two oblique gates that can be independently biased. The gate lengths are about 38 nm and are separated by a distance of 30 nm, the tilting angle being of 45o with respect to source and drain electrodes distanced at 190 nm. Electric measurements reveal specific properties of ballistic carrier transport, i.e. nonlinear drain voltage-drain current dependence, showing a saturation region, and negative differential resistance at certain bias voltages, which cannot be explained without physical mechanisms related to ballistic transport. Tens of ballistic transistors, with very large transconductances, were fabricated on a chip cut from a 4 inch graphene wafer. Such double-gate transistor configurations can be used also as extremely efficient, state-of-the-art photodetectors.