Electrical transport in suspended and double gated trilayer graphene

TL;DR

This paper reports on the fabrication of high-quality suspended and double gated trilayer graphene devices, demonstrating high mobility, ballistic transport, and electric field-induced energy gaps, with quantum Hall effects observed at low magnetic fields.

Contribution

It introduces a fabrication process for high-quality trilayer graphene devices and characterizes their electrical transport properties, including mobility and quantum Hall effects.

Findings

Charge carrier mobility exceeds 20000 cm^2/Vs

Ballistic transport observed over 200 nm scale

Large on/off current ratio up to 250 in ABC-stacked trilayers

Abstract

We present a fabrication process for high quality suspended and double gated trilayer graphene devices. The electrical transport measurements in these transistors reveal a high charge carrier mobility (higher than 20000 cm^2/Vs) and ballistic electric transport on a scale larger than 200nm. We report a particularly large on/off ratio of the current in ABC-stacked trilayers, up to 250 for an average electric displacement of -0.08 V/nm, compatible with an electric field induced energy gap. The high quality of these devices is also demonstrated by the appearance of quantum Hall plateaus at magnetic fields as low as 500mT.