Coulomb oscillations in three-layer graphene nanostructures

TL;DR

This paper reports on the fabrication and characterization of a tunable three-layer graphene single electron transistor, demonstrating Coulomb oscillations and Coulomb diamonds, with insights into localized states and transport gaps.

Contribution

It introduces a three-layer graphene SET with electrostatic tuning and detailed analysis of tunneling barriers and Coulomb blockade phenomena.

Findings

Observation of Coulomb oscillations and diamonds

Identification of localized states in constrictions

Charging energy of approximately 0.6 meV

Abstract

We present transport measurements on a tunable three-layer graphene single electron transistor (SET). The device consists of an etched three-layer graphene flake with two narrow constrictions separating the island from source and drain contacts. Three lateral graphene gates are used to electrostatically tune the device. An individual three-layer graphene constriction has been investigated separately showing a transport gap near the charge neutrality point. The graphene tunneling barriers show a strongly nonmonotonic coupling as function of gate voltage indicating the presence of localized states in the constrictions. We show Coulomb oscillations and Coulomb diamond measurements proving the functionality of the graphene SET. A charging energy of $\approx 0.6$ meV is extracted.