Electrostatic confinement of electrons in graphene nano-ribbons

TL;DR

This paper demonstrates electrostatic electron confinement in graphene nanoribbons using gate-induced pn junctions and disorder effects, with consistent results across multiple devices, advancing understanding of quantum effects in graphene nanostructures.

Contribution

It shows how gate voltages can electrostatically confine electrons in graphene nanoribbons, revealing Coulomb blockade and disorder effects in these devices.

Findings

Coulomb blockade observed in graphene nanoribbons

Electrostatic confinement achieved via pn junctions

Disorder-induced confinement in absence of pn junctions

Abstract

Coulomb blockade is observed in a graphene nanoribbon device with a top gate. When two pn junctions are formed via the back gate and the local top gate, electrons are confined between the pn junctions which act as the barriers. When no pn junctions are induced by the gate voltages, electrons are still confined, as a result of strong disorder, but in a larger area. Measurements on five other devices with different dimensions yield consistent results.