Electron Transport in Disordered Graphene Nanoribbons

TL;DR

This study investigates electron transport in disordered graphene nanoribbons, revealing a width-dependent transport gap, localization effects, and the influence of charging effects on activation energy across different temperatures.

Contribution

It provides new insights into the transport gap formation and charge localization in graphene nanoribbons, highlighting the role of geometric capacitance and charging effects.

Findings

Transport gap inversely proportional to width

Transition from thermally activated to variable range hopping

Charging effects significantly contribute to activation energy

Abstract

We report an electron transport study of lithographically fabricated graphene nanoribbons of various widths and lengths at different temperatures. At the charge neutrality point, a length-independent transport gap forms whose size is inversely proportional to the width. In this gap, electron is localized, and charge transport exhibits a transition between simple thermally activated behavior at higher temperatures and a variable range hopping at lower temperatures. By varying the geometric capacitance through the addition of top gates, we find that charging effects constitute a significant portion of the activation energy.