Disorder induced Coulomb gaps in graphene constrictions with different aspect ratios

We present electron transport measurements on lithographically defined and etched graphene nanoconstrictions with different aspect ratios including different lengths ( l ) and widths ( w ) . A roughly length-independent disorder induced effective energy gap can be observed around the charge neutrali...

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Bibliographic Details
Published in:Applied physics letters 2011-01, Vol.98 (3), p.032109-032109-3
Main Authors: Terrés, B., Dauber, J., Volk, C., Trellenkamp, S., Wichmann, U., Stampfer, C.
Format: Article
Language:English
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Summary:We present electron transport measurements on lithographically defined and etched graphene nanoconstrictions with different aspect ratios including different lengths ( l ) and widths ( w ) . A roughly length-independent disorder induced effective energy gap can be observed around the charge neutrality point. This energy gap scales inversely with the width even in regimes where the length of the constriction is smaller than its width ( l < w ) . In very short constrictions, we observe both resonances due to localized states or charged islands and an elevated overall conductance level ( 0.1 − 1 e 2 / h ) , which is strongly length-dependent in the gap region. This makes very short graphene constrictions interesting for highly transparent graphene tunneling barriers.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.3544580