Exceptional ballistic transport in epitaxial graphene nanoribbons.
Graphene nanoribbons will be essential components in future graphene nanoelectronics. However, in typical nanoribbons produced from lithographically patterned exfoliated graphene, the charge carriers travel only about ten nanometres between scattering events, resulting in minimum sheet resistances of about one kilohm per square. Here we show that 40-nanometre-wide graphene nanoribbons epitaxially grown on silicon carbide are single-channel room-temperature ballistic conductors on a length scale greater than ten micrometres, which is similar to the performance of metallic carbon nanotubes. This is equivalent to sheet resistances below 1 ohm per square, surpassing theoretical predictions for perfect graphene by at least an order of magnitude. In neutral graphene ribbons, we show that transport is dominated by two modes. One is ballistic and temperature independent; the other is thermally activated. Transport is protected from back-scattering, possibly reflecting ground-state properties of neutral graphene. At room temperature, the resistance of both modes is found to increase abruptly at a particular length--the ballistic mode at 16 micrometres and the other at 160 nanometres. Our epitaxial graphene nanoribbons will be important not only in fundamental science, but also--because they can be readily produced in thousands--in advanced nanoelectronics, which can make use of their room-temperature ballistic transport properties.
1] Institut für Festkörperphysik, Leibniz Universität, Hannover, Appelstrasse 2, 30167 Hannover, Germany [2].
Jens
J
Baringhaus
1] School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA [2].
Ming
M
Ruan
Institut für Festkörperphysik, Leibniz Universität, Hannover, Appelstrasse 2, 30167 Hannover, Germany.
Frederik
F
Edler
1] Université de Lorraine, UMR CNRS 7198, Institut Jean Lamour, BP 70239, 54506 Vandoeuvre-lès-Nancy, France [2] UR1 CNRS/Synchrotron SOLEIL, Saint-Aubin, 91192 Gif sur Yvette, France.
Antonio
A
Tejeda
Université de Lorraine, UMR CNRS 7198, Institut Jean Lamour, BP 70239, 54506 Vandoeuvre-lès-Nancy, France.
Muriel
M
Sicot
UR1 CNRS/Synchrotron SOLEIL, Saint-Aubin, 91192 Gif sur Yvette, France.
Amina
A
Taleb-Ibrahimi
Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Tennessee 37831, USA.
An-Ping
AP
Li
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
Zhigang
Z
Jiang
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
Edward H
EH
Conrad
1] School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA [2] Institut Néel, CNRS UJF-INP, 38042 Cedex 6, Grenoble, France.
Claire
C
Berger
Institut für Festkörperphysik, Leibniz Universität, Hannover, Appelstrasse 2, 30167 Hannover, Germany.
Christoph
C
Tegenkamp
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430, USA.
Walt A
WA
de Heer