Approaching ballistic transport in suspended graphene
The discovery of graphene 1 , 2 raises the prospect of a new class of nanoelectronic devices based on the extraordinary physical properties 3 , 4 , 5 , 6 of this one-atom-thick layer of carbon. Unlike two-dimensional electron layers in semiconductors, where the charge carriers become immobile at low...
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Published in | Nature nanotechnology Vol. 3; no. 8; pp. 491 - 495 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.08.2008
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | The discovery of graphene
1
,
2
raises the prospect of a new class of nanoelectronic devices based on the extraordinary physical properties
3
,
4
,
5
,
6
of this one-atom-thick layer of carbon. Unlike two-dimensional electron layers in semiconductors, where the charge carriers become immobile at low densities, the carrier mobility in graphene can remain high, even when their density vanishes at the Dirac point. However, when the graphene sample is supported on an insulating substrate, potential fluctuations induce charge puddles that obscure the Dirac point physics. Here we show that the fluctuations are significantly reduced in suspended graphene samples and we report low-temperature mobility approaching 200,000 cm
2
V
−1
s
−1
for carrier densities below 5 × 10
9
cm
−2
. Such values cannot be attained in semiconductors or non-suspended graphene. Moreover, unlike graphene samples supported by a substrate, the conductivity of suspended graphene at the Dirac point is strongly dependent on temperature and approaches ballistic values at liquid helium temperatures. At higher temperatures, above 100 K, we observe the onset of thermally induced long-range scattering.
The novel electronic properties of graphene can be compromised when it is supported on an insulating substrate. However, suspended graphene samples can display low-temperature mobility values that cannot be attained in semiconductors or non-suspended graphene, and the conductivity approaches ballistic values at liquid-helium temperatures. |
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Bibliography: | SourceType-Other Sources-1 ObjectType-Article-2 content type line 63 ObjectType-Correspondence-1 |
ISSN: | 1748-3387 1748-3395 |
DOI: | 10.1038/nnano.2008.199 |