language: en

[Confidential: not for distribution. Submitted to IOP Publishing for peer review]

27 November 2009

Conductivity engineering of graphene by defect formation

S.H.M. Jafri 1, * , K. Carva 2 , E. Widenkvist 3 , T. Blom 1, * , B. Sanyal 2 , J. Fransson 2 , O. Eriksson 2 , U. Jansson 3 , H. Grennberg 4 , O. Karis 2 , R.A. Quinlan 5 , B.C. Holloway 6 and K. Leifer 1
1 Department of Engineering Sciences,
Box 534, ˚
Ångström Laboratory, Uppsala University,
751 21 Uppsala, Sweden.
2 Department of Physics and Materials Science,
Box 534, ˚
Ångström Laboratory, Uppsala University,
751 21 Uppsala, Sweden.
3 Department of Materials Chemistry,
Box 534, ˚
Ångström Laboratory, Uppsala University,
751 21 Uppsala, Sweden.
4 Department of Biochemistry and Organic Chemistry,
Box 576,
Uppsala University,
751 23 Uppsala, Sweden.
5 Department of Applied Science, College of William and Mary,
325 McGlothin Street Hall, Williamsburg, 23187, Virginia, USA.
6 Luna Innovations Incorporated, NanoWorks Division,
521 Bridge Street, Danville, 24541, Virginia, USA.

[* These authors contributed equally to the experimental work]

E-mail: Klaus.Leifer@Angstrom.uu.se

Abstract. Transport measurements have revealed several exotic electronic properties of graphene. The possibility to influence the electronic structure and hence control the conductivity by adsorption or doping with adatoms is crucial in view of electronics applications. Here, we show that in contrast to expectation, the conductivity of graphene increases with increasing concentration of vacancy defects, by more than one order of magnitude. We obtain a pronounced enhancement of the conductivity after insertion of defects by both quantum mechanical transport calculations as well as experimental studies of carbon nano-sheets. Our finding is attributed to the defect induced mid-gap states, which create a region exhibiting metallic behavior around the vacancy defects. The modification of the conductivity of graphene by the implementation of stable defects is crucial for the creation of electronic junctions

PACS numbers: 73.61.Wp, 72.80.-r

[S.H.M. Jafri et al. Conductivity engineering of graphene 2]

1. Introduction