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Defect-induced Fermi level pinning and suppression of ambipolar behaviour in graphene

Defect-induced Fermi level pinning and suppression of ambipolar behaviour in graphene
Defect-induced Fermi level pinning and suppression of ambipolar behaviour in graphene
We report on systematic study of electronic transport behaviour of low-biased, disordered graphene nanowires. We reveal the emergence of unipolar transport as the defect concentration increases beyond 0.3% where an almost insulating behaviour is observed for n-type conduction whilst a metallic behaviour is observed for p-type conduction. The conductance shows a plateau that extends through the entire side above the Dirac point (n-branch) where the conductivity coincides with the minimum conductivity at the Dirac point. Raman spectroscopy and X-ray photoemission spectroscopy were used to probe the nature of the defects created by helium ion irradiation and revealed the presence of oxygen-carbon bonds as well as sp3sp3 configurations on the irradiated samples from C KLL Auger spectrum. The observed behaviour is attributed to oxygen groups created after the sputtering of carbon atoms by incident helium ions. These groups act as charge traps, pinning the Fermi level to the Dirac point.
0008-6223
1-20
Moktadir, Zakaria
34472668-ffda-4287-8fea-2c4f3bf1e2fa
Hang, Shuojin
81fcaaf8-4887-4c09-ae9d-0771be618f0b
Mizuta, Hiroshi
f14d5ffc-751b-472b-8dba-c8518c6840b9
Moktadir, Zakaria
34472668-ffda-4287-8fea-2c4f3bf1e2fa
Hang, Shuojin
81fcaaf8-4887-4c09-ae9d-0771be618f0b
Mizuta, Hiroshi
f14d5ffc-751b-472b-8dba-c8518c6840b9

Moktadir, Zakaria, Hang, Shuojin and Mizuta, Hiroshi (2015) Defect-induced Fermi level pinning and suppression of ambipolar behaviour in graphene. Carbon, 1-20. (doi:10.1016/j.carbon.2015.05.049).

Record type: Article

Abstract

We report on systematic study of electronic transport behaviour of low-biased, disordered graphene nanowires. We reveal the emergence of unipolar transport as the defect concentration increases beyond 0.3% where an almost insulating behaviour is observed for n-type conduction whilst a metallic behaviour is observed for p-type conduction. The conductance shows a plateau that extends through the entire side above the Dirac point (n-branch) where the conductivity coincides with the minimum conductivity at the Dirac point. Raman spectroscopy and X-ray photoemission spectroscopy were used to probe the nature of the defects created by helium ion irradiation and revealed the presence of oxygen-carbon bonds as well as sp3sp3 configurations on the irradiated samples from C KLL Auger spectrum. The observed behaviour is attributed to oxygen groups created after the sputtering of carbon atoms by incident helium ions. These groups act as charge traps, pinning the Fermi level to the Dirac point.

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More information

Accepted/In Press date: 17 May 2015
e-pub ahead of print date: 21 May 2015
Organisations: Electronics & Computer Science

Identifiers

Local EPrints ID: 377444
URI: https://eprints.soton.ac.uk/id/eprint/377444
ISSN: 0008-6223
PURE UUID: ba7bdd13-e0e6-4811-bee7-614cc43bc276

Catalogue record

Date deposited: 27 May 2015 14:46
Last modified: 18 Jul 2017 04:30

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