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Title: The emergence of quantum capacitance in epitaxial graphene
Authors: Ben Gouider Trabelsi, A.
Kusmartsev, F.V.
Forrester, Michael
Kusmartseva, Olga E.
Gaifullin, Marat
Cropper, Pat
Oueslati, M.
Keywords: Graphene
Quantum capacitance
Plasmonics
Raman spectroscopy
X-ray diffraction
Issue Date: 2016
Publisher: © Royal Society of Chemistry
Citation: BEN GOUIDER TRABELSI, A., 2016. The emergence of quantum capacitance in epitaxial graphene. Journal of Materials Chemistry C, 4, 5829.
Abstract: We found an intrinsic redistribution of charge arises between epitaxial graphene, which has intrinsically n-type doping, and an undoped substrate. In particular, we studied in detail epitaxial graphene layers thermally elaborated on C-terminated 4H-SiC( 4H-SiC(000-1)). We have investigated the charge distribution in graphene-substrate systems using Raman spectroscopy. The influence of the substrate plasmons on the longitudinal optical phonons of the SiC substrates has been detected. The associated charge redistribution reveals the formation of a capacitance between the graphene and the substrate. Thus, we give for the first time direct evidence that the excess negative charge in epitaxial monolayer graphene could be self-compensated by the SiC substrate without initial doping. This induced a previously unseen redistribution of the charge-carrier density at the substrate-graphene interface. There a quantum capacitor appears, without resorting to any intentional external doping, as is fundamentally required for epitaxial graphene. Although we have determined the electric field existing inside the capacitor and revealed the presence of a minigap (≈4.3meV) for epitaxial graphene on 4H-SiC face terminated carbon, it remains small in comparison to that obtained for graphene on face terminated Si. The fundamental electronic properties found here in graphene on SiC substrates may be important for developing the next generation of quantum technologies and electronic/plasmonic devices.
Description: This paper is in closed access until 27th May 2017.
Version: Accepted version
DOI: 10.1039/C6TC02048H
URI: https://dspace.lboro.ac.uk/2134/21741
Publisher Link: http://dx.doi.org/10.1039/C6TC02048H
ISSN: 2050-7526
Appears in Collections:Closed Access (Physics)

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