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Buffer layers inhomogeneity and coupling with epitaxial graphene unravelled by Raman scattering and graphene peeling.

Authors :
Wang, Tianlin
Huntzinger, Jean-Roch
Bayle, Maxime
Roblin, Christophe
Decams, Jean-Manuel
Zahab, Ahmed-Azmi
Contreras, Sylvie
Paillet, Matthieu
Landois, Périne
Source :
Carbon. Aug2020, Vol. 163, p224-233. 10p.
Publication Year :
2020

Abstract

The so-called buffer layer (BL) is a carbon rich reconstructed layer formed during SiC (0001) sublimation. The covalent bonds between some carbon atoms in this layer and underlying silicon atoms makes it different from epitaxial graphene. We report a systematical and statistical investigation of the BL signature and its coupling with epitaxial graphene by Raman spectroscopy. Three different BLs are studied: bare buffer layer obtained by direct growth (BL 0), interfacial buffer layer between graphene and SiC (c-BL 1) and the interfacial buffer layer without graphene above (u-BL 1). To obtain the latter, we develop a mechanical exfoliation of graphene by removing an epoxy-based resin or nickel layer. The BLs are ordered-like on the whole BL growth temperature range. BL 0 Raman signature may vary from sample to sample but forms patches on the same terrace. u-BL 1 share similar properties with BL 0 , albeit with more variability. These BLs have a strikingly larger overall intensity than BL with graphene on top. The signal high frequency side onset upshifts upon graphene coverage, unexplainable by a simple strain effect. Two fine peaks (1235, 1360 cm−1), present for epitaxial monolayer and absent for BL and transferred graphene. These findings point to a coupling between graphene and BL. Image 1 [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00086223
Volume :
163
Database :
Academic Search Index
Journal :
Carbon
Publication Type :
Academic Journal
Accession number :
143120350
Full Text :
https://doi.org/10.1016/j.carbon.2020.03.027