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We use aberration-corrected scanning transmission electron microscopy, electron energy-loss spectroscopy, atomic force microscopy, and the density functional theory to study the structural and electronic characteristics of graphene grown on the C face of SiC. We show that for high growth temperatures the graphene/SiC (000 1) interface is dominated by a thin amorphous film which strongly suppresses the epitaxy of graphene on the SiC substrate. This film maintains an almost fixed thickness regardless of the number of the overlying graphene layers, while its chemical signature shows the presence of C, Si, and O. Structurally, the amorphous area is inhomogeneous, as its Si concentration gradually decreases while approaching the first graphene layer, which is purely s p 2 hybridized. Ab initio calculations show that the evaporation process and the creation of Si vacancies on the C face of SiC strongly enhance the …
American Physical Society
Publication date: 
10 Apr 2015

G Nicotra, I Deretzis, M Scuderi, C Spinella, P Longo, Rositsa Yakimova, F Giannazzo, A La Magna

Biblio References: 
Volume: 91 Issue: 15 Pages: 155411
Physical Review B