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ZO phonon of a buffer layer and Raman mapping of hydrogenated buffer on SiC(0001)
Author(s) -
Rejhon Martin,
Kunc Jan
Publication year - 2019
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5533
Subject(s) - raman spectroscopy , graphene , intercalation (chemistry) , materials science , phonon , raman scattering , buffer (optical fiber) , substrate (aquarium) , analytical chemistry (journal) , stacking , layer (electronics) , hydrogen , condensed matter physics , nanotechnology , chemistry , optics , inorganic chemistry , telecommunications , physics , oceanography , organic chemistry , chromatography , geology , computer science
We have measured spatial Raman maps of hydrogen intercalated quasi‐free standing monolayer graphene (QFSMLG) on SiC(0001). We compare Raman spectra of QFSMLG with spectra of bare buffer layer, single‐layer graphene, and bare SiC substrate. We also present the evolution of QFSMLG Raman spectra with the temperature and duration of hydrogen intercalation. We present new Raman modes, and, on the basis of polarization resolved measurements, we attribute them to the totally symmetric out‐of‐plane optical phonon (ZO) modes of the buffer layer at the Γ and M points. We show that these modes are eliminated by hydrogen intercalation; thus, they indicate onset of buffer layer decoupling from the SiC substrate. The spatial mapping of Raman scattering reveals details of the optimal hydrogen intercalation at elevated temperatures. Further increase of the intercalation temperature leads to etching of the buffer layer and underlying SiC substrate. Therefore, we show that interplay between temperature and intercalation time is a promising route towards increased graphene grain size with reduced lattice strain.