Raman spectra of multilayer graphene under high temperatures

dc.creatorAndrei Alaferdov
dc.creatorRaluca Savu
dc.creatorCristiano Fantini Leite
dc.creatorLuiz Gustavo de Oliveira Lopes Cançado
dc.creatorStanislav Moshkalev
dc.date.accessioned2025-04-15T16:53:22Z
dc.date.accessioned2025-09-09T00:10:05Z
dc.date.available2025-04-15T16:53:22Z
dc.date.issued2020
dc.identifier.doihttps://doi.org/10.1088/1361-648X/ab95ce
dc.identifier.issn1361-648X
dc.identifier.urihttps://hdl.handle.net/1843/81620
dc.languageeng
dc.publisherUniversidade Federal de Minas Gerais
dc.relation.ispartofJournal of physics: condensed matter
dc.rightsAcesso Restrito
dc.subjectEspectroscopia de Raman
dc.subject.otherRaman spectra
dc.titleRaman spectra of multilayer graphene under high temperatures
dc.typeArtigo de periódico
local.citation.issue38
local.citation.volume32
local.description.resumoFor graphitic materials, Raman technique is a common method for temperature measurements through analysis of phonon frequencies. Temperature (T) induced downshift of the bond-stretching G mode (ΔG) is well known, but experimentally obtained thermal coefficients ΔG/ΔT vary considerably between diverse works. Further, ΔG/ΔT coefficients usually were evaluated for relatively low temperatures and found to differ strongly for mono, a few and multilayer graphene. We studied G band behavior in freely suspended multilayer graphene flakes (or graphite nanoflakes) under localized heating by a laser beam. Analysis of Stokes and anti-Stokes signals showed that G band has a complex structure and can be deconvoluted into several peaks that demonstrate distinctly different behavior under heating. A plausible assumption is that these peaks correspond to several groups of graphitic layers (surface, near-surface and bulk) and then different thermal coefficients were determined for these groups. This behavior can be explained by decreasing interaction between surface layers and underlying material at high temperatures that affects especially vibrational properties of a few outermost layers. Estimates of temperatures using anti-Stokes/Stokes intensity ratio (IaS/IS) were also done to give results comparable with those obtained from G band downshift, TΔG ≈ TaS/S, supporting the proposed model. The range of temperatures obtained by laser heating, as evaluated by both methods, was from 450 to 1200 K.
local.identifier.orcidhttps://orcid.org/0000-0002-0638-3829
local.identifier.orcidhttps://orcid.org/0000-0001-9866-3598
local.identifier.orcidhttps://orcid.org/0000-0003-0436-7857
local.identifier.orcidhttps://orcid.org/0000-0003-0816-0888
local.identifier.orcidhttps://orcid.org/0000-0002-6973-506X
local.publisher.countryBrasil
local.publisher.departmentICX - DEPARTAMENTO DE FÍSICA
local.publisher.initialsUFMG
local.url.externahttps://iopscience.iop.org/article/10.1088/1361-648X/ab95ce

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