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Raman Spectroscopy is able to probe disorder in graphene through defect-activated peaks. It is of great interest to link these features to the nature of disorder. Here we present a detailed analysis of the Raman spectra of graphene…

Mesoscale and Nanoscale Physics · Physics 2012-07-10 Axel Eckmann , Alexandre Felten , Artem Mishchenko , Liam Britnell , Ralph Krupke , Kostya S. Novoselov , Cinzia Casiraghi

The equilibrium optical phonons of graphene are well characterized in terms of anharmonicity and electron-phonon interactions, however their non-equilibrium properties in the presence of hot charge carriers are still not fully explored.…

Mesoscale and Nanoscale Physics · Physics 2018-02-15 C. Ferrante , A. Virga , L. Benfatto , M. Martinati , D. De Fazio , U. Sassi , C. Fasolato , A. K. Ott , P. Postorino , D. Yoon , G. Cerullo , F. Mauri , A. C. Ferrari , T. Scopigno

Edges naturally exist in a single-layer graphene sample. Similarly, individual graphene layers in a multilayer graphene sample contribute their own edges. We study the Raman spectrum at the edge of a graphene layer laid on n layer graphene…

Materials Science · Physics 2015-01-15 Q. -Q. Li , X. Zhang , W. -P. Han , Y. Lu , W. Shi , J. -B. Wu , P. -H. Tan

The authors report micro-Raman investigation of changes in the single and bilayer graphene crystal lattice induced by the low and medium energy electron-beam irradiation (5 and 20 keV). It was found that the radiation exposures results in…

Materials Science · Physics 2009-11-13 Desalegne Teweldebrhan , Alexander A. Balandin

We present a systematic study of the Raman spectra of optical phonons in graphene monolayers under tunable uniaxial tensile stress. Both the G and 2D bands exhibit significant red shifts. The G band splits into two distinct sub-bands (G+,…

Materials Science · Physics 2008-12-15 Mingyuan Huang , Hugen Yan , Changyao Chen , Daohua Song , Tony F. Heinz , James Hone

In contrary to the widely reported single and symmetric peak feature of G' (or 2D) band in Raman spectrum of graphene, we herein report the observation of splitting in G' band in free standing graphene. Our experimental findings provide a…

Materials Science · Physics 2015-06-04 Zhiqiang Luo , Chunxiao Cong , Jun Zhang , Qihua Xiong , Ting Yu

We present Raman spectroscopy measurements on single- and few-layer graphene flakes. Using a scanning confocal approach we collect spectral data with spatial resolution, which allows us to directly compare Raman images with scanning force…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 D. Graf , F. Molitor , K. Ensslin , C. Stampfer , A. Jungen , C. Hierold , L. Wirtz

We calculate the double resonant (DR) Raman spectrum of graphene, and determine the lines associated to both phonon-defect processes, and two-phonons ones. Phonon and electronic dispersions reproduce calculations based on density functional…

Mesoscale and Nanoscale Physics · Physics 2011-07-26 Pedro Venezuela , Michele Lazzeri , Francesco Mauri

We carried out micro-Raman spectroscopy of graphene layers over the temperature range from approximately 80 K to 370 K. The number of layers was independently confirmed by the quantum Hall measurements and atomic force microscopy. The…

Materials Science · Physics 2008-03-15 I. Calizo , A. A. Balandin , F. Miao , W. Bao , C. N. Lau

Under homogeneous uniaxial strains, the Raman 2D band of graphene involving two-phonon double-resonance scattering processes splits into two peaks and they altogether redshift strongly depending on the direction and magnitude of the strain.…

Mesoscale and Nanoscale Physics · Physics 2015-03-19 Duhee Yoon , Young-Woo Son , Hyeonsik Cheong

Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications. Here we review the recent results on the Raman spectroscopy and imaging of graphene. Raman spectroscopy and…

Materials Science · Physics 2008-10-17 Zhen hua Ni , Ying ying Wang , Ting Yu , Ze xiang Shen

Nanometer-scale graphene objects are attracting much research interest because of newly emerging properties originating from quantum confinement effects. We present Raman spectroscopy studies of graphene nanoribbons (GNRs) which are known…

Materials Science · Physics 2012-01-23 Sunmin Ryu , Janina Maultzsch , Melinda Y. Han , Philip Kim , Louis E. Brus

Avoiding charge density variations and impurities in graphene is vital for high-quality graphene-based devices. Here, we demonstrate an optical method using Raman 2D peak-split to monitor charge density variations in the range 1-25e10 cm-2.…

Applied Physics · Physics 2020-05-12 Zhuofa Chen , Nathan Ullberg , Mounika Vutukuru , David Barton , Anna K Swan

We present low-temperature Raman measurements on gate tunable graphene encapsulated in hexagonal boron nitride, which allows to study in detail the Raman G and 2D mode frequencies and line widths as function of the charge carrier density.…

Mesoscale and Nanoscale Physics · Physics 2023-02-15 Jens Sonntag , Kenji Watanabe , Takashi Taniguchi , Bernd Beschoten , Christoph Stampfer

The polarization dependences of the G, D, and 2D (G$'$) bands in Raman spectra at graphene bulk and edge are examined theoretically. The 2D and D bands have different selection rules at bulk and edge. At bulk, the 2D band intensity is…

Mesoscale and Nanoscale Physics · Physics 2010-11-15 K. Sasaki , K. Wakabayashi , T. Enoki

We investigate etched single-layer graphene nanoribbons with different widths ranging from 30 to 130 nm by confocal Raman spectroscopy. We show that the D-line intensity only depends on the edge-region of the nanoribbon and that…

Mesoscale and Nanoscale Physics · Physics 2011-05-06 Dominik Bischoff , Johannes Güttinger , Susanne Dröscher , Thomas Ihn , Klaus Ensslin , Christoph Stampfer

The 1+1 layer folded graphene sheets that deviate from AB stacking are successfully fabricated and their electronic structures are investigated by Raman spectroscopy. Significant blue shift of the 2D band of folded graphene compared to that…

Materials Science · Physics 2009-11-13 Zhenhua Ni , Yingying Wang , Ting Yu , Yumeng You , Zexiang Shen

Accurate and simple local strain assessment in graphene is one of the crucial tasks in device characterization. Raman spectroscopy is often used for that purpose through monitoring of the G and 2D modes. However, the shifts of those two…

Materials Science · Physics 2018-04-27 Elena del Corro , Ladislav Kavan , Martin Kalbac , Otakar Frank

The buffer layer has been analysed by combined micro-Raman and micro-transmission experiments. The epitaxial graphene growth on the (0001) Si face of 6H-SiC substrates was tuned to get a mixed surface at the early stage of graphitization…

Mesoscale and Nanoscale Physics · Physics 2012-12-07 A. Tiberj , J. R. Huntzinger , N. Camara , P. Godignon , J. Camassel

An experimental study of Raman scattering in N-layer graphene as a function of the top layer doping is reported. At high doping level, achieved by a CHF_3 plasma treatment, we observe a splitting of the $G$ band in the spectra of bilayer…

Mesoscale and Nanoscale Physics · Physics 2010-03-23 M. Bruna , S. Borini