Thermal conductivity measurements of suspended graphene with and without wrinkles by micro-Raman mapping

Chen, Shanshan; Li, Qiongyu; Zhang, Qimin; Qu, Yan; Ji, Hengxing; Ruoff, Rodney S.; Cai, Weiwei

doi:10.1088/0957-4484/23/36/365701

Cited by 131 publications

(100 citation statements)

References 14 publications

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“…23 The advantage of Raman spectroscopy and imaging in determining the number of graphene layers is that it does not depend on the substrate used. 24 Figures 6 and 7 show Raman intensity images of the sample S 7 on Quartz substrate obtained when plotting the peak intensity as a function of the spatial location for the three bands (1330 cm −1 in red, 1580 cm −1 in green and 2660 cm −1 in blue). From the mapping images, it is clear that the graphene sheets are uniformly …”

Section: Resultsmentioning

confidence: 99%

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Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

Gayathri

Prakash

Kottaisamy³

et al. 2014

AIP Advances

181

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The exfoliation of graphene from pristine graphite in a liquid phase was achieved successfully via sonication followed by centrifugation method. Ultraviolet–visible (UV–vis) spectra of the obtained graphene dispersions at different exfoliation time indicated that the concentration of graphene dispersion increased markedly with increasing exfoliation time. The sheet-like morphology of the exfoliated graphene was revealed by Scanning Electron Microscopy (SEM) image. Further, the morphological change in different exfoliation time was investigated by Atomic Force Microscopy (AFM). A complete structural and defect characterization was probed using micro-Raman spectroscopic technique. The shape and position of the 2D band of Raman spectra revealed the formation of bilayer to few layer graphene. Also, Raman mapping confirmed the presence of uniformly distributed bilayer graphene sheets on the substrate.

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Section: Resultsmentioning

confidence: 99%

“…22 The number of layers present in the sample can also be determined. 18 Raman mapping of graphene 23,24 has been made for micro-mechanically cleaved samples, graphene from CVD, etc.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

Gayathri

Prakash

Kottaisamy³

et al. 2014

AIP Advances

181

View full text Add to dashboard Cite

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“…While the general consensus is that the thermal conductivity of suspended graphene is greater than 2000 W/m K at room temperature, [2][3][4] sometimes contradictory findings of various approaches (molecular dynamics, [5][6][7][8] Boltzmann-Peierls, [9][10][11][12][13][14] Landauer, 4,15 non-equilibrium Green's function, 16,17 optical thermometry experiments 2,3,7,[18][19][20] ) have led to considerable confusion regarding the fundamental physics of thermal transport in graphene. One example relevant to this work is the size dependence of thermal conductivity of unstrained graphene devices, which has been predicted to diverge with increasing device size, [21][22][23][24] but for which conclusive experimental evidence is lacking.…”

Section: Introductionmentioning

confidence: 99%

Deviational simulation of phonon transport in graphene ribbons with ab initio scattering

Landon

Hadjiconstantinou

2014

Journal of Applied Physics

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We present a deviational Monte Carlo method for solving the Boltzmann-Peierls equation with ab initio 3-phonon scattering, for temporally and spatially dependent thermal transport problems in arbitrary geometries. Phonon dispersion relations and transition rates for graphene are obtained from density functional theory calculations. The ab initio scattering operator is simulated by an energy-conserving stochastic algorithm embedded within a deviational, low-variance Monte Carlo formulation. The deviational formulation ensures that simulations are computationally feasible for arbitrarily small temperature differences, while the stochastic treatment of the scattering operator is both efficient and exhibits no timestep error. The proposed method, in which geometry and phonon-boundary scattering are explicitly treated, is extensively validated by comparison to analytical results, previous numerical solutions and experiments. It is subsequently used to generate solutions for heat transport in graphene ribbons of various geometries and evaluate the validity of some common approximations found in the literature. Our results show that modeling transport in long ribbons of finite width using the homogeneous Boltzmann equation and approximating phonon-boundary scattering using an additional homogeneous scattering rate introduces an error on the order of 10% at room temperature, with the maximum deviation reaching 30% in the middle of the transition regime.

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“…Meanwhile, the needs of different SLGS engineering applications can be met by controlling the wrinkling geometry con¯guration, direction angle, wavelength and amplitude. [4][5][6][7][8][9][10][11] Thus, revealing the physical nature and evolution of the graphene wrinkling has remarkable academic value and engineering background.…”

Section: Introductionmentioning

confidence: 99%

Wrinkling in Graphene Subjected to Gradient Tension

Huang

Han

2015

NANO

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In the present study, the initiation and evolution mechanisms of wrinkles in a square single layer graphene sheet (SLGS) under gradient tensile displacements are investigated based on molecular dynamics (MD) simulations. The mechanism of wrinkling process is elucidated by studying the atomic out-of-plane displacements development of the key atoms in SLGS. It reveals that the loading and boundary conditions play dominant roles in the wrinkling deformation of graphene. The dependences of the wrinkling amplitude, wavelength, out-of-plane displacement, direction angle and wrinkling area ratio on the applied gradient tensile displacements are obtained. The e®ects of temperature, size of graphene and loading grads on graphene wrinkling are investigated.

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Thermal conductivity measurements of suspended graphene with and without wrinkles by micro-Raman mapping

Cited by 131 publications

References 14 publications

Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

Synthesis of few layer graphene by direct exfoliation of graphite and a Raman spectroscopic study

Deviational simulation of phonon transport in graphene ribbons with ab initio scattering

Wrinkling in Graphene Subjected to Gradient Tension

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