Rayleigh Imaging of Graphene and Graphene Layers

Casiraghi, Cinzia; Hartschuh, Achim; Lidorikis, Elefterios; Qian, Huihong; Harutyunyan, Hayk; Gokus, Tobias; Новоселов, К. С.; Ferrari, Andrea C.

doi:10.1021/nl071168m

Cited by 642 publications

(644 citation statements)

References 38 publications

(118 reference statements)

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“…Figure 4 shows the G band Raman intensity of graphene sheets on a 300 nm SiO 2 /Si substrate as a function of the number of layers [40]. The number of layers of graphene sheets is determined by Raman and contrast spectroscopy [44,46,47]. In addition to the graphene sheets with one, two, three, five, six, eight, and nine layers, samples a h have more than 10 layers, with thickness in the range ~5 nm (sample a) to ~50 nm (sample h), as determined by AFM.…”

Section: Interference Enhancement Of Graphene On a Sio 2 /Si Substratementioning

confidence: 99%

“…Multi-reflection/interference effects on contrast have been well documented in the literature but the multiple reflection of Raman signals has not [44,46,47]. By considering the multilayer interference of incident light as well as the multi-reflection of Raman signals in graphene/graphite based on Fresnel's equations, the above Raman results can be explained.…”

Section: Interference Enhancement Of Graphene On a Sio 2 /Si Substratementioning

confidence: 99%

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Raman spectroscopy and imaging of graphene

et al. 2008

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Graphene has many unique properties that make it an ideal material for fundamental studies as well as for potential applications. Here we review recent results on the Raman spectroscopy and imaging of graphene. We show that Raman spectroscopy and imaging can be used as a quick and unambiguous method to determine the number of graphene layers. The strong Raman signal of single layer graphene compared to graphite is explained by an interference enhancement model. We have also studied the effect of substrates, the top layer deposition, the annealing process, as well as folding (stacking order) on the physical and electronic properties of graphene. Finally, Raman spectroscopy of epitaxial graphene grown on a SiC substrate is presented and strong compressive strain on epitaxial graphene is observed. The results presented here are highly relevant to the application of graphene in nano-electronic devices and help in developing a better understanding of the physical and electronic properties of graphene.

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Section: Interference Enhancement Of Graphene On a Sio 2 /Si Substratementioning

confidence: 99%

Section: Interference Enhancement Of Graphene On a Sio 2 /Si Substratementioning

confidence: 99%

Raman spectroscopy and imaging of graphene

et al. 2008

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“…n 1 = n 3 = n) we find A = N πα/n = 2.3/n%. These equations are valid for N¡10 [27,76,83]. For N > 10 the thin film limit breaks down and the optical paths inside the film must be taken into account.…”

Section: Slg Absorption In the Thin Film Limitmentioning

confidence: 99%

Surface Plasmon Polariton Graphene Photodetectors

et al. 2015

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The combination of plasmonic nanoparticles and graphene enhances the responsivity and spectral selectivity of graphene-based photodetectors. However, the small area of the metal-graphene junction, where the induced electron-hole pairs separate, limits the photoactive region to sub-micron length scales. Here, we couple graphene with a plasmonic grating and exploit the resulting surface plasmon polaritons to deliver the collected photons to the junction region of a metal-graphenemetal photodetector. This results into a 400% enhancement of responsivity and a 1000% increase in photoactive length, combined with tunable spectral selectivity. The interference between surface plasmon polaritons and the incident wave introduces new functionalities, such as light flux attraction or repulsion from the contact edges, enabling the tailored design of the photodetector's spectral response. This architecture can also be used for surface plasmon bio-sensing with direct-electricreadout, eliminating the need of complicated optics.Graphene-based photodetectors (PDs) [1,2] have been reported with ultra-fast operating speeds (up to 262GHz from the measured intrinsic response time of graphene carriers [3]) and broadband operation from the visible and infrared [3][4][5][6][7][8][9][10][11][12][13][14][15][16] up to the THz [17][18][19]. The simplest graphene-based photodetection scheme relies on the metal-graphene-metal (MGM) architecture [5,7,8,11,[20][21][22], where the photoresponse is due to a combination of photo-thermoelectric and photovoltaic effects [5,7,8,11,[20][21][22]. For both mechanisms, the presence of a junction is required to spatially separate excited electronhole (e-h) pairs [5,7,8,11,[20][21][22]. At the metal-graphene junction, a work-function difference causes charge transfer and a shift of the graphene Fermi level underneath the contact [4,5,7,23], compared to that of graphene away from the contact [4,5,7,23], resulting into a build-up of an internal electric field (photovoltaic mechanism) [5,7,24,25] and into a difference of Seebeck coefficients (photo-thermoelectric mechanism) [11,21,26]. An alternative way to create a junction is to use a set of gate electrodes to electrostatically dope graphene [8,11].

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“…Due to the internal exceptionally high crystal quality [8,9] and massless Dirac fermions [10], monolayer graphene exhibits anomalous half integer quantum Hall effect [11], remarkable optical properties [12,13], ultra-high intrinsic strength [14], superior thermal conductivity [15] and extremely high charge carrier mobility [6,16,17]. It is referred to as a zero-gap semiconductor, showing an exceptionally high concentration of charge carriers and ballistic transport because of the unique Dirac cone band structure near the Fermi level.…”

Section: Introductionmentioning

confidence: 99%

Structure of graphene and its disorders: a review

Gao

Lee

et al. 2018

Science and Technology of Advanced Materials

495

187

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Monolayer graphene exhibits extraordinary properties owing to the unique, regular arrangement of atoms in it. However, graphene is usually modified for specific applications, which introduces disorder. This article presents details of graphene structure, including sp2 hybridization, critical parameters of the unit cell, formation of σ and π bonds, electronic band structure, edge orientations, and the number and stacking order of graphene layers. We also discuss topics related to the creation and configuration of disorders in graphene, such as corrugations, topological defects, vacancies, adatoms and sp3-defects. The effects of these disorders on the electrical, thermal, chemical and mechanical properties of graphene are analyzed subsequently. Finally, we review previous work on the modulation of structural defects in graphene for specific applications.

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Rayleigh Imaging of Graphene and Graphene Layers

Cited by 642 publications

References 38 publications

Raman spectroscopy and imaging of graphene

Raman spectroscopy and imaging of graphene

Surface Plasmon Polariton Graphene Photodetectors

Structure of graphene and its disorders: a review

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