Probing Charged Impurities in Suspended Graphene Using Raman Spectroscopy

Ni, Zhenhua; Yu, Ting; Luo, Zhi; Wang, Xiaocong; Liu, Lei; Wong, Chee Chung; Miao, Jianmin; Huang, Wei; Shen, Zexiang

doi:10.1021/nn900130g

Cited by 206 publications

(185 citation statements)

References 32 publications

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“…The experimental value for graphene samples on a substrate is typically I 2D /I G ≈ 5 [6,13]. For suspended samples, the ratio can be I 2D /I G ≈ 9 [28] and even I 2D /I G ≈ 17 [29]. Still, the experimental ratio is about 10 times smaller than the calculated one.…”

Section: Discussionmentioning

confidence: 94%

Calculation of the RamanGpeak intensity in monolayer graphene: role of Ward identities

Basko

2009

New J. Phys.

119

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The absolute integrated intensity of the single-phonon Raman peak at 1580cm −1 is calculated for a clean graphene monolayer. The resulting intensity is determined by the trigonal warping of the electronic bands and the anisotropy of the electron-phonon coupling, and is proportional to the second power of the excitation frequency. The main contribution to the process comes from the intermediate electron-hole states with typical energies of the order of the excitation frequency, contrary to what has been reported earlier. This occurs because of strong cancellations between different terms of the perturbation theory, analogous to Ward identities in quantum electrodynamics.

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Section: Discussionmentioning

confidence: 94%

Calculation of the RamanGpeak intensity in monolayer graphene: role of Ward identities

Basko

2009

New J. Phys.

119

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“…The well-defined Raman spectrum reflects the good crystallinity of the MnO 2 in the composite material. The observed reduction of the 2D peak intensity with respect to G peak is a clear indication of incorporation of MnO 2 as impurity to graphene foam which is due to the interaction of the graphene with MnO 2 [42]. The crystallographic structure of the composite was determined by XRD.…”

Section: Resultsmentioning

confidence: 99%

Microwave assisted synthesis of MnO2 on nickel foam-graphene for electrochemical capacitor

Bello

Fashedemi

Fabiane

et al. 2013

Electrochimica Acta

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A green chemistry approach (Hydrothermal Microwave Irradiation) has been used to deposit manganese oxide on nickel foam-graphene. The 3D graphene was synthesized using nickel foam template by chemical vapour deposition (CVD) technique. Raman spectroscopy, X-ray diffraction (XRD), scanning electron and transmission electron microscopies (SEM and TEM); have been used to characterize structure and surface morphology of the composite respectively. The Raman spectroscopy measurements on the samples reveal that 3D graphene consists of mostly few layers with low defect density. The composite was tested in a three electrode configuration for electrochemical capacitor, and exhibited a specific capacitance of 305 F g -1 at a current density of 1 A g -1 and showed excellent cycling stability. The obtained results demonstrate that microwave irradiation technique could be a promising approach to synthesis graphene based functional materials for electrochemical applications.

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“…[52][53][54] It is well known that the properties of graphene may be strongly influenced by the supporting substrate; hence studies on free-standing graphene are of enormous interest. [55][56][57] The graphene TEM grid was electrochemically tested with two well-known redox couples;…”

Section: Wetting and Electrochemistry Of Supported And Suspended Grapmentioning

confidence: 99%

Versatile Polymer-Free Graphene Transfer Method and Applications

Zhang

Güell

Kirkman

et al. 2016

ACS Appl. Mater. Interfaces

107

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A new method for transferring chemical vapor deposition (CVD)-grown monolayer graphene, to a variety of substrates is described. The method makes use of an organic/aqueous biphasic configuration, avoiding the use of any polymeric materials that can cause severe contamination problems. The graphene-coated copper foil sample (on which graphene was grown) sits at the interface between hexane and an aqueous etching solution of ammonium persulfate to remove the copper. With the aid of an Si/SiO2 substrate, the graphene layer is then transferred to a second hexane/water interface, to remove etching products. From this new location, CVD graphene is readily transferred to arbitrary substrates, including three dimensional architectures as represented by atomic force microscopy (AFM) tips and transmission electron microscopy (TEM) grids. Graphene produces a conformal layer on AFM tips, to the very end, allowing the easy production of tips for conductive AFM imaging. Graphene transferred to copper TEM grids provides large area, highly electrontransparent substrates for TEM imaging. These substrates can also be used as working electrodes for electrochemistry and high resolution wetting studies. By using scanning electrochemical cell microscopy, it is possible to make electrochemical and wetting measurements at either a free-standing graphene film or a copper-supported graphene area, and readily determine any differences in behavior.3

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Probing Charged Impurities in Suspended Graphene Using Raman Spectroscopy

Cited by 206 publications

References 32 publications

Calculation of the RamanGpeak intensity in monolayer graphene: role of Ward identities

Calculation of the RamanGpeak intensity in monolayer graphene: role of Ward identities

Microwave assisted synthesis of MnO2 on nickel foam-graphene for electrochemical capacitor

Versatile Polymer-Free Graphene Transfer Method and Applications

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