Raman characterization of defects and dopants in graphene

Beams, Ryan; Cançado, Luiz Gustavo; Novotny, Lukas

doi:10.1088/0953-8984/27/8/083002

Cited by 508 publications

(436 citation statements)

References 139 publications

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“…The results from the Raman spectroscopy fits well with the previously observed TEM imgaes. As can be seen in Figure 3a, the Raman spectra of the untreated sample shows two peaks, one at ~1330 cm -1 , called the D-peak and a second peak at ~1580 cm -1 , the G-peak [30][31][32]. As reported for Aerographite, this carbon foams is consits of sp 2 and sp 3 carbon [11], which should be the same behaviour for the presented carbon structure.…”

Section: Resultssupporting

confidence: 75%

“…The increase in the defect density can be explained by the diffusion and reorientation of carbon atoms and the simultaneously formation of defects in the formed sp 2 lattices. The D´-peak describes and confirms the assumtion of the defects in sp 2 lattices [32]. Furthermore, the ratio of G-band to D´-band decrease with increasing temperatures, which indicates a reduction of lattices defectes in the carbon layers.…”

Section: Analysis Methodssupporting

confidence: 73%

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Structural improvement of a bio-inspired 3D globular carbon foam by a continuously thermal treatment: A comprehensive study

Marx¹,

Beisch²,

Garlof³

et al. 2017

Adv Mater Sci

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The manufacturing of a 3D interconnected globular carbon foam, called Globugraphite, is based on the replication of the zinc oxide (ZnO) template morphology by carbon with simultaneous removing of the template material in the chemical vapour deposition (CVD -replica CVD (rCVD)) process. The growth mechanism of the presented carbon foam affected the formation of defects at the atomic level which leads in the following to graphitic pieces instead of layers. This substructure influences properties, such as electrical conductivity of the carbon foam negatively. By undergoing a temperature treatment at 1600°C, 1800°C, 2000°C and 2200°C in a protective gas atmosphere the carbon structure heals at the atomic level. The connection of the sp 2 /sp 3 graphitic pieces to graphitic sp 2 layers due to the thermal annealing is analysed via transmission electron microscopy (TEM) observation and Raman spectroscopy. Based on these analysis methods a model of the graphitization progress is created which explains the clearly increase of the electrical conductivity and the oxidation temperature.

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Section: Resultssupporting

confidence: 75%

Section: Analysis Methodssupporting

confidence: 73%

Structural improvement of a bio-inspired 3D globular carbon foam by a continuously thermal treatment: A comprehensive study

Marx¹,

Beisch²,

Garlof³

et al. 2017

Adv Mater Sci

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show abstract

“…35 In Raman spectroscopy, a defect is defined as any breaking of the symmetry of the graphene lattice, such as vacancy sites 36,37 and edges. 38,39 A more detailed discussion on the origin of Raman peaks is given by Beams et al 40 Among the graphite samples studied, the ID/IG ratio varies from less than 0.01 for Northern to 0.26 for Henglide graphite. As shown in the SI, ID/IG scales linearly with 1/L with a positive intercept, behaviour which implies the basal plane defect concentration to be roughly constant over these samples.…”

Section: Basic Characterisationmentioning

confidence: 99%

Differentiating Defect and Basal Plane Contributions to the Surface Energy of Graphite Using Inverse Gas Chromatography

et al. 2016

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Historically, reported values for the surface energy of graphite have covered a very wide range. Here we use finite-dilution inverse gas chromatography (FD-IGC) to show that the dispersive component of the surface energy of graphite has contributions from edge and basal plane defects as well as from the hexagonal carbon lattice. The surface energy associated with the defect-free hexagonal lattice is measured at high probe-coverage to be 63±7 mJ/m 2 , independent of graphite type. However, the surface energy measured at low probe coverage varied from 125-175 mJ/m 2 depending on the graphite type. Simulation of the FD-IGC output for different binding site distributions allows us to associate this low-coverage surface energy with the binding of probe molecules to high energy defect sites. Importantly, we find the rate of decay of surface energy with probe coverage to carry information about the defect density. By analysing the dependence of these properties on flake size, it is possible to separate out the contributions of edge and basal plane defects, estimating the basal plane defect content to be ~10 15 m -2 for all graphite samples. Comparison with simulation gives some

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“…The peak at 1570 cm −1 may be identified with the skeletal vibration of the graphitic domain [37]. The intensity for the 60 W plasma reduced sample shows significant decrease in intensity for the oxygenated functional groups of C-O-C and C-O-H. response originates due to defects or translational disorders whereas the G app band corresponds to scattering from the E 2g mode of the sp 2 graphitic domain superposed with contributions from D′, D+D′, and 2D′ [38][39][40]. The presence of a broad shoulder peak has been observed between D and G app band for the untreated, 20 W and 40 W plasma treated samples which disappears for the 60 W plasma treated sample.…”

Section: Resultsmentioning

confidence: 95%

Effect of plasma power on reduction of printable graphene oxide thin films on flexible substrates

Banerjee

Mahapatra

Pal

et al. 2018

Mater. Res. Express

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Graphene oxide prepared by graphene nanoplatelets and reduced by laser treatment A Longo, R Verucchi, L Aversa et al. AbstractRoom temperature hydrogen plasma treatment on solution processed 300 nm graphene oxide (GO) films on flexible indium tin oxide (ITO) coated polyethylene terephthalate (PET) substrates has been performed by varying the plasma power between 20 W and 60 W at a constant exposure time of 30 min with a view to examining the effect of plasma power on reduction of GO. X-ray powder diffraction (XRD) and Raman spectroscopic studies show that high energy hydrogen species generated in the plasma assist fast exfoliation of the oxygenated functional groups present in the GO samples. Significant decrease in the optical band gap is observed from 4.1 eV for untreated samples to 0.5 eV for 60 W plasma treated samples. The conductivity of the films treated with 60 W plasma power is estimated to be six orders of magnitude greater than untreated GO films and this enhancement of conductivity on plasma reduction has been interpreted in terms of UV-visible absorption spectra and density functional based first principle computational calculations. Plasma reduction of GO/ITO/ PET structures can be used for efficiently tuning the electrical and optical properties of reduced graphene oxide (rGO) for flexible electronics applications.

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Raman characterization of defects and dopants in graphene

Cited by 508 publications

References 139 publications

Structural improvement of a bio-inspired 3D globular carbon foam by a continuously thermal treatment: A comprehensive study

Structural improvement of a bio-inspired 3D globular carbon foam by a continuously thermal treatment: A comprehensive study

Differentiating Defect and Basal Plane Contributions to the Surface Energy of Graphite Using Inverse Gas Chromatography

Effect of plasma power on reduction of printable graphene oxide thin films on flexible substrates

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