Raman spectroscopy for the study of reduction mechanisms and optimization of conductivity in graphene oxide thin films

Díez-Betriu, Xavier; Álvarez-García, Susana; Botas, Cristina; Álvarez, Patricia; Sánchez-Marcos, J.; Prieto, C.; Menéndez, Rosa; Andrés, A. de

doi:10.1039/c3tc31124d

Cited by 282 publications

(217 citation statements)

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“…12,13 The stronger D peak in the Raman spectrum in Figure 3(e) shows that the RGO films contained large numbers of small-sized disordered sp 2 carbon (defects). [31][32][33] Also, a higher ratio between the D and G peak intensities than that of the as-deposited GO indicated that there was an increasing sp 2 carbon content and part of the oxygen groups had been removed, 32,33 which agrees well with the UV-visible absorption results. The XPS spectrum (Figure 3(f)) further directly indicates that there were residual oxygen groups in the films, determined by comparing the spectra before and after reduction.…”

supporting

confidence: 78%

Mid-infrared response of reduced graphene oxide and its high-temperature coefficient of resistance

Liang

2014

AIP Advances

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Much effort has been made to study the formation mechanisms of photocurrents in graphene and reduced graphene oxide films under visible and near-infrared light irradiation. A built-in field and photo-thermal electrons have been applied to explain the experiments. However, much less attention has been paid to clarifying the mid-infrared response of reduced graphene oxide films at room temperature. Thus, mid-infrared photoresponse and annealing temperature-dependent resistance experiments were carried out on reduced graphene oxide films. A maximum photocurrent of 75 μA was observed at room temperature, which was dominated by the bolometer effect, where the resistance of the films decreased as the temperature increased after they had absorbed light. The electrons localized in the defect states and the residual oxygen groups were thermally excited into the conduction band, forming a photocurrent. In addition, a temperature increase of 2 °C for the films after light irradiation for 2 minutes was observed using absorption power calculations. This work details a way to use reduced graphene oxide films that contain appropriate defects and residual oxygen groups as bolometer-sensitive materials in the mid-infrared range.

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supporting

confidence: 78%

Mid-infrared response of reduced graphene oxide and its high-temperature coefficient of resistance

Liang

2014

AIP Advances

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“…The experimental spectrum is similar to other reported Raman spectra for graphene oxide. 31,32 Specifically, the relatively large intensity and breadth of the "D" feature-typically associated with defects in graphene layers is consistent with the substantial sp 3 character of the first two graphene layers, as indicated by both experiment and theory. A calculated spectrum for the single phonon region of the first layer (Fig.…”

Section: Resultssupporting

confidence: 51%

Ordered three-fold symmetric graphene oxide/buckled graphene/graphene heterostructures on MgO(111) by carbon molecular beam epitaxy

et al. 2018

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KEYWORDSphotoemission, electron energy loss, low energy electron diffraction, density functional theory ABSTRACT Theory and experiment demonstrate the direct growth of a graphene oxide/buckled graphene/graphene heterostructure on an incommensurate MgO(111) substrate. X-ray photoelectron spectroscopy, electron energy loss, Auger electron spectroscopy, low energy electron diffraction, Raman spectroscopy and first-principles density functional theory (DFT) calculations all demonstrate that carbon molecular beam epitaxy on either a hydroxylated MgO(111) single crystal or a heavily twinned thin film surface at 850 K yields an initial C layer of highly ordered graphene oxide with C 3v symmetry. A 5x5 unit cell of carbon, with one missing atom, forms on a 4x4 unit cell of MgO, with the three C atoms surrounding the C vacancy surface forming covalent C-O bonds to substrate oxide sites. This leads to a bowed graphene-oxide with slightly modified D and G Raman lines and a calculated band gap of 0.36 eV. Continued C growth results in the second layer of graphene that is stacked AB with respect to the first layer and buckled conformably with the first layer while maintaining C 3v symmetry, lattice spacing and azimuthal orientation with the first layer. Carbon growth beyond the second layer yields graphene in azimuthal registry with the first two C layers, but with graphene-characteristic lattice spacing and πàπ* loss feature. This 3 rd layer is also p-type, as indicated by the 5.6 eV energy loss feature. The significant sp 3 character and C 3v symmetry of such heterostructures suggest that spin-orbit coupling is enabled, with implications for spintronics and other device applications.2

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“…2. The peak D is due to disorder of crystal lattice and formation of sp 3 bonds, the peak G is due to the presence of sp 2 bonds of carbon in the lattice of graphene [15,16]. Relationships of intensities of peaks I D /I G measured at different points of the sample before and after the reduction (at a temperature of 250°C), leads to a slight decrease in the average value of the ratio from 0.95 to 0.90.…”

Section: Nanosystems Study Of Electrical Conductivity Of Thermally Rementioning

confidence: 99%

Study of Electrical Conductivity of Thermally Reduced Graphene Oxide

Neustroev¹,

Nogovitsyna²,

Solovyova³

et al. 2015

RENSIT

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Raman spectroscopy for the study of reduction mechanisms and optimization of conductivity in graphene oxide thin films

Cited by 282 publications

References 32 publications

Mid-infrared response of reduced graphene oxide and its high-temperature coefficient of resistance

Mid-infrared response of reduced graphene oxide and its high-temperature coefficient of resistance

Ordered three-fold symmetric graphene oxide/buckled graphene/graphene heterostructures on MgO(111) by carbon molecular beam epitaxy

Study of Electrical Conductivity of Thermally Reduced Graphene Oxide

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