X-ray photoelectron investigation of carbon nanostructures in iron matrix

Шабанова, И. Н.; Makarova, L. I.; Terebova, N. S.; Lad’yanov, V. I.; Ніконова, Р. М.

doi:10.1016/j.elspec.2006.11.059

Cited by 2 publications

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“…Careful analysis of C 1 s spectrum in graphite indicates that it is a single peak, well described by an asymmetric Doniach‐Šunjic function . The situation of diamond is quite different: the literature data for BE of C 1 s peak are varying from about 284 eV to about 286 eV, what can be explained by the possible influence of sample charging due to the electrical insulation of this allotrope, especially if it is undoped. However, much more important are not the absolute BE values, but the chemical shift between graphite and diamond.…”

Section: Introductionmentioning

confidence: 89%

“…However, much more important are not the absolute BE values, but the chemical shift between graphite and diamond. The results of photoemission experiments and theoretical calculations of this shift give the values from 0–0.2 eV to relatively high values, varying between 0.7 and 1.5 eV . Again, the high scattering of these values can be explained by the effect of possible sample charging and/or by the presence of the BE shift between the surface and bulk of the diamond .…”

Section: Introductionmentioning

confidence: 99%

“…Again, the high scattering of these values can be explained by the effect of possible sample charging and/or by the presence of the BE shift between the surface and bulk of the diamond . However, most of the papers on the application of XPS for the characterization of DLC films were fixing the chemical shift between sp 2 and sp 3 states at about 0.5 – 1 eV, whereas other authors were claiming that this shift is very small and the reliable peak deconvolution is not applicable . Moreover, even if we would like to accept one of these BE values for C 1 s peak fitting, it is necessary to remember that in DLC films (as on the surface of any sample) always can be present some amount of aliphatic carbon, which is characterized by BE = 285.0 eV Therefore, the determination of sp 2 /sp 3 only on the basis of C 1 s peak fitting does not seem a very reliable method and its validity should be thoroughly questioned.…”

Section: Introductionmentioning

confidence: 99%

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Spectroscopy of carbon: from diamond to nitride films

Kačiulis

2012

Surface & Interface Analysis

175

166

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Every surface scientist knows about the importance of carbon spectroscopy: the signals of C 1 s and C KLL usually are indicating the surface cleanness, whereas C 1 s peak is often used as a reference for the calibration of energy scale. Carbon spectroscopy becomes even more important in the case of the studies dedicated to new carbon-based materials, such as nanotubes, graphene, diamond-like carbon (DLC), carbon nitride, carbides, etc. It is well-known that the carbon atoms can be arranged in a great variety of crystalline and disordered structures, because their electrons can hybridize in sp 3 , sp 2 and even in linear sp configurations. Namely, the hybridization of carbon electrons defines the mechanical, electrical and optical properties of these materials. Indeed, between the pure diamond (sp 3 ) and graphite (sp 2 ), there are many phases of amorphous material characterized by different sp 2 /sp 3 ratios and generally named DLC. Electron spectroscopies (X-ray photoelectron spectroscopy, Auger electron spectroscopy and electron energy loss spectroscopy) are widely recognized as analytical techniques, able to identify the bonds of diamond, graphite and amorphous phases of carbon. The binding energy of C 1 s spectrum together with its plasmon losses, the shape of Auger peak and valence band spectra can be used to characterize the structure of carbon-based materials. In this study, an overview is reported on carbon spectroscopy, comparing different experimental methods. Their application for the characterization of DLC and carbon nitride films, including the determination of carbon's sp 2 /sp 3 ratio is discussed and illustrated by experimental results obtained for a series of thin films of these materials.

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectroscopy of carbon: from diamond to nitride films

Kačiulis

2012

Surface & Interface Analysis

175

166

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“…However, Raman technique has a poor capability in quantitative analysis. XPS can be used to estimate the fraction of sp 2 ‐hybridised atoms in carbonaceous materials 8, 9…”

Section: Introductionmentioning

confidence: 99%

“…XPS can be used to estimate the fraction of sp 2 -hybridised atoms in carbonaceous materials. [8,9] XPS is a surface analytical technique which provides both chemical and binding information for a variety of materials. For carbon materials, the C 1s core energy level at around 280-290 eV, [10] the plasmon-loss energy at around 0-60 eV relative to C1s main peak [11] and the X-ray-excited Auger peaks at higher binding energy [11] all give phase information on the carbon present.…”

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confidence: 99%

Surface characterization on graphitization of nanodiamond powder annealed in nitrogen ambient

Xie

Gong

et al. 2010

Surface & Interface Analysis

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A nanodiamond thin film is deposited on a single crystal silicon substrate by dip-coating technique. Surface characterization of the unannealed nanodiamond sample, and the samples annealed at various temperatures in nitrogen ambient, is conducted by XPS and Raman spectroscopy. The fitting data of the C1s core level XPS peak reveal that the sp 2 /sp 3 ratio in the unannealed sample and the sample annealed at 900• C and 1500• C are 0.44, 0.55 and 6.08 respectively. All spectra including the C1s core level XPS spectrum, the plasmon energy-loss spectrum associated with C1s peak, C KVV Auger spectrum of the sample annealed at 900• C are similar to those of the unannealed sample. However, the spectra of the sample annealed at 1500• C are very different. Annealing at 900• C fails to produce appreciable graphitization, and an onion-like carbon structure with a small diamond core is formed when the nanodiamond is heated to 1500• C. Copyright c 2010 John Wiley & Sons, Ltd.Keywords: X-ray photoelectron spectroscopy (XPS); Raman spectroscopy; nanodiamond; sp 2 -hybridised; sp 3 -hybridised IntroductionNanodiamond is a potential cold cathode material in the electron field emission process [1,2] and has potential application in vacuum micro-and nanoelectronic devices. [3] The unique properties of nanodiamond are directly related to the microscopic structure, elemental and carbon bonding structure. [4] It is well known that the structure property of carbon material is determined by the sp 2 /sp 3 bonding ratio. Thermoannealing is an effective method to alter the structure of carbon material.[5] High-temperature annealing not only varies the chemical bonding structure of carbon material but also affects its field emission property. [6,7] The formation of a large fraction of sp 2 bonding carbon in the DLC film plays an important role in the enhancement of field emission property. [6] So far, in order to characterize carbon materials, a correct estimate of the abundance of sp 2 -hybridised atoms is of extraordinary importance. Raman spectroscopy can be used to identify sp 2 and sp 3 hybrids in C-based material owing its high sensitivity to light scattering. However, Raman technique has a poor capability in quantitative analysis. XPS can be used to estimate the fraction of sp 2 -hybridised atoms in carbonaceous materials. [8,9] XPS is a surface analytical technique which provides both chemical and binding information for a variety of materials. For carbon materials, the C 1s core energy level at around 280-290 eV, [10] the plasmon-loss energy at around 0-60 eV relative to C1s main peak [11] and the X-ray-excited Auger peaks at higher binding energy [11] all give phase information on the carbon present. Fitting the C1s core level peak is a common method used to quantify the sp 2 hybrids in C-based material. The C1s photoelectrons whose loss features reflects the different bond organization, and the Auger region whose width is correlated to the amount of sp 2 hybridised C-atoms. [12] In this paper, the unannealed nanodiamond sample a...

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X-ray photoelectron investigation of carbon nanostructures in iron matrix

Cited by 2 publications

References 0 publications

Spectroscopy of carbon: from diamond to nitride films

Spectroscopy of carbon: from diamond to nitride films

Surface characterization on graphitization of nanodiamond powder annealed in nitrogen ambient

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