Systematic variation of the Raman spectra of DLC films as a function of sp2:sp3 composition

Prawer, Steven; Nugent, K. W.; Lempert, G.; Grossman, Eitan; Kulik, J.; Avigal, I.; Kalish, R.

doi:10.1016/0925-9635(95)00363-0

Cited by 462 publications

(189 citation statements)

References 10 publications

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“…[24][25][26][27] All the a-C films show similar Raman spectra consisting of only the G peak around 1580 cm −1 and almost no D peak around 1350 cm −1 . The second order TO peak of the Si substrate can be observed at around 960 cm −1 , as shown in Fig.…”

Section: Raman Spectroscopymentioning

confidence: 86%

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Pulsed laser deposited tetrahedral amorphous carbon with high sp3 fractions and low optical bandgaps

Miyajima

Henley

Adamopoulos

et al. 2009

Journal of Applied Physics

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Amorphous carbon films with sp 3 bonded carbon fractions over 70% are deposited by pulsed laser deposition. However, the optical bandgap obtained from optical transmittance and spectroscopic ellipsometry analysis shows the values to be below 1.0 eV. A wide range of measurements such as electron energy loss spectroscopy, visible Raman, spectroscopic ellipsometry, optical transmittance, and electrical characterization are performed to elucidate the bonding configurations that dictate microstructural, optical and electrical properties, and their linkage to band structure changes. It is found that stress-induced electronic localized states play an important role in the physical properties of the films deposited. The optical bandgap is shown not to be a good measure of the electrical bandgap, especially for high electric field conduction in these tetrahedral amorphous carbon films.

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Section: Raman Spectroscopymentioning

confidence: 86%

“…Typically, the Raman spectral data were fitted by BrietWigner-Fano ͑BWF͒ 26,28 shape for the G peak and a Lorentzian for the D peak. 25 In this study, the Raman spectra of the a-C films were fitted with only a BWF line shape as the sp 3 fraction of the film is quite high ͑over 75%; see Fig.…”

Section: Raman Spectroscopymentioning

confidence: 99%

Pulsed laser deposited tetrahedral amorphous carbon with high sp3 fractions and low optical bandgaps

Miyajima

Henley

Adamopoulos

et al. 2009

Journal of Applied Physics

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“…In the actual analysis, the ratio of the intensity between the D and G peaks is considered to characterize the structure of the a-C:15H coating, rather than considering the overall intensity taken from one location to other.It is reported that the relative intensity height of the D peak is related to the microcrystalline size of the graphitic cluster, where lessgraphitic amorphous films have a lower H D /H G value [40][41][42][43]. Therefore, higher values of the H D /H G ratio imply transformation of the a-C:15H coating into graphite in the a-C:15H matrix under the present boundary-lubricated conditions [39].…”

Section: Coating Wear Analysismentioning

confidence: 98%

Tribological performance and tribochemical processes in a DLC/steel system when lubricated in a fully formulated oil and base oil

Kosarieh

Morina

Lainé

et al. 2013

Surface and Coatings Technology

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Abstract:Diamond-like carbon (DLC) coatings show extremely good promise for a number of applications in automotive components as they exhibit excellent tribological properties such as low friction and good wear resistance. This can impact on improved fuel economy and durability of the engine components. Much work has been reported on the dry sliding of DLC coatings with less so in lubricated contacts and, as such, there is a need to further understand the tribochemistry of lubricated DLC contacts. Commercially-available oils are normally optimized to work on ferrous surfaces. Previous studies on DLC lubricated contacts have tended to use model oil systems rather than fully formulated lubricants and from this an interesting picture of lubrication mechanisms is emerging. Optimising compatibility between a surface and a set of lubricant additives may lead to excellent durability (wear) as well as increased fuel economy (low friction). In this work, the friction and wear properties of a DLC coating under boundary lubrication conditions have been investigated and the tribological performance compared with that of an uncoated steel system. A pin-on-plate tribotester was used to run the experiments using High speed steel (HSS) M2 grade plates coated with 15 at.% hydrogenated DLC (a-C:15H) sliding against cast iron pins. A Group III mineral base oil, fully synthetic Group IV PAO and four different fully formulated oils were used in this study. Furthermore optical and scanning electron microscopes (SEM) were used to observe the wear scar and to assess the durability of the coatings. Energy-Dispersive X-ray analysis (EDX), X-ray Photoelectron Spectroscopy (XPS) and Raman spectroscopy analyses were performed on the tribofilms to understand the tribochemical interactions between oil additives and the a-C:15H coating.This study show that the durability of the a-C:15H coating strongly depends on the selected additive package in the oils. In addition the effect of detergent, dispersant and antioxidants on the performance of the Molybdenum-based friction modifier (Mo-FM) and ZDDP anti-wear additive were investigated and results are reported in this paper.

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“…It is important to note that there is no a priori reason to favor a particular fitting function. In literature, Gaussians are common 32,33 , but also asymmetrical line shapes as the Breit-WignerFano (BWF) are used 18,34 . The use of an asymmetric line shape is justified by the asymmetry of the vibrational density of states (DOS) towards lower wave numbers for graphite and amorphous carbon in the region of the D and G lines 35 .…”

Section: Peak Fittingmentioning

confidence: 99%

Influence of doping (Ti, V, Zr, W) and annealing on the sp2 carbon structure of amorphous carbon films

Adelhelm

Balden

Rinke

et al. 2009

Journal of Applied Physics

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The influence of the transition metal (Ti, V, Zr, W) doping on the carbon matrix nanostructuring during the thin film growth and subsequent annealing is investigated. Pure and metal-doped amorphous carbon films (a-C, a-C:Me) were deposited at room temperature by non-reactive magnetron sputtering. The carbon structure of as-deposited and post-annealed (up to 1300 K) samples was analyzed by X-ray diffraction (XRD) and Raman spectroscopy.The existence of graphene-like regions in a-C is concluded from a (10) diffraction peak. A comparison of the XRD and Raman results suggests that XRD probes only the small amount of 2-3 nm large graphene-like regions, whereas the majority of the sp 2 phase is present in smaller distorted aromatic clusters which are probed only by Raman spectroscopy. Annealing leads to an increase of the graphene size and the aromatic cluster size. During the carbon film growth the addition of metals enhances ordering of sp 2 carbon in sixfold aromatic clusters compared to a-C, Ti and Zr showing the strongest effect, W the lowest. This order qualitatively corresponds with the catalytic activity of the respective carbides found during graphitization of carbide-doped graphites published in the literature. With annealing, carbide crystallite formation and growth occurs in a-C:Me films, which destroys the initial carbon structure, reduces the size of the initially formed aromatic clusters and the differences in carbon structure introduced by different dopants. For high annealing temperatures the carbon structure of a-C:Me films is similar to that of a-C, and is determined only by the annealing temperature.2

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Systematic variation of the Raman spectra of DLC films as a function of sp2:sp3 composition

Cited by 462 publications

References 10 publications

Pulsed laser deposited tetrahedral amorphous carbon with high sp3 fractions and low optical bandgaps

Pulsed laser deposited tetrahedral amorphous carbon with high sp3 fractions and low optical bandgaps

Tribological performance and tribochemical processes in a DLC/steel system when lubricated in a fully formulated oil and base oil

Influence of doping (Ti, V, Zr, W) and annealing on the sp2 carbon structure of amorphous carbon films

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