Toward the Ultimate Tribological Interface: Surface Chemistry and Nanotribology of Ultrananocrystalline Diamond

Sumant, Anirudha V.; Grierson, David S.; Gerbi, J. E.; Birrell, James; Lanke, U. D.; Auciello, Orlando; Carlisle, John A.; Carpick, Robert W.

doi:10.1002/adma.200401264

Cited by 130 publications

(108 citation statements)

References 39 publications

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“…hybridization state of carbon atoms in the near-surface region of carbon-based materials, such as diamond [45][46][47][48][49] , amorphous carbon 14,29,[50][51][52] , graphene 53,54 , and polymers [55][56][57] . The dependence of the intensity of the detected spectral features on the orientation of the final state orbital with respect to the electric field vector of the incident photon beam 58 also allows the surface molecular orientation of nanomaterials [59][60][61] and adsorbates 62 to be investigated.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of the Carbon Hybridization State by Near Edge X-ray Absorption Fine Structure Spectroscopy

2016

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The characterization of the local bonding configuration of carbon in carbon-based materials is of paramount importance since the properties of such materials strongly depend on the distribution of carbon hybridization states, the local ordering, and the degree of hydrogenation. Carbon 1s near edge X-ray absorption fine structure (NEXAFS) spectroscopy is one of the most powerful techniques for gaining insights into the bonding configuration of near-surface carbon atoms. The common methodology for quantitatively evaluating the carbon hybridization state using C1s NEXAFS measurements, which is based on the analysis of the sample of interest and of a highly ordered pyrolytic graphite (HOPG) reference sample, was reviewed and critically assessed, noting that inconsistencies are found in the literature in applying this method. A theoretical rationale for the specific experimental conditions to be used for the acquisition of HOPG reference spectra is presented together with the potential sources of uncertainty and errors in the correctly computed fraction of sp 2 -bonded carbon. This provides a specific method for analyzing the distribution of carbon hybridization state using NEXAFS spectroscopy. As an illustrative example, a hydrogenated amorphous carbon film was analyzed using this method, and showed good agreement with X-ray photoelectron spectroscopy (which is surface sensitive).Furthermore, the results were consistent with analysis from Raman spectroscopy (which is not surface sensitive), indicating the absence of a structurally different near-surface region in this particular thin film material. The present work can assist surface scientists in the analysis of NEXAFS spectra for the accurate characterization of the structure of carbon-based materials.3

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Section: Introductionmentioning

confidence: 99%

Quantitative Evaluation of the Carbon Hybridization State by Near Edge X-ray Absorption Fine Structure Spectroscopy

2016

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“…An analogous comparison of theory and experiment arises in studies in the fracture of nanoscale diamond crystals. Interest in this material arises because of the development of ultrananocrystalline diamond (UNCD) films as potentially important coatings in the manufacture of microelectrical mechanical systems (MEMS) devices (64)(65)(66)(67)(68). UNCD consists of few-nanometer diamond crystallites that meet at atom-wide grain boundaries (69).…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Using theory and computation to model nanoscale properties

Schatz

2007

Proc. Natl. Acad. Sci. U.S.A.

102

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This article provides an overview of the use of theory and computation to describe the structural, thermodynamic, mechanical, and optical properties of nanoscale materials. Nanoscience provides important opportunities for theory and computation to lead in the discovery process because the experimental tools often provide an incomplete picture of the structure and/or function of nanomaterials, and theory can often fill in missing features crucial to understanding what is being measured. However, there are important challenges to using theory as well, as the systems of interest are usually too large, and the time scales too long, for a purely atomistic level theory to be useful. At the same time, continuum theories that are appropriate for describing larger-scale (micrometer) phenomena are often not accurate for describing the nanoscale. Despite these challenges, there has been important progress in a number of areas, and there are exciting opportunities that we can look forward to as the capabilities of computational facilities continue to expand. Some specific applications that are discussed in this paper include: self-assembly of supramolecular structures, the thermal properties of nanoscale molecular systems (DNA melting and nanoscale water meniscus formation), the mechanical properties of carbon nanotubes and diamond crystals, and the optical properties of silver and gold nanoparticles. molecular dynamics ͉ nanomaterials ͉ nanoparticle ͉ plasmon ͉ self-assembly N anoscience deals with the behavior of matter on length scales where a large number of atoms play a role, but where the system is still small enough that the material does not behave like bulk matter. For example, a 5-nm gold particle, which contains on the order of 10 5 atoms, absorbs light strongly at 520 nm, whereas bulk gold is reflective at this wavelength and small clusters of gold atoms have absorption at shorter wavelengths. The special properties associated with nanoscale systems like this have provided both challenges and opportunities for the use of theory and computation to play a role in the discovery process. The challenges arise from the fact that most theories that describe the properties of matter by using first-principles approaches in which all atoms (and even all electrons in these atoms) are explicitly described are close to or (more often) beyond their capability to describe such systems, even using the largest computer available. At the same time, continuum theories, which play such a useful role for micrometer-scale systems, are sometimes incapable of describing nanoscale properties due to incomplete incorporation of the underlying physics in the size-dependent materials parameters. However, the opportunities for theory to play a role are significant, as nanoscience often provides the smallest systems that are amenable to study using methods that involve macroscopic manipulation of nanoscale structures. Thus, it is possible to measure the structure and thermal properties of a single supramolecular assembly, observe the thermal ...

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“…Although diamond surfaces inherently possess attractive tribological properties [18][19][20] and high biocompatibility [21][22], the roughness of NCD and MCD actually diminish their overall tribological and biological compatibility.…”

Section: Introductionmentioning

confidence: 99%

Boron-doped ultrananocrystalline diamond synthesized with an H-rich/Ar-lean gas system

Zeng

Konicek

Moldovan

et al. 2015

Carbon

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This paper reports the recent development and applications of conductive borondoped ultrananocrystalline diamond (BD-UNCD). The authors have determined that BD-UNCD can be synthesized with an H-rich gaseous chemistry and a high CH 4 /H 2 ratio, which is opposite to previously reported methods with Ar-rich or H-rich gas compositions but utilizing very low CH 4 /H 2 ratio. The BD-UNCD has a resistivity as low as 0.01 ohm·cm, with low roughness (down to several nm) and a wide deposition temperature range (450-850¼C).The properties of this BD-UNCD were studied systematically using resistivity characterization, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and roughness measurements. Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy confirms that up to 97% of the UNCD is deposited as sp3 carbon.These series of measurements also reveal additional unique properties for this material, such as an ÒMÓ shape Raman signature, line-granular nano-cluster texture and high C-H bond surface content. A hypothesis is provided to explain why this new deposition strategy, with H-rich/Ar-free gas chemistry and CH 4 /H 2 ratio, is able to produce high sp3-content and/or 2 heavily doped UNCD. In addition, a few emerging applications for BD-UNCD in the field of atomic force microscopy, electrochemistry and biosensing are reviewed here.

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Toward the Ultimate Tribological Interface: Surface Chemistry and Nanotribology of Ultrananocrystalline Diamond

Cited by 130 publications

References 39 publications

Quantitative Evaluation of the Carbon Hybridization State by Near Edge X-ray Absorption Fine Structure Spectroscopy

Quantitative Evaluation of the Carbon Hybridization State by Near Edge X-ray Absorption Fine Structure Spectroscopy

Using theory and computation to model nanoscale properties

Boron-doped ultrananocrystalline diamond synthesized with an H-rich/Ar-lean gas system

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