We hypothesize a mechanistic model of how negatively-charged exclusion zones (EZs) are created. While the growth of EZs is known to be associated with the absorption of ambient photonic energy, the molecular dynamics giving rise to this process need greater elucidation. We believe they arise due to the formation of oxy-subhydride structures (OH−)(H2O)4 with a tetrahedral (sp3) (OH−)(H2O)3 core....

Diamond-like carbon films, amorphous hydrogenated or non-hydrogenated forms of carbon, are metastable amorphous materials characterized by attractive mechanical, optical, electrical, chemical and tribological properties. The films can be prepared at low temperatures by different techniques using a large variety of precursors and can be modified by incorporation of different elements such as N, ...

Recent advances in the fabrication and characterization of semiconductor and metallic nanowires are meeting the high expectations of nanotechnolgists. Although diamond has remarkable electronic and chemical properties, development of diamond nanowires has been slow, while the development of carbon nanotube-based technologies continues at a furious pace. Recently, the theoretical and experimenta...

We study the 514 and 244 nm Raman spectra of a wide variety of hydrogenated amorphous carbons (a-C:H). The hydrogen content can be estimated from the slope of the photoluminescence background (PL) of the spectra measured at 514.5 nm. Generally, the evolution of the sp and sp phases is not independent for as-deposited a-C:H samples. This, in principle, allows us to derive their structural and op...

Wear in self-mated tetrahedral amorphous carbon (ta-C) films is studied by molecular dynamics and nearedge X-ray absorption fine structure spectroscopy. Both theory and experiment demonstrate the formation of a soft amorphous carbon (a-C) layer with increased sp content, which grows faster than an a-C tribolayer found on selfmated diamond sliding under similar conditions. The faster sp ! sp tra...

A self-consistent environment-dependent tight binding method is used to examine electron emission-related properties of hydrogen passivated nano-diamond (ND) particles. For sizes larger than 2.5 nm particle bandgap was found to be equal to the bandgap of bulk diamond. Coulomb potential distributions and electron affinities of clusters were found to be insensitive to the particle size if it exce...

This investigation aims to develop a quantitative model to estimate the material removal of polycrystalline diamond composites (PCDCs) by dynamic friction polishing. The model accounts for the contributions from the constitutive characteristics and thermal properties of the materials and the key polishing parameters. It was found that the material removal was dominated by six dimensionless vari...

Diamond, diamond-like carbon (DLC), and other related materials (i.e., carbon nitride and cubic boron nitride [CBN]) are some of the hardest materials known and offer several other outstanding properties, such as high mechanical strength, chemical inertness, and very attractive friction and wear properties, that make them good prospects for a wide range of tribological applications, including r...

The general approach for describing and designing complex hierarchical icosahedral structures is discussed. Structural models of icosahedral carbon nanoparticles in which the local arrangement of atoms is virtually identical to that in diamond are derived. It is shown that icosahedral diamond-like particles can be transformed into onion-like shell structures (and vice versa) by the consecutive ...