Carbon diamondlike

The level of sp -bonded carbon can be detected either electrochem-ically or by Raman spectroscopy. Figure 14 shows a series of Raman spectra for the films shown in Fig. 13. It can be seen that the one-phonon diamond line at 1333 cm decreases in amplitude and increases in width from 12 to 43 cm as the CH4/H2 ratio increases. The scattering intensity centered at ca. 1525 cm also increases with increasing CH4/H2 ratio, indicative of higher levels of sp -bonded carbon. This nondiamond carbon is actually a mixture of sp - and sp -bonded carbon-diamondlike carbon and is not graphitic in nature. The higher defect density, due to the increased secondary nucleation, causes the increased line width and the increased opacity from the nondiamond carbon causes the re-... 

Group 5 (3), diamondlike carbides and (3), volatile nonmetallic carbides. A line through the box, eg, 0, indicates no carbide formation however, there may be some solubiUty of carbon in the melt. A question mark, eg, Ac , indicates the possibiUty of a carbide. 

Diamondlike Carbides. SiUcon and boron carbides form diamondlike carbides beryllium carbide, having a high degree of hardness, can also be iacluded. These materials have electrical resistivity ia the range of semiconductors (qv), and the bonding is largely covalent. Diamond itself may be considered a carbide of carbon because of its chemical stmeture, although its conductivity is low. 

There are many applications for diamonds and related materials, e.g., diamondlike carbon films, and there are potential applications for Fullerenes and carbon nanotubes that have not yet been realised. However, the great majority of engineering carbons, including most of those described in this book, have graphitic microstructures or disordered graphitic microstructures. Also, most engineering carbon materials are derived firom organic precursors by heat-treatment in inert atmospheres (carbonisation). A selection of technically-... 

Tsai, H., and Bogy, D. B., Characterization of Diamondlike Carbon Films and Their Application as Overcoat on Thin-Film Media for Magnetic Recording, J. Vac. Sci. Technol. A, 5(6) 3287-3312 (Nov/Dec 1987)... 

The work on carbon nitride solids is strongly related to research on diamondlike carbon (DLC) materials [5, 6]. DLC materials are thin film amorphous metastable carbon-based solids, pure or alloyed with hydrogen, which have properties similar to that of crystalline diamond (high hardness, low friction coefficient, high resistance to wear and chemical attack). This resemblance to diamond is due to the DLC structure, which is characterized by a high fraction of highly cross-linked sp -hybridized carbon atoms. To obtain this diamond-like structure... 

J. Andersson, R.A. Erck, and A. Erdemir, Frictional Behavior of Diamondlike Carbon Films in Vacuum and under Varying Water Vapor Pressure, Surf. Coat. Technology 163-164,535-540 (2003). 

In addition to C onions, C atoms condense into various kinds of chemically bonded forms, and they are known to have excellent physical properties depending on the bonding nature. This means that research and applications not only in the materials science but also in other scientific fields are expected. At JAERI, the optimum growth conditions have been successfully obtained for the preparation of high-quality Cgo, diamondlike carbon, and nanocrystalline diamond by means of ion-beam-assisted deposition [80-82]. The susceptibility of Ni/Cgo thin films to thermal treatment, the formation of nanocrystalline diamond and nanotubes due to codeposition of Co and Ceo, and the surface modification of glassy... 

Its structure resembles that of graphite, but the latter s flat planes of carbon hexagons are replaced in boron nitride by planes of hexagons of alternating B and N atoms (Fig. 14.31). Unlike graphite, it is white and does not conduct electricity. Under high pressure, boron nitride is converted to a very hard, diamondlike crystalline form called Borazon. In recent years, boron nitride nanotubes similar to those formed by carbon have been synthesized (Section 14.18), and they have been found to be semiconducting (see Box 14.2). 

In Section 2 we showed that the properties of amorphous carbon vary over a wide range. Graphite-like thin films are similar to thoroughly studied carbonaceous materials (glassy carbon and alike) in their electrode behavior. Redox reactions proceed in a quasi-reversible mode on these films [75], On the contrary, no oxidation or reduction current peaks were observed on diamondlike carbon electrodes in Ce3+/ 41, Fe(CN)63 4. and quinone/hydroquinone redox systems the measured current did not exceed the background current (see below, Section 6.5). We conventionally took the rather wide-gap DLC as a model material of the intercrystallite boundaries in the polycrystalline diamond. Note that the intercrystallite boundaries cannot consist of the conducting graphite-like carbon because undoped polycrystalline diamond films possess excellent dielectric characteristics. 

Fig. 12 Methods of growing diamondlike materials using solid carbon source.

Eerrari AC, Robertson J (2004) Raman spectroscopy of amorphous, nanostructured, diamondlike carbon, and nanodiamond. Philos Trans R Soc Lond A 362 2477-2512... 

Merkulov VI, Lannin JS, Munro CH, Asher SA, Veerasamy VS, Milne WI (1997) UV studies of tetrahedral bonding in diamondlike amorphous carbon. Phys Rev Lett 78 4869... 

Diamondlike Carbon and Hard Carbon-Based Sensors Sensors that are based upon diamond technology include thermistors, pressure and flow sensors, radiation detectors, and surface acoustic wave devices [103]. The relative ease of depositing prepattemed, dielectrically isolated insulating and. semiconducting (boron-doped p type) diamond films has made polycrystalline diamond-based sensors low-cost alternatives to those based on conventional semiconductors. Diamondlike carbon and diamond films synthesized by chemical... 

Milne, W.I. Electronic devices from diamondlike carbon. Semicond. Sci. Technol. 2003, 18, S81-S85. 

Hauert, R. Muller, U. An overview on tailored tribological and biological behavior of diamondlike carbon. Diamond Relat. Mater. 2003, 12, 171-177. 

Ferrari, A.C. Robertson, J. Resonant Raman spectroscopy of disordered, amorphous, and diamondlike carbon. Phys. Rev. B 2001, 64, 075414. 

In the diamond stmcture, carbon atoms are present in sp hybridization, with a tetrahedral stereochemistry and a face-centered cubic stmcture that is shown in Fig. 2.1. Besides natural diamond, synthetic diamond has been produced since General Electric first announced its successful high-pressure synthesis in 1955. Sintered polycrystalline diamond, different types of diamond films, and diamondlike carbon are other types of diamond-related synthetic materials, some of which are noncrystalline [13, 19] these solids have their own terminology [10, 20]. Unhke other carbonaceous solids, diamond has a rather limited and specific relevance to adsorption. Indeed, ever since the publication of a pioneering work... 

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