Hybridization diamond-like carbon

Carbon materials liave particular characteristics due to differences in chemical bond formation. Allotropic forms of carbon drat luive been discovered can be categorized into five types from file standpoint of the type of hybridization of the valence orbitals (1) sp -hybridization (2) sp -hybridization (3) sp-hybrid-ization (4) mixed hybridization (sp + sp ) and (5) a valance state characterized by a fractional degree of hybridization (sp , where 1 diamond-like carbon, and fullcrcnes correspond to groups (1), (3), (4), and (5), respectively. 

Ellipsometry quantification and rapid visual detection of DNA hybridization, using biotinylated target sequences, on amorphous sihcon and diamond-like carbon deposited on a porous polycarbonate membrane, creating a gold-coloured reflective test surface coated with immobihzed ssDNA capture probe were described by Ostroif et al. [38]. 

Identification of vapor grown diamond is accomplished by X-ray diffraction or electron diffraction using a transmission electron microscope (TEM) and by Raman spectroscopy. Diamond coatings show the characteristic first-order Raman peak for diamond at 1332cm [59]. In many cases, an additional peak located at 1550cm occurs in the Raman spectrum which is attributed to a highly disordered carbon phase (diamond-like carbon) [60]. This diamond-like carbon contains sp and sp hybridized C-atoms which do not coincide with graphite. 

Figure 14.1. Ratio of sp to sp hybrid bonds in diamond-like carbon (DLC) as a function of hydrogen content.PI...

Diamond-like carbon (DLC) films are hard, amorphous films with a significant fraction of sp -hybridized carbon atoms and which can contain a significant amount of hydrogen. Depending on the deposition conditions, these films can be fully amorphous or contain diamond crystallites. These materials are not called diamond unless a full three-dimensional crystalline lattice of diamond is proven. 

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... 

On the other hand, in covalently bonded materials like carbon, silicon, and germanium, the formation of energy bands first involves the hybridization of the outer s- and p-orbitals to form four identical orbitals, ilnh, which form an angle of 109.5° with each other, that is, each C, Si, and Ge atom is tetrahedrally coordinated with the other C, Si, and Ge atom, respectively (Figure 1.16), resulting in a diamond-type structure. 

Figure 11.21(a) schematically shows a structure composed of a twolayered carbon film deposited on an Al surface by the pulsed-evaporation vacuum technique. The structure consists of a diamond-like film (ta-C) with tetrahedral sp bonds between carbon atoms and an S-doped highly oriented sp -hybridized carbon film. Figure 11.21(b) represents the I-V characteristics of such a structure, which is a Al/sp carbon-sp carbon/Al junction. 

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