Silicon-hydrogen bond properties

The hydrogen content Ch greatly influences structure and consequently electronic and optoelectronic properties. An accurate measurement of Ch can be made with several ion-beam-based methods see e.g. Arnold Bik et al. [54]. A much easier accessible method is Fourier-transform infrared transmittance (FTIR) spectroscopy. The absorption of IR radiation is different for different silicon-hydrogen bonding configurations. The observed absorption peaks have been indentified [55-57] (for an overview, see Luft and Tsuo [6]). The hydrogen content can be determined from the absorption peak at 630 cm , which includes... 

The Raman spectrum of nanocrystalline silicon was used to determine the amounts of SiHs, SiH2 and SiH groups present/ IR measurements revealed vSiH bands in the initial stages of porous silicon formation on silicon surfaces vSiH and vSiN IR bands were used to probe hydrogen-bonding properties of nitrogen-doped silicon thin films Surface-IR observation of 5SiH modes showed the formation of Si-H units by decomposition of H2O on a clean Si(100)-(2 X 1) surface ... 

The formation of silicon-flvxyride bonds on the surface of silica after treatment with hydrogen fluoride was never proven directly. However, there is a pronounced change in the adsorption and wetting properties. The silica becomes hydrophobic as was mentioned in a patent to Kimberlin (279a). Neimark and collaborators (279b) found a type V isotherm in the methanol adsorption on silica gel which had been treated with a solution of SiF in absolute alcohol. Wilska (280) obtained a water-repellent silica when solutions of HaSiPg were precipitated with ammonia. The Si—F bond is hydrolyzed only slowly. A considerable fluorine content of 7-10% F was reported in an older patent (281) for a silica that had been prepared by hydrolysis of SiF. ... 

It is generally accepted that the only important polar adsoiption sites on the silica surface are the silanol functions, i.e., hydroxyl groups, that are attached to silicon atoms (2). They can interact with the sample molecules by hydrogen bonding and various physical observations ctAi be used to prove this statement. Complete dehydration of silica by beating, i.e., removal of all surface hydroxyl groups, yields a hydrophobia silica which no longer shows adsorption for unsaturated and polar molecules and is no more wetted by water (15). Chemical modification of the surface hydroxyls such as used in the preparation of chemically bonded phases also eliminates the selective adsorption properties of the silica. ... 

Structure//was one of the first known examples of hydrogen bridges between a transition metal and a main-group element other than boron. There are many interesting features in syntheses, bonding properties, and reactions of silicon-transition-metal compounds which can only be outlined in this article, which covers the literature up to 1973. But any survey achieves its aim if it stimulates further interest and research in its specific area. 

Of all the gas radicals near the surface, atomic hydrogen can penetrate farthest into the material. The diffusion of hydrogen and its removal and adsorption at the surface, described in Section 2.3.3, show that, at the deposition temperature, interstitial hydrogen can move quite rapidly into the bulk where it readily attaches to silicon dangling bonds. Hydrogen therefore has the fortimate property of being able to remove any subsurface defects left by the deposition process. 

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