Fluorinated amorphous silicon

When the evolution spectra is measured during illumination for deuter-ated fluorinated amorphous silicon, the deuterium evolution rate peaks are shifted to lower temperatures compared to measurements in the dark (Weil et al., 1988). Both the low temperature and high temperature peak positions shift = 20-30°C during illumination with 100mW/cm2 heat-... 

As a final example we display in Fig. 55 the density of states derived from a fluorinated amorphous silicon sample obtained by Hyun, Shur, and Madan... 

The tetrahedrally bonded materials, such as Si and Ge, possess only positional disorder however, materials of this type exhibit high density of defect states (DOS). It is only with the addition of elements such as hydrogen and/or a halogen, typically fluorine, that the DOS is reduced to a point such that electronic device applications emerge. These materials contain up to 10 atomic % hydrogen, commonly called hydrogenated amorphous silicon ( -Si H). 

Gordon et al. [59] proposed a figure of merit defined by the ratio of the electrical conductivity over the optical absorption coefficient in the visible spectral range. They tested many dopants for AP-CVD ZnO films, and obtained the highest figure of merit for fluorine-doped ZnO, which they used as TCO for amorphous silicon solar cells. 

Intrinsic Defect Formation in Fluorine-Doped Amorphous Silicon Dioxide.105... 

INTRINSIC DEFECT FORMATION IN FLUORINE-DOPED AMORPHOUS SILICON DIOXIDE... 

The FTIR spectra of fluorine-doped silicon dioxide thin films were used to characterise these species. " The IR spectra of amorphous SiO H (2.0 > x > 0) films include vSiOSi bands near 1050 and 1150cm 5SiOSi near 800 Features from vSiO were studied in the IR spectra of Si02.P205 films prepared by micro-pressure... 

Although CO2 dissolves many small molecules readily, it is a very poor solvent for most high molecular weight polymers. Currently, only amorphous or low melting fluoropolymers and silicone polymers are known to be very soluble in CO2 (T < 100 °C, P < 400 bar), or C02-philic, while many industrially important polymers are relatively insoluble. In 1992, we reported the successful homogenous free radical polymerization of a C02-philic fluorinated acrylate, 1,1-dihydroperfluorooctyl acrylate (FOA)2. Homogenous polymer synthesis in CO2 is fundamentally limited however, by the extremely low solubility of most polymers at readily accessible conditions. 

Two classes of polymeric materials, amorphous fluoropolymers and silicones, are the only commercially available polymers to exhibit appreciable solubility in SCCO2 at readily accessible temperatures and pressures (Figure 4.3). It has been proposed that this results from a special interaction between fluorine and carbon dioxide due to the polarity of both species. Silicones are also thought to dissolve because they have weak intermolecular interactions and flexible backbones. 

C. H. Lee and F. A. Kroger, Cathodic deposition of amorphous alloys of silicon, carbon and fluorine,... 

A new method allowing the prediction of many important physical properties of polymers prior to synthesis was presented in this book. Our quantitative structure-property relationships based on this method enable the prediction of the properties of uncrosslinked isotropic amorphous polymers constructed from nine key elements (carbon, nitrogen, oxygen, hydrogen, fluorine, silicon, sulfur, chlorine and bromine) from which most technologically important synthetic polymers are built. Some properties of crosslinked polymers can also be predicted. 

By analogy with photosensitive anodic films appearing over the surface of silicon during its treatment in fluorine-containing electrolytes, it can be suggested that the built-in film represents a mixed phase of electrochemical reaction products or results from the anodized surface amorphization [27,28]. In its turn, this indicates that under potentiostatic conditions the chemical processes at the SiC/HF junction are predominant. The results obtained emphasize that not every porous-like phase formed as a result of SiC anodization can be considered as PSC. 

SILICA (AMORPHOUS) SIO, Diatomite, Silicon diodde (amorphous), Diatomaoeoss earth, Diatomaceous sihea Fluorine, tmygen dilluoride. chlorine Irifiuoride Not combustaMe ... 

According to Her [1], the dissolution of amorphous silica above pH 2 is catalyzed by OH ions that are able to increase the coordination of silicon above four weakening the surrounding siloxane bonds to the network. This general nucleophilic mechanism could presumably occur via Sjv2-Si, S/ 2 Si, or S/ 2 -Si transition states or intermediates and could equally well explain alkoxide ion- or fluorine ion-catalyzed depolymerization mechanisms. 

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