Oxidation kinetics, germanium oxides

For the polymerization, either in the melt or solid phase, the reaction is driven to the polymer by removing ethylene glycol. The polymerization reaction is typically catalyzed by solutions consisting of antimony trioxide or germanium oxide. Both polycondensation catalysts also catalyze the reverse reaction, which is driven by an excess of ethylene glycol at melt conditions, generally above 255 °C. The polymerization reaction follows second-order kinetics with an activation energy of 22 000 cal/mol [6],... 

Cockeram and Rapp have evaluated the kinetics of silicide coatings on Ti [103] and have used a halide-activated pack-cementation method to form boron- and germanium-doped silicide coatings on orthorhombic alloy substrates [104]. The coatings greatly decreased the cyclic oxidation kinetics and microhardness measurements did not indicate diffusion of oxygen into the substrate. 

The oxidation of the deposited germanium is also a complicated process we found that mainly chemical oxidation by Gel4 takes place, together with some electrooxidation. It is likely that kinetic factors play a dominant role. 

Although not of primary concern in this review a number of experimenters have developed information on the oxidation rates of amorphous and polycrystalline films of germanium. While there is some disagreement on the role of porosity in the oxidation rate of such films, (17,18) the kinetics of the reaction appear to be strongly dependent on the morphology of the films and the ambient atmospheres to which they are initially exposed. Based on that information it would appear that implant areas should be annealed in situ or at least removed from vacuum to a controlled environment until final surface preparation is affected. This is particularly true of photovoltaic and photo-conductive devices where the uniformity of oxide, interface moisture content, uptake of carbon complexes etc. strongly affect the surface recombination currents and hence the device performance (77). 

J. Kiraly (Surface Oxidation Phenomena on a Germanium Single-Crystal Surface. II. Oxygen Absorption Kinetics) ibid. 74 (11), p. 553 (1968). 

The surface consists of terraces with a height of330 30 pm. Within the limits of error, this is the value that has to be expected for Ge(lll) bilayers. Furthermore, we could observe that the first electrodeposition leads to a less ordered sur ce sttucture with nanoclusters, which transforms on the time scale of about 1 h into a layered structure. With GeBr4 a transformation of clusters into such a layered sur ce was only partly seen, with GeCl4 this transformation could not be observed. The oxidation of the deposited germanium is also a complicated process. We found that mainly chemical oxidation by Gel4 takes place, together with some electrooxidation. It is likely that kinetic factors play a dominant role. 

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