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Neodymium- or erbium-doped silica films are deposited on single crystal silicon substrates using a sol-gel process and a spin-coating technique. These glasses are doped with neodymium or erbium in various Nd/Si or Er/Si atomic ratios up to 8% using neodymium nitrate or erbium nitrate as precursor. A preparation method of such films is described. Film rare earth concentration measured by Rutherford Backscattering Spectroscopy (RBS) is the same as in the initial liquid solution. Film thickness and refractive index are obtained by variable angle spectroscopic ellipsometry. We have shown that both RBS analysis and spectroscopic ellipsometry are powerful tools to control rare earth doping level and optical properties of the silica films.
The methods of thermally stimulated currents (TSC) together with low frequency dielectric spectroscopy (LFDS) are combined for the first time to study percolation phenomena. These take place within oil-resin mixtures which constitute conductor/insulator-like composite systems. Each of these techniques is shown to describe selectively one of two different kinds of relaxation processes in the oil component: first, anelastic dipolar movements and second, the circulation of free charges. The separate qualitative interpretations of the combined TSC/LFDS experiments lead to convergent estimations of the percolation thresholds of the two basic materials in oil-resin mixtures. The latter appear as critical concentrations for which the dielectric relaxation processes either comply suddenly with compensation laws or pre-existing compensation phenomena change in nature.
The water vapor and gas transport in polyimide films were analyzed using Harmon's model with accounts for case I transport and case II transport. Harmon's model was in good agreement with the experimental data. The diffusion coefficient obtained by Harmon's model was smaller than that obtained by using the short-time slope of mass uptake versus time with the exception of CO2 in polyimide. A comparison of the present model and the dual-mode sorption model, in which populations follow Henry's law and Langmuir type, was made.
Extensive analytical characterization indicates that the most significant contaminant following dry processing of As-implanted photoresist is not a carbon-based residue, but is in fact arsenic itself. The arsenic residue is an amorphous form of elemental arsenic, relatively free of oxygen or carbon, that is stable for long periods of time. Since arsenic is not particularly soluble in sulfuric acid, hydrogen peroxide, or their mixtures, it makes sense to pose questions regarding the optimum choice for post-dry processing wet chemical cleans.
Impression recovery in which the deformation temperature is the same as recovery temperature is studied for the first time. PMMA is deformed by impression above the glass transition temperature to a depth of less than 0.3 mm and recovered at the same temperature. Almost complete recovery of dimension is observed every time. The dimensional changes obey second order kinetics and the temperature dependence of the rate constant shows two consecutive processes with activation energies 440 kJ/mole (between 104 and 113 °C) and 95 kJ/mole (between 113 and 140 °C). Two pairs of defects of opposite signs are believed to be involved in the dimensional recovery processes.