A method for crystallizing amorphous silicon (a-Si) films at low temperatures is proposed. In the method, a-Si films are crystallized at temperatures lower than 400 °C by annealing in the presence of atomic hydrogen. The hydrogen atoms are generated by catalytic cracking reaction of H2 gas on a heated tungsten catalyzer in the catalytic chemical vapor deposition apparatus. It is found that the crystalline fraction of such an a-Si film is increased from 0% to several tens %, and at the same time the a-Si film itself is etched with the rate of several tens nm/min by annealing in atomic hydrogen. This increment of crystalline fraction appears dependent on the quality of initial a-Si films. It is implied that there are several types of a-Si even if the difference among a-Si films cannot be detected by Raman scattering spectroscopy and other means for measurements.
We consider the classical Arnold example of diffusion with two equal parameters. Such a system has two-dimensional partially hyperbolic invariant tori. We mainly focus on the tori whose ratio of frequencies is the golden mean. We present formal approximations of the three-dimensional invariant manifolds associated with this torus and numerical globalization of these manifolds. This allows one to obtain the splitting (of separatrices) vector and to compute its Fourier components. It is apparent that the Melnikov vector provides the dominant order of the splitting provided the contribution of each harmonic is computed after a suitable number of averaging steps, depending on the harmonic. We carry out the first-order analysis of the splitting based on that approach, mainly looking for bifurcations of the zero-level curves of the components of the splitting vector and of the homoclinic points.
Silicon nitride (SiN x ) films on Si and poly(ethylene terephthalate) (PET) substrates were prepared at approximately 150 C by catalytic chemical vapor deposition (Cat-CVD), using a SiH 4 /NH 3 gas mixture. A water vapor transmission rate as low as 0.2 g/m 2 day and an O 2 gas transmission rate of 0.6 cm 3 /m 2 day were achieved for a stoichiometric Si 3 N 4 film of 77 nm thickness. Although these transmission rates depended on N/Si ratio, no optical absorption was observed under preferable deposition conditions.
Inexpensive and sensitive graphite electrodes were fabricated by applying flame annealing to pencil-graphite rods (PGRs) as electrodes for water electrolysis cells. The resin (polymer, binder) on the surface of PGR was removed by flame annealing to make it porous, and the graphite electrodes with high activity and low cost were obtained. By flame annealing the PGR, although the PGR electrode became active upon water electrolysis, the PGR electrode became instable for long-time operation. The effects of flame annealing on PGR for water electrolysis were analyzed by SEM, FT-IR spectroscopy, Raman spectroscopy, NEXAFS, and electrochemical impedance spectroscopy (EIS).
The surface properties of a plastic substrate were changed by a novel surface treatment called atomic hydrogen annealing (AHA). In this method, a plastic substrate was exposed to atomic hydrogen generated by cracking hydrogen molecules on heated tungsten wire. For the substrate, surface roughness was increased and halogen elements (F and Cl) were selectively etched by AHA. AHA was useful for pretreatment before film deposition on a plastic substrate because the changes in surface state relate to adhesion improvement. It is concluded that this method is a promising technique for preparing highperformance plastic substrates at low temperatures.
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