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Pressurization influence on electrochemical impedance spectra (EIS) of both anode-supported and electrolyte-supported cells (ASC and ESC) are measured and compared using a high-pressure SOFC facility. In it both ASC and ESC apply the same single-cell setup, a planar full cell having 40 × 40 mm2 effective reactive area sandwiched by a pair of rib-channel flow distributors (interconnectors) on both anode and cathode, using the same flow rates (Qanode = 0.5 slpm H2 + 0.4 slpm N2 and Qcathode = 0.9 slpm air) at 850°C, with five different pressures (1 ∼ 5 atm). It is found that ASC is more sensitive to pressurization than ESC, of which power densities of ASC/ESC at 0.7 V increase from 309/193 mW cm−2 to 476/250 mW cm−2, as p increases from 1 atm to 5 atm, corresponding to a 54%/30% increase. This result is explained by EIS measured data, in which both ohmic and polarization resistances of ASC are smaller than that of ESC. Moreover, the ohmic resistance is independent of pressurization for both ASC and ESC, remaining constant regardless of either unloaded or loaded conditions, while the polarization resistance decreases noticeably with increasing pressure for both ASC and ESC.

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The Optical Emission Spectroscopy (OES) is used as a diagnostic tool for analyzing the plasma spectrum of Electron Cyclotron Resonance Chemical Vapor Deposition (ECR-CVD) in solar silicon oxide thin film process. In this study, the correlation between spectrum variation trend and a-SiOx film properties will be discussed.The results reveal when the total flow rate and working pressure are fixed, the silicon oxide deposition rate can be interpreted by SiH* spectroscopy. On the premise that the bond energy of reaction species is lower than the bond energy of Si-O bond, the O* spectroscopy intensity tends to to be a positive correlation with oxygen content of thin film. Based on the above results, we can develop and use the database from plasma spectra corresponding to film properties, and the processing time required for optimization of silicon oxide process can be reduced significantly. In addition to the film properties, it is noted that a different and opposite finding compared with PECVD is that the photo-conductivity of a-SiO x film increases and dark-conductivity decreases when microwave power augments. Finally, in 800W power, 200°C process temperaure and 5mTorr working pessure, it is found that the hydrogenated amorphous silicon oxide will transform to the crystalline phase when CO 2 /SiH 4 ratio is less than 0.2 and H 2 /SiH 4 ratio is greater than 10.

No abstract