| 摘要 |
PURPOSE:To permit easy determination of the timing for the adsorption of an anion by impressing specified current or potential to a test piece after immersing the test piece into a soln. CONSTITUTION:The holes among the electron-hole pairs generated by the irradiation of light are trapped into the surface level and the waveform of the photocurrent gives the shape (a) or (b) shown in the figure A when Cl<-> ions are not adsorbed on the surface of an oxide. On the other hand, the concn. of the impurity level to trap the holes decreases and the changes for trapping the holes decrease and the electrons are more easily trapped into the level created by the Cl<-> ions when the Cl<-> ions are adsorbed to said surface. The rate at which the photocurrent attenuates, therefore, decreases and the waveform thereof gives the shapes (a), (b) of the figure B. In the figure B (b), however, the e<-> in the fill band is likely to migrate to the soln. side via the level of the Cl<-> ions and therefore, the anode dark current flows in the stationary state. The adsorption of the ions on the surface is known from the change of the attenuation rate of the photocurrent in the waveform of said current.
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