Photocurrent and photopotential vs. time curves of thin gamma -Fe//2O//3 films ( less than 10 nm) deposited on Pt by MO-CVD were measured under intermittent illumination of white Xe arc light at various electrode potentials in neutral Na//2SO//4 solutions. Bode diagrams of the systems were also measured over a wide frequency range in darkness and under continuous illumination. Time-dependent changes in the transient photocurrent were similar to those in the differentiated photopotential, showing that intermittent illumination causes capacitance charging and discharging of the film. The Bode diagrams showed the existence of a surface state with a large relaxation time (2 ms-1 s) at the film-solution interface and the increase in the capacitance of the surface state with increasing potential and illumination. From these results, it is thought that both the transient photocurrent and the photopotential arise from the displacement of charges in the space-charge layer of the film. This is attributed to the trapping and accumulation of photo-generated holes in the surface state.
|Number of pages||10|
|Journal||Nippon Kinzoku Gakkai-si|
|Publication status||Published - 1988 Feb 1|
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