Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10269622 | Electrochimica Acta | 2005 | 8 Pages |
Abstract
The electrochemical impedance, photocurrent, and photopotential are measured in the supporting electrolyte solution (2.5 M H2SO4) for electrodes made of the undoped polycrystalline CVD diamond films annealed in vacuum at 1500-1640 °C. Analysis of the impedance spectra allowed concluding that both the amount of a nondiamond conducting phase in the electrode bulk and its conductivity increased upon annealing. With increasing annealing temperature, the photopotential passed through a maximum at â¼1570 °C. The photosensitivity of “metal-like” samples (annealed at temperatures â¥1630 °C) is negligibly small. Judging from the sign of the photopotential (positive) and photocurrent (cathodic), the studied material formally behaves as a p-type semiconductor. It is suggested that the photoeffects are caused by the structure defects, in particular, dislocations in diamond crystallites, formed close to intercrystalline boundaries during the high-temperature annealing.
Keywords
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Physical Sciences and Engineering
Chemical Engineering
Chemical Engineering (General)
Authors
Yu.V. Pleskov, M.D. Krotova, V.V. Elkin, V.G. Ralchenko, A.V. Khomich, R.A. Khmelnitskiy,