Photoelectrochemistry of Synthetic Diamond Electrodes

Synthetic polycrystalline diamond, owing to its enhanced chemical stability, may be thought to be a promising corrosion-stable electrode material, or protective coating for electrodes, e.g., for photo-electrochemical cells and sensors. On the other hand, electrochemical techniques can be used for the characterization of diamond films. In the present work we summarize our recent studies in the photoelectrochemistry of CVD diamond thin films. In particular, photocurrent spectra were recorded on the diamond/electrolyte solution contact (note that a semiconductor/electrolyte contact in many respects resembles the Schottky contact semiconductor/metal [ 1 ]); threshold energies were determined for the electron transitions in diamond, which can be related to the photo-current formation [ 2 ]. Photopotential transients, upon illumination with nanosecond laser flashes, were recorded for the films under open-circuit conditions. The transients were analyzed using a simple equivalent circuit of the electrodes, whose elements were calculated by the photopotential decay curves [ 3 ].