Control of the dynamics of photogenerated carriers at the boron-doped diamond electrolyte interface by variation of the surface termination

The photoelectrochemical response of boron-doped diamond electrode/electrol yte interfaces was examined to establish the influence of the chemical term ination at the diamond surface on the dynamics of photogenerated carriers. Photocurrent transients resulting from pulsed excimer laser irradiation at hydrogen-terminated (as-deposited) diamond electrodes and at oxygen-termina ted electrodes, which were prepared either by exposing the surface to oxyge n plasma or by anodic polarization in an electrolyte solution, were compare d. A significant difference between the photocarrier dynamics for these two surfaces was observed in terms of the full width at half-maximum of the ph otocurrent transients. The much faster decay rate that was observed for the oxygen-terminated surface is attributed to either the depassivation of dee p trapping sites due to removal of subsurface hydrogen or to the introducti on of defect recombination sites by the oxygen plasma. (C) 1999 The Electro chemical Society. S1099-0062(99)03-024-2. All rights reserved.