Control of the Dynamics of Photogenerated Carriers at the Boron-Doped Diamond/Electrolyte Interface by Variation of the Surface Termination

摘要

The photoelectrochemical response of boron-doped diamond electrode/electrolyte interfaces was examined toestablish the influence of the chemical termination at thediamond surface on the dynamics of photogenerated carriers.Photocurrent transients resulting from pulsed excimer laserirradiation at hydrogen-terminated (as-deposited) diamondelectrodes and at oxygen-terminated electrodes, which wereprepared either by exposing the surface to oxygen plasma or byanodic polarization in an electrolyte solution, were compared. Asignificant difference between the photocarrier dynamics forthese two surfaces was observed in terms of the full width athalf-maximum of the photocurrent transients. The much fasterdecay rate that was observed for the oxygen-terminated surface isattributed to either the depassivation of deep trapping sites due toremoval of subsurface hydrogen or to the introduction of defectrecombination sites by the oxygen plasma.