Synthetic diamond electrodes: Photoelectrochemical behavior of vacuum-annealed undoped polycrystalline diamond films

Abstract

The photocurrent and photopotential for undoped polycrystalline diamond film electrodes prepared by chemical vapor deposition and annealed in vacuum at 1500-1640 ° C are measured. The "metal-like" samples (annealed at ≥ 1630 ° C) have a negligible photosensitivity. Judging from the positive sign of the photopotential and the cathodic direction of the photocurrent, the material under study formally behaves as a p -type semiconductor. The photoeffects are presumably caused by structure defects, in particular, the dislocations in diamond crystallites formed close to intercrystalline boundaries during the high-temperature annealing.