SYNTHETIC DIAMOND ELECTRODES - PHOTOELECTROCHEMICAL INVESTIGATION OF UNDOPED AND BORON-DOPED POLYCRYSTALLINE THIN-FILMS

The photoelectrochemical behavior of polycrystalline diamond films, gr own on tungsten substrates by chemical vapor deposition (CVD), has bee n studied in 0.5M H2SO4 solution. Different types of films have been i nvestigated, with or without intentional doping with boron. Experiment al results point to a p-type behavior of boron-doped samples, while th e presence of an inversion of the photocurrent sign reveals an insulat ing behavior of undoped samples. Photocurrent spectra display differen t threshold energies, which have been related with possible defect lev els inside both types of diamond films.