PHOTOELECTRICAL EFFECTS IN HETEROSTRUCTURES BASED ON HF-CVD DIAMOND FILMS

Thin polycrystalline diamond films were grown on tungsten substrates from a mixture of 0.5%-1.5% methane or acetone and hydrogen by the hot filament CVD technique. Metal-diamond film-metal diodes were fabricated with Ni or Ti semitransparent electrodes on top of the films. Electrical and photoelectrical characteristics of the diodes were investigated. It was shown that in such diodes made with insulating undoped CVD diamond films, the built-in electrical held exists owing to the difference in barriers at the opposite metal-diamond interfaces. This barrier difference was measured using the photovoltage saturation method. It was shown that the photovoltaic elements develop maximum photovoltages of 0.7 V for the Ni electrode and I V for the Ti one at zero bias.