PHOTOSENSITIZATION OF DIAMOND THIN-FILMS

Photosensitization of diamond thin films, prepared by the hot-filament technique, has been achieved with thin overcoatings of hydrogenated amorphous silicon. It is observed that injection of electrons, photogenerated in the amorphous silicon, proceeds with efficiencies approaching unity. To reconcile this with the reported electron energy structures of these two materials, the presence of localized, acceptor-like states 2 eV above the valence band of diamond must be invoked. In addition their density must be sufficiently high to account for the inferred lower limit of 10-8 cm2 /V for the electron range.