Fabrication of tubular-volcano-type free-standing diamond films

Tubular-volcano-type free-standing diamond films were obtained by depositing dia mend films on an engraved Mo substrate having circular microwells, and then detaching the as-deposited diamond films from the substrate. The substrate side, i.e. the detached side from the substrate, of the film shows the formation of tubular-volcano-type structures. The inner diameters of these structures decreased gradually from the volcano top to the crater inside. A protrusion as high as similar to 50 mu m occurred at the summits of tubular-type volcanoes, compared with the base plane. For the tubular-volcano-type free-standing diamond films, the field emission characteristics were greatly enhanced, including lower turn-on voltages and higher current, compared with those of flat-type diamond film surfaces under identical conditions.