Field emission characteristics of polycrystalline and single-crystalline diamond grown on Si tips

Polycrystalline and single-crystal diamond coatings were grown on silicon field emitters by the hot filament CVD technique. The emission properties of both kinds of diamond coating were compared. Field emission from tips with a polycrystalline coating followed the Fowler-Nordheim emission law, and were characterized by a high maximum current (up to 500 μA) and good emission stability. The single-crystal coating demonstrated two emission modes: “hysteresis” and “normal” ones. In the “hysteresis” mode, the emission current saturated at about 2 μA. The transformation from “hysteresis” to “normal” behavior occurred with an increase of the voltage. Some possible emission mechanisms of diamond coated emitters are discussed.