Emission and Processing Requirements for Carbide Films on Mo Field Emitters

Abstract

AbstractWe have been working for many years on electron emission and surface properties of transition metal carbides. These studies have covered field, photo, and thermionic emission from bulk carbides as well as field and photo emission from carbide coatings and films on various substrates. Thin film carbide overcoatings have also been used on field emitter arrays of both Mo and Si. These unique carbide materials have electron emission properties making them attractive candidates for several applications. Uses for these carbides include FEA video displays, microwave applications, high current and small spot electron sources (e.g. accelerators and FELs), and cold cathodes for operation at tube pressures and in poor vacuums (e.g. FEAs, vacuum detectors, and neutralizing beams for ion thrusters).We report here on one aspect of our current research which deals with electron emission of ZrC films coating single Mo field emitters. The relevant application is Spindt-type field emitter arrays. Processing steps are evaluated showing the need for a clean substrate. After deposition treatments are also investigated. Emission degradation has been noted after exposure to air and we report on successful use of a hydrogen atmosphere to reverse those adverse effects.