MSM cathodes using /spl beta/-SiC

We have undertaken the development of a cold cathode, operating with low power and high efficiency, suitable for applications requiring modest emitted electron current densities over a broad area. The cathode consists of a sandwich of high-bandgap semiconductor material between an injecting substrate layer and a thin conducting layer which acts as the interface to the vacuum. This vacuum interface material is chosen to provide an electrical contact with the semiconductor material and must exhibit relatively low work function, resistance to corrosion or other damage, and compatibility with the semiconductor material onto which it is grown. The design is intended to provide operation of the cathode as follows. Electrons from the substrate are injected into the conduction band of the semiconductor, travel to the surface conducting film under the effect of a slight externally applied electrical bias, and are then emitted through the vacuum interface layer.