Non-thermionic cathodes-solid state electron emitters based on GaN and LaB/sub 6/

We report the first experimental demonstration of a GaN cold cathode emitter that uses bandgap engineering to achieve low voltage, room-temperature and durable emission from a flat surface. The device consists of a GaN pn junction and a thin layer of LaB/sub 6/. The device achieves effective negative electron affinity by injecting electrons from the conduction band of a p-type wide bandgap semiconductor into vacuum through an intermediary low workfunction material.