Non-thermionic cathodes - solid state electron emitters based on GaN and LaB₆

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 LaB₆. The device achieves effective negative electron affinity by injecting electrons from the conduction band of a p-type wide handgap semiconductor into vacuum through an intermediary low workfunction material.