Hot Electron Light Assisted Cathode by Electronically Tunable Negative Electron Affinity

Currently, negative electron affinity cathodes are considered as a potential high frequency photoemitters due to their relatively high external quantum efficiency and low mean transverse energies, however, they face challenges in terms of stability and complexity in their manufacturing process. In this research, we have developed an electronically adjustable cathode called Hot Electron Laser Assisted Cathode (HELAC) which uses negative electron surfaces and is fabricated using a simple and ex-situ technique. Despite not being fully optimized, the proof-of-concept device has demonstrated great air stability and an external quantum efficiency of around 0.5%. This work can give an idea of the possibilities and difficulties of designing new photocathodes with high quantum efficiency by using the negative electron affinity technique.