Semiconductor Physics and Characteristics of Tunable Negative Electron Affinity Photocathode with High Quantum Efficiency

Negative electron affinity (NEA) photocathodes have long been pursued as an efficient electron source due to their enhanced quantum efficiency, narrow energy spread and high brightness or current density. Conventionally, NEA is achieved by applying a thin layer of cesium-rich oxide onto a semiconductor surface, rendering it highly reactive, unstable, and susceptible to environmental conditions [1]. In a recent investigation focused on electrostatically generated tunable NEA surface [2], an NEA photocathode is explored that exhibits remarkable stability in ambient conditions and allows for electronic tuning of its electron affinity. The present work discusses an enhanced iteration of this device, characterized by improved quantum efficiency and reliability.