NEA surface AlGaN heterojunction tilted nanowire array photocathode for vacuum electron sources

Abstract

As the core component of the electron accelerator, the electron source is responsible for providing high-quality electron beams. GaN has a wide bandgap and must be driven by an ultraviolet laser, making it a strong candidate for photocathode electron source research. We established a theoretical model of photoemission for field-assisted negative electron affinity (NEA) AlGaN heterojunction tilted nanowire array photocathodes. The top-down built-in electric field facilitated the transport of photogenerated carriers within the nanowire. The inclination of the nanowires effectively improved the quantum efficiency of the photocathode. With the critical angle of incidence of ultraviolet, the quantum efficiency was up to 81.2%, and the collection efficiency was up to 51%. This work could provide theoretical support for the design and fabrication of high-quality photocathode electron sources.

Keywords

• AlGaN
• Nanowires
• Solar-blind
• Photocathode
• Photoelectron emission