High-quantum-efficiency ultraviolet solar-blind AlGaN photocathode detector with a sharp spectral sensitivity threshold at 300  nm

At present, most of the existing practical ultraviolet (UV) solar-blind detectors are based on Te-Cs photocathode image intensifiers. However, limited by their photoemission characteristics, it is difficult for the Te-Cs-based photocathodes to achieve both high quantum efficiency in the application band and high cutoff ratio in the non-applied band simultaneously. In this paper, a high-quantum-efficiency UV solar-blind detector based on AlGaN photocathodes with a sharp spectral sensitivity threshold at 300 nm is reported. The proposed AlGaN photocathode has extremely high quantum efficiency (i.e., 20%) in the 210-275 nm band, while the efficiency curve steeply reduces to 2% at 300 nm, showing obviously superior performance than the existing Te-Cs photocathodes.