“…Ultraviolet (UV) detection is essential in various technical fields including applications in flame sensing, environmental monitoring, and spatial optical communications [1,2,3,4]. To date, various UV photodetectors (PDs) using different structures, such as Schottky junctions [5,6], metal–semiconductor–metal sandwich structures [7,8], p–n junctions [9,10,11], and photoelectrochemical cells [12,13,14], have been proposed. Among these structures, p–n heterojunctions are the most effective because of the improved separation efficiency of photoexcited electron–hole pairs by the built-in electric field (BEF) [15,16,17].…”