Comprehensive Enhancements of GaN Ultraviolet Photodiodes via Indium-Surfactant-Assisted Mg-δ-Doped p-Type GaN

Front-illuminated GaN-based p-i-n photodiodes (PDs) incorporating indium-surfactant -assisted (ISA) Mg-δ-doped p-GaN were fabricated and systematically characterized. Hall-effect measurements at room temperature revealed a hole concentration of~1.5 × 1018 cm−3 in the ISA Mg-δ-doped p-GaN, significantly higher than that of uniformly Mg-doped p-GaN (~3.7 × 1017 cm−3). Devices employing ISA Mg-δ-doped p-GaN exhibited reduced leakage current, enhanced responsivity, faster response speed, improved reliability, and lower noise current compared to control PDs. These comprehensive performance enhancements, attributed to the improved crystalline quality and the optimized electric field distribution, suggest significant potential in practical UV applications.