Doping and Defect Control in AlGaN-Based Deep Ultraviolet LEDs: Strategies for Enhanced Performance

AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) are widely regarded for their potential in critical applications such as sterilization, water purification, and photolithography, operating in the 200-280 nm wavelength range. However, their performance remains limited by high defect densities, inefficient p-type doping, and low light extraction efficiency, which collectively reduce the external quantum efficiency (EQE). This paper provides a comprehensive review of current doping strategies, with an emphasis on optimizing both n-type and p-type conductivity, particularly in high-aluminum-content AlGaN. Moreover, the impact of threading dislocations and point defects on material properties is analyzed, alongside recent advancements in epitaxial growth methods like metal-organic chemical vapor deposition (MOCVD) aimed at reducing defect densities. Although significant progress has been made in defect management and doping efficiency, challenges remain, particularly in enhancing p-type doping activation. The paper concludes by suggesting future directions, including co-doping strategies and stress compensation layers, to further improve DUV LED performance and enable more efficient, commercially viable devices.