Optimization of AlGaN-based deep ultraviolet light-emitting diodes with superlattice-doped staggered-stepped electron-blocking layers

Deep ultraviolet light-emitting diodes (DUV-LEDs) suffer from significant electron leakage and insufficient hole injection, which result in low carrier injection efficiency and poor output power. The superlattice-doped staggered-stepped (SD-SS) electron-blocking layer (EBL) is proposed to reduce electron leakage and improve hole injection. Advanced Physical Model of Semiconductor Devices (APSYS) software is employed to simulate DUV-LEDs with rectangular EBL, stepped EBL, staggered-stepped (SS) EBL, and SD-SS EBL. Based on the traditional stepped EBL, the SS EBL is designed to enhance electron confinement. In the SS EBL, low-concentration doping is applied in regions with high Al composition to alleviate the difficulty of p-type doping, whereas high-concentration doping is used in regions with low Al composition to improve hole generation. This forms a superlattice doping structure, resulting in the formation of SD-SS EBL. Simulation results indicate that the utilization of SD-SS EBL reduces electron leakage in the p-type region, enhances hole injection in the multiple quantum wells, and increases the radiative recombination rate. When the injection current is 60 mA, the proposed structure achieves an external quantum efficiency of 5.05% and an output power of 13.2 mW. In conclusion, the SD-SS EBL contributes to enhancing electron confinement, reducing the difficulty of p-type doping, and increasing hole generation, which provides valuable insights for developing high-efficiency DUV-LEDs.