Graded AlGaN/AlGaN Superlattice Insert Layer Improved Performance of AlGaN-Based Deep Ultraviolet Light-Emitting Diodes

An Al composition graded superlattice AlGaN/AlGaN layer was adopted in AlGaN-based deep ultraviolet light-emitting diodes as a hole reserving layer and relieved the strain between the last quantum barrier and the AlGaN electron blocking layer. The simulation shows that the light output power and internal quantum efficiency of the newly structure are higher and the efficiency droop decreases from 43.6% to 28.8%, due to which the inserted layer weakened the polarization field in the MQWs, suppressed the electron leakage, and increased the hole injection efficiency.