中国物理B ›› 2023, Vol. 32 ›› Issue (5): 58503-058503.doi: 10.1088/1674-1056/ac9de7
Yi-Wei Cao(曹一伟)1, Quan-Jiang Lv(吕全江)1,†, Tian-Peng Yang(杨天鹏)2,3, Ting-Ting Mi(米亭亭)3, Xiao-Wen Wang(王小文)3, Wei Liu(刘伟)3, and Jun-Lin Liu(刘军林)1,‡
Yi-Wei Cao(曹一伟)1, Quan-Jiang Lv(吕全江)1,†, Tian-Peng Yang(杨天鹏)2,3, Ting-Ting Mi(米亭亭)3, Xiao-Wen Wang(王小文)3, Wei Liu(刘伟)3, and Jun-Lin Liu(刘军林)1,‡
摘要: We investigate the polarization-induced doping in the gradient variation of Al composition in the p-Al$_{0.75}$Ga$_{0.25}$N/Al$_{x}$Ga$_{1-x}$N hole injection layer (HIL) for deep ultraviolet light-emitting diodes (DUV-LEDs) with an ultra-thin p-GaN (4 nm) ohmic contact layer capable of emitting 277 nm. The experimental results show that the external quantum efficiency (EQE) and wall plug efficiency (WPE) of the structure graded from 0.75 to 0.55 in the HIL reach 5.49% and 5.04%, which are improved significantly by 182% and 209%, respectively, compared with the structure graded from 0.75 to 0.45, exhibiting a tremendous improvement. Both theoretical speculations and simulation results support that the larger the difference between 0.75 and $x$ in the HIL, the higher the hole concentration that should be induced; thus, the DUV-LED has a higher internal quantum efficiency (IQE). Meanwhile, as the value of $x$ decreases, the absorption of the DUV light emitted from the active region by the HIL is enhanced, reducing the light extraction efficiency (LEE). The IQE and LEE together affect the EQE performance of DUV-LEDs. To trade off the contradiction between the enhanced IQE and decreased LEE caused by the decrease in Al composition, the Al composition in the HIL was optimized through theoretical calculations and experiments.
中图分类号: (Light-emitting devices)