Efficiency enhancement of ultraviolet light-emitting diodes with segmentally graded p-type AlGaN layer

Wang Lin-Yuan¹, Song Wei-Dong¹, Hu Wen-Xiao¹, Li Guang¹, Luo Xing-Jun¹, Wang Hu¹, Xiao Jia-Kai¹, Guo Jia-Qi¹, Wang Xing-Fu¹, Hao Rui³, Yi Han-Xiang³, Wu Qi-Bao^{2, ‡}, Li Shu-Ti^{1, §}

(a)–(d) Energy band diagrams of UV-LEDs with different structures; (e)–(h) corresponding electrostatic field profiles. The inset in panel (h) is the enlarged electrostatic field distribution diagram within the last QW and QB of structure A and D.