%A Guang Li(李光), Lin-Yuan Wang(王林媛), Wei-Dong Song(宋伟东), Jian Jiang(姜健), Xing-Jun Luo(罗幸君), Jia-Qi Guo(郭佳琦), Long-Fei He(贺龙飞), Kang Zhang(张康), Qi-Bao Wu(吴启保), Shu-Ti Li(李述体) %T Enhanced performance of AlGaN-based ultraviolet light-emitting diodes with linearly graded AlGaN inserting layer in electron blocking layer %0 Journal Article %D 2019 %J Chin. Phys. B %R 10.1088/1674-1056/28/5/058502 %P 58502-058502 %V 28 %N 5 %U {https://cpb.iphy.ac.cn/CN/abstract/article_121622.shtml} %8 2019-05-05 %X

The conventional stationary Al content AlGaN electron blocking layer (EBL) in ultraviolet light-emitting diode (UV LED) is optimized by employing a linearly graded AlGaN inserting layer which is 2.0 nm Al0.3Ga0.7N/5.0 nm AlxGa1-xN/8.0 nm Al0.3Ga0.7N with decreasing value of x. The results indicate that the internal quantum efficiency is significantly improved and the efficiency droop is mitigated by using the proposed structure. These improvements are attributed to the increase of the effective barrier height for electrons and the reduction of the effective barrier height for holes, which result in an increased hole injection efficiency and a decreased electron leakage into the p-type region. In addition, the linearly graded AlGaN inserting layer can generate more holes in EBL due to the polarization-induced hole doping and a tunneling effect probably occurs to enhance the hole transportation to the active regions, which will be beneficial to the radiative recombination.