Photonics Research, 2019, 7 (4): 040000B1, Published Online: Apr. 11, 2019
Increasing the hole energy by grading the alloy composition of the p-type electron blocking layer for very high-performance deep ultraviolet light-emitting diodes
Abstract
It is well known that the p-type AlGaN electron blocking layer (p-EBL) can block hole injection for deep ultraviolet light-emitting diodes (DUV LEDs). The polarization induced electric field in the p-EBL for [0001] oriented DUV LEDs makes the holes less mobile and thus further decreases the hole injection capability. Fortunately, enhanced hole injection is doable by making holes lose less energy, and this is enabled by a specifically designed p-EBL structure that has a graded AlN composition. The proposed p-EBL can screen the polarization induced electric field in the p-EBL. As a result, holes will lose less energy after going through the proposed p-EBL, which correspondingly leads to the enhanced hole injection. Thus, an external quantum efficiency of 7.6% for the 275 nm DUV LED structure is obtained.
Zi-Hui Zhang, Jianquan Kou, Sung-Wen Huang Chen, Hua Shao, Jiamang Che, Chunshuang Chu, Kangkai Tian, Yonghui Zhang, Wengang Bi, Hao-Chung Kuo. Increasing the hole energy by grading the alloy composition of the p-type electron blocking layer for very high-performance deep ultraviolet light-emitting diodes[J]. Photonics Research, 2019, 7(4): 040000B1.