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

Author Affiliations
1 Institute of Micro-Nano Photoelectron and Electromagnetic Technology Innovation, School of Electronics and Information Engineering, Hebei University of Technology, Key Laboratory of Electronic Materials and Devices of Tianjin, Tianjin 300401, China
2 e-mail: zh.zhang@hebut.edu.cn
3 Department of Photonics and Institute of Electro-Optical Engineering, Taiwan Chiao Tung University, Hsinchu 30010, China
4 Department of Electrical Engineering and Computer Sciences and TBSI, University of California at Berkeley, Berkeley, California 94720, USA
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.
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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.

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