Enhanced external quantum efficiencies of AlGaN-based deep-UV LEDs using reflective passivation layer

Su-Hui Lin, Ming-Chun Tseng, Kang-Wei Peng, Shouqiang Lai, Meng-Chun Shen, Ray-Hua Horng, Shui-Yang Lien, Dong-Sing Wuu, Hao-Chung Kuo, Tingzhu Wu, and Zhong Chen
Opt. Express 29, 37835-37844 (2021) — Published in November 2021


In this study, deep ultraviolet light-emitting diodes (DUV-LEDs) with a reflective passivation layer (RPL) were investigated. The RPL consists of HfO2/SiO2 stacks as distributed Bragg reflectors, which are deposited on two DUV-LEDs with different p-GaN thicknesses. The RPL structure improved the external quantum efficiency droops of the DUV-LEDs with thick and thin p-GaN, thereby increasing their light output power by 18.4% and 39.4% under injection current of 500 mA and by 17.9% and 37.9% under injection current of 1000 mA, respectively. The efficiency droops of the DUV-LEDs with and without the RPL with thick p-GaN were 20.1% and 19.1% and with thin p-GaN were 18.0% and 15.6%, respectively. The DUV-LEDs with the RPL presented improved performance. The above results demonstrate the potential for development of the RPLs for DUV-LED applications.