Light extraction efficiency enhancement of deep ultraviolet light-emitting diodes using wafer-scale SiO<sub>2</sub>-based patterned dielectric nanostructures
Yufan Wei, Maocheng Shan, Zhiwei Gao, Yongming Zhao, Zhencheng Li, Zhenyu Chen, Yuhui Zeng, Zhengang Liang, Xiantai Tian, Yang Peng, Feng Wu, Changqing Chen, Hao‐Chung Kuo, Jiangnan Dai
Abstract
The progress of AlGaN-based deep ultraviolet light-emitting diodes is significantly limited by their unideal light extraction efficiency. In this work, a cost-efficient nanosphere lithography technique is utilized to fabricate wafer-scale SiO 2 -based patterned dielectric nanostructures on the backside of sapphire substrates. Mapping results and statistical analyses demonstrate a uniform optical power enhancement across the entire chip, and the average power can be increased by 16.7% with almost identical peak wavelength and slightly enhanced operating voltage. The light output power of the LEDs with the patterned film exhibits a substantial enhancement of 34.0% compared to conventional LEDs at an injected current of 330 mA, accompanied by a 1.34-fold increase in light extraction efficiency. Finite-difference time-domain simulations indicate that the nanostructures on the patterned film effectively weakened total internal reflection at the sapphire/air interface. The above results validate the scalability of this method for industrial mass production of high-power DUV LEDs.