Transparent p-type layer with highly reflective Rh/Al p-type electrodes for improving the performance of AlGaN-based deep-ultraviolet light-emitting diodes
Liubing Wang, Fujun Xu, Jing Lang, Jiaming Wang, Lisheng Zhang, Xuzhou Fang, Ziyao Zhang, Xueqi Guo, Ji Chen, Xiangning Kang, Ning Tang, Xinqiang Wang, Zhixin Qin, Weikun Ge, Bo Shen
Abstract
Abstract We attempt to improve the light extraction of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) by introducing a highly transparent p-type layer together with reflective Rh/Al p-type electrodes. The p-GaN contact layer is thinned to balance the Ohmic contact and DUV light transmittance, which helps the Rh/Al p-type electrodes realize high reflection as well as good electrical performance. After optimization, the Rh/Al reflective p-type electrodes present reflectance of greater than 70% and specific contact resistivity of 3.75 × 10 −4 Ω·cm 2 . Due to the improvement in the light extraction efficiency, the highest wall-plug efficiency of 278 nm DUV-LEDs is improved by 57% compared to the conventional configuration with Ni/Au as the p-type electrodes.