Liu Kexi, Jiang Ke, Wang Bingxiang, Wang Xianjun, Ben Jianwei, Zhang Shanli, Chen Yang, Jia Yuping, Liu Mingrui, Sun Xiaojuan, Li Dabing
Opt Lett. 2024 Jul 15;49(14):4030-4033. doi: 10.1364/OL.532520.
In this work, we propose a highly reflective Ni/Pt/Al p-electrode for AlGaN-based deep ultraviolet (DUV) light-emitting diodes (LEDs) with a wavelength of 276 nm. AlGaN-based DUV LEDs with traditional Al-based reflectivity electrodes suffer from device degradation and wall-plug efficiency (WPE) droop due to the Al diffusion during electrode annealing. By inserting a Pt layer between the Ni contact layer and the Al reflective layer, the contact characteristics of the p-electrode can be optimized by blocking the diffusion of the O and Al atoms, maintaining a high reflectivity of over 80% near 280 nm. Compared to the AlGaN-based DUV LEDs with Ni/Au traditional p-electrodes and Ni/Al traditional reflective p-electrodes, the WPE of the LED with a highly reflective Ni/Pt/Al p-electrode is improved by 10.3% and 30.5%, respectively. Besides, compared to the other novel reflective p-electrodes using multiple annealing or evaporation processes reported for the AlGaN-based DUV LEDs, we provide a new, to the best of our knowledge, optimization method for single evaporation and annealing p-type reflective electrodes, featured with a simpler and more convenient process flow.
在这项工作中，我们为波长为276 nm的基于AlGaN的深紫外（DUV）发光二极管（LED）提出了一种高反射率的Ni/Pt/Al p型电极。基于AlGaN的DUV LED采用传统的基于Al的反射电极时，由于电极退火过程中的Al扩散，会出现器件退化和壁插效率（WPE）下降的问题。通过在Ni接触层和Al反射层之间插入一层Pt，可以通过阻挡O和Al原子的扩散来优化p型电极的接触特性，在280 nm附近保持超过80%的高反射率。与采用Ni/Au传统p型电极和Ni/Al传统反射p型电极的基于AlGaN的DUV LED相比，采用高反射率Ni/Pt/Al p型电极的LED的WPE分别提高了10.3%和30.5%。此外，与报道的用于基于AlGaN的DUV LED的其他采用多次退火或蒸发工艺的新型反射p型电极相比，据我们所知，我们提供了一种用于单次蒸发和退火p型反射电极的新的优化方法，其工艺流程更简单、更方便。
