Chen Dingbo, Wang Zhe, Hu Fang-Chen, Shen Chao, Chi Nan, Liu Wenjun, Zhang David Wei, Lu Hong-Liang
Opt Express. 2021 Oct 25;29(22):36559-36566. doi: 10.1364/OE.439596.
The quantum efficiency of GaN-based micro-light-emitting diodes (micro-LEDs) is of great significance for their luminescence and detection applications. Optimized passivation process can alleviate the trapping of carriers by sidewall defects, such as dangling bonds, and is regarded as an effective way to improve the quantum efficiency of micro-LEDs. In this work, an AlN passivation layer was prepared by atomic layer deposition to improve the electro-optical and photoelectric conversion efficiency in GaN-based micro-LEDs. Compared to conventional AlO passivation, the AlN passivation process has a stronger ability to eliminate the sidewall defects of micro-LEDs due to the homogeneous passivation interface. Our experiments show that the AlN-passivated device exhibits two orders of magnitude lower forward leakage and a smaller ideality factor, which leads to significantly enhanced external quantum efficiency (EQE). For 25*25 μm micro-LEDs, the EQE of the AlN-passivated device was 18.3% and 57.7% higher than that of the AlO-passivated device in luminescence application and detection application, respectively.
基于氮化镓的微型发光二极管（微型LED）的量子效率对其发光和检测应用具有重要意义。优化的钝化工艺可以减轻诸如悬空键等侧壁缺陷对载流子的捕获，被视为提高微型LED量子效率的有效方法。在这项工作中，通过原子层沉积制备了AlN钝化层，以提高基于氮化镓的微型LED的电光和光电转换效率。与传统的AlO钝化相比，由于钝化界面均匀，AlN钝化工艺消除微型LED侧壁缺陷的能力更强。我们的实验表明，AlN钝化器件的正向泄漏降低了两个数量级，理想因子更小，这导致外部量子效率（EQE）显著提高。对于25×25μm的微型LED，在发光应用和检测应用中，AlN钝化器件的EQE分别比AlO钝化器件高18.3%和57.7%。
