Zhang Xiu, Li Shuqi, Wang Baoxing, Chen Baojin, Guo Haojie, Yue Rui, Cai Yong
School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei 230026, China.
Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, CAS, Suzhou 215123, China.
Micromachines (Basel). 2023 Feb 24;14(3):534. doi: 10.3390/mi14030534.
This work investigates a self-masking technology for roughening the surface of light-emitting diodes (LEDs). The carbonized photoresist with a naturally nano/micro-textured rough surface was used as a mask layer. After growing the SiN passivation layer on LEDs, the texture pattern of the mask layer was transferred to the surface of the passivation layer via reactive ion beam (RIE) dry etching, resulting in LEDs with nano-textured surfaces. This nano-textured surface achieved by self-masking technology can alleviate the total internal reflection at the top interface and enhance light scattering, thereby improving the light extraction efficiency. As a result, the wall-plug efficiency (WPE) and external quantum efficiency (EQE) of rough-surface LEDs reached 53.9% and 58.8% at 60 mA, respectively, which were improved by 10.3% and 10.5% compared to that of the flat-surface SiN-passivated LED. Additionally, at the same peak, both LEDs emit a wavelength of 451 nm at 350 mA. There is also almost no difference between the I-V characteristics of LEDs before and after roughening. The proposed self-masking surface roughening technology provides a strategy for LEE enhancement that is both cost-effective and compatible with conventional fabrication processes.
本工作研究了一种用于使发光二极管（LED）表面粗糙化的自掩膜技术。具有天然纳米/微米纹理粗糙表面的碳化光刻胶被用作掩膜层。在LED上生长SiN钝化层之后，通过反应离子束（RIE）干法刻蚀将掩膜层的纹理图案转移到钝化层表面，从而得到具有纳米纹理表面的LED。通过自掩膜技术实现的这种纳米纹理表面可以减轻顶部界面处的全内反射并增强光散射，进而提高光提取效率。结果，粗糙表面LED在60 mA时的壁插效率（WPE）和外量子效率（EQE）分别达到53.9%和58.8%，与平面SiN钝化LED相比分别提高了10.3%和10.5%。此外，在相同峰值下，两种LED在350 mA时均发射波长为451 nm的光。粗糙化前后LED的I-V特性之间也几乎没有差异。所提出的自掩膜表面粗糙化技术为提高光提取效率提供了一种既经济又与传统制造工艺兼容的策略。
