Liu Chuanbiao, Feng Feng, Liu Zhaojun
Harbin Institute of Technology, Harbin 150006, China.
Department of Electrical and Electronic Engineering, The Southern University of Science and Technology, Shenzhen 518000, China.
Nanomaterials (Basel). 2023 Jul 30;13(15):2213. doi: 10.3390/nano13152213.
This work explores the pivotal role of laser lift-off (LLO) as a vital production process in facilitating the integration of Micro-LEDs into display modules. We specifically investigate the LLO process applied to high-performance gallium nitride (GaN)-based green Micro-LED arrays, featuring a pixel size of 20 × 38 μm on a patterned sapphire substrate (PSS). Scanning electron microscopy (SEM) observations demonstrate the preservation of the GaN film and sapphire substrate, with no discernible damage. We conduct a comprehensive analysis of the optoelectrical properties of the Micro-LEDs both before and after the LLO process, revealing significant enhancements in light output power (LOP) and external quantum efficiency (EQE). These improvements are attributed to more effective light extraction from the remaining patterns on the GaN backside surface. Furthermore, we examine the electroluminescence spectra of the Micro-LEDs under varying current conditions, revealing a slight change in peak wavelength and an approximate 10% decrease in the full width at half maximum (FWHM), indicating improved color purity. The current-voltage (I-V) curves obtained demonstrate the unchanged forward voltage at 2.17 V after the LLO process. Our findings emphasize the efficacy of LLO in optimizing the performance and color quality of Micro-LEDs, showcasing their potential for seamless integration into advanced display technologies.
这项工作探讨了激光剥离（LLO）作为一种关键生产工艺在促进将微型发光二极管（Micro-LED）集成到显示模块中的核心作用。我们专门研究了应用于基于高性能氮化镓（GaN）的绿色Micro-LED阵列的LLO工艺，这些阵列在图案化蓝宝石衬底（PSS）上的像素尺寸为20×38μm。扫描电子显微镜（SEM）观察表明，GaN薄膜和蓝宝石衬底得以保留，没有明显损坏。我们对LLO工艺前后Micro-LED的光电特性进行了全面分析，结果显示光输出功率（LOP）和外部量子效率（EQE）有显著提高。这些改进归因于从GaN背面剩余图案中更有效地提取光。此外，我们研究了不同电流条件下Micro-LED的电致发光光谱，发现峰值波长略有变化，半高宽（FWHM）约降低10%，表明颜色纯度有所提高。所获得的电流-电压（I-V）曲线表明，LLO工艺后正向电压在2.17V保持不变。我们的研究结果强调了LLO在优化Micro-LED性能和颜色质量方面的有效性，展示了它们无缝集成到先进显示技术中的潜力。
