Son Kyung Rock, Lee Tae Ho, Lee Byeong Ryong, Im Hyun Sik, Kim Tae Geun
School of Electrical Engineering, Korea University, Seongbuk-gu, Seoul, 02841, Korea.
Physics and Semiconductor Science, Dongguk University, Jung-gu, Seoul, 04620, Korea.
Small. 2018 Dec;14(49):e1801032. doi: 10.1002/smll.201801032. Epub 2018 Oct 4.
Microlight-emitting diodes (µLEDs) are emerging solutions for both high-quality displays and lighting technologies. However, the overall light output power density of these devices is low, as the emission area is shielded by the p-electrodes required for current injection. In this study, instead of the more conventionally used indium tin oxide (ITO), an AlN thin film with nanoscale conducing filaments (CFs) is used, referred to as CF-AlN, as a transparent conducting electrode (TCE), to enhance the output power density from the same emission area. As a result of this modification, the electroluminescence intensity is enhanced by 10% at an injection current of 10 mA, and the current density is improved by 13% at a forward voltage of 4.9 V, in comparison to the parameters observed with ITO-based µLEDs. This improvement is attributed to the higher transmittance of CF-AlN TCEs, together with efficient hole injection from the p-electrode into the light-emitting layer, through the CFs formed in the AlN layer. In addition, using transmission electron microscopy analyses, the origin of the CFs is directly identified as the diffusion of In and Sn ions, which provides critical insight into the conduction mechanism of AlN-based TCEs.
微发光二极管（µLED）是用于高质量显示器和照明技术的新兴解决方案。然而，这些器件的整体光输出功率密度较低，因为发射区域被电流注入所需的p电极屏蔽。在本研究中，使用具有纳米级导电细丝（CF）的AlN薄膜（称为CF-AlN）作为透明导电电极（TCE），以替代更常用的氧化铟锡（ITO），从而提高相同发射区域的输出功率密度。与基于ITO的µLED相比，这种改进使得在10 mA注入电流下电致发光强度提高了10%，在4.9 V正向电压下电流密度提高了13%。这种改进归因于CF-AlN TCE的更高透射率，以及通过AlN层中形成的CF从p电极到发光层的有效空穴注入。此外，通过透射电子显微镜分析，直接确定了CF的起源是In和Sn离子的扩散，这为基于AlN的TCE的传导机制提供了关键见解。
