Kim Sungjoo, Yoo Chul Jong, Park Jae Yong, Baek Sangwon, Cho Won Seok, Lee Jong-Lam
Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH) Pohang 790-784 Korea
Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH) Pohang 790-784 Korea.
RSC Adv. 2018 Nov 1;8(65):37021-37027. doi: 10.1039/c8ra06773b.
Refractive-index (RI)-matched nanostructures are implemented in GaN-based light-emitting diodes (LEDs) for enhancing light output efficiency. The RI-matched indium tin oxide (ITO) nanostructures are successfully implemented in GaN-based lateral LEDs by using ITO sol-gel and nanoimprint lithography. The ITO sol-gel nanostructures annealed at 300 °C have RI of 1.95, showing high transparency of 90% and high diffused transmittance of 34%. Consequently, the light output power in LEDs with the RI-matched nanostructures increases by 8% in comparison with that in LEDs containing flat ITO. Ray tracing and finite-difference time-domain (FDTD) simulations show that the RI-matched nanostructures on the transparent current spreading layer dramatically reduce Fresnel reflection loss at the interface of the current spreading layer with the nanostructure and extract confined waveguide lights in LEDs.
折射率（RI）匹配的纳米结构被应用于基于氮化镓的发光二极管（LED）中，以提高光输出效率。通过使用氧化铟锡（ITO）溶胶 - 凝胶和纳米压印光刻技术，成功地在基于氮化镓的横向LED中实现了RI匹配的ITO纳米结构。在300°C退火的ITO溶胶 - 凝胶纳米结构的RI为1.95，具有90%的高透明度和34%的高漫透射率。因此，与包含平面ITO的LED相比，具有RI匹配纳米结构的LED中的光输出功率增加了8%。光线追踪和时域有限差分（FDTD）模拟表明，透明电流扩展层上的RI匹配纳米结构显著降低了电流扩展层与纳米结构界面处的菲涅尔反射损耗，并提取了LED中受限的波导光。
