Abdelkhalik Mohamed S, Vaskin Aleksandr, López Toni, Berghuis Anton Matthijs, Abass Aimi, Rivas Jaime Gómez
Department of Applied Physics and Science Education, and Eindhoven Hendrik Casimir Institute, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Lumileds Germany GmbH, D-52068 Aachen, Germany.
Nanophotonics. 2023 Aug 4;12(18):3553-3562. doi: 10.1515/nanoph-2023-0257. eCollection 2023 Sep.
Light-Emitting Diodes (LEDs) exhibit a typical Lambertian emission, raising the need for secondary optics to tailor their emission depending on specific applications. Here, we introduce plasmonic metasurfaces to InGaN green emitting quantum wells for LEDs to control their far-field emission directionality and enhance the collection efficiency. The proposed mechanism is based on surface lattice resonances (SLRs) and relies on the near-field coupling between the InGaN multiple quantum wells (MQWs) and periodic arrays of aluminum (Al) nanodisks. Fourier microscopy measurements reveal that the angular photoluminescence emission pattern depends on the lattice constant of the metasurfaces. We demonstrate that integrating Al metasurfaces in LED wafers can enhance the collected outcoupled light intensity by a factor of 5 compared to the same sample without metasurfaces. We have also performed numerical calculations of the far-field emission based on the reciprocity principle and obtained a very good agreement with the experimental data. The proposed approach controls the emission directionality without the need for secondary optics and it does not require post-etching of the GaN, which makes it a potential candidate to control and enhance the generated light from micro-LEDs.
发光二极管（LED）呈现出典型的朗伯发射特性，这就需要二次光学元件来根据特定应用调整其发射特性。在此，我们将等离子体超表面引入到用于LED的InGaN绿色发光量子阱中，以控制其远场发射方向性并提高收集效率。所提出的机制基于表面晶格共振（SLR），并依赖于InGaN多量子阱（MQW）与铝（Al）纳米盘周期性阵列之间的近场耦合。傅里叶显微镜测量结果表明，角向光致发光发射图案取决于超表面的晶格常数。我们证明，与没有超表面的相同样品相比，在LED晶圆中集成Al超表面可以将收集到的出射光强度提高5倍。我们还基于互易原理对远场发射进行了数值计算，并与实验数据取得了很好的一致性。所提出的方法无需二次光学元件即可控制发射方向性，并且不需要对GaN进行后蚀刻，这使其成为控制和增强微LED产生的光的潜在候选方案。
