[TuP3D] D. Photonic devices and related technologies

2:00 PM - 4:00 PM JST(5:00 AM - 7:00 AM UTC)

[TuP3D-19 LN] Geometry-Controlled Inter-rod Optical Coupling Effect in InGaN/GaN Micro-LED Structures

〇Min-Seok Lee¹, Sung-Un Kim¹, Jeong-Kyun Oh¹, Geon-Yeong Kim¹, Yong-Ho Ra¹ (1. Jeonbuk National University (Korea))

GaN nanorod (NR) micro-LEDs offer excellent light extraction potential for next-generation VR/MR/XR displays. To understand the effect of NR geometry on optical performance, we ran 3D-FDTD simulations. Our results confirm that cylindrical NRs confine light vertically much better than trapezoidal ones, effectively suppressing lateral leakage. Applying these findings, we fabricated InGaN/GaN NR arrays using a top-down approach-combining nanoimprint lithography, ICP-RIE, and a KOH wet etch. This process yielded clear cylindrical profiles with minimal sidewall damage. Optical testing via μ- PL and TRPL showed a highly stable emission peak around 455 nm, with virtually no spectral shift under varying excitation. Furthermore, TRPL revealed longer carrier lifetimes in the arrays compared to isolated structures. We attribute this to optical coupling between neighboring nanorods, which drives photon recycling boosting efficiency. Ultimately, our optimized cylindrical NR array achieved roughly an 11-fold enhancement in large-area emission intensity compared to unoptimized designs. This work clearly demonstrates that carefully controlling NR geometry is crucial for managing light propagation in high-resolution micro-LEDs.