Fabrication of Multi-Stair mesa structure through chemical treatment to enhance the optoelectronic performance of Micro-LED arrays

Journal article, 2026

In recent years, Micro-light-emitting diode (Micro-LED) have received great attention in both academic and industry due to their excellent performance. During the miniaturization process, the performance degradation caused by sidewall defects seriously affects their development. Using chemical methods for sidewall treatment was an effective approach. In this paper, we fabricated three different-sized Micro-LED array and studied the influence of potassium hydroxide (KOH) treatment on their optoelectronic properties. Unlike previous studies, a multi-stair mesa structure was prepared by leveraging the shrinkage effect of photoresist during the inductively couple plasma (ICP) etching and the anisotropic etching properties of KOH solution on GaN. Through simulation, it was found that compared with the arc-like structure (without treatment), the multi-stair structure exhibited better light extraction efficiency (LEE) and higher light intensity distribution. For the 10 μm sample, the LEE increased by 12.19 %, and the light field intensity at 0° increased by approximately 9.89 %. In the I-V measure, the carrier transport characteristics of the samples with treatment were optimized, and the reverse leakage current was significantly reduced. For the 7 μm sample, the leakage current density decreased by 82.2 % at −1 V. In addition, the luminous characteristics of the samples were also greatly optimized. The external quantum efficiency (EQE) of the samples had all increased by more than 20 %. Meanwhile, the luminance of the samples was also significantly improved. These experimental results provide important data for the design and preparation of Micro-LED arrays.