Optical and microstructural characterization of Micro-LED with sidewall treatment
Fan Yang, Yu Xu, Lu Li, Xin Cai, Jianjie Li, Jiahao Tao, Shunan Zheng, Bing Cao, Ke Xu
Abstract
Abstract The traditional influence on the sidewall damage of Micro-LED was mostly focused on the research of I-V-L. In this paper, we discussed the influence of Micro-LED sidewall damage from the perspective of optical and microstructural characterization. Scanning electron microscopy showed that the Micro-LED structure with smaller size was more irregular after inductively coupled plasma etching. High-resolution transmission electron microscopy and energy dispersive x-ray spectroscopy analysis showed that the area of the upper and lower regions of the quantum well was inconsistent, there was about 2 nm lattice disorder on the surface of the sidewall of the mesa, and oxygen and silicon impurity atoms were enriched. For optical characterization, a method combining laser scanning confocal microscopy and photoluminescence (PL) was proposed to evaluate the optical performance of the mesa. The results showed that the luminescence of Micro-LED mesa was uneven, the luminous intensity at the edge of the mesa was reduced by more than 65%, and the luminous wavelength was shifted by several nanometers. Finally, we optimized the sidewall treatment process, effectively improved the performance of Micro-LED devices by combining tetramethylammonium hydroxide treatment and SiO 2 passivation, and increased the luminous intensity of Micro-LED 2 μ m away from the edge by about 4.7 times and PL uniformity was greatly improved. These results provided an available reference for the development of Micro-LED.