Size effects of AlGaInP red vertical micro-LEDs on silicon substrate
Kaili Fan, Tao Jin, Yongzhou Zhao, Panyuan Li, Wenchao Sun, Licai Zhu, Jinguang Lv, Yuxin Qin, Qiang Wang, Jingqiu Liang, Weibiao Wang
Abstract
To study the size effect of AlGaInP red micro-LEDs on the silicon substrate, we fabricated five AlGaInP red micro-LEDs with different pixel sizes (160 × 160, 80 × 80, 40 × 40, 20 × 20, and 10 × 10 µm2) and studied their electrical and optical properties. Smaller micro-LEDs have smaller leakage current and larger series resistance and can withstand higher current density without the current crowding effect. Due to the larger perimeter-to-area ratio of small-sized micro-LEDs, non-radiative recombination increases, which leads to a lower EQE. But smaller micro-LEDs can alleviate the problem of the high-current efficiency droop. In addition, because of a better heat dissipation under a high injection current, smaller micro-LEDs (>80 µm) have a smaller center wavelength shift. These experimental results provide important data for designing and fabricating red micro-LEDs with different pixel sizes for diverse future applications.