Effects of KOH treatment on the performance of Micro-LED arrays under different temperatures

During the miniaturization of Micro-light-emitting diodes (Micro-LEDs), sidewall defects seriously affect its industrialization progress. The KOH treatment is an important method to remove defects and improve device performance. Furthermore, in many application scenarios, devices need to operate in high-temperature environments. Therefore, temperature-dependent measurement can better reflect actual requirements. This study fabricated a Micro-LED array with a 10 μm mesa size and analyzed the effect of KOH treatment on the optoelectronic properties at different temperatures. Analysis of carrier transport characteristics showed that after KOH treatment, the growth rates of carrier tunneling and Shockley-Read-Hall (SRH) recombination induced by high temperature were effectively slowed down. The electroluminescence (EL) spectra showed that, when the temperature increased from room temperature (RT) to 100°C at 0.5 mA, the EL intensity of the KOH-Sample decreased by 39.87%, which was slightly less than the 40.24% attenuation of the Ref-Sample. For the KOH-Sample, from RT to 100°C, their luminance attenuation was 15.11% at 0.5 mA and dropped to 10.66% at 1 mA. Perhaps due to the more significant influence of Auger recombination, when the temperature increased from RT to 100°C, the external quantum efficiency (EQE) of the KOH-Sample attenuated by 37.58%, which was higher than the 19.68% attenuation of the Ref-Sample. This notwithstanding, the EQE of the KOH-Sample was still higher than that of the Ref-Sample at 100°C. These experimental results provided important data support for the design and fabrication of Micro-LED arrays.