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GaN green LEDs grown on the Si substrate are expected to become low-cost and high-efficiency green light sources in future years, thus promoting the potential of GaN-on-Si green micro-LEDs for display and visible light communication (VLC), but the performances of the GaN-on-Si green micro-LEDs have yet to be fully investigated. In terms of display, a nondestructive transfer printing process is adopted and the characteristics of GaN-on-Si green micro-LEDs before and after being transferred to the glass substrate are presented in this work. The removal of the Si substrate causes almost no electrical damage to the device, and at a low current density of 1 A/cm2, the EQE of the micro-LED can be doubled and the device can still maintain good color purity. In terms of VLC, a −3 dB bandwidth up to 613 MHz has been achieved for 80 μm micro-LED under the current density of 2 kA/cm2, and a data rate of 4.65 Gbps is obtained. These results indicate that GaN-on-Si green micro-LEDs have great application prospects in both display and communication fields.

Micro-LED has attracted tremendous attention as next-generation display, but InGaN red-green-blue (RGB) based high-efficiency micro-LEDs, especially red InGaN micro-LED, face significant challenges and the optoelectronic performance is inevitably affected by environmental factors such as varying temperature and operating current density. Here, we demonstrated the RGB InGaN micro-LEDs, and investigated the effects of temperature and current density for the InGaN RGB micro-LED display. We found that temperature increase can lead to the changes of electrical characteristics, the shifts in electroluminescence spectra, the increase of full width at half maximum and the decreases of light output power, external quantum efficiency, power efficiency, and ambient contrast ratios, while current density increase can also give rise to different changing trends of the varieties of parameters mentioned just above for the RGB micro-LED display, creating great challenges for its application in practical scenarios. Despite of the varying electrical and optical charateristics, relatively high and stable colour gamut of the RGB display can be maintained under changing temperature and current density. Based on the results above, mechanisms on the temperature and current density effects were analyzed in detail, which would be helpful to predict the parameters change of micro-LED display caused by temperature and current density, and provided guidance for improving the performance of InGaN micro-LED display in the future.

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