Size-dependent characteristics of GaN-based micro-LEDs for simultaneous display and wireless optical communication

Micro-light-emitting diode (micro-LED) has been widely concerned in the field of display and wireless optical communication due to its excellent optoelectronic characteristics, but the reduction of the pixel size has a significant impact on the performance of GaN-based micro-LEDs, which then affects the display and wireless optical communication applications.In this work, different sizes of violet and blue GaN-based micro-LEDs have been successfully fabricated, and the size-dependent characteristics of micro-LEDs in display and communication applications have been systematically studied.It can be found that the pixel size reduction of the micro-LEDs from 80 to 10 m leads to an obvious decrease in light output power (LOP) by 88.30 % and 44.10 % for blue and violet micro-LEDs, respectively, and a decrease in peak external quantum efficiency (EQE) by 55.14 % and 46.25 % for blue and violet micro-LEDs, respectively.Additionally, micro-LEDs with smaller sizes tend to exhibit a less obvious shift of peak wavelength and smaller broadening of full-width at half-maximum (FWHM) with the increases of current density, showing the potential to achieve a stable display with high quality.Also, the influence of current density on chrominance coordinate migration is determined, which shows that the driving current density corresponding to the maximum EQE can promote display efficiency and color gamut.In addition, the violet and blue micro-LEDs with a diameter of 20 m show potential in balancing between the LOP and the modulation bandwidth to achieve the highest data rates of 1.347 and 1.032 Gbps, respectively, in wireless optical communication applications.The results of this study are of great significance for optimizing the pixel size of the micro-LED to improve the performance in display and wireless optical communication applications in the future.