Monolithic integrated all-GaN-based µLED display by selective area regrowth

This work demonstrates an all-GaN-based µLED display with monolithic integrated HEMT and µLED pixels using the selective area regrowth method. The monochrome µLED-HEMT display has a resolution of 20 × 20 and a pixel pitch of 80 µm. With the optimized regrowth pattern, the µLED-HEMT achieves a maximum light output power of 36.2 W/cm² and a peak EQE of 3.36%, mainly due to the improved crystal quality of regrown µLED. TMAH treatment and Al₂O₃ surface passivation are also performed to minimize the impact of nonradiative recombination caused by the dry etching damage. With a custom-designed driving circuit board, images of “HKUST” are successfully shown on the µLED-HEMT display.