Paper accepted in Optics Letters!

1 min read · Thu, Aug 19 2021

The paper reports the new device fabrication for the green micro-LEDs. The micro-LEDs have recently gathered considerable interest for next-generation display applications, such as smartphones and watches, augmented reality (AR), and virtual reality (VR) devices.

Here we proposed an implantation-free approach to fabricating ultra-small InGaN-based micro-light-emitting diodes (µLEDs). The selective p-GaN areas were passivated intentionally using H2 plasma treatment and served as the electrical isolation regions to prevent the current from injecting into the InGaN quantum wells below. Three kinds of green µLEDs, which are two squircle shapes with widths of 5 and 4 µm and one circular shape with a diameter of 2.7 µm, were successfully realized. The squircle µLED pixels that were arranged with a gap of 4 µm between pixels exhibited good luminescence uniformity. The current-voltage characteristics indicate that the series resistance and the turn-on voltage increase as the dimension of the µLED decreases. That originates from the diffusion of the hydrogen atoms into the unexpected conductive p-GaN area. The light output power density and the calculated external quantum efficiency of the µLEDs from 5-µm-squircle to 2.7-µm-circle were enhanced by 10-20% when compared to 98 × 98 µm2 µLEDs that were fabricated using mesa etching.