606-nm InGaN Amber Micro-Light-Emitting Diodes With an On-Wafer External Quantum Efficiency of 0.56%

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The paper reports the device performances of the amber micro-LEDs. The on-wafer external quantum efficiency was as high as 0.56%. 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.

We demonstrated amber InGaN 47 × 47 μm² micro-light-emitting diodes (μLEDs) with the peak wavelength of 606 nm and full-width at maximum (FWHM) of 50 nm at 20 A/cm². The amber μLEDs exhibited a 33-nm blue-shift of the peak wavelength and obtain broader FWHMs to approximately 56 nm at 5 to 100 A/cm². The peak on-wafer external quantum efficiency was 0.56% at 20 A/cm2. The characteristic temperature was 50–80 K at 20 to 60 A/cm² but increased to 120–140 K at 80 to 100 A/cm². The strong increase in the characteristic temperature from 60 to 80A/cm² could mainly be attributed to the saturation of the Shockley-Read-Hallnon-radiative recombination at high current densities.​ ​