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

We demonstrated amber InGaN $47\times 47\,\,\mu \text{m}^{{2}}$ micro-light-emitting diodes ( $\mu $ LEDs) with the peak wavelength of 606 nm and full-width at maximum (FWHM) of 50 nm at 20 A/cm². The amber $\mu $ LEDs 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 80 A/cm² could mainly be attributed to the saturation of the Shockley-Read-Hall non-radiative recombination at high current densities.