High-Brightness InGaN/GaN Micro-LEDs With Secondary Peak Effect for Displays

The green InGaN/GaN micro light-emitting diode (Micro-LED) is a significant component in micro-display whereas lack of size dependence and high injected current analysis. In this letter, different size Micro-LEDs were fabricated and the electro-optical characteristics were measured. The size-dependence phenomenon for EQE “efficiency droop”, luminous flux and brightness were observed and discussed. All sizes Micro-LEDs exhibited an extremely high brightness as 37.5k and 67.6k nits at 1 A/cm ² , 2.89M and 3.81M nits at 300 A/cm ² for 25 and $200~\mu \text{m}$ respectively. In addition, the elevating current densities from 160 to 6400 A/cm ² were injected into $25~\mu \text{m}$ Micro-LED and the electroluminescence (EL) spectra transformation of different current densities were depicted. The green to blue shift and secondary peak effect, which promise an opportunity to modulate the emission wavelength for higher quality and lower the barrier of mass transfer technology, were observed and analyzed through the spectra.