University of Michigan in the USA has claimed the highest external quantum efficiency (EQE) and smallest linewidth so far for red-emitting indium gallium nitride (InGaN) micro-LEDs, using photonic crystal (PhC) structures [Yuanpeng Wu et al, Light: Science & Applications v15, p133, 2026] Further, the emission wavelength was stable for a wide range of injection currents. The 5nm full-width at half maximum (FWHM) was about one order of magnitude narrower than previously reported values. The researchers see narrow linewidths as “paramount for achievin…