Circularly polarized (0001) InGaN-based LED integrated with GaN metasurface

Ultrasmall-sized circularly polarized (CP) light-emitting devices are highly desired for a wide range of applications. However, most conventional approaches toward CP light-emitting diodes (CP-LEDs) have critical challenges in either device durability, polarization degree, or quantum efficiency to be addressed. Herein, we propose a (0001) InGaN-based CP-LED with a single-layer metasurface directly integrated on the light-emitting surface to convert unpolarized light into CP light. The metasurface is composed of GaN and achieves an efficient CP light exhibiting both a high circular polarization degree of 0.87 and a high transmission efficiency of around 35% for vertically extracted light. The CP-LED consists of inorganic materials that are highly stable under operating conditions, and these findings show that the novel, to the best of our knowledge, CP light source can overcome the conventional trade-off relationship between quantum efficiency and polarization degree.