Review Of the Light Extraction Efficiency of Gan Leds

Various new methods have emerged to enhance the light extraction efficiency (LEE) of Gallium Nitride (GaN)-based Light Emitting Diodes (LEDs),. This review examines several key techniques, including surface texturization, patterning of the GaN and substrate interface, chip geometry design, integration with photonic crystals, and epitaxial micro/nano structures. Surface texturization improves LEE by reducing light reflection and increasing scattering, although it may introduce surface defects. Interface patterning optimizes light propagation but increases manufacturing costs. Chip geometry design allows for specific light extraction paths but may pose manufacturing challenges due to complex designs. Photonic crystal technology enhances LEE though controlling light refraction but requires precise fabrication techniques. Among these approaches, epitaxial micro/nanostructures stand out for providing optimal control of the light extraction path while minimizing material waste and structural damage, despite the more demanding epitaxial conditions. Therefore, epitaxial micro/nano structures are considered the optimal strategy for significantly improving LEE in GaN-based LEDs, paving the way for more efficient and sustainable lighting technologies.