Air-voids embedded high efficiency InGaN-light emitting diode

Abstract

To improve the light extraction efficiency of InGaN-light emitting diode (LED), inverted hexagonal cone shaped air voids with {10–11} GaN crystal planes were formed between a patterned sapphire substrate and GaN epitaxial layer using a H3PO4-based hot chemical etching method. The air-voids embedded LED showed 12% and 210% higher optical power than a patterned substrate LED and a flat substrate LED, respectively. A ray tracing simulation revealed that the light extraction through the top face of the air-voids embedded LED was dramatically increased due to a strong light reflection and redirection by the air voids.