Nitride-based LEDs with oblique sidewalls and a light guiding structure

The authors propose a simple method to further improve light extraction efficiency of GaN-based phosphoric acid etched light-emitting diodes (LED) by forming a light guiding structure on a sapphire substrate. Compared with conventional LEDs, it was found that the output intensity of the phosphoric acid etched LEDs with a light guiding structure was 40% higher. It was also found that the light guiding structure can effectively enhance LED output intensity in the vertical directions. (Some figures in this article are in colour only in the electronic version)