Self-Assembled Periodic Silica Nanosphere Arrays on Wet-Etched Patterned Sapphire Substrate for a High-Light-Extraction-Efficiency Light-Emitting Diode

We have developed a periodical self-assembled method of patterning the sapphire substrate with silica nanospheres for light-emitting diode (LED) applications. Using this method, silica nanospheres were directed to self-assemble in a periodic fashion on a wet-etched patterned sapphire substrate (WPSS). Moreover, we fabricated an InGaN/GaN-based LED on the silica-nanosphere-assembled WPSS. The light output power of the resultant LED was about 2.23 and 1.7 times higher than that of the LEDs grown on planar sapphire and WPSS, respectively. Moreover, the light extraction efficiency of the silica-nanosphere-assembled WPSS LED was 37% higher than that of conventional LED.