Fabrication of oxide-based nano-patterned sapphire substrate to improve the efficiency of GaN-based of LED

In this study, an oxide-based nano-patterned sapphire substrate (ONPSS) was used as the substrate for a nitride-based light emitting diode (LED) in order to enhance the LED's internal quantum efficiency and light extraction efficiency. The ONPSS was fabricated by a direct spin-on-glass printing technique, which is simple, easy, and relatively low-cost technique. Conventional PSSs are generally fabricated by photolithography and a sapphire etching process. However, the process reported here, it is possible to fabricate an oxide-based PSS without the sapphire etching process. After a GaN-based blue LED device was grown on the ONPSS, we measured the photoluminescence and electroluminescence intensity to confirm the light extraction efficiency and internal quantum efficiency of the LED. Compared to a GaN LED grown on an unpatterned sapphire, the ONPSS-based LED exhibited a 100% increase in light output power without electrical degradation. (C) 2015 The Japan Society of Applied Physics