Formation of TiO2 Nano Pattern on GaN-Based Light-Emitting Diodes for Light Extraction Efficiency

A TiO2 nano-structure was formed on the indium-tin-oxide electrode of a GaN-based light-emitting diode (LED) in order to enhance the light extraction efficiency. The UV bi-layer imprinting and lift-off processes were used to form the TiO2 nano-structure without any plasma etching process, which can lead to degradation of the electrical properties of the device. As a result, the light output power of the LED on the patterned sapphire substrate (PSS) with the TiO2 nano-structure was enhanced up to 12% compared to identical LED formed on the PSS without TiO2 nano-structure. No electrical degradation was observed for the patterned LED device. (C) 2010 The Japan Society of Applied Physics