Enhancement of light extraction in GaN based LED structures using TiO2 nano-structures

TiO2 nano-patterns were formed on the indium-tin-oxide (ITO) layer of GaN based light emitting diodes (LEDs) without a residual layer using a sot-imprinting process. A polydimethylsiloxane mold replicated from a Si master was used as the imprint stamp for the sol-imprinting process. The light extraction efficiency of LEDs was enhanced by the TiO2 nano-patterns formed on the ITO layer because the TiO2 nanopatterns locally modulated the refractive index of the ITO layer and enhanced the scattering of light at the ITO layer. Consequently, directly fabricated TiO2 nano-patterns on the ITO layer can esoln hance the light extraction efficiency of LEDs without plasma-induced damage. (C) 2010 Elsevier Ltd. All rights reserved.