Enhancement of light extraction efficiency of ultraviolet light emitting diodes by patterning of SiO2 nanosphere arrays

Abstract

Here we introduce a simple and robust method to improve the light extraction efficiency of ultraviolet light emitting diodes (UV LEDs). Although many previous efforts have focused on etching the GaN surfaces, we employed a simple solution process to texture the GaN surface. Arrays of SiO2 nanosphere monolayers were spun cast onto a polymer layer. consisting of benzocyclobutene (BCB) resins: subsequently, the bottom half of the SiO2 nanospheres sunk into the BCB layer. The resulting array formed in a hexagonal-like pattern of 'nano-lenses' and the photoluminescence measurement exhibited that these patterns enhanced the light extracting efficiency of UV LEDs by 23%. (C) 2008 Elsevier B.V. All rights reserved.