Fabrication of moth-eye structure on p-GaN layer of GaN-based LEDs for improvement of light extraction

Abstract

Moth-eye structures were produced on a p-GaN top cladding layer by UV imprint and inductively coupled plasma (ICP) etch processes in order to improve the light extraction efficiency of GaN-based green light-emitting diodes (LEDs). The height and shape of moth-eye structures were adjusted by controlling the thickness of Cr mask layer and ICP etching time. The transmittance of LED device stacks with moth-eye structure was increased up to 1.5-2.5 times, compared to identical LED sample without moth-eye structure and the intensity of photoluminescence from the InGaN multi-quantum well layer of LED sample with moth-eye structure was 5-7 times higher than that of the LED sample without the moth-eye structure. (C) 2009 Elsevier B.V. All rights reserved.