Nanoscale ITO/ZnO layer-texturing for high-efficiency InGaN/GaN light emitting diodes

We propose a simple technique to improve the light extraction efficiency of GaN-based light emitting diodes (LEDs) by using nanoscale ITO/ZnO layer-texturing. The Surface texturing of the ITO and ZnO layers was performed using a wet chemical etching and a spin-coating process, respectively. It has been found that the light extraction efficiency of the ITO-/ZnO-textured LED was 34.5% greater than that of a conventional LED with a planar ITO, at 20 mA of current injection. A high level of multiple light scattering at the textured surface promoted a high-efficiency in the InGaN/GaN LEDs. In addition, the individual performance of the ITO and ZnO texturing on the LED Surface was also investigated. The lowered forward voltage of the ITO/ZnO layer-textured LED indicated this could be a damage-free approach for device fabrication. (C) 2009 Elsevier B.V. All rights reserved.