Improved light extraction of GaN-based light-emitting diodes with surface-patterned ITO

Abstract

The surface patterning of the indium tin oxide (ITO) transparent current layer has been investigated to improve the light extraction efficiency of GaN-based light-emitting diodes (LEDs). LEDs with periodic micro-hexagon patterned ITO have been fabricated utilizing standard lithography techniques and inductively coupled plasma (ICP) technology. The luminance intensity of the LED chips with patterned ITO following 160 s ICP etching was enhanced by about 50% compared to the LED chips with unpatterned ITO. Detailed processing parameters are provided. scanning electron microscopy (SEM) and atomic force microscopy (AFM) are used to examine the micro-structures. The results indicate that the surface-patterned ITO technique could have potential applications in high-power GaN-based LEDs. © 2008 Elsevier Ltd. All rights reserved.