Improved output power of 400-nm InGaN/AlGaN LEDs using a novel surface roughening technique

Abstract

Near-ultraviolet (UV) InGaN/AlGaN light-emitting diodes (LEDs) with three kinds of naturally textured surfaces were grown by atmosphere-pressure metalorganic chemical vapor deposition. The electroluminescence intensities of the 400-nm LED bare chips with nano-hole and micro-island textured morphologies show 30% and 40%. in magnitude higher than that of the flat surface LED sample. Both textured surfaces greatly increased the escape probability of photons inside the LED structure. A naturally coral like surface was developed for the near-UV LED, where the textured p-GaN layer was fabricated using the successive growth of the micro-island followed by the nano-hole p-GaN layers. As much as 31.6% increased light Output power of the coral-like textured LED was achieved using this novel surface roughening technique. (C) 2008 Elsevier B.V. All rights reserved.