Photoelectrochemical roughening of p‐GaN for light extraction from GaN/InGaN light emitting diodes

A method for photoelectrochemical (PEC) etching of Ga-face, p -type GaN is presented using GaN/InGaN heterostructures. This technique, which does not require any special epitaxial structure, flip chip bonding, or complicated processing, is used to roughen p -side-up lightemitting diodes (LEDs) to increase extraction efficiency. The extraction efficiency is increased by 20 ± 5% for roughened LEDs compared to nearby unetched LEDs, without any effect on the electrical properties of the devices. This is the first report of rapid, external-bias free PEC etching of p -type GaN, which could have broad applications to low-damage selective etching for a variety of electronic and optical devices. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)