Fabrication of reflective GaN mesa sidewalls for the application to high extraction efficiency LEDs

We proposed and demonstrated a modified GaN light‐emitting diode (LED) structure. The structure was made by integrating angled sidewalls to an otherwise conventional LED structure. Various GaN sidewall angles were obtained by adjusting etch conditions and the etched surface roughness was ∼2 nm. Near‐field emission patterns indicated that the angled sidewalls efficiently deflect photons that are initially guided laterally within the GaN epilayer into the off‐surface direction. For sidewall angle of 30°, total surface emission strength was improved by a factor exceeding 3. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)