GaN Thickness Effect on Directional Light Enhancement from GaN-Based Film-Transferred Photonic Crystal Light-Emitting Diodes

Abstract

Directional light enhancement behavior including collimated far-field patterns sensitively depending on both photonic crystal (PhC) lattice constant and GaN thickness from GaN film-transferred light-emitting diodes (FTLEDs) with a triangular PhC lattice has been experimentally studied. Far-field pattern measurement in the Gamma-M and Gamma-K directions of GaN PhC FTLEDs with various lattice constants and GaN thicknesses revealed different far-field profiles as detemined on the basis of guided mode extraction of Bragg's diffraction. Additionally, three-dimensional (3D) far-field measurement revealing the PhC diffraction patterns was also demonstrated. We also used the 3D finite-different time-domain method to confirm the experimental results. (C) 2010 The Japan Society of Applied Physics