Zinc Sulphide Overlayer Two-Dimensional Photonic Crystal for Enhanced Extraction of Light from a Micro Cavity Light-Emitting Diode

Abstract

A two-dimensional (2D) ZnS photonic crystal was deposited on the surface of a one-dimensional (1 D) III-nitride micro cavity light-emitting diode (LED), to intermix the light extraction features of both structures (ID+2D). The deposition of an ideal micro-cavity optical thickness of approximate to lambda/2 is impractical for Ill-nitride LEDs, and in realistic multi-mode devices a large fraction of the light is lost to internal refraction as guided light. Therefore, a 2D photonic crystal on the surface of the LED was used to diffract and thus redirect this guided light out of the semiconductor over several hundred microns. Additionally, the employment of a post-epitaxy ZnS 2D photonic crystal avoided the typical etching into the GaN:Mg contact layer, a procedure which can cause damage to the near surface. [DOI: 10.1143/JJAP.47.7827]