Light extraction from GaN‐based LED structures on silicon‐on‐insulator substrates

Abstract

AbstractNano‐patterning of GaN‐based devices is a promising technology in the development of high output power devices. Recent researches have been focused on the realization of two‐dimensional (2D) photonic crystal (PhC) structure to improve light extraction efficiency and to control the direction of emission. In this study, we have demonstrated improved light extraction from green light emitting diode (LED) structures on thin silicon‐on‐insulator (SOI) substrates using surface nanopatterning. Scanning electron microscopy (SEM) is used to probe the size, shape, and etch depth of nano‐patterns on the LED surfaces. Different types of nanopatterns were created by e‐beam lithography and inductively coupled plasma etching. The LED structures after post processing are studied by photoluminescence (PL) measurements. The GaN nanophotonic structures formed by ICP etching led to more than five‐fold increase in the intensity of the green emission. The improved light extraction is due to the combination of SOI substrate reflectivity and photonic structures on top GaN LED surfaces. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)