AVS 52nd International Symposium
    Science of Semiconductor White Light Topical Conference Monday Sessions
       Session WL-MoA

Invited Paper WL-MoA7
Photonic Crystals for Enhanced Light Extraction in InGaN LEDs

Monday, October 31, 2005, 4:00 pm, Room 310

Session: Science of Semiconductor White Lighting
Presenter: A.J. Fischer, Sandia National Laboratories
Authors: A.J. Fischer, Sandia National Laboratories
D.D. Koleske, Sandia National Laboratories
G.R. Hadley, Sandia National Laboratories
J.R. Wendt, Sandia National Laboratories
R.J. Shul, Sandia National Laboratories
J.J. Wierer, Lumileds Lighting
M.R. Krames, Lumileds Lighting
Correspondent: Click to Email
In order to realize semiconductor-based white lighting with efficacies of 200 lm/Watt, InGaN light emitting diodes (LEDs) must have wall plug efficiencies on the order of 50% or better.  Even when internal quantum efficiencies approach 100%, most LEDs suffer from poor light extraction efficiency.  The majority of photons generated inside of a high index semiconductor bounce around due to total internal reflection where they have a high probability of being reabsorbed.  Many methods have been used to improve the extraction efficiency of LEDs including chip shaping, surface texturing, and resonant cavity LEDs.  Photonic crystals can also be used to enhance extraction efficiency by either suppressing emission of light into waveguiding modes or by extracting waveguiding modes via Bragg scattering.  We have fabricated InGaN LEDs with an incorporated photonic lattice by etching holes into the GaN surface.  E-beam lithography was used for submicron pattern transfer and Cl-based inductively-coupled plasma reactive ion etching was used to etch holes in GaN.  For these LED structures, the photonic lattice improves light extraction by extracting light emitted into waveguiding modes.  An overview of light extraction from InGaN LEDs will be given as well as recent device results from InGaN photonic crystal LEDs.  Sandia National Labs is a multi program laboratory operated by Sandia Corporation, a Lockheed Martin Company for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.