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Title: Light Extraction Enhancement in GaInN Light-Emitting Diodes by Graded-Refractive-Index Indium-Tin-Oxide Anti-Reflection Contact.

Abstract

Abstract not provided.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1148125
Report Number(s):
SAND2007-4171J
522641
DOE Contract Number:
DE-AC04-94AL85000
Resource Type:
Journal Article
Resource Relation:
Journal Name: Advanced Materials; Related Information: Proposed for publication in Advanced Materials.
Country of Publication:
United States
Language:
English

Citation Formats

Fischer, Arthur Joseph, Crawford, Mary H., Kim, Jong Kyu, Chhajed, Sameer, Schubert, Martin F., Schubert, E. Fred, Cho, Jaehee, KIM, HYUNSOO, and SONE, CHEOLSOO. Light Extraction Enhancement in GaInN Light-Emitting Diodes by Graded-Refractive-Index Indium-Tin-Oxide Anti-Reflection Contact.. United States: N. p., 2007. Web.
Fischer, Arthur Joseph, Crawford, Mary H., Kim, Jong Kyu, Chhajed, Sameer, Schubert, Martin F., Schubert, E. Fred, Cho, Jaehee, KIM, HYUNSOO, & SONE, CHEOLSOO. Light Extraction Enhancement in GaInN Light-Emitting Diodes by Graded-Refractive-Index Indium-Tin-Oxide Anti-Reflection Contact.. United States.
Fischer, Arthur Joseph, Crawford, Mary H., Kim, Jong Kyu, Chhajed, Sameer, Schubert, Martin F., Schubert, E. Fred, Cho, Jaehee, KIM, HYUNSOO, and SONE, CHEOLSOO. Fri . "Light Extraction Enhancement in GaInN Light-Emitting Diodes by Graded-Refractive-Index Indium-Tin-Oxide Anti-Reflection Contact.". United States. doi:.
@article{osti_1148125,
title = {Light Extraction Enhancement in GaInN Light-Emitting Diodes by Graded-Refractive-Index Indium-Tin-Oxide Anti-Reflection Contact.},
author = {Fischer, Arthur Joseph and Crawford, Mary H. and Kim, Jong Kyu and Chhajed, Sameer and Schubert, Martin F. and Schubert, E. Fred and Cho, Jaehee and KIM, HYUNSOO and SONE, CHEOLSOO},
abstractNote = {Abstract not provided.},
doi = {},
journal = {Advanced Materials},
number = ,
volume = ,
place = {United States},
year = {Fri Jun 01 00:00:00 EDT 2007},
month = {Fri Jun 01 00:00:00 EDT 2007}
}
  • A method for enhancing the light-extraction efficiency of GaInN light-emitting diodes (LEDs) by complete elimination of total internal reflection is reported. Analytical calculations show that GaInN LEDs with multilayer graded-refractive-index pillars, in which the thickness and refractive index of each layer are optimized, have no total internal reflection. This results in a remarkable improvement in light-extraction efficiency. GaInN LEDs with five-layer graded-refractive-index pillars, fabricated by cosputtering TiO{sub 2} and SiO{sub 2}, show a light-output power enhanced by 73% and a strong side emission, consistent with analytical calculations and ray-tracing simulations.
  • Amorphous titanium oxide (a-TiO{sub x}:OH) films prepared by plasma-enhanced chemical-vapor deposition at 200 and 25 deg. C are in turn deposited onto the GaN-based light-emitting diode (LED) to enhance the associated light extraction efficiency. The refractive index, porosity, and photocatalytic effect of the deposited films are correlated strongly with the deposition temperatures. The efficiency is enhanced by a factor of {approx}1.31 over that of the uncoated LEDs and exhibited an excellent photocatalytic property after an external UV light irradiation. The increase in the light extraction is related to the reduction in the Fresnel transmission loss and the enhancement of themore » light scattering into the escape cone by using the graded-refractive-index a-TiO{sub x}:OH film with porous structures.« less
  • The authors report the enhancement of hole injection using an indium tin oxide (ITO) anode covered with ultraviolet (UV) ozone-treated Ag nanodots for fac tris (2-phenylpyridine) iridium Ir(ppy){sub 3}-doped phosphorescent organic light-emitting diodes (OLEDs). X-ray photoelectron spectroscopy and UV-visible spectrometer analysis exhibit that UV-ozone treatment of the Ag nanodots dispersed on the ITO anode leads to formation of Ag{sub 2}O nanodots with high work function and high transparency. Phosphorescent OLEDs fabricated on the Ag{sub 2}O nanodot-dispersed ITO anode showed a lower turn-on voltage and higher luminescence than those of OLEDs prepared with a commercial ITO anode. It was thought that,more » as Ag nanodots changed to Ag{sub 2}O nanodots by UV-ozone treatment, the decrease of the energy barrier height led to the enhancement of hole injection in the phosphorescent OLEDs.« less
  • The characteristics of green phosphorescent organic light-emitting diodes (OLEDs) fabricated on ITO/glass substrates pretreated with low-energy O{sub 2} and Cl{sub 2} plasma were compared. At 20 mA/cm{sup 2}, the OLEDs with O{sub 2} and Cl{sub 2} plasma-treated indium tin oxide (ITO) had voltages of 9.6 and 7.6 eV, and brightness of 9580 and 12380 cd/m{sup 2}, respectively. At {approx}10{sup 4} cd/m{sup 2}, the latter had a 30% higher external quantum efficiency and a 74% higher power efficiency. Photoelectron spectroscopies revealed that Cl{sub 2} plasma treatment created stable In-Cl bonds and raised the work function of ITO by up to 0.9more » eV. These results suggest that the better energy level alignment at the chlorinated ITO/organic interface enhances hole injection, leading to more efficient and more reliable operation of the OLEDs. The developed plasma chlorination process is very effective for surface modification of ITO and compatible with the fabrication of various organic electronics.« less