TITLE

Enhancement of light extraction in ultraviolet light-emitting diodes using nanopixel contact design with Al reflector

AUTHOR(S)
Lobo, N.; Rodriguez, H.; Knauer, A.; Hoppe, M.; Einfeldt, S.; Vogt, P.; Weyers, M.; Kneissl, M.
PUB. DATE
February 2010
SOURCE
Applied Physics Letters;Feb2010, Vol. 96 Issue 8, p081109
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
We report on a nanopixel contact design for nitride-based ultraviolet light-emitting diodes to enhance light extraction. The structure consists of arrays of Pd ohmic contact pixels and an overlying Al reflector layer. Based on this design a twofold increase in the light output, compared to large area Pd square contacts is demonstrated. Theoretical calculations and experiments reveal that a nanopixel spacing of 1 μm or less is required to enable current overlap in the region between the nanopixels due to current spreading in the p-GaN layer and to ensure current injection into the entire active region. Light emitted in the region between the nanopixels will be reflected by the Al layer enhancing the light output. The dependence of the light extraction on the nanopixel size and spacing is investigated.
ACCESSION #
48352121

 

Related Articles

  • High-reflectivity Pd/Ni/Al/Ti/Au ohmic contacts to p-type GaN for ultraviolet light-emitting diodes. Chen, Guan-Ting; Pan, Chang-Chi; Fang, Chi-Shin; Huang, Tzu-Chien; Chyi, Jen-Inn; Chang, Mao-Nan; Huang, Sheng-Bang; Hsu, Jung-Tsung // Applied Physics Letters;10/4/2004, Vol. 85 Issue 14, p2797 

    Thermal stability, optical reflectivity, and contact resistivity of Pd/Ni/Al/Ti/Au ohmic contacts to p-type GaN were investigated. In contrast to its Pd/Al/Ti/Au counterparts, Pd/Ni/Al/Ti/Au contacts retained their specific contact resistivity (<2×10-2 Ω cm2) and reflectivity (>76%) after...

  • Study of hole concentration of 1,4-bis[N-(1-naphthyl)-N′-phenylamino]-4,4′ diamine doped with tungsten oxide by admittance spectroscopy. Hsieh, Ming-Ta; Chang, Chan-Ching; Chen, Jenn-Fang; Chen, Chin H. // Applied Physics Letters;9/4/2006, Vol. 89 Issue 10, p103510 

    The effect of tungsten oxide (WO3) incorporation into 1,4-bis[N-(1-naphthyl)-N′-phenylamino]-4,4′ diamine (NPB) layer is investigated in NPB-tris(8-hydroxyquinoline)aluminium heterojunction organic light-emitting diodes. The admittance spectroscopy studies show that increasing the...

  • Enhanced hole injection and transport in molybdenum-dioxide-doped organic hole-transporting layers. Matsushima, Toshinori; Adachi, Chihaya // Journal of Applied Physics;Feb2008, Vol. 103 Issue 3, p034501 

    We have found that molybdenum dioxide (MoO2) is an excellent dopant for enhancing electrical conductivities in organic hole-transporting layers. We fabricated hole-only devices with an alpha-sexithiophene (α-6T) layer doped with MoO2 at various concentrations to investigate how doping MoO2...

  • A methodology for performance evaluation of LEDs based on ac small signal analysis. Souza Coêlho, Isnaldo J.; da Silva, James N. // Journal of Microwaves, Optoelectronics & Electromagnetic Applica;Dec2013, Vol. 12 Issue 2, p580 

    This paper shows fundamentals and results that support a promising methodology for evaluation in locus of a LED from its own radiating signal, and that allows monitoring of its aging by remote inference on which degradation mechanism is acting internally to the device's structure. It brings out...

  • Low-resistance and highly-reflective Zn–Ni solid solution/Ag ohmic contacts for flip-chip light-emitting diodes. June-O Song, K.; Dong-Seok Leem; Kwak, J.S.; Nam, O.H.; Park, Y.; Tae-Yeon Seong // Applied Physics Letters;12/15/2003, Vol. 83 Issue 24, p4990 

    We have investigated a Zn–Ni solid solution/Ag scheme for use in producing high-quality ohmic contacts for flip-chip light-emitting diodes (LEDs). The as-deposited contact shows nonlinear I–V characteristics. However, oxidizing the contacts at temperatures of 350–550 °C...

  • Contact formation at the C60/alkali-metal fluoride/Al interface. Helander, M. G.; Wang, Z. B.; Lu, Z. H. // Applied Physics Letters;8/25/2008, Vol. 93 Issue 8, p083311 

    Efficient contact formation is critical in organic electroluminescence and photovoltaic devices that utilize fullerene (C60). Unlike traditional electron transport molecules, such as tris-(8-hydroxy-quinolinato)aluminum (Alq3), C60 is found to be highly selective of injection layers. Charge...

  • Surface plasmon leakage in its coupling with an InGaN/GaN quantum well through an Ohmic contact. Yeh, Dong-Ming; Huang, Chi-Feng; Lu, Yen-Cheng; Chen, Cheng-Yen; Tang, Tsung-Yi; Huang, Jeng-Jie; Shen, Kun-Ching; Yang, Ying-Jay; Yang, C. C. // Applied Physics Letters;8/6/2007, Vol. 91 Issue 6, p063121 

    The authors demonstrate the leakage of surface plasmon (SP) through the Ohmic contact of either p-type or n-type GaN layer in the coupling process between SP and an InGaN/GaN quantum well (QW). It is shown that the photoluminescence (PL) intensity is significantly reduced when an Ohmic contact...

  • Nano-sized light emitting diodes by near field laser exposure. Intonti, Francesca; Matarazzo, Vitantonio; Nasir, Ateeq; Makarovsky, Oleg; Campion, Richard; Patanè, Amalia; Kumar, Santosh; Rastelli, Armando; Schmidt, Oliver G.; Gurioli, Massimo // Applied Physics Letters;5/2/2011, Vol. 98 Issue 18, p183102 

    We report a postfabrication process for the realization of nanosized light emitting diodes. The method is based on the exposure of the device to an Ar+ laser through an aperture near field optical microscope and can produce a large (>100 fold) increase in the electroluminescence within a near...

  • Nanoparticle-induced resonant tunneling behaviors in small molecule organic light-emitting devices. Zheng, Tianhang; Choy, Wallace C. H.; Sun, Yuxiu // Applied Physics Letters;3/23/2009, Vol. 94 Issue 12, p123303 

    We report a hybrid nanoparticle/organic device with strong resonant tunneling behavior by introducing ligand-capped Ag nanoparticles between indium tin oxide and hole transport layer in small molecule organic light-emitting devices. The dependences of resonant tunneling current on the thickness...

Share

Read the Article

Courtesy of VIRGINIA BEACH PUBLIC LIBRARY AND SYSTEM

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics