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Energy Express

Energy Express

  • Editor: Christian Seassal
  • Vol. 22, Iss. S4 — Jun. 30, 2014
  • pp: A1071–A1078

Enhanced light extraction from GaN based light-emitting diodes using a hemispherical NiCoO lens

Do-Hyun Kim, Dong Su Shin, and Jinsub Park  »View Author Affiliations

Optics Express, Vol. 22, Issue S4, pp. A1071-A1078 (2014)

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We report on the improvement of light extraction efficiency from GaN-based light-emitting diodes (LEDs) using Ni1-xCoxO nanoparticles (NPs) formed on the p-GaN layer. After formation of Ni1-xCoxO hemispherical lens arrays on the blue LEDs by drop-casting colloidal NPs, electroluminescence (EL) and photoluminescence (PL) measurements are conducted to investigate the electrical and optical properties. The PL and EL intensities from the blue LEDs with the Ni1-xCoxO NPs are 1.74 and 1.61 times greater, respectively, than a conventional LED. Finally, a hybrid approach using ZnO nanorod arrays grown on the NiCoO hemispherical lens shows further increase of light extraction by 3.8 and 6.2 times compared to LEDs with bare NiCoO NPs and without any NPs, respectively. Finite-difference time-domain (FDTD) simulation results also agree well with the experimental results. The enhancement of light extraction from LEDs with ZnO nanorods and NiCoO NPs can be attributed to an enlarged escape angle cone and increased probability of light scattering.

© 2014 Optical Society of America

OCIS Codes
(160.6000) Materials : Semiconductor materials
(230.3670) Optical devices : Light-emitting diodes
(220.4241) Optical design and fabrication : Nanostructure fabrication

ToC Category:
Light-Emitting Diodes

Original Manuscript: February 24, 2014
Revised Manuscript: April 10, 2014
Manuscript Accepted: April 23, 2014
Published: May 28, 2014

Do-Hyun Kim, Dong Su Shin, and Jinsub Park, "Enhanced light extraction from GaN based light-emitting diodes using a hemispherical NiCoO lens," Opt. Express 22, A1071-A1078 (2014)

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