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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 14 — Jul. 2, 2012
  • pp: 15997–16002

Micro/nano structures induced by femtosecond laser to enhance light extraction of GaN-based LEDs

Tien-Li Chang, Zhao-Chi Chen, and Yeeu-Chang Lee  »View Author Affiliations


Optics Express, Vol. 20, Issue 14, pp. 15997-16002 (2012)
http://dx.doi.org/10.1364/OE.20.015997


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Abstract

Surface texturing has been widely adopted to enhance the light extraction efficiency of light-emitting diodes (LEDs), and chemical etching is a technique commonly used to produce surface texturing. This study employed femtosecond lasers to apply ITO films directly onto the surface of LEDs to generate periodic micro/nanostructures and roughen the surface without contact or chemical substances. As a result, photons emitted in the active region escape into the free space, due to the scattering effect produced by texturing. This study discovered that light-emitting efficiency increases with surface roughness, and achieved an improvement of 18%. Caution regarding laser fluence was required during laser processing to avoid damaging the LED beneath the ITO film, which could detract from the electrical characteristics.

© 2012 OSA

OCIS Codes
(220.4000) Optical design and fabrication : Microstructure fabrication
(230.3670) Optical devices : Light-emitting diodes
(320.2250) Ultrafast optics : Femtosecond phenomena
(220.4241) Optical design and fabrication : Nanostructure fabrication

ToC Category:
Optical Devices

History
Original Manuscript: May 10, 2012
Revised Manuscript: June 8, 2012
Manuscript Accepted: June 20, 2012
Published: June 28, 2012

Citation
Tien-Li Chang, Zhao-Chi Chen, and Yeeu-Chang Lee, "Micro/nano structures induced by femtosecond laser to enhance light extraction of GaN-based LEDs," Opt. Express 20, 15997-16002 (2012)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-14-15997


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References

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