OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 25 — Dec. 7, 2009
  • pp: 22311–22319

Evaluation of InGaN/GaN light-emitting diodes of circular geometry

X. H. Wang, W. Y. Fu, P. T. Lai, and H. W. Choi  »View Author Affiliations


Optics Express, Vol. 17, Issue 25, pp. 22311-22319 (2009)
http://dx.doi.org/10.1364/OE.17.022311


View Full Text Article

Enhanced HTML    Acrobat PDF (377 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

Blue GaN light emitting diodes (LEDs) in the shape of cuboids and circular disks have been fabricated by laser micromachining. The proposed circular geometry serves to enhance overall light extraction on a macro-scale and to improve uniformity of the emission pattern due to the rotational symmetry of the chip. Analysis of the chip shaping effect is carried out by ray-tracing simulations and further supported with mathematical modeling using ideal LED models, and subsequently verified with fabricated devices. In comparison, a 10% improvement in overall emission was observed for circular LEDs over the regular cuboids, consistent with simulations and calculations. The measured emission pattern from the circular LED confirms the axial symmetry of the emission beam.

© 2009 OSA

OCIS Codes
(220.0220) Optical design and fabrication : Optical design and fabrication
(230.3670) Optical devices : Light-emitting diodes

ToC Category:
Optical Devices

History
Original Manuscript: August 24, 2009
Revised Manuscript: November 6, 2009
Manuscript Accepted: November 16, 2009
Published: November 23, 2009

Citation
X. H. Wang, W. Y. Fu, P. T. Lai, and H. W. Choi, "Evaluation of InGaN/GaN light-emitting diodes of circular geometry," Opt. Express 17, 22311-22319 (2009)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-17-25-22311


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. D. S. Han, J. Y. Kim, S. I. Na, S. H. Kim, K. D. Lee, B. Kim, and S. J. Park, “Improvement of light extraction efficiency of flip-chip light-emitting diode by texturing the bottom side-surface of sapphire substrate,” IEEE Photon. Technol. Lett. 18(13), 1406–1408 (2006). [CrossRef]
  2. T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004). [CrossRef]
  3. H. W. Choi, M. D. Dawson, P. R. Edwards, and R. W. Martin, “High extraction efficiency InGaN micro-ring light-emitting diodes,” Appl. Phys. Lett. 83(22), 4483–4485 (2003). [CrossRef]
  4. S. X. Jin, J. Li, J. Y. Lin, and H. X. Jiang, “InGaN/GaN quantum well interconnected microdisk light emitting diodes,” Appl. Phys. Lett. 77(20), 3236–3238 (2000). [CrossRef]
  5. W. N. Ng, C. H. Leung, P. T. Lai, and H. W. Choi, “Photonic crystal light-emitting diodes fabricated by microsphere lithography,” Nanotechnology 19(25), 255302 (2008). [CrossRef] [PubMed]
  6. P. Royo, R. P. Stanley, and A. Ilegems, “Analytical Calculation of the Extraction Efficiency of Microcavity Light-Emitting Diodes for Display and Fiber Coupling Applications,” IEEE J. Sel. Top. Quantum Electron. 8(2), 207–218 (2002). [CrossRef]
  7. D. S. Liu, T. W. Lin, B. W. Huang, F. S. Juang, P. H. Lei, and C. Z. Hu, “Light-extraction enhancement in GaN-based light-emitting diodes using grade-refractive-index amorphous titanium oxide films with porous structures,” Appl. Phys. Lett. 94(14), 143502 (2009). [CrossRef]
  8. C. Wiesmann, K. Bergenek, N. Linder, and U. T. Schwarz, “Photonic crystal LEDs – designing light extraction,” Laser Photonics Rev. 3(3), 262–286 (2009). [CrossRef]
  9. W. Y. Fu, K. N. Hui, X. H. Wang, K. K. Y. Wong, P. T. Lai, and H. W. Choi, “Geometrical Shaping of InGaN Light-emitting Diodes by Laser Micromachining,” IEEE Photon. Technol. Lett. 21(15), 1078–1080 (2009). [CrossRef]
  10. C. C. Kao, H. C. Kuo, H. W. Huang, J. T. Chu, Y. C. Peng, Y. L. Hsieh, C. Y. Luo, S. C. Wang, C. C. Yu, and C. F. Lin, “Light-output enhancement in a nitride-based light-emitting diode with 22 degrees undercut sidewalls,” IEEE Photon. Technol. Lett. 17(1), 19–21 (2005). [CrossRef]
  11. X. H. Wang, P. T. Lai, and H. W. Choi, “Laser Micro-machining of Optical Microstructures with Inclined Sidewall Profile,” J. Vac. Sci. Technol. B 27(3), 1048–1052 (2009). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited