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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 10 — May. 9, 2011
  • pp: 9385–9391

Light outcoupling effect in GaN light-emitting diodes via convex microstructures monolithically fabricated on sapphire substrate

Tae Su Oh, Hyun Jeong, Yong Seok Lee, Ah Hyun Park, Tae Hoon Seo, Hun Kim, Kang Jea Lee, Mun Seok Jeong, and Eun-Kyung Suh  »View Author Affiliations

Optics Express, Vol. 19, Issue 10, pp. 9385-9391 (2011)

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GaN-based light-emitting diode (LED) was fabricated on the sapphire substrate with monolithic convex microstructures (CMs) array. Using confocal scanning electroluminescence (EL), we have directly observed the strong outcoupling phenomenon of the light confined in a LED via the CMs array. This outcoupled light could be efficiently converged on the convex center through consecutive reflections at the flat area and the curved slant area of the CMs array. Compared to the conventional LED, the ray tracing simulation and far field EL results of the LED with a CM array showed efficient light extraction toward the top surface, i.e., 0-5, 40-45 and 60-65 degree by the outcoupling effect. We conclude that the outcoupled optical path via CMs is the dominant factor of the enhanced light extraction in the LED with a CM array.

© 2011 OSA

OCIS Codes
(160.6000) Materials : Semiconductor materials
(180.1790) Microscopy : Confocal microscopy
(230.3670) Optical devices : Light-emitting diodes

ToC Category:
Optical Devices

Original Manuscript: March 18, 2011
Revised Manuscript: April 22, 2011
Manuscript Accepted: April 23, 2011
Published: April 28, 2011

Tae Su Oh, Hyun Jeong, Yong Seok Lee, Ah Hyun Park, Tae Hoon Seo, Hun Kim, Kang Jea Lee, Mun Seok Jeong, and Eun-Kyung Suh, "Light outcoupling effect in GaN light-emitting diodes via convex microstructures monolithically fabricated on sapphire substrate," Opt. Express 19, 9385-9391 (2011)

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  1. S. Nakamura, “Current status of GaN-based solid state lighting,” MRS Bull. 34(02), 101–107 (2009). [CrossRef]
  2. J. J. Wierer, M. R. Krames, J. E. Epler, N. F. Gardner, M. G. Craford, J. R. Wendt, J. A. Simmons, and M. M. Sigalas, “InGaN/GaN quantum-well heterostructures light-emitting diodes employing photonic crystal structures,” Appl. Phys. Lett. 84(19), 3885 (2004). [CrossRef]
  3. Z. Liliental-Weber and D. Cherns, “Microstructure of lateral overgrown GaN layers,” J. Appl. Phys. 89(12), 7833–7840 (2001). [CrossRef]
  4. J.-F. Carlin, C. Zellweger, J. Dorsaz, S. Nicolay, G. Christmann, E. Feltin, R. Butté, and N. Grandjean, “Progresses in III-nitride distributed Bragg reflectors and microcavities using AlInN/GaN materials,” Phys. Status Solidi 242(11), 2326–2344 (2005) (b). [CrossRef]
  5. J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN light-emitting diodes by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008). [CrossRef]
  6. T. S. Oh, H. Jeong, Y. S. Lee, J. D. Kim, T. H. Seo, H. Kim, A. H. Park, K. J. Lee, and E.-K. Suh, “Coupling of InGaN/GaN multiquantum-wells photoluminescence to surface plasmons in platinum nanocluster,” Appl. Phys. Lett. 95(11), 111112 (2009). [CrossRef]
  7. T. V. Cuong, H. S. Cheong, H. G. Kim, H. Y. Kim, C.-H. Hong, E. K. Suh, H. K. Cho, and B. H. Kong, “enhanced light output from aligned micropit InGaN-based light emitting diodes using wet-etch sapphire patterning,” Appl. Phys. Lett. 90(13), 131107 (2007). [CrossRef]
  8. M. Yamada, T. Mitani, Y. Narukawa, S. Shioji, I. Niki, S. Sonobe, K. Deguchi, M. Sano, and T. Mukai, “InGaN-based near-ultraviolet and blue-light-emitting diodes with high external quantum efficiency using a patterned sapphire substrate,” Jpn. J. Appl. Phys. 41(12B), L1431–L1433 (2002). [CrossRef]
  9. D.-H. Jang, J.-I. Shim, and K. Y. Yoo, “Theoretical analysis on the light extraction efficiency of GaN-based light-emitting diodes by using the ray tracing method,” J. Korean Phys. Soc. 54(6), 2373–2377 (2009). [CrossRef]
  10. H.-Y. Shin, S. K. Kwon, Y. I. Chang, M. J. Cho, and K. H. Park, “Reducing dislocation density in GaN films using a cone-shaped patterned sapphire substrate,” J. Cryst. Growth 311(17), 4167–4170 (2009). [CrossRef]
  11. C.-T. Chang, S.-K. Hsiao, E. Y. Chang, Y.-L. Hsiao, C.-Y. Lu, H.-C. Chang, K.-W. Cheng, and C.-T. Lee, “460-nm InGaN-based LEDs grown on fully inclined hemisphere-shape-patterned sapphire substrate with submicrometer spacing,” IEEE Photon. Technol. Lett. 21(19), 1366–1368 (2009). [CrossRef]
  12. T. S. Oh, S. H. Kim, T. K. Kim, Y. S. Lee, H. Jeong, G. M. Yang, and E.-K. Suh, “GaN-based light-emitting diodes on micro-lens patterned sapphire substrate,” Jpn. J. Appl. Phys. 47(7), 5333–5336 (2008). [CrossRef]
  13. S.-H. Park, H. Jeon, Y.-J. Sung, and G.-Y. Yeom, “Refractive sapphire microlenses fabricated by chlorine-based inductively coupled plasma etching,” Appl. Opt. 40(22), 3698–3702 (2001). [CrossRef]
  14. Y. Nakano, O. Fujishima, and T. Kachi, “Effect of p-type activation ambient on acceptor levels in Mg-doped GaN,” J. Appl. Phys. 96(1), 415–419 (2004). [CrossRef]
  15. T. S. Oh, H. Jeong, Y. S. Lee, T. H. Seo, A. H. Park, H. Kim, K. J. Lee, M. S. Jeong, and E.-K. Suh, “Defect structure originating from threading dislocations within the GaN film grown on a convex patterned sapphire substrate,” Thin Solid Films 519(8), 2398–2401 (2011). [CrossRef]
  16. G. A. Onushkin, S.-S. Hong, J.-H. Lee, J.-S. Park, J.-K. Son, M.-H. Kim, and Y. J. Park, “Local electroluminescence and time-resolved photoluminescence study of InGaN light-emitting diodes,” Appl. Phys. Lett. 95(10), 101904 (2009). [CrossRef]

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