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Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 21 — Oct. 21, 2013
  • pp: 25381–25388

Effects of current crowding on light extraction efficiency of conventional GaN-based light-emitting diodes

Bin Cao, Shuiming Li, Run Hu, Shengjun Zhou, Yi Sun, Zhiying Gan, and Sheng Liu  »View Author Affiliations


Optics Express, Vol. 21, Issue 21, pp. 25381-25388 (2013)
http://dx.doi.org/10.1364/OE.21.025381


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Abstract

Current crowding effects (CCEs) on light extraction efficiency (LEE) of conventional GaN-based light-emitting diodes (LEDs) are analyzed through Monte Carlo ray-tracing simulation. The non-uniform radiative power distribution of the active layer of the Monte Carlo model is obtained based on the current spreading theory and rate equation. The simulation results illustrate that CCE around n-pad (n-CCE) has little effect on LEE, while CCE around p-pad (p-CCE) results in a notable LEE droop due to the significant absorption of photons emitted under p-pad. LEE droop is alleviated by a SiO2 current blocking layer (CBL) and reflective p-pad. Compared to the conventional LEDs without CBL, the simulated LEE of LEDs with CBL at 20 A/cm2 and 70 A/cm2 is enhanced by 7.7% and 19.0%, respectively. It is further enhanced by 7.6% and 11.4% after employing a reflective p-pad due to decreased absorption. These enhancements are in accordance with the experimental results. Output power of LEDs with CBL is enhanced by 8.7% and 18.2% at 20 A/cm2 and 70 A/cm2, respectively. And the reflective p-pad results in a further enhancement of 8.9% and 12.7%.

© 2013 OSA

OCIS Codes
(230.0230) Optical devices : Optical devices
(230.3670) Optical devices : Light-emitting diodes

ToC Category:
Optical Devices

History
Original Manuscript: May 23, 2013
Revised Manuscript: July 14, 2013
Manuscript Accepted: September 6, 2013
Published: October 17, 2013

Citation
Bin Cao, Shuiming Li, Run Hu, Shengjun Zhou, Yi Sun, Zhiying Gan, and Sheng Liu, "Effects of current crowding on light extraction efficiency of conventional GaN-based light-emitting diodes," Opt. Express 21, 25381-25388 (2013)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-21-21-25381


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References

  1. E. F. Schubert, Light-Emitting Diodes (Cambridge University, 2006).
  2. S. Liu and X. Luo, LED Packaging for Lighting Applications: Design, Manufacturing, and Testing (John Wiley & Sons, 2011).
  3. A. I. Zhmakin, “Enhancement of light extraction from light emitting diodes,” Phys. Rep.498(4-5), 189–241 (2011). [CrossRef]
  4. T. X. Lee, C. Y. Lin, S. H. Ma, and C. C. Sun, “Analysis of position-dependent light extraction of GaN-based LEDs,” Opt. Express13(11), 4175–4179 (2005). [CrossRef] [PubMed]
  5. T. X. Lee, K. F. Gao, W. T. Chien, and C. C. Sun, “Light extraction analysis of GaN-based light-emitting diodes with surface texture and/or patterned substrate,” Opt. Express15(11), 6670–6676 (2007). [CrossRef] [PubMed]
  6. C. C. Sun, C. Y. Chen, H. Y. He, C. C. Chen, W. T. Chien, T. X. Lee, and T. H. Yang, “Precise optical modeling for silicate-based white LEDs,” Opt. Express16(24), 20060–20066 (2008). [CrossRef] [PubMed]
  7. Z. Liu, K. Wang, X. Luo, and S. Liu, “Precise optical modeling of blue light-emitting diodes by Monte Carlo ray-tracing,” Opt. Express18(9), 9398–9412 (2010). [CrossRef] [PubMed]
  8. C. Sommer, F. P. Wenzl, P. Hartmann, P. Pachler, M. Schweighart, S. Tasch, and G. Leising, “Tailoring of the color conversion elements in phosphor-converted high-power LEDs by optical simulations,” IEEE Photon. Technol. Lett.20(9), 739–741 (2008). [CrossRef]
  9. M. V. Bogdanov, K. A. Bulashevich, O. V. Khokhlev, I. Y. Evstratov, M. S. Ramm, and S. Y. Karpov, “Current crowding effect on light extraction efficiency of thin-film LEDs,” Phys. Status Solidi7(7–8), 2124–2126 (2010) (c).
  10. B. Cao, S. Zhou, and S. Liu, “Effects of ITO pattern on the electrical and optical characteristics of LEDs,” ESC J. Solid State Sci. Technol.2(1), R24–R28 (2013). [CrossRef]
  11. X. Guo and E. F. Schubert, “Current crowding and optical saturation effects in GaInN/GaN light-emitting diodes grown on insulating substrates,” Appl. Phys. Lett.78(21), 3337–3339 (2001). [CrossRef]
  12. C. Huh, J. M. Lee, D. J. Kim, and S. J. Park, “Improvement in light-output efficiency of InGaN/GaN multiple-quantum well light-emitting diodes by current blocking layer,” J. Appl. Phys.92(5), 2248–2250 (2002). [CrossRef]
  13. P. Wang, W. Wei, B. Cao, Z. Gan, and S. Liu, “Simulation of current spreading for GaN-based light-emitting diodes,” Opt. Laser Technol.42(5), 737–740 (2010). [CrossRef]
  14. S. J. Chang, C. F. Shen, M. H. Hsieh, C. T. Kuo, T. K. Ko, W. S. Chen, and S. C. Shei, “Nitride-based LEDs with a hybrid Al mirror+TiO2/SiO2 DBR backside reflector,” J. Lightwave Technol.26(17), 3131–3136 (2008). [CrossRef]
  15. S. Zhou, F. Fang, B. Cao, S. Liu, and H. Ding, “Enhancement in light output power of LEDs with reflective current blocking layer and backside hybrid reflector,” Sci. China Technol. Sc.56(6), 1544–1549 (2013). [CrossRef]
  16. H. Y. Ryu and J. I. Shim, “Effect of current spreading on the efficiency droop of InGaN light-emitting diodes,” Opt. Express19(4), 2886–2894 (2011). [CrossRef] [PubMed]
  17. W. B. Joyce and S. H. Wemple, “Steady-state junction-current distributions in thin resistive films on semiconductor junctions (solutions of∇v2=±ev, ” J. Appl. Phys.41(9), 3818 (1970). [CrossRef]
  18. H. Kim and S. N. Lee, “Theoretical considerations on current spreading in GaN-based light emitting diodes fabricated with top-emission geometry,” J. Electrochem. Soc.157(5), H562–H564 (2010). [CrossRef]
  19. J. M. Shah, Y. L. Li, T. Gessmann, and E. F. Schubert, “Experimental analysis and theoretical model for anomalously high ideality factors (n>2.0) in AlGaN/GaN p-n junction diodes,” J. Appl. Phys.94(4), 2627–2631 (2003). [CrossRef]
  20. H. Y. Ryu, H. S. Kim, and J. I. Shim, “Rate equation analysis of efficiency droop in InGaN light-emitting diodes,” Appl. Phys. Lett.95(8), 081114 (2009). [CrossRef]
  21. P. Kivisaari, L. Riuttanen, J. Oksanen, S. Suihkonen, M. Ali, H. Lipsanen, and J. Tulkki, “Electrical measurement of internal quantum efficiency and extraction efficiency of III-N light-emitting diodes,” Appl. Phys. Lett.101(2), 021113 (2012). [CrossRef]
  22. C. C. Sun, T. X. Lee, Y. C. Lo, C. C. Chen, and S. Y. Tsai, “Light extraction enhancement of GaN-based LEDs through passive/active photon recycling,” Opt. Commun.284(20), 4862–4868 (2011). [CrossRef]
  23. S. J. Chang, C. F. Shen, W. S. Chen, T. K. Ko, C. T. Kuo, K. H. Yu, S. C. Shei, and Y. Z. Chiou, “Nitride-based LEDs with an insulating SiO2 layer underneath p-pad electrodes,” Electrochem. Solid-State Lett.10(6), H175–H177 (2007). [CrossRef]
  24. J. C. Chen, G. J. Shen, F. S. Hwu, H. I. Chen, J. K. Shen, T. X. Lee, and C. C. Sun, “Electrical-optical analysis of a GaN/sapphire LED chip by considering the resistivity of the current-spreading layer,” Opt. Rev.16(2), 213–215 (2009). [CrossRef]
  25. N. M. Lin, S. C. Shei, S. J. Chang, and X. F. Zeng, “GaN-based LEDs with omnidirectional metal underneath an insulating SiO2 Layer,” IEEE Photon. Technol. Lett.24(10), 815–817 (2012). [CrossRef]

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