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

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References

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  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).
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  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).
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  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).
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    [CrossRef]
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  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).
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  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]
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  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]

2013 (2)

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]

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]

2012 (2)

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]

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]

2011 (3)

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]

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]

A. I. Zhmakin, “Enhancement of light extraction from light emitting diodes,” Phys. Rep.498(4-5), 189–241 (2011).
[CrossRef]

2010 (4)

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).

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]

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]

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]

2009 (2)

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]

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]

2008 (3)

2007 (2)

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]

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]

2005 (1)

2003 (1)

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]

2002 (1)

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]

2001 (1)

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]

1970 (1)

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]

Ali, M.

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]

Bogdanov, M. V.

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).

Bulashevich, K. A.

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).

Cao, B.

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]

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]

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]

Chang, S. J.

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]

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]

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]

Chen, C. C.

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]

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]

Chen, C. Y.

Chen, H. I.

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]

Chen, J. C.

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]

Chen, W. S.

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]

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]

Chien, W. T.

Chiou, Y. Z.

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]

Ding, H.

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]

Evstratov, I. Y.

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).

Fang, F.

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]

Gan, Z.

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]

Gao, K. F.

Gessmann, T.

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]

Guo, X.

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]

Hartmann, P.

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]

He, H. Y.

Hsieh, M. H.

Huh, C.

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]

Hwu, F. S.

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]

Joyce, W. B.

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]

Karpov, S. Y.

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).

Khokhlev, O. V.

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).

Kim, D. J.

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]

Kim, H.

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]

Kim, H. S.

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]

Kivisaari, P.

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]

Ko, T. K.

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]

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]

Kuo, C. T.

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]

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]

Lee, J. M.

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]

Lee, S. N.

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]

Lee, T. X.

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]

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]

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]

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]

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]

Leising, G.

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]

Li, Y. L.

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]

Lin, C. Y.

Lin, N. M.

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]

Lipsanen, H.

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]

Liu, S.

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]

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]

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]

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]

Liu, Z.

Lo, Y. C.

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]

Luo, X.

Ma, S. H.

Oksanen, J.

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]

Pachler, P.

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]

Park, S. J.

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]

Ramm, M. S.

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).

Riuttanen, L.

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]

Ryu, H. Y.

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]

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]

Schubert, E. F.

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]

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]

Schweighart, M.

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]

Shah, J. M.

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]

Shei, S. C.

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]

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]

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]

Shen, C. F.

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]

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]

Shen, G. J.

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]

Shen, J. K.

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]

Shim, J. I.

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]

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]

Sommer, C.

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]

Suihkonen, S.

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]

Sun, C. C.

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]

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]

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]

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]

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]

Tasch, S.

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]

Tsai, S. Y.

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]

Tulkki, J.

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]

Wang, K.

Wang, P.

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]

Wei, W.

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]

Wemple, S. H.

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]

Wenzl, F. P.

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]

Yang, T. H.

Yu, K. H.

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]

Zeng, X. F.

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]

Zhmakin, A. I.

A. I. Zhmakin, “Enhancement of light extraction from light emitting diodes,” Phys. Rep.498(4-5), 189–241 (2011).
[CrossRef]

Zhou, S.

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]

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]

Appl. Phys. Lett. (3)

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]

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]

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]

Electrochem. Solid-State Lett. (1)

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]

ESC J. Solid State Sci. Technol. (1)

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]

IEEE Photon. Technol. Lett. (2)

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]

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]

J. Appl. Phys. (3)

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]

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]

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]

J. Electrochem. Soc. (1)

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]

J. Lightwave Technol. (1)

Opt. Commun. (1)

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]

Opt. Express (5)

Opt. Laser Technol. (1)

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]

Opt. Rev. (1)

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]

Phys. Rep. (1)

A. I. Zhmakin, “Enhancement of light extraction from light emitting diodes,” Phys. Rep.498(4-5), 189–241 (2011).
[CrossRef]

Phys. Status Solidi (1)

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).

Sci. China Technol. Sc. (1)

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]

Other (2)

E. F. Schubert, Light-Emitting Diodes (Cambridge University, 2006).

S. Liu and X. Luo, LED Packaging for Lighting Applications: Design, Manufacturing, and Testing (John Wiley & Sons, 2011).

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Figures (5)

Fig. 1
Fig. 1

(a) Schematic diagram of the conventional LED chip (b) contour of current density distribution in the active layer of conventional GaN-based LEDs with n-CCE [10].

Fig. 2
Fig. 2

Current spreading length Ls versus injected current density ηinj of LED (a) without CBL and (b) with CBL.

Fig. 3
Fig. 3

LEE of LEDs with current crowding around (a) p-pad and (b) n-pad.

Fig. 4
Fig. 4

LEEs of LEDs with ITO sheet resistance of 45.1Ω/□ when reflectivity of p-pad varies.

Fig. 5
Fig. 5

L-I-V relationships of LEDs without CBL, with CBL and with RCBL. The inset is TEM image of the deposited SiO2/ITO/Al layers underneath the p-pad of the LED with RCBL.

Equations (10)

Equations on this page are rendered with MathJax. Learn more.

J(x)= J 0 exp(x/ L s )
L s = 2 n ideal kT/q J 0 ( ρ ITO + ρ n )
I= J inj S= i J( x i )S( x i )
J(x) η inj /(qd)=An(x)+B n 2 (x)+C n 3 (x)
η IQE = η inj η rad
η rad =B n 2 /(An+B n 2 +C n 3 )
B n 2 = η IQE J(x)/(qd)
R(x)=γdB n 2
R(x)=γJ(x) η IQE /q
η IQE =a+bexp(J(x)/c)

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