Abstract

We demonstrate two types of GaN-based flip-chip light-emitting diodes (FCLEDs) with highly reflective Ag/TiW and indium-tin oxide (ITO)/distributed Bragg reflector (DBR) p-type Ohmic contacts. We show that a direct Ohmic contact to p-GaN layer using pure Ag is obtained when annealed at 600°C in N2 ambient. A TiW diffusion barrier layer covered onto Ag is used to suppress the agglomeration of Ag and thus maintain high reflectance of Ag during high temperature annealing process. We develop a strip-shaped SiO2 current blocking layer beneath the ITO/DBR to alleviate current crowding occurring in FCLED with ITO/DBR. Owing to negligibly small spreading resistance of Ag, however, our combined numerical and experimental results show that the FCLED with Ag/TiW has a more favorable current spreading uniformity in comparison to the FCLED with ITO/DBR. As a result, the light output power of FCLED with Ag/TiW is 7.5% higher than that of FCLED with ITO/DBR at 350 mA. The maximum output power of the FCLED with Ag/TiW obtained at 305.6 A/cm2 is 29.3% larger than that of the FCLED with ITO/DBR obtained at 278.9 A/cm2. The improvement appears to be due to the enhanced current spreading and higher optical reflectance provided by the Ag/TiW.

© 2017 Optical Society of America

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References

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    [PubMed]
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  22. H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).
  23. C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).
  24. A. E. Chernyakov, K. A. Bulashevich, S. Y. Karpov, and A. L. Zakgeim, “Experimental and theoretical study of electrical, thermal, and optical characteristics of InGaN/GaN high-power flip-chip LEDs,” Phys. Status Solidi., A Appl. Mater. Sci. 210(3), 466–469 (2013).
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    [PubMed]
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    [PubMed]
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  33. N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).
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    [PubMed]
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  38. http://www.str-soft.com/products/SpeCLED/index.htm

2017 (7)

C. M. Kang, D. J. Kong, J. P. Shim, S. Kim, S. B. Choi, J. Y. Lee, J. H. Min, D. J. Seo, S. Y. Choi, and D. S. Lee, “Fabrication of a vertically-stacked passive-matrix micro-LED array structure for a dual color display,” Opt. Express 25(3), 2489–2495 (2017).

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

K. Rae, C. Foucher, B. Guilhabert, M. S. Islim, L. Yin, D. Zhu, R. A. Oliver, D. J. Wallis, H. Haas, N. Laurand, and M. D. Dawson, “InGaN µLEDs integrated onto colloidal quantum dot functionalized ultra-thin glass,” Opt. Express 25(16), 19179–19184 (2017).

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

2016 (6)

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

S. M. Sadaf, Y. H. Ra, T. Szkopek, and Z. Mi, “Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes,” Nano Lett. 16(2), 1076–1080 (2016).
[PubMed]

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

B. P. Yonkee, E. C. Young, S. P. DenBaars, S. Nakamura, and J. S. Speck, “Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction,” Appl. Phys. Lett. 109(19), 191104 (2016).
[PubMed]

J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

D. Hwang, B. P. Yonkee, B. S. Addin, R. M. Farrell, S. Nakamura, J. S. Speck, and S. DenBaars, “Photoelectrochemical liftoff of LEDs grown on freestanding c-plane GaN substrates,” Opt. Express 24(20), 22875–22880 (2016).
[PubMed]

2015 (2)

H. Y. Ryu, “Modification of internal quantum efficiency and efficiency droop in GaN-based flip-chip light-emitting diodes via the Purcell effect,” Opt. Express 23(19), A1157–A1166 (2015).
[PubMed]

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

2014 (7)

R. H. Horng, S. H. Chuang, C. H. Tien, S. C. Lin, and D. S. Wuu, “High performance GaN-based flip-chip LEDs with different electrode patterns,” Opt. Express 22(103Suppl 3), A941–A946 (2014).
[PubMed]

Z. Y. Zhang, M. Kawamura, Y. Abe, and K. H. Kim, “Thermal stability of Ag films with various interface layers,” Jpn. J. Appl. Phys. 53(4), 048003 (2014).

W. C. Chong and K. M. Lau, “Performance enhancements of flip-chip light-emitting diodes with high-density n-type point-contacts,” IEEE Electron Device Lett. 35(10), 1049–1051 (2014).

B. C. Lin, C. H. Chiu, C. Y. Lee, H. V. Han, P. M. Tu, T. P. Chen, Z. Y. Li, P. T. Lee, C. C. Lin, G. C. Chi, C. H. Chen, B. Fan, C. Y. Chang, and H. C. Kuo, “Performance enhancement of GaN-based flip-chip ultraviolet light-emitting diodes with a RPD AlN nucleation layer on patterned sapphire substrate,” Opt. Mater. Express 4(8), 1632–1640 (2014).

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

S. Zhou, B. Cao, S. Yuan, and S. Liu, “Enhanced luminous efficiency of phosphor-converted LEDs by using back reflector to increase reflectivity for yellow light,” Appl. Opt. 53(34), 8104–8110 (2014).
[PubMed]

T. Wei, Z. Huo, Y. Zhang, H. Zheng, Y. Chen, J. Yang, Q. Hu, R. Duan, J. Wang, Y. Zeng, and J. Li, “Efficiency enhancement of homoepitaxial InGaN/GaN light-emitting diodes on free-standing GaN substrate with double embedded SiO2 photonic crystals,” Opt. Express 22(Suppl 4), A1093–A1100 (2014).
[PubMed]

2013 (1)

A. E. Chernyakov, K. A. Bulashevich, S. Y. Karpov, and A. L. Zakgeim, “Experimental and theoretical study of electrical, thermal, and optical characteristics of InGaN/GaN high-power flip-chip LEDs,” Phys. Status Solidi., A Appl. Mater. Sci. 210(3), 466–469 (2013).

2012 (2)

2011 (1)

2010 (1)

H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).

2009 (2)

J. H. Son, Y. H. Song, H. K. Yu, and J. L. Lee, “Effects of Ni cladding layers on suppression of Ag agglomeration in Ag-based Ohmic contacts on p-GaN,” Appl. Phys. Lett. 95(6), 062108 (2009).

J. J. Wierer, A. David, and M. M. Megens, “III-nitride photonic-crystal light-emitting diodes with high extraction efficiency,” Nat. Photonics 3(3), 163–169 (2009).

2007 (1)

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

2006 (3)

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

2005 (1)

J. O. Song, J. S. Kwak, Y. Park, and T. Y. Seong, “Ohmic and degradation mechanisms of Ag contacts on p-type GaN,” Appl. Phys. Lett. 86(6), 062104 (2005).

2004 (1)

H. W. Jang and J. L. Lee, “Mechanism for ohmic contact formation of Ni/Ag contacts on p-type GaN,” Appl. Phys. Lett. 85(24), 5920–5922 (2004).

2001 (2)

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, 3337–3339 (2001).

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Abe, Y.

Z. Y. Zhang, M. Kawamura, Y. Abe, and K. H. Kim, “Thermal stability of Ag films with various interface layers,” Jpn. J. Appl. Phys. 53(4), 048003 (2014).

Addin, B. S.

Aldaz, R. I.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Amano, H.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Arif, R. A.

H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).

Bae, S. Y.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Baik, K. H.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Bhardwaj, J.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Bulashevich, K. A.

A. E. Chernyakov, K. A. Bulashevich, S. Y. Karpov, and A. L. Zakgeim, “Experimental and theoretical study of electrical, thermal, and optical characteristics of InGaN/GaN high-power flip-chip LEDs,” Phys. Status Solidi., A Appl. Mater. Sci. 210(3), 466–469 (2013).

Cao, B.

Cesaratto, J. M.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Chang, C. S.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Chang, C. Y.

Chang, S. J.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Chen, C. H.

Chen, Q.

J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

Chen, T. P.

Chen, W. S.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Chen, Y.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

T. Wei, Z. Huo, Y. Zhang, H. Zheng, Y. Chen, J. Yang, Q. Hu, R. Duan, J. Wang, Y. Zeng, and J. Li, “Efficiency enhancement of homoepitaxial InGaN/GaN light-emitting diodes on free-standing GaN substrate with double embedded SiO2 photonic crystals,” Opt. Express 22(Suppl 4), A1093–A1100 (2014).
[PubMed]

Chen, Z.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Chernyakov, A. E.

A. E. Chernyakov, K. A. Bulashevich, S. Y. Karpov, and A. L. Zakgeim, “Experimental and theoretical study of electrical, thermal, and optical characteristics of InGaN/GaN high-power flip-chip LEDs,” Phys. Status Solidi., A Appl. Mater. Sci. 210(3), 466–469 (2013).

Chi, G. C.

Chiu, C. H.

Cho, J.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Choi, S. B.

Choi, S. Y.

Chong, W. C.

W. C. Chong and K. M. Lau, “Performance enhancements of flip-chip light-emitting diodes with high-density n-type point-contacts,” IEEE Electron Device Lett. 35(10), 1049–1051 (2014).

Choy, H.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Christenson, G.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Chuang, S. H.

Cich, M. J.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Craven, M. D.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

David, A.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

J. J. Wierer, A. David, and M. M. Megens, “III-nitride photonic-crystal light-emitting diodes with high extraction efficiency,” Nat. Photonics 3(3), 163–169 (2009).

Dawson, M. D.

Deb, P.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

DeLille, R. A.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Demir, H. V.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

DenBaars, S.

DenBaars, S. P.

B. P. Yonkee, E. C. Young, S. P. DenBaars, S. Nakamura, and J. S. Speck, “Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction,” Appl. Phys. Lett. 109(19), 191104 (2016).
[PubMed]

Duan, R.

Ellis, B.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Epler, J. E.

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

Fan, B.

Farrell, R. M.

Feng, Y.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Foucher, C.

Gao, Y.

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

Gardner, N. F.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Götz, W.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Gui, C.

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

Guilhabert, B.

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, 3337–3339 (2001).

Ha, G. Y.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Haas, H.

Han, H. V.

Han, I. K.

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

Hasanov, N.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Holcomb, M. O.

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

Honda, Y.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Horng, R. H.

Hsu, Y. P.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Hu, H.

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

Hu, Q.

Huang, K.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Huo, Z.

Hurni, C. A.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Hwang, D.

Hwang, H. Y.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Ikarashi, N.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Islim, M. S.

Jang, H. W.

H. W. Jang and J. L. Lee, “Mechanism for ohmic contact formation of Ni/Ag contacts on p-type GaN,” Appl. Phys. Lett. 85(24), 5920–5922 (2004).

Jeon, J. W.

Jho, Y. D.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Jiang, S.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Jiang, X.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Jiao, Q.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Kang, C. M.

Karpov, S. Y.

A. E. Chernyakov, K. A. Bulashevich, S. Y. Karpov, and A. L. Zakgeim, “Experimental and theoretical study of electrical, thermal, and optical characteristics of InGaN/GaN high-power flip-chip LEDs,” Phys. Status Solidi., A Appl. Mater. Sci. 210(3), 466–469 (2013).

Kawamura, M.

Z. Y. Zhang, M. Kawamura, Y. Abe, and K. H. Kim, “Thermal stability of Ag films with various interface layers,” Jpn. J. Appl. Phys. 53(4), 048003 (2014).

Kern, R. S.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Kim, H.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Kim, H. D.

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

Kim, J. Y.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Kim, K. H.

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

Z. Y. Zhang, M. Kawamura, Y. Abe, and K. H. Kim, “Thermal stability of Ag films with various interface layers,” Jpn. J. Appl. Phys. 53(4), 048003 (2014).

Kim, S.

Kim, S. J.

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

Kim, T. G.

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

Ko, T. K.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Kong, D. J.

Krames, M. R.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Kuo, H. C.

Kwak, J. S.

J. O. Song, J. S. Kwak, Y. Park, and T. Y. Seong, “Ohmic and degradation mechanisms of Ag contacts on p-type GaN,” Appl. Phys. Lett. 86(6), 062104 (2005).

Kwon, M. K.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Lau, K. M.

W. C. Chong and K. M. Lau, “Performance enhancements of flip-chip light-emitting diodes with high-density n-type point-contacts,” IEEE Electron Device Lett. 35(10), 1049–1051 (2014).

Laurand, N.

Lee, C. Y.

Lee, D. S.

C. M. Kang, D. J. Kong, J. P. Shim, S. Kim, S. B. Choi, J. Y. Lee, J. H. Min, D. J. Seo, S. Y. Choi, and D. S. Lee, “Fabrication of a vertically-stacked passive-matrix micro-LED array structure for a dual color display,” Opt. Express 25(3), 2489–2495 (2017).

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Lee, H. J.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Lee, J. L.

J. H. Son, Y. H. Song, H. K. Yu, and J. L. Lee, “Effects of Ni cladding layers on suppression of Ag agglomeration in Ag-based Ohmic contacts on p-GaN,” Appl. Phys. Lett. 95(6), 062108 (2009).

H. W. Jang and J. L. Lee, “Mechanism for ohmic contact formation of Ni/Ag contacts on p-type GaN,” Appl. Phys. Lett. 85(24), 5920–5922 (2004).

Lee, J. W.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Lee, J. Y.

Lee, P. T.

Lee, S. N.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Lee, Y. T.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Lekhal, K.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Li, D.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Li, J.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

T. Wei, Z. Huo, Y. Zhang, H. Zheng, Y. Chen, J. Yang, Q. Hu, R. Duan, J. Wang, Y. Zeng, and J. Li, “Efficiency enhancement of homoepitaxial InGaN/GaN light-emitting diodes on free-standing GaN substrate with double embedded SiO2 photonic crystals,” Opt. Express 22(Suppl 4), A1093–A1100 (2014).
[PubMed]

Li, Z. Y.

Lim, J. H.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Lin, B. C.

Lin, C. C.

Lin, S. C.

Lin, Y. C.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Liu, G. Y.

H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).

Liu, L.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Liu, M.

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

Liu, S.

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

S. Zhou, B. Cao, S. Yuan, and S. Liu, “Enhanced luminous efficiency of phosphor-converted LEDs by using back reflector to increase reflectivity for yellow light,” Appl. Opt. 53(34), 8104–8110 (2014).
[PubMed]

Liu, W.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Liu, X.

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

Lowery, C.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Lu, S. P.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Ludowise, M. J.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Lv, J.

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

Margalith, T.

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

Martin, P. S.

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Megens, M. M.

J. J. Wierer, A. David, and M. M. Megens, “III-nitride photonic-crystal light-emitting diodes with high extraction efficiency,” Nat. Photonics 3(3), 163–169 (2009).

Mi, Z.

S. M. Sadaf, Y. H. Ra, T. Szkopek, and Z. Mi, “Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes,” Nano Lett. 16(2), 1076–1080 (2016).
[PubMed]

Min, J. H.

Min, J. W.

S. Y. Bae, J. W. Min, H. Y. Hwang, K. Lekhal, H. J. Lee, Y. D. Jho, D. S. Lee, Y. T. Lee, N. Ikarashi, Y. Honda, and H. Amano, “III-nitride core-shell nanorod array on quartz substrates,” Sci. Rep. 7, 45345 (2017).
[PubMed]

Na, S. I.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Nakamura, S.

B. P. Yonkee, E. C. Young, S. P. DenBaars, S. Nakamura, and J. S. Speck, “Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction,” Appl. Phys. Lett. 109(19), 191104 (2016).
[PubMed]

D. Hwang, B. P. Yonkee, B. S. Addin, R. M. Farrell, S. Nakamura, J. S. Speck, and S. DenBaars, “Photoelectrochemical liftoff of LEDs grown on freestanding c-plane GaN substrates,” Opt. Express 24(20), 22875–22880 (2016).
[PubMed]

O’Shea, J. J.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Oliver, R. A.

Park, I. K.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Park, S. J.

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

Park, Y.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

J. O. Song, J. S. Kwak, Y. Park, and T. Y. Seong, “Ohmic and degradation mechanisms of Ag contacts on p-type GaN,” Appl. Phys. Lett. 86(6), 062104 (2005).

Ra, Y. H.

S. M. Sadaf, Y. H. Ra, T. Szkopek, and Z. Mi, “Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes,” Nano Lett. 16(2), 1076–1080 (2016).
[PubMed]

Rae, K.

Ryu, H. Y.

Sadaf, S. M.

S. M. Sadaf, Y. H. Ra, T. Szkopek, and Z. Mi, “Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes,” Nano Lett. 16(2), 1076–1080 (2016).
[PubMed]

Schmidt, P. J.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Schubert, E. F.

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, 3337–3339 (2001).

Seo, D. J.

Seong, T. Y.

W. S. Yum, J. W. Jeon, J. S. Sung, and T. Y. Seong, “Highly reliable Ag/Zn/Ag ohmic reflector for high-power GaN-based vertical light-emitting diode,” Opt. Express 20(17), 19194–19199 (2012).
[PubMed]

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

J. O. Song, J. S. Kwak, Y. Park, and T. Y. Seong, “Ohmic and degradation mechanisms of Ag contacts on p-type GaN,” Appl. Phys. Lett. 86(6), 062104 (2005).

Sharma, V. K.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Shchekin, O. B.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

Shei, S. C.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Shen, B.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Shen, C. F.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Shen, Y. C.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Shim, J. I.

Shim, J. P.

Shin, H. W.

S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
[PubMed]

Soer, W. A.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Son, J. H.

J. H. Son, Y. H. Song, H. K. Yu, and J. L. Lee, “Effects of Ni cladding layers on suppression of Ag agglomeration in Ag-based Ohmic contacts on p-GaN,” Appl. Phys. Lett. 95(6), 062108 (2009).

Sone, C.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Song, J. O.

J. O. Song, J. S. Kwak, Y. Park, and T. Y. Seong, “Ohmic and degradation mechanisms of Ag contacts on p-type GaN,” Appl. Phys. Lett. 86(6), 062104 (2005).

Song, Y. H.

J. H. Son, Y. H. Song, H. K. Yu, and J. L. Lee, “Effects of Ni cladding layers on suppression of Ag agglomeration in Ag-based Ohmic contacts on p-GaN,” Appl. Phys. Lett. 95(6), 062108 (2009).

Speck, J. S.

B. P. Yonkee, E. C. Young, S. P. DenBaars, S. Nakamura, and J. S. Speck, “Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction,” Appl. Phys. Lett. 109(19), 191104 (2016).
[PubMed]

D. Hwang, B. P. Yonkee, B. S. Addin, R. M. Farrell, S. Nakamura, J. S. Speck, and S. DenBaars, “Photoelectrochemical liftoff of LEDs grown on freestanding c-plane GaN substrates,” Opt. Express 24(20), 22875–22880 (2016).
[PubMed]

Spinger, B.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Steigerwald, D. A.

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Steranka, F. M.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Stockman, S. A.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Subramanya, S.

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Sun, X. W.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Sung, J. S.

Szkopek, T.

S. M. Sadaf, Y. H. Ra, T. Szkopek, and Z. Mi, “Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes,” Nano Lett. 16(2), 1076–1080 (2016).
[PubMed]

Tan, S. T.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Tandon, A.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Tansu, N.

H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).

Tien, C. H.

Trottier, T. A.

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

Tsai, J. M.

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

Tu, P. M.

Tyagi, A.

C. A. Hurni, A. David, M. J. Cich, R. I. Aldaz, B. Ellis, K. Huang, A. Tyagi, R. A. DeLille, M. D. Craven, F. M. Steranka, and M. R. Krames, “Bulk GaN flip-chip violet light-emitting diodes with optimized efficiency for high-power operation,” Appl. Phys. Lett. 106(3), 031101 (2015).

Wallis, D. J.

Wang, J.

Wang, R.

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

Wei, T.

Wierer, J. J.

J. J. Wierer, A. David, and M. M. Megens, “III-nitride photonic-crystal light-emitting diodes with high extraction efficiency,” Nat. Photonics 3(3), 163–169 (2009).

J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

Wildeson, I. H.

J. Bhardwaj, J. M. Cesaratto, I. H. Wildeson, H. Choy, A. Tandon, W. A. Soer, P. J. Schmidt, B. Spinger, P. Deb, O. B. Shchekin, and W. Götz, “Progress in high-luminance LED technology for solid-state lighting,” Phys. Status Solidi., A Appl. Mater. Sci. 214(8), 1600826 (2017).

Wuu, D. S.

Yang, J.

Yin, L.

Yonkee, B. P.

D. Hwang, B. P. Yonkee, B. S. Addin, R. M. Farrell, S. Nakamura, J. S. Speck, and S. DenBaars, “Photoelectrochemical liftoff of LEDs grown on freestanding c-plane GaN substrates,” Opt. Express 24(20), 22875–22880 (2016).
[PubMed]

B. P. Yonkee, E. C. Young, S. P. DenBaars, S. Nakamura, and J. S. Speck, “Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction,” Appl. Phys. Lett. 109(19), 191104 (2016).
[PubMed]

Yoon, S.

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

Young, E. C.

B. P. Yonkee, E. C. Young, S. P. DenBaars, S. Nakamura, and J. S. Speck, “Silver free III-nitride flip chip light-emitting-diode with wall plug efficiency over 70% utilizing a GaN tunnel junction,” Appl. Phys. Lett. 109(19), 191104 (2016).
[PubMed]

Yu, H. K.

J. H. Son, Y. H. Song, H. K. Yu, and J. L. Lee, “Effects of Ni cladding layers on suppression of Ag agglomeration in Ag-based Ohmic contacts on p-GaN,” Appl. Phys. Lett. 95(6), 062108 (2009).

Yu, T.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Yuan, S.

Yum, W. S.

Zakgeim, A. L.

A. E. Chernyakov, K. A. Bulashevich, S. Y. Karpov, and A. L. Zakgeim, “Experimental and theoretical study of electrical, thermal, and optical characteristics of InGaN/GaN high-power flip-chip LEDs,” Phys. Status Solidi., A Appl. Mater. Sci. 210(3), 466–469 (2013).

Zeng, Y.

Zhang, G.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Zhang, L.

S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
[PubMed]

Zhang, Y.

Zhang, Y. P.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Zhang, Z. Y.

Z. Y. Zhang, M. Kawamura, Y. Abe, and K. H. Kim, “Thermal stability of Ag films with various interface layers,” Jpn. J. Appl. Phys. 53(4), 048003 (2014).

Zhao, H.

Zhao, H. P.

H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).

Zhao, P.

Zheng, C.

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

Zheng, H.

Zhou, S.

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
[PubMed]

J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

S. Zhou, B. Cao, S. Yuan, and S. Liu, “Enhanced luminous efficiency of phosphor-converted LEDs by using back reflector to increase reflectivity for yellow light,” Appl. Opt. 53(34), 8104–8110 (2014).
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Zhu, B.

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Zhu, D.

Appl. Opt. (1)

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H. W. Jang and J. L. Lee, “Mechanism for ohmic contact formation of Ni/Ag contacts on p-type GaN,” Appl. Phys. Lett. 85(24), 5920–5922 (2004).

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J. J. Wierer, D. A. Steigerwald, M. R. Krames, J. J. O’Shea, M. J. Ludowise, G. Christenson, Y. C. Shen, C. Lowery, P. S. Martin, S. Subramanya, W. Götz, N. F. Gardner, R. S. Kern, and S. A. Stockman, “High-power AlGaInN flip-chip light-emitting diodes,” Appl. Phys. Lett. 78(22), 3379–3381 (2001).

O. B. Shchekin, J. E. Epler, T. A. Trottier, T. Margalith, D. A. Steigerwald, M. O. Holcomb, P. S. Martin, and M. R. Krames, “High performance thin-film flip-chip InGaN-GaN light-emitting diodes,” Appl. Phys. Lett. 89(7), 071109 (2006).

J. H. Son, Y. H. Song, H. K. Yu, and J. L. Lee, “Effects of Ni cladding layers on suppression of Ag agglomeration in Ag-based Ohmic contacts on p-GaN,” Appl. Phys. Lett. 95(6), 062108 (2009).

J. O. Song, J. S. Kwak, Y. Park, and T. Y. Seong, “Ohmic and degradation mechanisms of Ag contacts on p-type GaN,” Appl. Phys. Lett. 86(6), 062104 (2005).

J. Y. Kim, S. I. Na, G. Y. Ha, M. K. Kwon, I. K. Park, J. H. Lim, and S. J. Park, “Thermally stable and highly reflective AgAl alloy for enhancing light extraction efficiency in GaN light-emitting diodes,” Appl. Phys. Lett. 88(4), 043507 (2006).

IEEE Electron Device Lett. (1)

W. C. Chong and K. M. Lau, “Performance enhancements of flip-chip light-emitting diodes with high-density n-type point-contacts,” IEEE Electron Device Lett. 35(10), 1049–1051 (2014).

IEEE Photonics Technol. Lett. (1)

H. Kim, K. H. Baik, J. Cho, J. W. Lee, S. Yoon, H. Kim, S. N. Lee, C. Sone, Y. Park, and T. Y. Seong, “High-reflectance and thermally stable AgCu alloy p-type reflectors for GaN-based light-emitting diodes,” IEEE Photonics Technol. Lett. 19(5), 336–338 (2007).

IEEE Trans. Adv. Packag. (1)

S. J. Chang, W. S. Chen, Y. C. Lin, C. S. Chang, T. K. Ko, Y. P. Hsu, C. F. Shen, J. M. Tsai, and S. C. Shei, “Nitride-based flip-chip LEDs with transparent ohmic contacts and reflective mirrors,” IEEE Trans. Adv. Packag. 29(3), 403–408 (2006).

J. Vac. Sci. Technol. B (1)

N. Hasanov, B. Zhu, V. K. Sharma, S. P. Lu, Y. P. Zhang, W. Liu, S. T. Tan, X. W. Sun, and H. V. Demir, “Improved performance of InGaN/GaN flip-chip light-emitting diodes through the use of robust Ni/Ag/TiW mirror contacts,” J. Vac. Sci. Technol. B 34(1), 011209 (2016).

Jpn. J. Appl. Phys. (1)

Z. Y. Zhang, M. Kawamura, Y. Abe, and K. H. Kim, “Thermal stability of Ag films with various interface layers,” Jpn. J. Appl. Phys. 53(4), 048003 (2014).

Nano Lett. (1)

S. M. Sadaf, Y. H. Ra, T. Szkopek, and Z. Mi, “Monolithically Integrated Metal/Semiconductor Tunnel Junction Nanowire Light-Emitting Diodes,” Nano Lett. 16(2), 1076–1080 (2016).
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Nat. Photonics (1)

J. J. Wierer, A. David, and M. M. Megens, “III-nitride photonic-crystal light-emitting diodes with high extraction efficiency,” Nat. Photonics 3(3), 163–169 (2009).

Opt. Express (9)

H. Y. Ryu, “Modification of internal quantum efficiency and efficiency droop in GaN-based flip-chip light-emitting diodes via the Purcell effect,” Opt. Express 23(19), A1157–A1166 (2015).
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K. Rae, C. Foucher, B. Guilhabert, M. S. Islim, L. Yin, D. Zhu, R. A. Oliver, D. J. Wallis, H. Haas, N. Laurand, and M. D. Dawson, “InGaN µLEDs integrated onto colloidal quantum dot functionalized ultra-thin glass,” Opt. Express 25(16), 19179–19184 (2017).

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Opt. Laser Technol. (2)

S. Zhou, C. Zheng, J. Lv, Y. Gao, R. Wang, and S. Liu, “GaN-based flip-chip LEDs with highly reflective ITO/DBR p-type and via hole-based n-type contacts for enhanced current spreading and light extraction,” Opt. Laser Technol. 92, 95–100 (2017).

S. Zhou, M. Liu, H. Hu, Y. Gao, and X. Liu, “Effect of ring-shaped SiO2 current blocking layer thickness on the external quantum efficiency of high power light-emitting diodes,” Opt. Laser Technol. 97, 137–143 (2017).

Opt. Mater. Express (1)

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J. Lv, C. Zheng, Q. Chen, S. Zhou, and S. Liu, “High power InGaN/GaN flip-chip LEDs with via-hole-based two-level metallization electrodes,” Phys. Status Solidi., A Appl. Mater. Sci. 213(12), 3150–3156 (2016).

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S. J. Kim, H. D. Kim, K. H. Kim, H. W. Shin, I. K. Han, and T. G. Kim, “Fabrication of wide-bandgap transparent electrodes by using conductive filaments: Performance breakthrough in vertical-type GaN LED,” Sci. Rep. 4, 5827 (2014).
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H. Hu, S. Zhou, X. Liu, Y. Gao, C. Gui, and S. Liu, “Effects of GaN/AlGaN/Sputtered AlN nucleation layers on performance of GaN-based ultraviolet light-emitting diodes,” Sci. Rep. 7, 44627 (2017).
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S. Jiang, Y. Feng, Z. Chen, L. Zhang, X. Jiang, Q. Jiao, J. Li, Y. Chen, D. Li, L. Liu, T. Yu, B. Shen, and G. Zhang, “Study on light extraction from GaN-based green light-emitting diodes using anodic aluminum oxide pattern and nanoimprint lithography,” Sci. Rep. 6, 21573 (2016).
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Solid-State Electron. (1)

H. P. Zhao, G. Y. Liu, R. A. Arif, and N. Tansu, “Current injection efficiency induced efficiency-droop in InGaN quantum well light-emitting diodes,” Solid-State Electron. 54(10), 1119–1124 (2010).

Other (1)

http://www.str-soft.com/products/SpeCLED/index.htm

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Figures (7)

Fig. 1
Fig. 1 Schematic illustration of fabrication process for FCLED with highly reflective Ag/TiW Ohmic contact.
Fig. 2
Fig. 2 Schematic illustration of fabrication process for FCLED with highly reflective ITO/DBR Ohmic contact.
Fig. 3
Fig. 3 (a) Schematic of FCLED with highly reflective Ag/TiW Ohmic contact. (b) Top-view SEM image of FCLED with Ag/TiW. The four etched n-contact vias and two n-contact fingers were designed to spread current. (c) Cross-sectional SEM image of FCLED with Ag/TiW milled by FIB along A-A direction. (d) Cross-sectional SEM image of FCLED with Ag/TiW milled by FIB along B-B direction. The sidewall of the etched vias is covered by SiO2 passivation layer. (e) Schematic of FCLED with highly reflective ITO/DBR Ohmic contact. (f) Top-view SEM image of FCLED with ITO/DBR. Three p-contact fingers and two n-contact fingers were used to enhance current spreading. Contact to ITO by drilling nine vias through DBR on the right side of the chip. (g) Cross-sectional SEM image of FCLED with ITO/DBR milled by FIB along C-C direction. The inset is the magnified SEM image showing p-GaN/SiO2 CBL/ITO/DBR multilayers. (h) Cross-sectional SEM image of FCLED with ITO/DBR milled by FIB along D-D direction. The sidewall of the etched vias is covered by Ta2O5/SiO2 DBR.
Fig. 4
Fig. 4 (a) Schematic and optical microscopy image of the Ag CTLM pads. (b) I–V characteristic curves measured for pure Ag contact to p-GaN layer when annealed under different temperatures. (c) I–V characteristic curves measured for ITO contact to p-GaN layer when annealed under different temperatures. (d) I–V characteristic curves measured for the different CTLM spacing of the pure Ag deposited on p-GaN layer after annealing at 600°C. (e) I–V characteristic curves measured for the different CTLM spacing of the ITO deposited on p-GaN layer after annealing at 300°C. (f) Reflectance spectra of the as-deposited Ag (100 nm)/TiW (80 nm) and ITO (90 nm)/DBR (2.6 μm) films on quartz substrates.
Fig. 5
Fig. 5 Current density distribution in the active region of FCLEDs at 350 mA under 300 K ambient temperature. (a) Current density distribution in the active region of FCLED with Ag/TiW. (b) Current density distribution in the active region, while there are no p-/n-contact fingers or SiO2 CBL in the FCLED with ITO/DBR. (c) Current density distribution in the active region, while there are only p-/n-contact fingers in the FCLED with ITO/DBR. (d) Current density distribution in the active region, while there are p-/n-contact fingers and SiO2 CBL in the FCLED with ITO/DBR.
Fig. 6
Fig. 6 (a-d) Measured light emission intensity distributions in the FCLED with Ag/TiW at 150, 250, 350, and 500 mA, respectively. (e-h) Measured light emission intensity distributions in the FCLED with ITO/DBR at 150, 250, 350, and 500 mA, respectively.
Fig. 7
Fig. 7 (a) Current versus voltage for FCLEDs with Ag/TiW and ITO/DBR. (b) Light output power and external quantum efficiency versus current for FCLEDs with Ag/TiW and ITO/DBR. (c) Far-field radiation pattern of FCLEDs with Ag/TiW and ITO/DBR at 350 mA. (d) EL spectrum of FCLED measured at 350 mA.

Tables (1)

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Table 1 Simulation results of current density distribution in the active region of FCLEDs with Ag/TiW and ITO/DBR at 150, 250, 350, and 500 mA, respectively

Equations (2)

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J(x)= J 0 exp(x/ L s )
L s = 2 n ideal (KT/q) J 0 ( ρ s,pcontact + ρ s,nGaN )

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