Abstract

In this study, indium-tin oxide (ITO)/Al-doped zinc oxide (AZO) composite films were fabricated by pulsed laser deposition and used as transparent contact layers (TCLs) in GaN-based blue light emitting diodes (LEDs). The ITO/AZO TCLs were composed of the thin ITO (50 nm) films and AZO films with various thicknesses from 200 to 1000 nm. Conventional LED with ITO (200 nm) TCL prepared by E-beam evaporation was fabricated and characterized for comparison. From the transmittance spectra, the ITO/AZO films exhibited high transparency above 90% at wavelength of 465 nm. The sheet resistance of ITO/AZO TCL decreased as the AZO thickness increased, which could be attributed to the increase in a carrier concentration, leading to a decrease in the forward bias of LED. The LEDs with ITO/AZO composite TCLs showed better light extraction as compared to LED with ITO TCL in compliance with simulation. When an injection current of 20 mA was applied, the output power for LEDs fabricated with ITO/AZO TCLs had 45%, 63%, and 71% enhancement as compared with those fabricated using ITO (200 nm) TCL for the AZO thicknesses of 200, 460, and 1000 nm, respectively.

© 2011 OSA

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    [CrossRef]
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    [CrossRef]
  11. T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
    [CrossRef]
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  14. C. L. Jia, K. M. Wang, X. L. Wang, X. J. Zhang, and F. Lu, “Formation of c-axis oriented ZnO optical waveguides by radio-frequency magnetron sputtering,” Opt. Express 13(13), 5093–5099 (2005).
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  15. S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
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  16. N. Yoshii, A. Nakamura, S. Hosaka, and J. Temmyo, “Investigation of morphology and crystallinity of ZnO crystal formed by side-flow-type MOCVD,” J. Electrochem. Soc. 156(7), K117–K120 (2009).
    [CrossRef]
  17. M. C. Lin, Y. J. Chang, M. J. Chen, and C. J. Chu, “Characteristics of Zr-doped ZnO thin films grown by atomic layer deposition,” J. Electrochem. Soc. 158(6), D395–D398 (2011).
    [CrossRef]
  18. areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
    [CrossRef]
  19. J. Chen, L. Wang, X. Su, L. Kong, G. Liu, and X. Zhang, “InGaZnO semiconductor thin film fabricated using pulsed laser deposition,” Opt. Express 18(2), 1398–1405 (2010).
    [CrossRef] [PubMed]
  20. S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
    [CrossRef]
  21. G. K. Reeves and H. B. Harrison, “Obtaining the specific contact resistance from transmission line model measurements,” IEEE Electron Device Lett. 3(5), 111–113 (1982).
    [CrossRef]
  22. B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
    [CrossRef]
  23. J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
    [CrossRef]
  24. J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
    [CrossRef]

2011 (2)

M. C. Lin, Y. J. Chang, M. J. Chen, and C. J. Chu, “Characteristics of Zr-doped ZnO thin films grown by atomic layer deposition,” J. Electrochem. Soc. 158(6), D395–D398 (2011).
[CrossRef]

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

2010 (4)

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

J. Chen, L. Wang, X. Su, L. Kong, G. Liu, and X. Zhang, “InGaZnO semiconductor thin film fabricated using pulsed laser deposition,” Opt. Express 18(2), 1398–1405 (2010).
[CrossRef] [PubMed]

2009 (1)

N. Yoshii, A. Nakamura, S. Hosaka, and J. Temmyo, “Investigation of morphology and crystallinity of ZnO crystal formed by side-flow-type MOCVD,” J. Electrochem. Soc. 156(7), K117–K120 (2009).
[CrossRef]

2008 (1)

J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
[CrossRef]

2007 (4)

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

J. Y. Kim, M. K. Kwon, J. P. Kim, and S. J. Park, “Enhanced light extraction from triangular GaN-based light-emitting diodes,” IEEE Photon. Technol. Lett. 19(23), 1865–1867 (2007).
[CrossRef]

2006 (1)

2005 (3)

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

C. L. Jia, K. M. Wang, X. L. Wang, X. J. Zhang, and F. Lu, “Formation of c-axis oriented ZnO optical waveguides by radio-frequency magnetron sputtering,” Opt. Express 13(13), 5093–5099 (2005).
[CrossRef] [PubMed]

B. Y. Oh, M. C. Jeong, W. Lee, and J. M. Myoung, “Properties of transparent conductive ZnO:Al films prepared by co-sputtering,” J. Cryst. Growth 274(3-4), 453–457 (2005).
[CrossRef]

2004 (2)

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, “III-nitride blue and ultraviolet photonic crystal light emitting diodes,” Appl. Phys. Lett. 84(4), 466–468 (2004).
[CrossRef]

2003 (1)

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

2001 (1)

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

1999 (2)

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

T. Minami, T. Miyata, and T. Yamamoto, “Stability of transparent conducting oxide films for use at high temperatures,” J. Vac. Sci. Technol. A 17(4), 1822–1826 (1999).
[CrossRef]

1994 (1)

S. Nakamura, T. Mukai, and M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64(13), 1687–1689 (1994).
[CrossRef]

1982 (1)

G. K. Reeves and H. B. Harrison, “Obtaining the specific contact resistance from transmission line model measurements,” IEEE Electron Device Lett. 3(5), 111–113 (1982).
[CrossRef]

Abare, A. C.

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

Ahmed, N.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Buchinsky, O.

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

Chang, S. C.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Chang, Y. J.

M. C. Lin, Y. J. Chang, M. J. Chen, and C. J. Chu, “Characteristics of Zr-doped ZnO thin films grown by atomic layer deposition,” J. Electrochem. Soc. 158(6), D395–D398 (2011).
[CrossRef]

Chen, J.

Chen, M. J.

M. C. Lin, Y. J. Chang, M. J. Chen, and C. J. Chu, “Characteristics of Zr-doped ZnO thin films grown by atomic layer deposition,” J. Electrochem. Soc. 158(6), D395–D398 (2011).
[CrossRef]

Chen, S. L.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Chen, T. M.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Cho, H. K.

Choe, Y. H.

Choi, J.

Choi, J.-H.

Choi, Y. S.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Chong, K. K.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Chu, C. J.

M. C. Lin, Y. J. Chang, M. J. Chen, and C. J. Chu, “Characteristics of Zr-doped ZnO thin films grown by atomic layer deposition,” J. Electrochem. Soc. 158(6), D395–D398 (2011).
[CrossRef]

Cohen, D. A.

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

Coldren, L. A.

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

DenBaars, S. P.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

Dong, B. Z.

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

Fan, Y. M.

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

Fang, G. J.

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

Fu, Y. C.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Fujii, T.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Gao, Y.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Guan, W.-J.

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

Han, S. K.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Hansen, M.

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

Harrison, H. B.

G. K. Reeves and H. B. Harrison, “Obtaining the specific contact resistance from transmission line model measurements,” IEEE Electron Device Lett. 3(5), 111–113 (1982).
[CrossRef]

Hassan, M. M.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Hong, S. I.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Hong, S. K.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Horng, R. H.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Hosaka, S.

N. Yoshii, A. Nakamura, S. Hosaka, and J. Temmyo, “Investigation of morphology and crystallinity of ZnO crystal formed by side-flow-type MOCVD,” J. Electrochem. Soc. 156(7), K117–K120 (2009).
[CrossRef]

Houng, M. P.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Hsu, J. T.

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

Hu, E. L.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Hung, C. I.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Hung, M. T.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Jang, J.

Jeon, D. M.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Jeong, J. H.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Jeong, M. C.

B. Y. Oh, M. C. Jeong, W. Lee, and J. M. Myoung, “Properties of transparent conductive ZnO:Al films prepared by co-sputtering,” J. Cryst. Growth 274(3-4), 453–457 (2005).
[CrossRef]

Jia, C. L.

Jiang, H. X.

T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, “III-nitride blue and ultraviolet photonic crystal light emitting diodes,” Appl. Phys. Lett. 84(4), 466–468 (2004).
[CrossRef]

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

Jin, S. X.

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

Kang, J. W.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Kim, J.

Kim, J. G.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Kim, J. H.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Kim, J. P.

J. Y. Kim, M. K. Kwon, J. P. Kim, and S. J. Park, “Enhanced light extraction from triangular GaN-based light-emitting diodes,” IEEE Photon. Technol. Lett. 19(23), 1865–1867 (2007).
[CrossRef]

Kim, J. W.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Kim, J. Y.

J. Y. Kim, M. K. Kwon, J. P. Kim, and S. J. Park, “Enhanced light extraction from triangular GaN-based light-emitting diodes,” IEEE Photon. Technol. Lett. 19(23), 1865–1867 (2007).
[CrossRef]

Kim, K. H.

T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, “III-nitride blue and ultraviolet photonic crystal light emitting diodes,” Appl. Phys. Lett. 84(4), 466–468 (2004).
[CrossRef]

Kim, S. H.

Kim, S.-K.

Kim, Y. C.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Kong, L.

Ku, H.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Kuo, C. H.

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

Kwon, M. K.

J. Y. Kim, M. K. Kwon, J. P. Kim, and S. J. Park, “Enhanced light extraction from triangular GaN-based light-emitting diodes,” IEEE Photon. Technol. Lett. 19(23), 1865–1867 (2007).
[CrossRef]

Lai, W. C.

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

Lee, B.

Lee, J. S.

Lee, J. W.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Lee, J. Y.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Lee, K.

Lee, K.-D.

Lee, M. L.

J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
[CrossRef]

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

Lee, W.

B. Y. Oh, M. C. Jeong, W. Lee, and J. M. Myoung, “Properties of transparent conductive ZnO:Al films prepared by co-sputtering,” J. Cryst. Growth 274(3-4), 453–457 (2005).
[CrossRef]

Lee, Y.-H.

Li, J.

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

Lin, J. Y.

T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, “III-nitride blue and ultraviolet photonic crystal light emitting diodes,” Appl. Phys. Lett. 84(4), 466–468 (2004).
[CrossRef]

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

Lin, M. C.

M. C. Lin, Y. J. Chang, M. J. Chen, and C. J. Chu, “Characteristics of Zr-doped ZnO thin films grown by atomic layer deposition,” J. Electrochem. Soc. 158(6), D395–D398 (2011).
[CrossRef]

Lin, P. R.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Liou, B. W.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Liu, C. C.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Liu, G.

Liu, S. P.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Lu, F.

Lu, Y. S.

J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
[CrossRef]

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

Mahmood, A.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Mahmood, N.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Margalith, T.

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

Mehmood, M.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Minami, T.

T. Minami, T. Miyata, and T. Yamamoto, “Stability of transparent conducting oxide films for use at high temperatures,” J. Vac. Sci. Technol. A 17(4), 1822–1826 (1999).
[CrossRef]

Miyata, T.

T. Minami, T. Miyata, and T. Yamamoto, “Stability of transparent conducting oxide films for use at high temperatures,” J. Vac. Sci. Technol. A 17(4), 1822–1826 (1999).
[CrossRef]

Muhammad Khan, T.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Mukai, T.

S. Nakamura, T. Mukai, and M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64(13), 1687–1689 (1994).
[CrossRef]

Myoung, J. M.

B. Y. Oh, M. C. Jeong, W. Lee, and J. M. Myoung, “Properties of transparent conductive ZnO:Al films prepared by co-sputtering,” J. Cryst. Growth 274(3-4), 453–457 (2005).
[CrossRef]

Nakamura, A.

N. Yoshii, A. Nakamura, S. Hosaka, and J. Temmyo, “Investigation of morphology and crystallinity of ZnO crystal formed by side-flow-type MOCVD,” J. Electrochem. Soc. 156(7), K117–K120 (2009).
[CrossRef]

Nakamura, S.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

S. Nakamura, T. Mukai, and M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64(13), 1687–1689 (1994).
[CrossRef]

Oder, T. N.

T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, “III-nitride blue and ultraviolet photonic crystal light emitting diodes,” Appl. Phys. Lett. 84(4), 466–468 (2004).
[CrossRef]

Oh, B. Y.

B. Y. Oh, M. C. Jeong, W. Lee, and J. M. Myoung, “Properties of transparent conductive ZnO:Al films prepared by co-sputtering,” J. Cryst. Growth 274(3-4), 453–457 (2005).
[CrossRef]

Ou, S. L.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Pan, S. M.

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

Park, J. S.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Park, S. J.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

J. Y. Kim, M. K. Kwon, J. P. Kim, and S. J. Park, “Enhanced light extraction from triangular GaN-based light-emitting diodes,” IEEE Photon. Technol. Lett. 19(23), 1865–1867 (2007).
[CrossRef]

Park, T. Y.

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

Raza, Q.

areA. Mahmood, N. Ahmed, Q. Raza, T. Muhammad Khan, M. Mehmood, M. M. Hassan, and N. Mahmood, “Effect of thermal annealing on the structural and optical properties of ZnO thin films deposited by the reactive e-beam evaporation technique,” Phys. Scr. 82(6), 065801 (2010).
[CrossRef]

Reeves, G. K.

G. K. Reeves and H. B. Harrison, “Obtaining the specific contact resistance from transmission line model measurements,” IEEE Electron Device Lett. 3(5), 111–113 (1982).
[CrossRef]

Senoh, M.

S. Nakamura, T. Mukai, and M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64(13), 1687–1689 (1994).
[CrossRef]

Shakya, J.

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

Sharma, R.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Sheu, J. K.

J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
[CrossRef]

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

Shu, K. W.

J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
[CrossRef]

Song, J. H.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Su, X.

Temmyo, J.

N. Yoshii, A. Nakamura, S. Hosaka, and J. Temmyo, “Investigation of morphology and crystallinity of ZnO crystal formed by side-flow-type MOCVD,” J. Electrochem. Soc. 156(7), K117–K120 (2009).
[CrossRef]

Tu, R. C.

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

Tun, C. J.

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

Uang, K. M.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Wang, C. C.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Wang, J.-F.

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

Wang, K. M.

Wang, L.

Wang, S. J.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Wang, X. L.

Wang, Y. H.

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

Wu, C. K.

K. M. Uang, S. J. Wang, S. L. Chen, C. K. Wu, S. C. Chang, T. M. Chen, and B. W. Liou, “High-power GaN-based light-emitting diodes with transparent indium zinc oxide films,” Jpn. J. Appl. Phys. 44(4BNo. 4B), 2516–2519 (2005).
[CrossRef]

Wuu, D. S.

S. P. Liu, D. S. Wuu, S. L. Ou, Y. C. Fu, P. R. Lin, M. T. Hung, and R. H. Horng, “Highly ultraviolet-transparent ZnO:Al conducting layers by pulsed laser deposition,” J. Electrochem. Soc. 158(5), K127–K130 (2011).
[CrossRef]

Yamamoto, T.

T. Minami, T. Miyata, and T. Yamamoto, “Stability of transparent conducting oxide films for use at high temperatures,” J. Vac. Sci. Technol. A 17(4), 1822–1826 (1999).
[CrossRef]

Yang, S. M.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Yao, T.

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

Yeh, R. C.

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

Yoshii, N.

N. Yoshii, A. Nakamura, S. Hosaka, and J. Temmyo, “Investigation of morphology and crystallinity of ZnO crystal formed by side-flow-type MOCVD,” J. Electrochem. Soc. 156(7), K117–K120 (2009).
[CrossRef]

Zhang, X.

Zhang, X. J.

Zhao, X.-Z.

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

Appl. Phys. Lett. (8)

S. Nakamura, T. Mukai, and M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett. 64(13), 1687–1689 (1994).
[CrossRef]

H. X. Jiang, S. X. Jin, J. Li, J. Shakya, and J. Y. Lin, “III-nitride blue microdisplays,” Appl. Phys. Lett. 78(9), 1303–1305 (2001).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

T. N. Oder, K. H. Kim, J. Y. Lin, and H. X. Jiang, “III-nitride blue and ultraviolet photonic crystal light emitting diodes,” Appl. Phys. Lett. 84(4), 466–468 (2004).
[CrossRef]

C. C. Wang, H. Ku, C. C. Liu, K. K. Chong, C. I. Hung, Y. H. Wang, and M. P. Houng, “Enhancement of the light output performance for GaN-based light-emitting diodes by bottom pillar structure,” Appl. Phys. Lett. 91(12), 121109 (2007).
[CrossRef]

T. Y. Park, Y. S. Choi, J. W. Kang, J. H. Jeong, S. J. Park, D. M. Jeon, J. W. Kim, and Y. C. Kim, “Enhanced optical power and low forward voltage of GaN-based light-emitting diodes with Ga-doped ZnO transparent conducting layer,” Appl. Phys. Lett. 96(5), 051124 (2010).
[CrossRef]

T. Margalith, O. Buchinsky, D. A. Cohen, A. C. Abare, M. Hansen, S. P. DenBaars, and L. A. Coldren, “Indium tin oxide contacts to gallium nitride optoelectronic devices,” Appl. Phys. Lett. 74(26), 3930–3932 (1999).
[CrossRef]

J. K. Sheu, Y. S. Lu, M. L. Lee, W. C. Lai, C. H. Kuo, and C. J. Tun, “Enhanced efficiency of GaN-based light-emitting diodes with periodic textured Ga-doped ZnO transparent contact layer,” Appl. Phys. Lett. 90(26), 263511 (2007).
[CrossRef]

IEEE Electron Device Lett. (1)

G. K. Reeves and H. B. Harrison, “Obtaining the specific contact resistance from transmission line model measurements,” IEEE Electron Device Lett. 3(5), 111–113 (1982).
[CrossRef]

IEEE J. Quantum Electron. (1)

J. K. Sheu, M. L. Lee, Y. S. Lu, and K. W. Shu, “Ga-doped ZnO transparent conductive oxide films applied to GaN-based light-emitting diodes for improving light extraction efficiency,” IEEE J. Quantum Electron. 44(12), 1211–1218 (2008).
[CrossRef]

IEEE Photon. Technol. Lett. (2)

S. M. Pan, R. C. Tu, Y. M. Fan, R. C. Yeh, and J. T. Hsu, “Enhanced output power of InGaN–GaN light-emitting diodes with high-transparency nickel-oxide–indium-tin-oxide ohmic contacts,” IEEE Photon. Technol. Lett. 15(5), 646–648 (2003).
[CrossRef]

J. Y. Kim, M. K. Kwon, J. P. Kim, and S. J. Park, “Enhanced light extraction from triangular GaN-based light-emitting diodes,” IEEE Photon. Technol. Lett. 19(23), 1865–1867 (2007).
[CrossRef]

J. Appl. Phys. (1)

B. Z. Dong, G. J. Fang, J.-F. Wang, W.-J. Guan, and X.-Z. Zhao, “Effect of thickness on structural, electrical, and optical properties of ZnO:Al films deposited by pulsed laser deposition,” J. Appl. Phys. 101(3), 033713 (2007).
[CrossRef]

J. Cryst. Growth (2)

B. Y. Oh, M. C. Jeong, W. Lee, and J. M. Myoung, “Properties of transparent conductive ZnO:Al films prepared by co-sputtering,” J. Cryst. Growth 274(3-4), 453–457 (2005).
[CrossRef]

S. M. Yang, S. K. Han, J. W. Lee, J. H. Kim, J. G. Kim, S. K. Hong, J. Y. Lee, J. H. Song, S. I. Hong, J. S. Park, and T. Yao, “Microstructural investigation of ZnO films grown on (1 1 1) Si substrates by plasma-assisted molecular beam epitaxy,” J. Cryst. Growth 312(9), 1557–1562 (2010).
[CrossRef]

J. Electrochem. Soc. (3)

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Figures (6)

Fig. 1
Fig. 1

AFM images of (a) ITO (200 nm) deposited by e-beam evaporation and (b) ITO (50 nm) deposited by PLD.

Fig. 2
Fig. 2

Transmittance spectra of ITO (200 and 1000 nm) and ITO/AZO films with various AZO thicknesses from 200 to 1000 nm.

Fig. 3
Fig. 3

Trace-Pro simulation taken from GaN-based LEDs with (a) ITO (200 nm), (b) ITO/AZO (200 nm), (c) ITO/AZO (460 nm), and (d) ITO/AZO (1000 nm) TCLs.

Fig. 4
Fig. 4

Current–voltage characteristics of InGaN/GaN MQW LED samples with the ITO (200 nm) and ITO/AZO (200-1000 nm) TCLs measured at room temperature.

Fig. 5
Fig. 5

Photographs of LEDs fabricated with (a) ITO (200 nm), (b) ITO/AZO (200 nm), (c) ITO/AZO (460 nm), and (d) ITO/AZO (1000 nm) TCLs, driven at a certain operation current of 0.5 mA.

Fig. 6
Fig. 6

Light output powers as a function of injection current for the LEDs fabricated with ITO (200 nm) and ITO/AZO (200-1000 nm) TCLs.

Tables (1)

Tables Icon

Table 1 The Transmittance at Wavelength of 465 nm and Sheet Resistance of ITO/AZO (200-1000 nm), and the Contact Resistance between ITO/AZO (200-1000 nm) and p-GaN Layer Evaluated from TLM

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