Abstract

Optimal length of ZnO nanorods (NRs) on blue InGaN light-emitting diodes (LEDs) was investigated to improve the light-extraction efficiency (LEE) of the LED. X-ray diffraction, photoluminescence spectroscopy, and micro-Raman spectroscopy were employed to determine the structural and optical properties of the ZnO NRs with length of 300 nm and 5 μm grown by a hydrothermal method. From the conventional light output power versus injection current (L-I) measurement, we found that the light output power of the LEDs with 300-nm- and 5-μm-long ZnO NRs was approximately 14.6% and 40.7% greater, respectively, than that of the LED without the ZnO NRs at an operating current of 20 mA. In addition, there were almost no changes to the electrical properties of the ZnO-NR-coated LEDs. The effect of the length of the ZnO NRs on the LEE of the LEDs was theoretically verified with three-dimensional finite-difference time-domain (FDTD) analysis. The FDTD images of the optical power and far-field radiation patterns of the LEDs showed that more photons were guided to the out of the LED by the longer ZnO NRs than by the shorter ZnO NRs grown on the LEDs.

© 2015 Optical Society of America

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2015 (3)

P. Pust, P. J. Schmidt, and W. Schnick, “A revolution in lighting,” Nat. Mater. 14(5), 454–458 (2015).
[Crossref] [PubMed]

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

G. Pezzotti and W. Zhu, “Resolving stress tensor components in space from polarized Raman spectra: polycrystalline alumina,” Phys. Chem. Chem. Phys. 17(4), 2608–2627 (2015).
[Crossref] [PubMed]

2014 (3)

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

R.-H. Horng, B.-R. Wu, C.-H. Tien, S.-L. Ou, M.-H. Yang, H.-C. Kuo, and D.-S. Wuu, “Performance of GaN-based light-emitting diodes fabricated using GaN epilayers grown on silicon substrates,” Opt. Express 22(S1Suppl 1), A179–A187 (2014).
[Crossref] [PubMed]

B. H. Kim and J. W. Kwon, “Metal catalyst for low-temperature growth of controlled zinc oxide nanowires on arbitrary substrates,” Sci. Rep. 4, 4379 (2014).
[PubMed]

2013 (2)

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

D. Singh, A. A. Narasimulu, L. Garcia-Gancedo, Y. Q. Fu, T. Hasan, S. S. Lin, J. Geng, G. Shao, and J. K. Luo, “Vertically aligned smooth ZnO nanorod films for planar device applications,” J. Mater. Chem. C Mater. Opt. Electron. Devices 1(14), 2525–2528 (2013).
[Crossref]

2012 (2)

H. Jeong, Y. H. Kim, T. H. Seo, H. S. Lee, J. S. Kim, E.-K. Suh, and M. S. Jeong, “Enhancement of light output power in GaN-based light-emitting diodes using hydrothermally grown ZnO micro-walls,” Opt. Express 20(10), 10597–10604 (2012).
[Crossref] [PubMed]

E. Matioli, S. Brinkley, K. M. Kelchner, Y.-L. Hu, S. Nakamura, S. DenBaars, J. Speck, and C. Weisbuch, “High-brightness polarized light-emitting diodes,” Light Sci. Appl. 1(8), e22 (2012).
[Crossref]

2010 (2)

G. Zou, H. Luo, Y. Zhang, J. Xiong, Q. Wei, M. Zhuo, J. Zhai, H. Wang, D. Williams, N. Li, E. Bauer, X. Zhang, T. M. McCleskey, Y. Li, A. K. Burrell, and Q. X. Jia, “A chemical solution approach for superconducting and hard epitaxial NbC film,” Chem. Commun. (Camb.) 46(41), 7837–7839 (2010).
[Crossref] [PubMed]

K. S. Kim, S.-M. Kim, H. Jeong, M. S. Jeong, and G. Y. Jung, “Enhancement of light extraction through the wave-guiding effect of ZnO sub-microrods in InGaN blue light-emitting diodes,” Adv. Funct. Mater. 20(7), 1076–1082 (2010).
[Crossref]

2009 (5)

R. Zhang, P.-G. Yin, N. Wang, and L. Guo, “Photoluminescence and Raman scattering of ZnO nanorods,” Solid State Sci. 11(4), 865–869 (2009).
[Crossref]

T. K. Kim, S. H. Kim, S. S. Yang, J. K. Son, K. H. Lee, Y. G. Hong, K. H. Shim, J. W. Yang, K. Y. Lim, S. J. Bae, and G. M. Yang, “GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al2O3 powder,” Appl. Phys. Lett. 94(16), 161107 (2009).
[Crossref]

K.-K. Kim, S. Lee, H. Kim, J.-C. Park, S.-N. Lee, Y. Park, S.-J. Park, and S.-W. Kim, “Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution,” Appl. Phys. Lett. 94(7), 071118 (2009).
[Crossref]

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).
[Crossref]

S. Pimputkar, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics 3(4), 180–182 (2009).
[Crossref]

2008 (3)

S. J. An, J. H. Chae, G.-C. Yi, and G. H. Park, “Enhanced light output of GaN-based light-emitting diodes with ZnO nanorod arrays,” Appl. Phys. Lett. 92(12), 121108 (2008).
[Crossref]

K. McGroddy, A. David, E. Matioli, M. Iza, S. Nakamura, S. DenBaars, J. S. Speck, C. Weisbuch, and E. L. Hu, “Directional emission control and increased light extraction in GaN photonic crystal light emitting diodes,” Appl. Phys. Lett. 93(10), 103502 (2008).
[Crossref]

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

2007 (3)

Y.-K. Ee, R. A. Arif, N. Tansu, P. Kumnorkaew, and J. F. Gilchrist, “Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using SiO2/polystyrene microlens arrays,” Appl. Phys. Lett. 91(22), 221107 (2007).
[Crossref]

J. Zhong, H. Chen, G. Saraf, Y. Lu, C. K. Choi, J. J. Song, D. M. Mackie, and H. Shen, “Integrated ZnO nanotips on GaN light emitting diodes for enhanced emission efficiency,” Appl. Phys. Lett. 90(20), 203515 (2007).
[Crossref]

Y. Gong, T. Andelman, G. Neumark, S. O’Brien, and I. Kuskovsky, “Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification,” Nanoscale Res. Lett. 2(6), 297–302 (2007).
[Crossref]

2006 (2)

Z.-P. Sun, L. Liu, L. Zhang, and D.-Z. Jia, “Rapid synthesis of ZnO nano-rods by one-step, room-temperature, solid-state reaction and their gas-sensing properties,” Nanotechnology 17(9), 2266–2270 (2006).
[Crossref]

J. K. Kim, T. Gessmann, E. F. Schubert, J.-Q. Xi, H. Luo, J. Cho, C. Sone, and Y. Park, “GaInN light-emitting diode with conductive omnidirectional reflector having a low-refractive-index indium-tin oxide layer,” Appl. Phys. Lett. 88(1), 013501 (2006).
[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. Koschny, M. Kafesaki, E. N. Economou, and C. M. Soukoulis, “Effective medium theory of left-handed materials,” Phys. Rev. Lett. 93(10), 107402 (2004).
[Crossref] [PubMed]

2003 (1)

B. Liu and H. C. Zeng, “Hydrothermal synthesis of ZnO nanorods in the diameter regime of 50 nm,” J. Am. Chem. Soc. 125(15), 4430–4431 (2003).
[Crossref] [PubMed]

1997 (1)

F. A. Ponce and D. P. Bour, “Nitride-based semiconductors for blue and green light-emitting devices,” Nature 386(6623), 351–359 (1997).
[Crossref]

1995 (1)

H. Morkoç and S. N. Mohammad, “High-luminosity blue and blue-green gallium nitride light-emitting diodes,” Science 267(5194), 51–55 (1995).
[Crossref] [PubMed]

1987 (1)

Ahn, Y. H.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

An, S. J.

S. J. An, J. H. Chae, G.-C. Yi, and G. H. Park, “Enhanced light output of GaN-based light-emitting diodes with ZnO nanorod arrays,” Appl. Phys. Lett. 92(12), 121108 (2008).
[Crossref]

Andelman, T.

Y. Gong, T. Andelman, G. Neumark, S. O’Brien, and I. Kuskovsky, “Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification,” Nanoscale Res. Lett. 2(6), 297–302 (2007).
[Crossref]

Arif, R. A.

Y.-K. Ee, R. A. Arif, N. Tansu, P. Kumnorkaew, and J. F. Gilchrist, “Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using SiO2/polystyrene microlens arrays,” Appl. Phys. Lett. 91(22), 221107 (2007).
[Crossref]

Bae, S. J.

T. K. Kim, S. H. Kim, S. S. Yang, J. K. Son, K. H. Lee, Y. G. Hong, K. H. Shim, J. W. Yang, K. Y. Lim, S. J. Bae, and G. M. Yang, “GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al2O3 powder,” Appl. Phys. Lett. 94(16), 161107 (2009).
[Crossref]

Baeg, K.-J.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Bauer, E.

G. Zou, H. Luo, Y. Zhang, J. Xiong, Q. Wei, M. Zhuo, J. Zhai, H. Wang, D. Williams, N. Li, E. Bauer, X. Zhang, T. M. McCleskey, Y. Li, A. K. Burrell, and Q. X. Jia, “A chemical solution approach for superconducting and hard epitaxial NbC film,” Chem. Commun. (Camb.) 46(41), 7837–7839 (2010).
[Crossref] [PubMed]

Bour, D. P.

F. A. Ponce and D. P. Bour, “Nitride-based semiconductors for blue and green light-emitting devices,” Nature 386(6623), 351–359 (1997).
[Crossref]

Brinkley, S.

E. Matioli, S. Brinkley, K. M. Kelchner, Y.-L. Hu, S. Nakamura, S. DenBaars, J. Speck, and C. Weisbuch, “High-brightness polarized light-emitting diodes,” Light Sci. Appl. 1(8), e22 (2012).
[Crossref]

Burrell, A. K.

G. Zou, H. Luo, Y. Zhang, J. Xiong, Q. Wei, M. Zhuo, J. Zhai, H. Wang, D. Williams, N. Li, E. Bauer, X. Zhang, T. M. McCleskey, Y. Li, A. K. Burrell, and Q. X. Jia, “A chemical solution approach for superconducting and hard epitaxial NbC film,” Chem. Commun. (Camb.) 46(41), 7837–7839 (2010).
[Crossref] [PubMed]

Chae, J. H.

S. J. An, J. H. Chae, G.-C. Yi, and G. H. Park, “Enhanced light output of GaN-based light-emitting diodes with ZnO nanorod arrays,” Appl. Phys. Lett. 92(12), 121108 (2008).
[Crossref]

Char, K.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Chen, H.

J. Zhong, H. Chen, G. Saraf, Y. Lu, C. K. Choi, J. J. Song, D. M. Mackie, and H. Shen, “Integrated ZnO nanotips on GaN light emitting diodes for enhanced emission efficiency,” Appl. Phys. Lett. 90(20), 203515 (2007).
[Crossref]

Chhajed, S.

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

Cho, J.

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

J. K. Kim, T. Gessmann, E. F. Schubert, J.-Q. Xi, H. Luo, J. Cho, C. Sone, and Y. Park, “GaInN light-emitting diode with conductive omnidirectional reflector having a low-refractive-index indium-tin oxide layer,” Appl. Phys. Lett. 88(1), 013501 (2006).
[Crossref]

Cho, Y.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Choi, C. K.

J. Zhong, H. Chen, G. Saraf, Y. Lu, C. K. Choi, J. J. Song, D. M. Mackie, and H. Shen, “Integrated ZnO nanotips on GaN light emitting diodes for enhanced emission efficiency,” Appl. Phys. Lett. 90(20), 203515 (2007).
[Crossref]

Choi, I.-S.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Choi, S.-B.

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

Crawford, M. H.

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

David, A.

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).
[Crossref]

K. McGroddy, A. David, E. Matioli, M. Iza, S. Nakamura, S. DenBaars, J. S. Speck, C. Weisbuch, and E. L. Hu, “Directional emission control and increased light extraction in GaN photonic crystal light emitting diodes,” Appl. Phys. Lett. 93(10), 103502 (2008).
[Crossref]

DenBaars, S.

E. Matioli, S. Brinkley, K. M. Kelchner, Y.-L. Hu, S. Nakamura, S. DenBaars, J. Speck, and C. Weisbuch, “High-brightness polarized light-emitting diodes,” Light Sci. Appl. 1(8), e22 (2012).
[Crossref]

K. McGroddy, A. David, E. Matioli, M. Iza, S. Nakamura, S. DenBaars, J. S. Speck, C. Weisbuch, and E. L. Hu, “Directional emission control and increased light extraction in GaN photonic crystal light emitting diodes,” Appl. Phys. Lett. 93(10), 103502 (2008).
[Crossref]

DenBaars, S. P.

S. Pimputkar, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Prospects for LED lighting,” Nat. Photonics 3(4), 180–182 (2009).
[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]

Economou, E. N.

T. Koschny, M. Kafesaki, E. N. Economou, and C. M. Soukoulis, “Effective medium theory of left-handed materials,” Phys. Rev. Lett. 93(10), 107402 (2004).
[Crossref] [PubMed]

Ee, Y.-K.

Y.-K. Ee, R. A. Arif, N. Tansu, P. Kumnorkaew, and J. F. Gilchrist, “Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using SiO2/polystyrene microlens arrays,” Appl. Phys. Lett. 91(22), 221107 (2007).
[Crossref]

Fischer, A. J.

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

Fu, Y. Q.

D. Singh, A. A. Narasimulu, L. Garcia-Gancedo, Y. Q. Fu, T. Hasan, S. S. Lin, J. Geng, G. Shao, and J. K. Luo, “Vertically aligned smooth ZnO nanorod films for planar device applications,” J. Mater. Chem. C Mater. Opt. Electron. Devices 1(14), 2525–2528 (2013).
[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]

Garcia-Gancedo, L.

D. Singh, A. A. Narasimulu, L. Garcia-Gancedo, Y. Q. Fu, T. Hasan, S. S. Lin, J. Geng, G. Shao, and J. K. Luo, “Vertically aligned smooth ZnO nanorod films for planar device applications,” J. Mater. Chem. C Mater. Opt. Electron. Devices 1(14), 2525–2528 (2013).
[Crossref]

Geng, J.

D. Singh, A. A. Narasimulu, L. Garcia-Gancedo, Y. Q. Fu, T. Hasan, S. S. Lin, J. Geng, G. Shao, and J. K. Luo, “Vertically aligned smooth ZnO nanorod films for planar device applications,” J. Mater. Chem. C Mater. Opt. Electron. Devices 1(14), 2525–2528 (2013).
[Crossref]

Gessmann, T.

J. K. Kim, T. Gessmann, E. F. Schubert, J.-Q. Xi, H. Luo, J. Cho, C. Sone, and Y. Park, “GaInN light-emitting diode with conductive omnidirectional reflector having a low-refractive-index indium-tin oxide layer,” Appl. Phys. Lett. 88(1), 013501 (2006).
[Crossref]

Gilchrist, J. F.

Y.-K. Ee, R. A. Arif, N. Tansu, P. Kumnorkaew, and J. F. Gilchrist, “Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using SiO2/polystyrene microlens arrays,” Appl. Phys. Lett. 91(22), 221107 (2007).
[Crossref]

Gong, Y.

Y. Gong, T. Andelman, G. Neumark, S. O’Brien, and I. Kuskovsky, “Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification,” Nanoscale Res. Lett. 2(6), 297–302 (2007).
[Crossref]

Guo, L.

R. Zhang, P.-G. Yin, N. Wang, and L. Guo, “Photoluminescence and Raman scattering of ZnO nanorods,” Solid State Sci. 11(4), 865–869 (2009).
[Crossref]

Han, H. N.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Han, J. T.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Hasan, T.

D. Singh, A. A. Narasimulu, L. Garcia-Gancedo, Y. Q. Fu, T. Hasan, S. S. Lin, J. Geng, G. Shao, and J. K. Luo, “Vertically aligned smooth ZnO nanorod films for planar device applications,” J. Mater. Chem. C Mater. Opt. Electron. Devices 1(14), 2525–2528 (2013).
[Crossref]

Hong, Y. G.

T. K. Kim, S. H. Kim, S. S. Yang, J. K. Son, K. H. Lee, Y. G. Hong, K. H. Shim, J. W. Yang, K. Y. Lim, S. J. Bae, and G. M. Yang, “GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al2O3 powder,” Appl. Phys. Lett. 94(16), 161107 (2009).
[Crossref]

Horng, R.-H.

Hu, E. L.

K. McGroddy, A. David, E. Matioli, M. Iza, S. Nakamura, S. DenBaars, J. S. Speck, C. Weisbuch, and E. L. Hu, “Directional emission control and increased light extraction in GaN photonic crystal light emitting diodes,” Appl. Phys. Lett. 93(10), 103502 (2008).
[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]

Hu, Y.-L.

E. Matioli, S. Brinkley, K. M. Kelchner, Y.-L. Hu, S. Nakamura, S. DenBaars, J. Speck, and C. Weisbuch, “High-brightness polarized light-emitting diodes,” Light Sci. Appl. 1(8), e22 (2012).
[Crossref]

Iza, M.

K. McGroddy, A. David, E. Matioli, M. Iza, S. Nakamura, S. DenBaars, J. S. Speck, C. Weisbuch, and E. L. Hu, “Directional emission control and increased light extraction in GaN photonic crystal light emitting diodes,” Appl. Phys. Lett. 93(10), 103502 (2008).
[Crossref]

Jang, J.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Jeong, H.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

H. Jeong, Y. H. Kim, T. H. Seo, H. S. Lee, J. S. Kim, E.-K. Suh, and M. S. Jeong, “Enhancement of light output power in GaN-based light-emitting diodes using hydrothermally grown ZnO micro-walls,” Opt. Express 20(10), 10597–10604 (2012).
[Crossref] [PubMed]

K. S. Kim, S.-M. Kim, H. Jeong, M. S. Jeong, and G. Y. Jung, “Enhancement of light extraction through the wave-guiding effect of ZnO sub-microrods in InGaN blue light-emitting diodes,” Adv. Funct. Mater. 20(7), 1076–1082 (2010).
[Crossref]

Jeong, H. J.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Jeong, M. S.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

H. Jeong, Y. H. Kim, T. H. Seo, H. S. Lee, J. S. Kim, E.-K. Suh, and M. S. Jeong, “Enhancement of light output power in GaN-based light-emitting diodes using hydrothermally grown ZnO micro-walls,” Opt. Express 20(10), 10597–10604 (2012).
[Crossref] [PubMed]

K. S. Kim, S.-M. Kim, H. Jeong, M. S. Jeong, and G. Y. Jung, “Enhancement of light extraction through the wave-guiding effect of ZnO sub-microrods in InGaN blue light-emitting diodes,” Adv. Funct. Mater. 20(7), 1076–1082 (2010).
[Crossref]

Jeong, S.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Jeong, S. Y.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Jia, D.-Z.

Z.-P. Sun, L. Liu, L. Zhang, and D.-Z. Jia, “Rapid synthesis of ZnO nano-rods by one-step, room-temperature, solid-state reaction and their gas-sensing properties,” Nanotechnology 17(9), 2266–2270 (2006).
[Crossref]

Jia, Q. X.

G. Zou, H. Luo, Y. Zhang, J. Xiong, Q. Wei, M. Zhuo, J. Zhai, H. Wang, D. Williams, N. Li, E. Bauer, X. Zhang, T. M. McCleskey, Y. Li, A. K. Burrell, and Q. X. Jia, “A chemical solution approach for superconducting and hard epitaxial NbC film,” Chem. Commun. (Camb.) 46(41), 7837–7839 (2010).
[Crossref] [PubMed]

Joo, K.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Jung, G. Y.

K. S. Kim, S.-M. Kim, H. Jeong, M. S. Jeong, and G. Y. Jung, “Enhancement of light extraction through the wave-guiding effect of ZnO sub-microrods in InGaN blue light-emitting diodes,” Adv. Funct. Mater. 20(7), 1076–1082 (2010).
[Crossref]

Kafesaki, M.

T. Koschny, M. Kafesaki, E. N. Economou, and C. M. Soukoulis, “Effective medium theory of left-handed materials,” Phys. Rev. Lett. 93(10), 107402 (2004).
[Crossref] [PubMed]

Kelchner, K. M.

E. Matioli, S. Brinkley, K. M. Kelchner, Y.-L. Hu, S. Nakamura, S. DenBaars, J. Speck, and C. Weisbuch, “High-brightness polarized light-emitting diodes,” Light Sci. Appl. 1(8), e22 (2012).
[Crossref]

Kim, B. H.

B. H. Kim and J. W. Kwon, “Metal catalyst for low-temperature growth of controlled zinc oxide nanowires on arbitrary substrates,” Sci. Rep. 4, 4379 (2014).
[PubMed]

Kim, H.

K.-K. Kim, S. Lee, H. Kim, J.-C. Park, S.-N. Lee, Y. Park, S.-J. Park, and S.-W. Kim, “Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution,” Appl. Phys. Lett. 94(7), 071118 (2009).
[Crossref]

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

Kim, H. Y.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Kim, J.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Kim, J. K.

J. K. Kim, S. Chhajed, M. F. Schubert, E. F. Schubert, A. J. Fischer, M. H. Crawford, J. Cho, H. Kim, and C. Sone, “Light-extraction enhancement of GaInN light-emitting diodes by graded-refractive-index indium tin oxide anti-reflection contact,” Adv. Mater. 20(4), 801–804 (2008).
[Crossref]

J. K. Kim, T. Gessmann, E. F. Schubert, J.-Q. Xi, H. Luo, J. Cho, C. Sone, and Y. Park, “GaInN light-emitting diode with conductive omnidirectional reflector having a low-refractive-index indium-tin oxide layer,” Appl. Phys. Lett. 88(1), 013501 (2006).
[Crossref]

Kim, J. S.

Kim, K. S.

K. S. Kim, S.-M. Kim, H. Jeong, M. S. Jeong, and G. Y. Jung, “Enhancement of light extraction through the wave-guiding effect of ZnO sub-microrods in InGaN blue light-emitting diodes,” Adv. Funct. Mater. 20(7), 1076–1082 (2010).
[Crossref]

Kim, K.-K.

K.-K. Kim, S. Lee, H. Kim, J.-C. Park, S.-N. Lee, Y. Park, S.-J. Park, and S.-W. Kim, “Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution,” Appl. Phys. Lett. 94(7), 071118 (2009).
[Crossref]

Kim, S. H.

T. K. Kim, S. H. Kim, S. S. Yang, J. K. Son, K. H. Lee, Y. G. Hong, K. H. Shim, J. W. Yang, K. Y. Lim, S. J. Bae, and G. M. Yang, “GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al2O3 powder,” Appl. Phys. Lett. 94(16), 161107 (2009).
[Crossref]

Kim, S.-M.

K. S. Kim, S.-M. Kim, H. Jeong, M. S. Jeong, and G. Y. Jung, “Enhancement of light extraction through the wave-guiding effect of ZnO sub-microrods in InGaN blue light-emitting diodes,” Adv. Funct. Mater. 20(7), 1076–1082 (2010).
[Crossref]

Kim, S.-W.

K.-K. Kim, S. Lee, H. Kim, J.-C. Park, S.-N. Lee, Y. Park, S.-J. Park, and S.-W. Kim, “Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution,” Appl. Phys. Lett. 94(7), 071118 (2009).
[Crossref]

Kim, T. K.

T. K. Kim, S. H. Kim, S. S. Yang, J. K. Son, K. H. Lee, Y. G. Hong, K. H. Shim, J. W. Yang, K. Y. Lim, S. J. Bae, and G. M. Yang, “GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al2O3 powder,” Appl. Phys. Lett. 94(16), 161107 (2009).
[Crossref]

Kim, Y. H.

Kimura, Y.

Ko, Y. H.

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

Koschny, T.

T. Koschny, M. Kafesaki, E. N. Economou, and C. M. Soukoulis, “Effective medium theory of left-handed materials,” Phys. Rev. Lett. 93(10), 107402 (2004).
[Crossref] [PubMed]

Kumnorkaew, P.

Y.-K. Ee, R. A. Arif, N. Tansu, P. Kumnorkaew, and J. F. Gilchrist, “Enhancement of light extraction efficiency of InGaN quantum wells light emitting diodes using SiO2/polystyrene microlens arrays,” Appl. Phys. Lett. 91(22), 221107 (2007).
[Crossref]

Kuo, H.-C.

Kuskovsky, I.

Y. Gong, T. Andelman, G. Neumark, S. O’Brien, and I. Kuskovsky, “Origin of defect-related green emission from ZnO nanoparticles: effect of surface modification,” Nanoscale Res. Lett. 2(6), 297–302 (2007).
[Crossref]

Kwon, J. W.

B. H. Kim and J. W. Kwon, “Metal catalyst for low-temperature growth of controlled zinc oxide nanowires on arbitrary substrates,” Sci. Rep. 4, 4379 (2014).
[PubMed]

Lee, D.-S.

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

Lee, G.-D.

J. Kim, H. Woo, K. Joo, S. Tae, J. Park, D. Moon, S. H. Park, J. Jang, Y. Cho, J. Park, H. Yuh, G.-D. Lee, I.-S. Choi, Y. Nanishi, H. N. Han, K. Char, and E. Yoon, “Less strained and more efficient GaN light-emitting diodes with embedded silica hollow nanospheres,” Sci. Rep. 3, 3201 (2013).
[PubMed]

Lee, G.-W.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
[Crossref] [PubMed]

Lee, H. S.

H. Jeong, D. J. Park, H. S. Lee, Y. H. Ko, J. S. Yu, S.-B. Choi, D.-S. Lee, E.-K. Suh, and M. S. Jeong, “Light-extraction enhancement of a GaN-based LED covered with ZnO nanorod arrays,” Nanoscale 6(8), 4371–4378 (2014).
[Crossref] [PubMed]

H. Jeong, Y. H. Kim, T. H. Seo, H. S. Lee, J. S. Kim, E.-K. Suh, and M. S. Jeong, “Enhancement of light output power in GaN-based light-emitting diodes using hydrothermally grown ZnO micro-walls,” Opt. Express 20(10), 10597–10604 (2012).
[Crossref] [PubMed]

Lee, K. H.

T. K. Kim, S. H. Kim, S. S. Yang, J. K. Son, K. H. Lee, Y. G. Hong, K. H. Shim, J. W. Yang, K. Y. Lim, S. J. Bae, and G. M. Yang, “GaN-based light-emitting diode with textured indium tin oxide transparent layer coated with Al2O3 powder,” Appl. Phys. Lett. 94(16), 161107 (2009).
[Crossref]

Lee, S.

K.-K. Kim, S. Lee, H. Kim, J.-C. Park, S.-N. Lee, Y. Park, S.-J. Park, and S.-W. Kim, “Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution,” Appl. Phys. Lett. 94(7), 071118 (2009).
[Crossref]

Lee, S.-N.

K.-K. Kim, S. Lee, H. Kim, J.-C. Park, S.-N. Lee, Y. Park, S.-J. Park, and S.-W. Kim, “Enhanced light extraction efficiency of GaN-based light-emitting diodes with ZnO nanorod arrays grown using aqueous solution,” Appl. Phys. Lett. 94(7), 071118 (2009).
[Crossref]

Lee, Y. H.

H. Jeong, S. Y. Jeong, D. J. Park, H. J. Jeong, S. Jeong, J. T. Han, H. J. Jeong, S. Yang, H. Y. Kim, K.-J. Baeg, S. J. Park, Y. H. Ahn, E.-K. Suh, G.-W. Lee, Y. H. Lee, and M. S. Jeong, “Suppressing spontaneous polarization of p-GaN by graphene oxide passivation: Augmented light output of GaN UV-LED,” Sci. Rep. 5, 7778 (2015).
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Figures (6)

Fig. 1
Fig. 1 Fully fabricated blue InGaN light-emitting diode (LED). (a) Electroluminescence spectrum of the fabricated blue InGaN LED. The peak wavelength of the LED is at 455 nm. The inset shows a 3-dimensional (3D) schematic of the final structure of the LED with Cr/Au electrodes as the n-p contacts. (b) A magnified 3D schematic of the LED structure, with the individual layers labeled.
Fig. 2
Fig. 2 Fabrication of ZnO nanorods (NRs) on the blue InGaN LEDs. 3D schematics of the: (a) blue InGaN LED, ZnO seed layer, and photoresist (PR) layer used for the laser holographic lithography (LHL) process, (b) periodic pattern of holes in the PR, and the ZnO NRs grown through the holes of the LHL-patterned PR layer (c) before and (d) after the PR layer is removed (e) Plane-view scanning electron microscopy (SEM) image of the LHL-patterned PR layer. (f) Cross-sectional SEM image of the ZnO NRs grown on the surface of the LED through the LHL-patterned PR layer. (g) A magnified SEM image of the bottom of the ZnO NRs. (h) Cross-sectional SEM image of the ZnO NRs formed on the surface of the LED.
Fig. 3
Fig. 3 Optical and structural properties of the ZnO NRs. Cross-sectional SEM images of the ZnO NRs grown on the surface of the LEDs (a) with and (b) without the LHL-patterned PR layer. X-ray diffraction (XRD) patterns of the ZnO NRs grown on c-plane sapphire substrates (c) with and (d) without the LHL-patterned PR layer. PL spectra of the ZnO NRs (e) grown with and (f) without the LHL-patterned PR layer. Raman spectra of the ZnO NRs grown on a c-plane sapphire substrates (g) with and (h) without the LHL-patterned PR layer.
Fig. 4
Fig. 4 Device performance. (a) Light output power versus current (L-I) curves of the conventional LED and LEDs with the 300-nm- and 5-μm-long ZnO NRs. The insets show optical microscope images of the (i) conventional LED, (ii) LED with 300-nm-long ZnO NRs, and (iii) LED with 5-μm-long ZnO NRs operating at 5 mA. (b) Current versus voltage (I-V) curves of the conventional LED and LEDs with the 300-nm- and 5-μm-long ZnO NRs.
Fig. 5
Fig. 5 3D finite-difference time-domain (FDTD) analysis. (a) The variation of refractive index along the vertical structure of the LEDs with and without the ZnO NRs. The FDTD images calculated for the optical power of the (b) conventional LED, (d) LED with 300-nm-long ZnO NRs, and (f) LED with 5-μm-long ZnO NRs. Calculated far-field radiation patterns of the (c) conventional LED, (e) LED with 300-nm-long ZnO NRs, and (g) LED with 5-μm-long ZnO NRs.
Fig. 6
Fig. 6 Light-extraction efficiency (LEE) enhancement factor of the blue InGaN LEDs as a function of the thickness of the optical waveguide layer on the LED.

Tables (1)

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Table 1 FDTD-calculated parameters for a dipole oriented along the x-, y-, and z-axes (λ = 450 nm).

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