Abstract

Patterned graded-refractive-index (GRIN) coatings that offer the controllability of far-field emission pattern and polarization properties of GaInN light-emitting diodes (LEDs) are investigated. Compared with a planar reference LED, the light-output power of an LED with patterned GRIN coatings (GRIN LED) is enhanced by about 69%. Furthermore, the GRIN LED has bidirectional emission peaks at about 45° off-surface-normal and polarized light emission with the maximum polarization ratio occurring at the same angle, i.e. the intensity maximum and the polarization-ratio maximum coincide. The large off-surface-normal emission of the GRIN LED results from the strong light extraction through the sidewalls of the GRIN pillars, which is in good agreement with results predicted from ray-tracing simulations.

© 2012 OSA

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  1. N. Horiuchi, “Light-emitting diodes: Natural white light,” Nat. Photonics 4(11), 738 (2010).
    [CrossRef]
  2. J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
    [CrossRef]
  3. E. F. Schubert, Light Emitting Diodes, 2nd ed. (Cambridge University Press, 2006).
  4. E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308(5726), 1274–1278 (2005).
    [CrossRef] [PubMed]
  5. M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
    [CrossRef]
  6. 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]
  7. H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
    [CrossRef]
  8. A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
    [CrossRef]
  9. A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
    [CrossRef]
  10. J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
    [CrossRef]
  11. M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
    [CrossRef]
  12. J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
    [CrossRef]

2011 (2)

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

2010 (1)

N. Horiuchi, “Light-emitting diodes: Natural white light,” Nat. Photonics 4(11), 738 (2010).
[CrossRef]

2008 (1)

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

2007 (3)

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

2005 (2)

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308(5726), 1274–1278 (2005).
[CrossRef] [PubMed]

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

2004 (1)

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]

1990 (1)

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Bradley, D. D. C.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Brown, A. R.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Burns, P. L.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Burroughes, J. H.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Chhajed, S.

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

Cho, J.

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Craford, M. G.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[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]

Friend, R. H.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[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]

Harbers, G.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

Holmes, A. B.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Horiuchi, N.

N. Horiuchi, “Light-emitting diodes: Natural white light,” Nat. Photonics 4(11), 738 (2010).
[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]

Jiang, H. X.

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

Kim, G. B.

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

Kim, H.

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Kim, J. K.

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308(5726), 1274–1278 (2005).
[CrossRef] [PubMed]

Kim, K. H.

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

Knabe, K.

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

Krames, M. R.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

Lee, J. W.

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Li, J.

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

Lin, G. B.

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

Lin, J. Y.

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

Mackay, K.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Marks, R. N.

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Meyaard, D.

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

Mont, F. W.

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

Mueller, G. O.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

Mueller-Mach, R.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[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]

Noemaun, A. N.

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

Park, Y.

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Poxson, D. J.

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

Schubert, E. F.

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308(5726), 1274–1278 (2005).
[CrossRef] [PubMed]

Schubert, M. F.

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

Seong, T.-Y.

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Shakya, J.

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[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]

Shchekin, O. B.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

Sone, C.

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Yoon, S.

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

Zhou, L.

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

Appl. Phys. Lett. (5)

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]

H. Kim, J. Cho, J. W. Lee, S. Yoon, H. Kim, C. Sone, Y. Park, and T.-Y. Seong, “Enhanced light extraction of GaN-based light-emitting diodes by using textured n-type GaN layers,” Appl. Phys. Lett. 90(16), 161110 (2007).
[CrossRef]

J. K. Kim, A. N. Noemaun, F. W. Mont, D. Meyaard, E. F. Schubert, D. J. Poxson, H. Kim, C. Sone, and Y. Park, “Elimination of total internal reflection in GaInN LEDs by graded-refractive-index micropillars,” Appl. Phys. Lett. 93(22), 221111 (2008).
[CrossRef]

M. F. Schubert, S. Chhajed, J. K. Kim, E. F. Schubert, and J. Cho, “Polarization of light emission by 460 nm GaInN∕GaN light-emitting diodes grown on (0001) oriented sapphire substrates,” Appl. Phys. Lett. 91(5), 051117 (2007).
[CrossRef]

J. Shakya, K. Knabe, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Polarization of III-nitride blue and ultraviolet light-emitting diodes,” Appl. Phys. Lett. 86(9), 091107 (2005).
[CrossRef]

J. Appl. Phys. (1)

A. N. Noemaun, F. W. Mont, G. B. Lin, J. Cho, E. F. Schubert, G. B. Kim, C. Sone, and J. K. Kim, “Optically functional surface composed of patterned graded-refractive-index coatings to enhance light extraction of GaInN LEDs,” J. Appl. Phys. 110(5), 054510 (2011).
[CrossRef]

J. Disp. Technol. (1)

M. R. Krames, O. B. Shchekin, R. Mueller-Mach, G. O. Mueller, L. Zhou, G. Harbers, and M. G. Craford, “Status and future of high-power light-emitting diodes for solid-state lighting,” J. Disp. Technol. 3(2), 160–175 (2007).
[CrossRef]

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

A. N. Noemaun, F. W. Mont, J. Cho, E. F. Schubert, G. B. Kim, and C. Sone, “Inductively coupled plasma etching of graded-index layers of TiO2 and SiO2 using ITO hard mask,” J. Vac. Sci. Technol. A 29(5), 051302 (2011).
[CrossRef]

Nat. Photonics (1)

N. Horiuchi, “Light-emitting diodes: Natural white light,” Nat. Photonics 4(11), 738 (2010).
[CrossRef]

Nature (1)

J. H. Burroughes, D. D. C. Bradley, A. R. Brown, R. N. Marks, K. Mackay, R. H. Friend, P. L. Burns, and A. B. Holmes, “Light-emitting diodes based on conjugated polymers,” Nature 347(6293), 539–541 (1990).
[CrossRef]

Science (1)

E. F. Schubert and J. K. Kim, “Solid-state light sources getting smart,” Science 308(5726), 1274–1278 (2005).
[CrossRef] [PubMed]

Other (1)

E. F. Schubert, Light Emitting Diodes, 2nd ed. (Cambridge University Press, 2006).

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Figures (5)

Fig. 1
Fig. 1

(a) Top-view scanning electron micrograph of an array of rhombus-shaped GRIN micro-pillars on the N-face GaN surface of a thin-film GaInN LED. (b) Cross-section-view focused ion beam micrograph of a GRIN micro-pillar on the N-face GaN surface of a thin-film GaInN LED.

Fig. 2
Fig. 2

Schematic of the GRIN pillar on the top surface of a GaInN LED and illustration of light rays that are extracted through the pillar.

Fig. 3
Fig. 3

Far-field emission intensity as a function of the emission angle for LEDs coated with GRIN pillars with different pillar diameter and spacing as simulated by ray tracing.

Fig. 4
Fig. 4

Measured far-field emission intensity as a function of the emission angle for a planar LED, a crystallographically wet-etched LED, and a GRIN LED.

Fig. 5
Fig. 5

Measured TE and TM polarization intensity as well as the degree of polarization as a function of the emission angle for (a) a planar LED, (b) a crystallographically wet-etched LED, and (c) a GRIN LED (the dashed line shows the results simulated by rigorous coupled wave analysis).

Equations (1)

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Degreeofpolarization= | I TE I TM | I TE + I TM

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