Abstract

The performance characteristics of green light-emitting diodes (LEDs) grown by metal–organic chemical-vapor deposition were investigated to study the dependence of the device performance on the materials and the growth conditions of p-type layer grown after the InGaN multiple-quantum-well active region. The electrical and structural qualities of Mg-doped p-In<sub>0.04</sub> Ga<sub>0.96</sub> N and p-GaN layers grown under different growth conditions were studied to optimize the growth conditions of p-type hole injection layers of green LEDs. A free-hole concentration of p = 1.6×10<sup>18</sup> cm<sup>-3</sup> of with a resistivity of 0.33 Ω · cm was achieved for p-GaN:Mg layers grown at 1040°C. Lower hole concentrations and mobilities and rough surfaces were obtained when the growth temperature was decreased to 930°C in H<sub>2</sub> ambient. In the case of p - In<sub>0.04</sub>Ga<sub>0.96</sub>N grown at 840 °C N<sub>2</sub>, a significant improvement of the hole concentration was achieved due to the reduced ionization activation energy of Mg acceptors in InGaN. Also we observed that as-grown p-GaN layers grown in N<sub>2</sub> ambient showed p-type properties without Mg dopant activation. The electrical and optical properties of In<sub>0.25</sub> Ga<sub>0.75</sub> N/GaN multiple-quantum-well green LEDs with such different p-layers were investigated. The electroluminescence intensity was improved for the LEDs with p-In<sub>0.04</sub> layers grown at 840°C as compared to the LEDs with p-GaN layers grown at higher temperatures due to the reduced thermal damage to the active region, high hole injection, and low piezoelectric field induced in the active region. p-InGaN layers are very attractive candidates for the p-layer in green LED structures. The low temperature and N<sub>2</sub> ambient used during the growth of InGaN layers are beneficial to protect the InGaN active region containing high-indium composition quantum-well layers in addition to the advantage of providing a higher hole concentration. However, the LEDs with p-In<sub>0.04</sub> Ga<sub>0.96</sub> N layer showed a slightly higher turn on voltage which could originate from the potential barrier for hole transport at the interface of the p-InGaN layer and the last GaN quantum-well barrier. to reduce this problem, we designed and characterized an LED structure having a graded indium composition in the p-In<sub>0.04</sub> Ga<sub>0.96</sub>N layer in order to improve hole transport into the active region. Optimized LEDs with p-InGaN layers grown in a N<sub>2</sub> ambient showed much brighter electroluminescence due to low damage to the active region during p-InGaN layer growth.

© 2007 IEEE

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  2. S. Muthu, F. J. P. Schuurmans, M. D. Pashley, "Red, green, and blue LEDs for white light illumination," IEEE J. Select. Topic Quantum Electron. 8, 333-338 (2002).
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  4. T. Matsuoka, H. Okamoto, M. Nakao, H. Harima, E. Kurimoto, "Optical bandgap energy of wurtzite InN," App. Phys. Lett. 81, 1246-1248 (2002).
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  7. C.-C. Chou, C.-M. Lee, J.-I. Chyi, "Interdiffusion of In and Ga in InGaN/GaN multiple quantum wells," Appl. Phys. Lett. 78, 314-316 (2001).
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  9. F. Bernardini, V. Fiorentini, "Spontaneous versus piezoelectric polarization in III-V nitrides: Conceptual aspects and practical consequences," Phys. Status Solidi B. 216, 391-398 (1999).
  10. T. Takeuchi, S. Sota, M. Katsuragawa, M. Komori, H. Takeuchi, H. Amano, I. Akasaki, "Quantum-confined Stark effect due to piezoelectric fields in GaInN strained quantum wells," Jpn. J. Appl. Phys. 36, 2L382-L385 (1997).
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  13. G. Franssen, T. Suski, P. Perlin, R. Bohdan, A. Bercha, W. Trzeciakowski, I. Makarowa, P. Prystawko, M. Leszczyski, I. Grzegory, S. Porowski, S. Kokenyesi, "Fully-screened polarization-induced electric fields in blue/violet InGaN/GaN light-emitting devices grown on bulk GaN," Appl. Phys. Lett. 87, 041109-1-041109-3 (2005).
  14. N. F. Gardner, J. C. Kim, J. J. Wierer, Y. C. Shen, M. R. Krames, "Polarization anisotropy in the electroluminescence of $m$-plane InGaN-GaN multiple-quantum-well light-emitting diodes," Appl. Phys. Lett. 86, 111101-1-111101-3 (2005).
  15. C.-F. Lin, J.-H. Zheng, Z.-J. Yang, J.-J. Dai, D.-Y. Lin, C.-Y. Chang, Z.-X. Lai, C. S. Hong, "High-efficiency InGaN-based light-emitting diodes with nanoporous GaN:Mg structure," Appl. Phys. Lett. 88, 083121-1-083121-3 (2006).
  16. W. Götz, N. M. Johnson, J. Walker, D. P. Bour, R. A. Street, "Activation of acceptors in Mg-doped GaN grown by metalorganic chemical vapor deposition," Appl. Phys. Lett. 68, 667-669 (1996).
  17. W. Lee, J. Limb, J.-H. Ryou, D. Yoo, T. Chung, R. D. Dupuis, "Influence of growth temperature and growth rate of p-GaN layers on the characteristics of green light emitting diodes," J. Electron. Mater. 35, 587-591 (2006).
  18. S. Kitamura, K. Hiramatsu, N. Sawaki, "Fabrication of GaN hexagonal pyramids on dot-patterned GaN/sapphire substrates via selective metalorganic vapor phase epitaxy," Jpn. J. Appl. Phys. 34, L1184-L1186 (1995).
  19. K. Kumakura, T. Makimoto, N. Kobayashi, "High hole concentrations in Mg-doped InGaN grown by MOVPE," J. Crystal Growth 221, 267-270 (2000).
  20. K. Kumakura, T. Makimoto, N. Kobayashi, "Mg-acceptor activation mechanism and transport characteristics in p-type InGaN grown by metalorganic vapor phase epitaxy," J. Appl. Phys. 93, 3370-3375 (2003).
  21. M. E. Lin, G. Xue, G. L. Zhou, J. E. Greene, H. Morkoç, "$p$-type zinc-blende GaN on GaAs substrates," Appl. Phys. Lett. 63, 932-933 (1993).
  22. C. Wang, R. F. Davis, "Deposition of highly resistive, undoped, and $p$-type, magnesium-doped gallium nitride films by modified gas source molecular beam epitaxy," Appl. Phys. Lett. 63, 990-992 (1993).
  23. M. Rubin, N. Newman, J. S. Chan, T. C. Fu, J. T. Ross, "$p$-type gallium nitride by reactive ion-beam molecular beam epitaxy with ion implantation, diffusion, or coevaporation of Mg," Appl. Phys. Lett. 64, 64-66 (1994).
  24. Z. H. Wu, M. Stevens, F. A. Ponce, W. Lee, J. H. Ryou, D. Yoo, R. D. Dupuis, "Mapping the electrostatic potential profile across AlGaN/AlN/GaN heterostructures by electron holography," Appl. Phys. Lett. 90, 032101-1-032101-3 (2007).

2007 (1)

Z. H. Wu, M. Stevens, F. A. Ponce, W. Lee, J. H. Ryou, D. Yoo, R. D. Dupuis, "Mapping the electrostatic potential profile across AlGaN/AlN/GaN heterostructures by electron holography," Appl. Phys. Lett. 90, 032101-1-032101-3 (2007).

2006 (2)

C.-F. Lin, J.-H. Zheng, Z.-J. Yang, J.-J. Dai, D.-Y. Lin, C.-Y. Chang, Z.-X. Lai, C. S. Hong, "High-efficiency InGaN-based light-emitting diodes with nanoporous GaN:Mg structure," Appl. Phys. Lett. 88, 083121-1-083121-3 (2006).

W. Lee, J. Limb, J.-H. Ryou, D. Yoo, T. Chung, R. D. Dupuis, "Influence of growth temperature and growth rate of p-GaN layers on the characteristics of green light emitting diodes," J. Electron. Mater. 35, 587-591 (2006).

2005 (3)

C. S. Kim, H. G. Kim, C.-H. Hong, "Effect of compressive strain relaxation in GaN blue light-emitting diodes with variation of $n^{+}$-GaN thickness on its device performance," Appl. Phys. Lett. 87, 013502-1-013502-3 (2005).

G. Franssen, T. Suski, P. Perlin, R. Bohdan, A. Bercha, W. Trzeciakowski, I. Makarowa, P. Prystawko, M. Leszczyski, I. Grzegory, S. Porowski, S. Kokenyesi, "Fully-screened polarization-induced electric fields in blue/violet InGaN/GaN light-emitting devices grown on bulk GaN," Appl. Phys. Lett. 87, 041109-1-041109-3 (2005).

N. F. Gardner, J. C. Kim, J. J. Wierer, Y. C. Shen, M. R. Krames, "Polarization anisotropy in the electroluminescence of $m$-plane InGaN-GaN multiple-quantum-well light-emitting diodes," Appl. Phys. Lett. 86, 111101-1-111101-3 (2005).

2003 (3)

K. Kumakura, T. Makimoto, N. Kobayashi, "Mg-acceptor activation mechanism and transport characteristics in p-type InGaN grown by metalorganic vapor phase epitaxy," J. Appl. Phys. 93, 3370-3375 (2003).

F. A. Ponce, S. Srinivasan, A. Bell, L. Geng, R. Liu, M. Stevens, J. Cai, H. Omiya, H. Marui, S. Tanaka, "Microstructure and electronic properties of InGaN alloys," Phys. Stat. Sol. B 240, 273-284 (2003).

T. Asano, T. Tojyo, T. Mizuno, M. Takeya, S. Ikeda, K. Shibuya, T. Hino, S. Uchida, M. Ikeda, "100-mW kink free blue-violet laser diodes with low aspect ratio," IEEE J. Quantum Electron. 39, 135-140 (2003).

2002 (2)

S. Muthu, F. J. P. Schuurmans, M. D. Pashley, "Red, green, and blue LEDs for white light illumination," IEEE J. Select. Topic Quantum Electron. 8, 333-338 (2002).

T. Matsuoka, H. Okamoto, M. Nakao, H. Harima, E. Kurimoto, "Optical bandgap energy of wurtzite InN," App. Phys. Lett. 81, 1246-1248 (2002).

2001 (1)

C.-C. Chou, C.-M. Lee, J.-I. Chyi, "Interdiffusion of In and Ga in InGaN/GaN multiple quantum wells," Appl. Phys. Lett. 78, 314-316 (2001).

2000 (1)

K. Kumakura, T. Makimoto, N. Kobayashi, "High hole concentrations in Mg-doped InGaN grown by MOVPE," J. Crystal Growth 221, 267-270 (2000).

1999 (1)

F. Bernardini, V. Fiorentini, "Spontaneous versus piezoelectric polarization in III-V nitrides: Conceptual aspects and practical consequences," Phys. Status Solidi B. 216, 391-398 (1999).

1998 (2)

M. D. McCluskey, L. T. Romano, B. S. Krusor, N. M. Johnson, T. Suski, J. Jun, "Interdiffusion of In and Ga in InGaN quantum wells," Appl. Phys. Lett. 73, 1281-1283 (1998).

M. D. McCluskey, L. T. Romano, B. S. Krusor, D. P. Bohr, N. M. Johnson, S. Brennan, "Phase separation in InGaN/GaN multiple quantum wells," Appl. Phys. Lett. 72, 1730-1732 (1998).

1997 (1)

T. Takeuchi, S. Sota, M. Katsuragawa, M. Komori, H. Takeuchi, H. Amano, I. Akasaki, "Quantum-confined Stark effect due to piezoelectric fields in GaInN strained quantum wells," Jpn. J. Appl. Phys. 36, 2L382-L385 (1997).

1996 (1)

W. Götz, N. M. Johnson, J. Walker, D. P. Bour, R. A. Street, "Activation of acceptors in Mg-doped GaN grown by metalorganic chemical vapor deposition," Appl. Phys. Lett. 68, 667-669 (1996).

1995 (1)

S. Kitamura, K. Hiramatsu, N. Sawaki, "Fabrication of GaN hexagonal pyramids on dot-patterned GaN/sapphire substrates via selective metalorganic vapor phase epitaxy," Jpn. J. Appl. Phys. 34, L1184-L1186 (1995).

1994 (1)

M. Rubin, N. Newman, J. S. Chan, T. C. Fu, J. T. Ross, "$p$-type gallium nitride by reactive ion-beam molecular beam epitaxy with ion implantation, diffusion, or coevaporation of Mg," Appl. Phys. Lett. 64, 64-66 (1994).

1993 (2)

M. E. Lin, G. Xue, G. L. Zhou, J. E. Greene, H. Morkoç, "$p$-type zinc-blende GaN on GaAs substrates," Appl. Phys. Lett. 63, 932-933 (1993).

C. Wang, R. F. Davis, "Deposition of highly resistive, undoped, and $p$-type, magnesium-doped gallium nitride films by modified gas source molecular beam epitaxy," Appl. Phys. Lett. 63, 990-992 (1993).

App. Phys. Lett. (1)

T. Matsuoka, H. Okamoto, M. Nakao, H. Harima, E. Kurimoto, "Optical bandgap energy of wurtzite InN," App. Phys. Lett. 81, 1246-1248 (2002).

Appl. Phys. Lett. (4)

G. Franssen, T. Suski, P. Perlin, R. Bohdan, A. Bercha, W. Trzeciakowski, I. Makarowa, P. Prystawko, M. Leszczyski, I. Grzegory, S. Porowski, S. Kokenyesi, "Fully-screened polarization-induced electric fields in blue/violet InGaN/GaN light-emitting devices grown on bulk GaN," Appl. Phys. Lett. 87, 041109-1-041109-3 (2005).

C.-F. Lin, J.-H. Zheng, Z.-J. Yang, J.-J. Dai, D.-Y. Lin, C.-Y. Chang, Z.-X. Lai, C. S. Hong, "High-efficiency InGaN-based light-emitting diodes with nanoporous GaN:Mg structure," Appl. Phys. Lett. 88, 083121-1-083121-3 (2006).

W. Götz, N. M. Johnson, J. Walker, D. P. Bour, R. A. Street, "Activation of acceptors in Mg-doped GaN grown by metalorganic chemical vapor deposition," Appl. Phys. Lett. 68, 667-669 (1996).

C. Wang, R. F. Davis, "Deposition of highly resistive, undoped, and $p$-type, magnesium-doped gallium nitride films by modified gas source molecular beam epitaxy," Appl. Phys. Lett. 63, 990-992 (1993).

Appl. Phys. Lett. (8)

M. Rubin, N. Newman, J. S. Chan, T. C. Fu, J. T. Ross, "$p$-type gallium nitride by reactive ion-beam molecular beam epitaxy with ion implantation, diffusion, or coevaporation of Mg," Appl. Phys. Lett. 64, 64-66 (1994).

Z. H. Wu, M. Stevens, F. A. Ponce, W. Lee, J. H. Ryou, D. Yoo, R. D. Dupuis, "Mapping the electrostatic potential profile across AlGaN/AlN/GaN heterostructures by electron holography," Appl. Phys. Lett. 90, 032101-1-032101-3 (2007).

M. E. Lin, G. Xue, G. L. Zhou, J. E. Greene, H. Morkoç, "$p$-type zinc-blende GaN on GaAs substrates," Appl. Phys. Lett. 63, 932-933 (1993).

N. F. Gardner, J. C. Kim, J. J. Wierer, Y. C. Shen, M. R. Krames, "Polarization anisotropy in the electroluminescence of $m$-plane InGaN-GaN multiple-quantum-well light-emitting diodes," Appl. Phys. Lett. 86, 111101-1-111101-3 (2005).

C. S. Kim, H. G. Kim, C.-H. Hong, "Effect of compressive strain relaxation in GaN blue light-emitting diodes with variation of $n^{+}$-GaN thickness on its device performance," Appl. Phys. Lett. 87, 013502-1-013502-3 (2005).

M. D. McCluskey, L. T. Romano, B. S. Krusor, N. M. Johnson, T. Suski, J. Jun, "Interdiffusion of In and Ga in InGaN quantum wells," Appl. Phys. Lett. 73, 1281-1283 (1998).

M. D. McCluskey, L. T. Romano, B. S. Krusor, D. P. Bohr, N. M. Johnson, S. Brennan, "Phase separation in InGaN/GaN multiple quantum wells," Appl. Phys. Lett. 72, 1730-1732 (1998).

C.-C. Chou, C.-M. Lee, J.-I. Chyi, "Interdiffusion of In and Ga in InGaN/GaN multiple quantum wells," Appl. Phys. Lett. 78, 314-316 (2001).

IEEE J. Quantum Electron. (1)

T. Asano, T. Tojyo, T. Mizuno, M. Takeya, S. Ikeda, K. Shibuya, T. Hino, S. Uchida, M. Ikeda, "100-mW kink free blue-violet laser diodes with low aspect ratio," IEEE J. Quantum Electron. 39, 135-140 (2003).

IEEE J. Select. Topic Quantum Electron. (1)

S. Muthu, F. J. P. Schuurmans, M. D. Pashley, "Red, green, and blue LEDs for white light illumination," IEEE J. Select. Topic Quantum Electron. 8, 333-338 (2002).

J. Appl. Phys. (1)

K. Kumakura, T. Makimoto, N. Kobayashi, "Mg-acceptor activation mechanism and transport characteristics in p-type InGaN grown by metalorganic vapor phase epitaxy," J. Appl. Phys. 93, 3370-3375 (2003).

J. Crystal Growth (1)

K. Kumakura, T. Makimoto, N. Kobayashi, "High hole concentrations in Mg-doped InGaN grown by MOVPE," J. Crystal Growth 221, 267-270 (2000).

J. Electron. Mater. (1)

W. Lee, J. Limb, J.-H. Ryou, D. Yoo, T. Chung, R. D. Dupuis, "Influence of growth temperature and growth rate of p-GaN layers on the characteristics of green light emitting diodes," J. Electron. Mater. 35, 587-591 (2006).

Jpn. J. Appl. Phys. (2)

S. Kitamura, K. Hiramatsu, N. Sawaki, "Fabrication of GaN hexagonal pyramids on dot-patterned GaN/sapphire substrates via selective metalorganic vapor phase epitaxy," Jpn. J. Appl. Phys. 34, L1184-L1186 (1995).

T. Takeuchi, S. Sota, M. Katsuragawa, M. Komori, H. Takeuchi, H. Amano, I. Akasaki, "Quantum-confined Stark effect due to piezoelectric fields in GaInN strained quantum wells," Jpn. J. Appl. Phys. 36, 2L382-L385 (1997).

Phys. Stat. Sol. B (1)

F. A. Ponce, S. Srinivasan, A. Bell, L. Geng, R. Liu, M. Stevens, J. Cai, H. Omiya, H. Marui, S. Tanaka, "Microstructure and electronic properties of InGaN alloys," Phys. Stat. Sol. B 240, 273-284 (2003).

Phys. Status Solidi B. (1)

F. Bernardini, V. Fiorentini, "Spontaneous versus piezoelectric polarization in III-V nitrides: Conceptual aspects and practical consequences," Phys. Status Solidi B. 216, 391-398 (1999).

Other (2)

B. Gil, Group III Nitride Semiconductor Compounds (Oxford University Press, 1998).

M. Krames, DoE Workshop on Solid State Lighting (2003).

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