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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 19, Iss. 15 — Jul. 18, 2011
  • pp: 14662–14670

Implementation of an indium-tin-oxide (ITO) direct-Ohmic contact structure on a GaN-based light emitting diode

Yi-Jung Liu, Chien-Chang Huang, Tai-You Chen, Chi-Shiang Hsu, Jian-Kai Liou, Tsung-Yuan Tsai, and Wen-Chau Liu  »View Author Affiliations

Optics Express, Vol. 19, Issue 15, pp. 14662-14670 (2011)

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A GaN-based light-emitting diode (LED) with a direct-Ohmic contact structure, formed by an indium-tin-oxide (ITO) transparent film and Au thermal-diffused and removed layer, is studied. By depositing an Au metallic film on the Mg-doped GaN layer followed by thermal annealing and removed processes, an ITO direct-Ohmic contact at p-GaN/ITO interface is formed. An enhanced light output power of 18.0% is also found at this condition. This is mainly attributed to the larger and more uniform light-emission area resulted from the improved current spreading capability by the use of an ITO direct-Ohmic contact structure.

© 2011 OSA

OCIS Codes
(160.0160) Materials : Materials
(230.0230) Optical devices : Optical devices
(250.0250) Optoelectronics : Optoelectronics
(260.0260) Physical optics : Physical optics

ToC Category:
Optical Devices

Original Manuscript: February 22, 2011
Revised Manuscript: April 2, 2011
Manuscript Accepted: April 2, 2011
Published: July 15, 2011

Yi-Jung Liu, Chien-Chang Huang, Tai-You Chen, Chi-Shiang Hsu, Jian-Kai Liou, Tsung-Yuan Tsai, and Wen-Chau Liu, "Implementation of an indium-tin-oxide (ITO) direct-Ohmic contact structure on a GaN-based light emitting diode," Opt. Express 19, 14662-14670 (2011)

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  1. X. Guo and E. F. Schubert, “Current crowding in GaN/InGaN light emitting diodes on insulating substrates,” J. Appl. Phys. 90(8), 4191 (2001). [CrossRef]
  2. L. Zhou, W. Lanford, A. T. Ping, I. Adesida, J. W. Yang, and A. Khan, “Low resistance Ti/Pt/Au ohmic contacts to p-type GaN,” Appl. Phys. Lett. 76(23), 3451 (2000). [CrossRef]
  3. Y. J. Liu, C. H. Yen, L. Y. Chen, T. H. Tsai, T. Y. Tsai, and W. C. Liu, “On a GaN-based light-emitting diode with a p-GaN/i-InGaN superlattice structure,” IEEE Electron Device Lett. 30(11), 1149–1151 (2009). [CrossRef]
  4. K. M. Chang, J. Y. Chu, and C. C. Cheng, “Highly reliable GaN-based light-emitting diodes formed by p–In0.1Ga0.9N–ITO structure,” IEEE Photon. Technol. Lett. 16, 1807 (2004). [CrossRef]
  5. C. S. Chang, S. J. Chang, Y. K. Su, C. H. Kuo, W. C. Lai, Y. C. Lin, Y. P. Hsu, S. C. Shei, J. M. Tsai, H. M. Lo, J. C. Ke, and J. K. Sheu, “High brightness InGaN green LEDs with an ITO on n ++ -SPS upper contact,” IEEE Trans. Electron. Dev. 50(11), 2208–2212 (2003). [CrossRef]
  6. T. Gessmann, Y. L. Li, E. L. Waldron, J. W. Graff, and J. K. Sheu, “Ohmic contacts to p-type GaN mediated by polarization fields in thin InxGa1-xN capping layers,” Appl. Phys. Lett. 80(6), 986 (2002). [CrossRef]
  7. Y. J. Liu, C. H. Yen, C. H. Hsu, K. H. Yu, L. Y. Chen, T. H. Tsai, and W. C. Liu, “Impact of An indium oxide/indium–tin oxide mixed structure for GaN-based light-emitting diodes,” Opt. Rev. 16(6), 575–577 (2009). [CrossRef]
  8. S. K. Julita, G. Szymon, L. S. Elzbieta, P. Ryszard, N. Grzegorz, L. Michał, P. Piotr, T. Ewa, K. Jan, and K. Stanisław, “Ni–Au contacts to p-type GaN – Structure and properties,” Solid-State Electron. 54(7), 701–709 (2010). [CrossRef]
  9. J. L. Lee, M. Weber, J. K. Kim, J. W. Lee, Y. J. Park, T. Kim, and K. Lynn, “Ohmic contact formation mechanism of nonalloyed Pd contacts to p-type GaN observed by positron annihilation spectroscopy,” Appl. Phys. Lett. 74(16), 2289 (1999). [CrossRef]
  10. Y. Koide, T. Maeda, T. Kawakami, S. Fujita, T. Uemura, N. Shibata, and M. Murakami, “Effects of annealing in an oxygen ambient on electrical properties of ohmic contacts to p-type GaN,” J. Electron. Mater. 28(3), 341–346 (1999). [CrossRef]
  11. S. Nakahara and E. Kinsbron, “Room temperature interdiffusion study of Au/Ga thin film couples,” Thin Solid Films 113(1), 15–26 (1984). [CrossRef]
  12. M. Puselj and J. Schubert, “Kristallstruktur von Au2Ga,” J. Less-Common Met. 38(1), 83–90 (1974). [CrossRef]
  13. I. Waki, H. Fujioka, M. Oshima, H. Miki, and A. Fukizawa, “Low-temperature activation of Mg-doped GaN using Ni films,” Appl. Phys. Lett. 78(19), 2899 (2001). [CrossRef]
  14. J. S. Jang, “High output power GaN-based light-emitting diodes using an electrically reverse-connected p-Schottky diode and p-InGaN–GaN superlattice,” Appl. Phys. Lett. 93(8), 081118 (2008). [CrossRef]
  15. Y. J. Liu, C. H. Yen, K. H. Yu, P. L. Lin, L. Y. Chen, T. H. Tsai, T. Y. Tsai, and W. C. Liu, “Characteristics of an AlGaInP-based light emitting diode with an indium-tin-oxide (ITO) direct Ohmic contact structure,” IEEE J. Quantum Electron. 46(2), 246–252 (2010). [CrossRef]

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