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Enhanced light output power of near UV light emitting diodes with graphene / indium tin oxide nanodot nodes for transparent and current spreading electrodeTae Hoon Seo, Kang Jea Lee, Ah Hyun Park, Chang-Hee Hong, Eun-Kyung Suh, Seung Jin Chae, Young Hee Lee, Tran Viet Cuong, Viet Hung Pham, Jin Suk Chung, Eui Jung Kim, and Seong-Ran Jeon »View Author Affiliations
Tae Hoon Seo,1
Kang Jea Lee,1
Ah Hyun Park,1
Chang-Hee Hong,1
Eun-Kyung Suh,1,*
Seung Jin Chae,2
Young Hee Lee,2
Tran Viet Cuong,3
Viet Hung Pham,3
Jin Suk Chung,3
Eui Jung Kim,3
and Seong-Ran Jeon4
1School of Semiconductor and Chemical Engineering & Semiconductor Physics Research Center, Chonbuk National University, Jeonju 561-756, Korea, 2BK21 Physics Division, WCU department of Energy Science, Sungkyunkwan Advanced Institute of Nanotechnology, Center for Nanotubes and Nanostructured Composites, Sungkyungkyun University, Suwon 440-746, Korea, 3School of Chemical Engineering and Bioengineering, University of Ulsan, Ulsan 680-749, Korea 4Korea Photonics Technology Institute (KOPTI), Gwangju 500-460, Korea *Corresponding author: eksuh@jbnu.ac.kr |
Optics Express, Vol. 19, Issue 23, pp. 23111-23117 (2011)
http://dx.doi.org/10.1364/OE.19.023111
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Abstract
We report GaN-based near ultraviolet (UV) light emitting diode (LED) that combines indium tin oxide (ITO) nanodot nodes with two-dimensional graphene film as a UV-transparent current spreading electrode (TCSE) to give rise to excellent UV emission efficiency. The light output power of 380 nm emitting UV-LEDs with graphene film on ITO nanodot nodes as TCSE was enhanced remarkably compared to conventional TCSE. The increase of the light output power is attributed to high UV transmittance of graphene, effective current spreading and injection, and texturing effect by ITO nanodots.
© 2011 OSA
OCIS Codes
(160.6000) Materials : Semiconductor materials
(230.0230) Optical devices : Optical devices
(230.3670) Optical devices : Light-emitting diodes
ToC Category:
Optical Devices
History
Original Manuscript: August 25, 2011
Revised Manuscript: October 6, 2011
Manuscript Accepted: October 13, 2011
Published: October 31, 2011
Citation
Tae Hoon Seo, Kang Jea Lee, Ah Hyun Park, Chang-Hee Hong, Eun-Kyung Suh, Seung Jin Chae, Young Hee Lee, Tran Viet Cuong, Viet Hung Pham, Jin Suk Chung, Eui Jung Kim, and Seong-Ran Jeon, "Enhanced light output power of near UV light emitting diodes with graphene / indium tin oxide nanodot nodes for transparent and current spreading electrode," Opt. Express 19, 23111-23117 (2011)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-19-23-23111
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References
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- H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, “Work function of purified and oxidised carbon nanotubes,” Synth. Met.103(1-3), 2494–2495 (1999). [CrossRef]
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- F. Guneş, H.-J. Shin, C. Biswas, G. H. Han, E. S. Kim, S. J. Chae, J. Y. Choi, and Y. H. Lee, “Layer-by-layer doping of few-layer graphene film,” ACS Nano4(8), 4595–4600 (2010). [CrossRef] [PubMed]
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- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- T. V. Cuong, V. H. Pham, Q. T. Tran, S. H. Hahn, J. S. Chung, E. W. Shin, and E. J. Kim, “Photoluminescence and Raman studies of graphene thin films prepared by reduction of graphene oxide,” Mater. Lett.64(3), 399–401 (2010). [CrossRef]
- V. H. Pham, T. V. Cuong, S. H. Hur, E. W. Shin, J. S. Kim, J. S. Chung, and E. J. Kim, “Fast and simple fabrication of a large transparent chemically-converted graphene film by spray-coating,” Carbon48(7), 1945–1951 (2010). [CrossRef]
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- V. H. Pham, T. V. Cuong, S. H. Hur, E. W. Shin, J. S. Kim, J. S. Chung, and E. J. Kim, “Fast and simple fabrication of a large transparent chemically-converted graphene film by spray-coating,” Carbon48(7), 1945–1951 (2010). [CrossRef]
- T. V. Cuong, V. H. Pham, Q. T. Tran, S. H. Hahn, J. S. Chung, E. W. Shin, and E. J. Kim, “Photoluminescence and Raman studies of graphene thin films prepared by reduction of graphene oxide,” Mater. Lett.64(3), 399–401 (2010). [CrossRef]
- P. Guéret, P. Buchmann, K. Daetwyler, and P. Vettiger, “Resistance of very small area ohmic contacts on GaAs,” Appl. Phys. Lett.55(17), 1735–1737 (1989). [CrossRef]
- H. W. Choi, C. W. Jeon, M. D. Dawson, P. R. Edwards, R. W. Martin, and S. Tripathy, “Mechanism of enhanced light output efficiency in InGaN-based microlight emitting diodes,” J. Appl. Phys.93(10), 5978–5982 (2003). [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]
- K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science306(5696), 666–669 (2004). [CrossRef] [PubMed]
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- K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science306(5696), 666–669 (2004). [CrossRef] [PubMed]
- X. Wang, L. Zhi, and K. Mullen, “Transparent, conductive graphene electrodes for dye-sensitized solar cells,” Nano Lett.8(1), 323–327 (2008). [CrossRef] [PubMed]
- N. F. Gardner, G. O. Muller, Y. C. Shen, G. Chen, S. Watanabe, W. Gotz, and M. R. Krames, “Blue emitting InGaN–GaN double-heterostructure light-emitting diodes reaching maximum quantum efficiency above 200 A/cm2,” Appl. Phys. Lett.91(24), 243506-1–243506-3 (2007).
- D. Li, M. B. Müller, S. Gilje, R. B. Kaner, and G. G. Wallace, “Processable aqueous dispersions of graphene nanosheets,” Nat. Nanotechnol.3(2), 101–105 (2008). [CrossRef] [PubMed]
- Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, and R. S. Ruoff, “Graphene and graphene oxide: synthesis, properties, and applications,” Adv. Mater. (Deerfield Beach Fla.)22(35), 3906–3924 (2010). [CrossRef] [PubMed]
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- 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]
- K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science306(5696), 666–669 (2004). [CrossRef] [PubMed]
- W. S. Hummers and R. E. Offeman, “Preparation of Graphitic Oxide,” J. Am. Chem. Soc.80(6), 1339–1339 (1958). [CrossRef]
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. H. Seo, T. S. Oh, T. S. Lee, H. Jeong, J. D. Kim, H. Kim, A. H. Park, K. J. Lee, C.-H. Hong, and E.-K. Suh, “Enhanced Light Extraction in GaN-Based Light Emitting Diodes with Holographically Fabricated Concave Hemisphere-Shaped Patterning on Indium-Tin-Oxide Layer,” Jpn. J. Appl. Phys.49, 092101-1–092101-3 (2010).
- H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, “Work function of purified and oxidised carbon nanotubes,” Synth. Met.103(1-3), 2494–2495 (1999). [CrossRef]
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. H. Seo, T. S. Oh, T. S. Lee, H. Jeong, J. D. Kim, H. Kim, A. H. Park, K. J. Lee, C.-H. Hong, and E.-K. Suh, “Enhanced Light Extraction in GaN-Based Light Emitting Diodes with Holographically Fabricated Concave Hemisphere-Shaped Patterning on Indium-Tin-Oxide Layer,” Jpn. J. Appl. Phys.49, 092101-1–092101-3 (2010).
- G. H. Jo, M. H. Choe, C. Y. Cho, J. H. Kim, W. J. Park, S. C. Lee, W. K. Hong, T. W. Kim, S. J. Park, B. H. Hong, Y. H. Kahng, and T. H. Lee, “Large-scale patterned multi-layer graphene films as transparent conducting electrodes for GaN light-emitting diodes,” Nanotechnology21, 175201-1–175201-6 (2010).
- 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), 051124-1–051124-3 (2010).
- 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), 051124-1–051124-3 (2010).
- G. H. Jo, M. H. Choe, C. Y. Cho, J. H. Kim, W. J. Park, S. C. Lee, W. K. Hong, T. W. Kim, S. J. Park, B. H. Hong, Y. H. Kahng, and T. H. Lee, “Large-scale patterned multi-layer graphene films as transparent conducting electrodes for GaN light-emitting diodes,” Nanotechnology21, 175201-1–175201-6 (2010).
- H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, “Work function of purified and oxidised carbon nanotubes,” Synth. Met.103(1-3), 2494–2495 (1999). [CrossRef]
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- T. V. Cuong, V. H. Pham, Q. T. Tran, S. H. Hahn, J. S. Chung, E. W. Shin, and E. J. Kim, “Photoluminescence and Raman studies of graphene thin films prepared by reduction of graphene oxide,” Mater. Lett.64(3), 399–401 (2010). [CrossRef]
- V. H. Pham, T. V. Cuong, S. H. Hur, E. W. Shin, J. S. Kim, J. S. Chung, and E. J. Kim, “Fast and simple fabrication of a large transparent chemically-converted graphene film by spray-coating,” Carbon48(7), 1945–1951 (2010). [CrossRef]
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, and R. S. Ruoff, “Graphene and graphene oxide: synthesis, properties, and applications,” Adv. Mater. (Deerfield Beach Fla.)22(35), 3906–3924 (2010). [CrossRef] [PubMed]
- W. S. Wong, T. Sands, N. W. Cheung, M. Kneissl, D. P. Bour, P. Mei, L. T. Romano, and N. M. Johnson, “Fabrication of thin-film InGaN light-emitting diode membranes by laser lift-off,” Appl. Phys. Lett.75(10), 1360–1362 (1999). [CrossRef]
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, and R. S. Ruoff, “Graphene and graphene oxide: synthesis, properties, and applications,” Adv. Mater. (Deerfield Beach Fla.)22(35), 3906–3924 (2010). [CrossRef] [PubMed]
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, “Work function of purified and oxidised carbon nanotubes,” Synth. Met.103(1-3), 2494–2495 (1999). [CrossRef]
- W. S. Wong, T. Sands, N. W. Cheung, M. Kneissl, D. P. Bour, P. Mei, L. T. Romano, and N. M. Johnson, “Fabrication of thin-film InGaN light-emitting diode membranes by laser lift-off,” Appl. Phys. Lett.75(10), 1360–1362 (1999). [CrossRef]
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. H. Seo, T. S. Oh, T. S. Lee, H. Jeong, J. D. Kim, H. Kim, A. H. Park, K. J. Lee, C.-H. Hong, and E.-K. Suh, “Enhanced Light Extraction in GaN-Based Light Emitting Diodes with Holographically Fabricated Concave Hemisphere-Shaped Patterning on Indium-Tin-Oxide Layer,” Jpn. J. Appl. Phys.49, 092101-1–092101-3 (2010).
- 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]
- N. F. Gardner, G. O. Muller, Y. C. Shen, G. Chen, S. Watanabe, W. Gotz, and M. R. Krames, “Blue emitting InGaN–GaN double-heterostructure light-emitting diodes reaching maximum quantum efficiency above 200 A/cm2,” Appl. Phys. Lett.91(24), 243506-1–243506-3 (2007).
- S. H. Tu, C. J. Lan, S. H. Wang, M. L. Lee, K. H. Chang, R. M. Lin, J. Y. Chang, and J. K. Sheu, “InGaN gallium nitride light-emitting diodes with reflective electrode pads and textured gallium-doped ZnO contact layer,” Appl. Phys. Lett.96(13), 133504-1–133504-3 (2010).
- 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]
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- V. H. Pham, T. V. Cuong, S. H. Hur, E. W. Shin, J. S. Kim, J. S. Chung, and E. J. Kim, “Fast and simple fabrication of a large transparent chemically-converted graphene film by spray-coating,” Carbon48(7), 1945–1951 (2010). [CrossRef]
- T. V. Cuong, V. H. Pham, Q. T. Tran, S. H. Hahn, J. S. Chung, E. W. Shin, and E. J. Kim, “Photoluminescence and Raman studies of graphene thin films prepared by reduction of graphene oxide,” Mater. Lett.64(3), 399–401 (2010). [CrossRef]
- F. Guneş, H.-J. Shin, C. Biswas, G. H. Han, E. S. Kim, S. J. Chae, J. Y. Choi, and Y. H. Lee, “Layer-by-layer doping of few-layer graphene film,” ACS Nano4(8), 4595–4600 (2010). [CrossRef] [PubMed]
- 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]
- Z. Luo, Y. Lu, L. A. Somers, and A. T. C. Johnson, “High yield preparation of macroscopic graphene oxide membranes,” J. Am. Chem. Soc.131(3), 898–899 (2009). [CrossRef] [PubMed]
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- T. H. Seo, T. S. Oh, T. S. Lee, H. Jeong, J. D. Kim, H. Kim, A. H. Park, K. J. Lee, C.-H. Hong, and E.-K. Suh, “Enhanced Light Extraction in GaN-Based Light Emitting Diodes with Holographically Fabricated Concave Hemisphere-Shaped Patterning on Indium-Tin-Oxide Layer,” Jpn. J. Appl. Phys.49, 092101-1–092101-3 (2010).
- Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, and R. S. Ruoff, “Graphene and graphene oxide: synthesis, properties, and applications,” Adv. Mater. (Deerfield Beach Fla.)22(35), 3906–3924 (2010). [CrossRef] [PubMed]
- F. Bonaccorso, Z. Sun, T. Hasan, and A. C. Ferrari, “Graphene photonics and optoelectronics,” Nat. Photonics4(9), 611–622 (2010). [CrossRef]
- D. W. Kim, H. Y. Lee, G. Y. Yeom, and Y. J. Sung, “A study of transparent contact to vertical GaN-based light-emitting diodes,” J. Appl. Phys.98(5), 0531021–0531024 (2005).
- H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, “Work function of purified and oxidised carbon nanotubes,” Synth. Met.103(1-3), 2494–2495 (1999). [CrossRef]
- T. V. Cuong, V. H. Pham, Q. T. Tran, S. H. Hahn, J. S. Chung, E. W. Shin, and E. J. Kim, “Photoluminescence and Raman studies of graphene thin films prepared by reduction of graphene oxide,” Mater. Lett.64(3), 399–401 (2010). [CrossRef]
- H. W. Choi, C. W. Jeon, M. D. Dawson, P. R. Edwards, R. W. Martin, and S. Tripathy, “Mechanism of enhanced light output efficiency in InGaN-based microlight emitting diodes,” J. Appl. Phys.93(10), 5978–5982 (2003). [CrossRef]
- S. H. Tu, C. J. Lan, S. H. Wang, M. L. Lee, K. H. Chang, R. M. Lin, J. Y. Chang, and J. K. Sheu, “InGaN gallium nitride light-emitting diodes with reflective electrode pads and textured gallium-doped ZnO contact layer,” Appl. Phys. Lett.96(13), 133504-1–133504-3 (2010).
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- P. Guéret, P. Buchmann, K. Daetwyler, and P. Vettiger, “Resistance of very small area ohmic contacts on GaAs,” Appl. Phys. Lett.55(17), 1735–1737 (1989). [CrossRef]
- D. Li, M. B. Müller, S. Gilje, R. B. Kaner, and G. G. Wallace, “Processable aqueous dispersions of graphene nanosheets,” Nat. Nanotechnol.3(2), 101–105 (2008). [CrossRef] [PubMed]
- S. H. Tu, C. J. Lan, S. H. Wang, M. L. Lee, K. H. Chang, R. M. Lin, J. Y. Chang, and J. K. Sheu, “InGaN gallium nitride light-emitting diodes with reflective electrode pads and textured gallium-doped ZnO contact layer,” Appl. Phys. Lett.96(13), 133504-1–133504-3 (2010).
- X. Wang, L. Zhi, and K. Mullen, “Transparent, conductive graphene electrodes for dye-sensitized solar cells,” Nano Lett.8(1), 323–327 (2008). [CrossRef] [PubMed]
- N. F. Gardner, G. O. Muller, Y. C. Shen, G. Chen, S. Watanabe, W. Gotz, and M. R. Krames, “Blue emitting InGaN–GaN double-heterostructure light-emitting diodes reaching maximum quantum efficiency above 200 A/cm2,” Appl. Phys. Lett.91(24), 243506-1–243506-3 (2007).
- W. S. Wong, T. Sands, N. W. Cheung, M. Kneissl, D. P. Bour, P. Mei, L. T. Romano, and N. M. Johnson, “Fabrication of thin-film InGaN light-emitting diode membranes by laser lift-off,” Appl. Phys. Lett.75(10), 1360–1362 (1999). [CrossRef]
- H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, “Work function of purified and oxidised carbon nanotubes,” Synth. Met.103(1-3), 2494–2495 (1999). [CrossRef]
- X. S. Li, W. W. Cai, J. H. An, S. Kim, J. Nah, D. X. Yang, R. D. Piner, A. Velamakanni, I. Jung, E. Tutuc, S. K. Banerjee, L. Colombo, and R. S. Ruoff, “Large-area synthesis of high-quality and uniform graphene films on copper foils,” Science324(5932), 1312–1314 (2009). [CrossRef] [PubMed]
- D. W. Kim, H. Y. Lee, G. Y. Yeom, and Y. J. Sung, “A study of transparent contact to vertical GaN-based light-emitting diodes,” J. Appl. Phys.98(5), 0531021–0531024 (2005).
- T. V. Cuong, V. H. Pham, J. S. Chung, E. W. Shin, D. H. Yoo, S. H. Hahn, J. S. Huh, G. H. Rue, E. J. Kim, S. H. Hur, G. S. Rue, E. J. Kim, S. H. Hur, and P. A. Kohl, “Solution-processed ZnO-chemically converted graphene gas sensor,” Mater. Lett.64(22), 2479–2482 (2010). [CrossRef]
- K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, “Electric field effect in atomically thin carbon films,” Science306(5696), 666–669 (2004). [CrossRef] [PubMed]
- X. Wang, L. Zhi, and K. Mullen, “Transparent, conductive graphene electrodes for dye-sensitized solar cells,” Nano Lett.8(1), 323–327 (2008). [CrossRef] [PubMed]
- Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, and R. S. Ruoff, “Graphene and graphene oxide: synthesis, properties, and applications,” Adv. Mater. (Deerfield Beach Fla.)22(35), 3906–3924 (2010). [CrossRef] [PubMed]
ACS Nano
- F. Guneş, H.-J. Shin, C. Biswas, G. H. Han, E. S. Kim, S. J. Chae, J. Y. Choi, and Y. H. Lee, “Layer-by-layer doping of few-layer graphene film,” ACS Nano4(8), 4595–4600 (2010). [CrossRef] [PubMed]
Adv. Mater. (Deerfield Beach Fla.)
- Y. Zhu, S. Murali, W. Cai, X. Li, J. W. Suk, J. R. Potts, and R. S. Ruoff, “Graphene and graphene oxide: synthesis, properties, and applications,” Adv. Mater. (Deerfield Beach Fla.)22(35), 3906–3924 (2010). [CrossRef] [PubMed]
Appl. Phys. Lett.
- T. H. Seo, K. J. Lee, T. S. Oh, Y. S. Lee, H. Jeong, A. H. Park, H. Kim, Y. R. Choi, E.-K. Suh, T. V. Cuong, V. H. Pham, J. S. Chung, and E. J. Kim, “Graphene network on indium tin oxide nanodot nodes for transparent and current spreading electrode in InGaN/GaN light emitting diode,” Appl. Phys. Lett.98(25), 251114-1–251114-3 (2011).
- N. F. Gardner, G. O. Muller, Y. C. Shen, G. Chen, S. Watanabe, W. Gotz, and M. R. Krames, “Blue emitting InGaN–GaN double-heterostructure light-emitting diodes reaching maximum quantum efficiency above 200 A/cm2,” Appl. Phys. Lett.91(24), 243506-1–243506-3 (2007).
- W. S. Wong, T. Sands, N. W. Cheung, M. Kneissl, D. P. Bour, P. Mei, L. T. Romano, and N. M. Johnson, “Fabrication of thin-film InGaN light-emitting diode membranes by laser lift-off,” Appl. Phys. Lett.75(10), 1360–1362 (1999). [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.-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), 051124-1–051124-3 (2010).
- S. H. Tu, C. J. Lan, S. H. Wang, M. L. Lee, K. H. Chang, R. M. Lin, J. Y. Chang, and J. K. Sheu, “InGaN gallium nitride light-emitting diodes with reflective electrode pads and textured gallium-doped ZnO contact layer,” Appl. Phys. Lett.96(13), 133504-1–133504-3 (2010).
- P. Guéret, P. Buchmann, K. Daetwyler, and P. Vettiger, “Resistance of very small area ohmic contacts on GaAs,” Appl. Phys. Lett.55(17), 1735–1737 (1989). [CrossRef]
Carbon
- V. H. Pham, T. V. Cuong, S. H. Hur, E. W. Shin, J. S. Kim, J. S. Chung, and E. J. Kim, “Fast and simple fabrication of a large transparent chemically-converted graphene film by spray-coating,” Carbon48(7), 1945–1951 (2010). [CrossRef]
IEEE J. Quantum Electron.
- 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. Am. Chem. Soc.
- W. S. Hummers and R. E. Offeman, “Preparation of Graphitic Oxide,” J. Am. Chem. Soc.80(6), 1339–1339 (1958). [CrossRef]
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