To obtain a high field emission (FE) current with a low driving voltage, it is important to control and optimize carbon nanofiber (CNF) array patterns for FE. While there have been various means for controlling CNF array patterns reported over the past few decades, array patterning using lithography is the method typically used to control CNF morphology. Because lithography uses many masks and is costly, it is necessary to establish a simpler process. In this study, the grain size and distribution of catalysts with phase separation were controlled. A system which controls the morphology of small bundles of CNFs was constructed with the distance between the bundles kept constant in order to obtain a higher FE current. The Ni catalyst layer for forming the CNF morphology was separated by noncatalytic Cr grains formed by cosputtering. As a result, it was possible to control the Ni content, the grain size and synthesis density of CNFs in the alloy with a varying number of nickel pellets placed on the chromium target. This method is an epochmaking CNF patterning technique very different from lithography.
Cite this paper
N. Shimoi and S. Tanaka, "Optimized Distribution and Morphology of Carbon Nanofibers for a Field Emitter Grown by Nickel and Chromium Cosputtering," Materials Sciences and Applications, Vol. 4 No. 4, 2013, pp. 225-230. doi: 10.4236/msa.2013.44027.
 R. H. Fowler and L. W. Nordheim, “Electron Emission in Intense Electric Fields,” Proceedings of the Royal Society A, Vol. 119, No. 781, 1928, pp. 173-181.
 C. A. Spindt, I. Brodie, L. Humphery and E. R. Westerberg, “Physical Properties of Thin-Film Field Emission Cathodes with Molybdenum Cones,” Journal of Applied Physics, Vol. 47, No. 12, 1976, pp. 5248-5263.
 K. H. Park, J. H. Yim, S. Lee and K. H. Koh, “Catalyst-Assisted Hot Filament Chemical Vapor Deposition and Characterization of Carbon Nanostructures,” Thin Solid Films, Vol. 501, No. 1-2, 2006, pp. 233-237.
 I. Willems, Z. Kónya, J.-F. Colomer, G. Van Tendeloo, N. Nagaraju, A. Fonseca and J. B. Nagy, “Control of the Outer Diameter of Thin Carbon Nanotubes Synthesized by Catalytic Decomposition of Hydrocarbons,” Chemical Physics Letters, Vol. 317, No. 1-2, 2000, pp. 71-76.
 S. L. Sung, S. H. Tsai, C. H. Tseng, F. K. Chiang, X. W. Liu and H. C. Shih, “Well-Aligned Carbon Nitride Nanotubes Synthesized in Anodic Alumina by Electron Cyclotron Resonance Chemical Vapor Deposition,” Applied Physics Letters, Vol. 74, No. 2, 1999, pp. 197-199.
 A. Di Bartolomeo, A. Scarfato, F. Giubileo, F. Bobba, M. Biasiucci, A. M. Cucolo, S. Santucci and M. Passacantando, “A Local Field Emission Study of Partially Aligned Carbon-Nanotubes by Atomic Force Microscope Probe,” Carbon, Vol. 45, No. 15, 2007, pp. 2957-2971.
 W. A. de Heer, A. Chatelain and D. Ugarte, “A Carbon Nanotube Field-Emission Electron Source,” Science, Vol. 270, No. 5239, 1995, pp. 1179-1180.
 W. B. Choi, D. S. Chung, S. H. Park and J. M. Kim, “A 4.5-in Fully Sealed Carbon Nanotube-Based Field-Emission Flat-Panel Display,” SID Symposium Digest of Technical Papers, Vol. 30, No. 1, 1999, pp. 1134-1137.
 L. Nilsson, O. Groening, C. Emmenegger, O. Kuettel, E. Schaller and L. Schlapbach, “Scanning Field Emission from Patterned Carbon Nanotube Films,” Applied Physics Letters, Vol. 76, No. 15, 2000, pp. 2071-2073.
 Z. Yuning, L. Wei, Z. Xiaobing, and W. Baoping, “Calculation of the Emission Performance of the Carbon Nanotube Array,” Applied Surface Science, Vol. 245, No. 1-4, 2005, pp. 400-406. doi:10.1016/j.apsusc.2004.10.042
 Y.-H. Wu, C.-M. Hsu, C.-T. Chia, I.-N. Lin and C.-L. Cheng, “Field Emission and Raman Spectroscopy Studies of Atomic Hydrogen Etching on Boron and Nitrogen Doped DLC Films,” Diamond and Related Materials, Vol. 11, No. 3, 2002, pp. 804-808.
 L. Xinghui, Z. Changchun and L. Yukui, “Energy Band Structure Effect of Individual Single-Walled Carbon Nanotubes on Field Emission Characteristics,” Physica B: Condensed Matter, Vol. 344, No. 1-4, 2004, pp. 243-248.
 Y. J. Jung, G. H. Son, J. H. Park, Y. W. Kim, A. S. Berdinsky, J.-B. Yoo and C.-Y. Park, “Fabrication and Properties of Under-Gated Triode with CNT Emitter for Flat Lamp,” Diamond and Related Materials, Vol. 14, No. 11-12, 2005, pp. 2109-2112.
 J.-H. Han, T. Y. Lee, D. Y. Kim, J.-B. Yoo, C.-Y. Park, J. J. Choi, T. Jung, I. T. Han and J. M. Kim, “Field Emission Properties of Carbon Nanotubes Grown on Co/TiN Coated Ta Substrate for Cathode in Microwave Power Amplifier,” Diamond and Related Materials, Vol. 13, No. 4-8, 2004, pp. 987-993.
 D. Kim, S. H. Lim, A. J. Guilley, C. S. Cojocaru, J. E. Bourée, L. Vila, J. H. Ryu, K. C. Park and J. Jang, “Growth of Vertically Aligned Arrays of Carbon Nanotubes for High Field Emission,” Thin Solid Films, Vol. 516, No. 5, 2008, pp. 706-709.
 X. Q. Wang, M. Wang, H. L. Ge, Q. Chen and Y. B. Xu, “Modeling and Simulation for the Field Emission of Carbon Nanotubes Array,” Physica E, Vol. 30, No. 1-2, 2005, pp. 101-106. doi:10.1016/j.physe.2005.07.012
 Y. Li and H.-W. Cheng, “Numerical Simulation of Field Emission Efficiency of Anodic Aluminum Oxide Carbon Nanotube Field Emitter in the Triode Structure,” Computer Physics Communications, Vol. 179, No. 1-3, 2008, pp. 107-111. doi:10.1016/j.cpc.2008.01.026
 W. Liu, C. Zhu, C. Meng and F. Zeng, “On the Uniformity of Field Emission in Screen Printed CNT-Cathodes: The Effects of the Cathode Roughness,” Microelectronics Journal, Vol. 37, No. 5, 2006, pp. 404-408.
 T. Matsuda, M. Mesko, A. Ogino and M. Nagatsu, “Synthesis of Vertically Aligned Carbon Nanotubes on Submicron-Sized Dot-Catalyst Array Using Plasma CVD Method,” Diamond and Related Materials, Vol. 17, No. 4-5, 2008, pp. 772-775.
 S. H. Jeong and K. H. Lee, “Fabrication of the Aligned and Patterned Carbon Nanotube Field Emitters Using the Anodic Aluminum Oxide Nano-Template on a Si Wafer,” Synthetic Metals, Vol. 139, No. 2, 2003, pp. 385-390.
 M. A. Guillorn, M. L. Simpson G. J. Bordonaro, V. I. Merkulov, L. R. Baylor and D. H. Lowndes, “Fabrication of Gated Cathode Structures Using an in situ Grown Vertically Aligned Carbon Nanofiber as a Field Emission Element,” Journal of Vacuum Science and Technology B, Vol. 19, No. 2, 2001, pp. 573-578. doi:10.1116/1.1358855
 J. Erlebacher, M. J. Aziz, E. Chason, M. B. Sinclair and J. A. Floro, “Spontaneous Pattern Formation on Ion Bombarded Si(001),” Physical Review Letters, Vol. 82, No. 11, 1999, pp. 2330-2333. doi:10.1103/PhysRevLett.82.2330
 A. L. Wang, C. Neff, E. Graugnard, Y. Ding, J. S. King, L. A. Pranger, R. Tannenbaum, Z. L. Wang and C. J. Summers, “Photonic Crystals Fabricated Using Patterned Nanorod Arrays,” Advanced Materials, Vol. 17, No. 17, 2005, pp. 2103-2106. doi:10.1002/adma.200500546
 P. Chen, H.-B. Zhang, G.-D. Lin, Q. Hong and K. R. Tsai, “Growth of Carbon Nanotubes by Catalytic Decomposition of CH4 or CO on a Ni-MgO Catalyst,” Carbon, Vol. 35, No. 10-11, 1997, pp. 1495-1501.
 W. B. Choi, Y. W. Jin, H. Y. Kim, S. J. Lee, M. J. Yun, J. H. Kang, Y. S. Choi, N. S. Park, N. S. Lee and J. M. Kim, “Electrophoresis Deposition of Carbon Nanotubes for Triode-Type Field Emission Display,” Applied Physics Letters, Vol. 78, No. 11, 2001, pp. 1547-1549.
 M. Tanemura, T. Okita, J. Tanaka, M. Kitazawa, K. Itoh, L. Miao, S. Tanemura, S. P. Lau, H. Yang and L. Huang, “Room-Temperature Growth and Applications of Carbon Nanofibers: A Review,” IEEE Transactions on Nanotechnology, Vol. 5, No. 5, 2006, pp. 587-594.
 N. Sano, M. Naito and T. Kikuchi, “Enhanced Field Emission Properties of Films Consisting of Fe-Core Carbon Nanotubes Prepared under Magnetic Field,” Carbon, Vol. 45, No. 1, 2007, pp. 78-82.
 N. Shimoi and S.-I. Tanaka, “Enhancement of Electron Field Emission from Carbon Nanofiber Bundles Separately Grown on Ni Catalyst in Ni-Cr Alloy,” Carbon, Vol. 47, No. 5, 2009, pp. 1258-1263.
 Z. B. He, C. S. Lee, J.-L. Maurice, D. Pribat, P. Haghi-Ashtiani and C. S. Cojocaru, “Vertically Oriented Nickel Nanorod/Carbon Nanofiber Core/Shell Structures Synthesized by Plasma-Enhanced Chemical Vapor Deposition, Carbon, Vol. 49, No. 14, 2011, pp. 4710-4718.
 N. Shimoi and S.-I. Tanaka, “Numerically Optimized Bundle Size and Distribution of Carbon Nanofibers for a Field Emitter,” Carbon, Vol. 48, No. 3, 2010, pp. 905-911. doi:10.1016/j.carbon.2009.10.045