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Stability of amorphous Ta–O nanotubes prepared by anodization: Thermal and structural analyses

Published online by Cambridge University Press:  31 March 2014

Ryusuke Nakamura*
Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Naka-ku, Sakai 599-8531, Japan
Kohta Asano
National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8565, Japan
Manabu Ishimaru
Department of Materials Science and Engineering, Kyushu Institute of Technology, Tobata, Kitakyushu, Fukuoka 804-8550, Japan
Kazuhisa Sato
Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
Masahide Takahashi
Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
Hiroshi Numakura
Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, Sakai 599-8531, Japan
a)Address all correspondence to this author. e-mail:
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Amorphous Ta–O nanotubes (NTs) prepared by anodization in a sulfuric-acid-based solution have been found to contain considerable amounts of extra oxygen and sulfur. Their structural and thermal stability has been studied by combining x-ray diffractometry, transmission electron microscopy, and thermal analysis. The amorphous Ta–O, whose composition was estimated to be Ta2O6.6S0.7, crystallizes into orthorhombic β-Ta2O5 at temperatures around 1073 K by an endothermic reaction, at which excess oxygen and impurity sulfur are released. The amorphous NTs were found to be thermally more stable than stoichiometric amorphous Ta2O5, whose crystallization temperature is around 973 K. Excess oxygen and impurity sulfur, which form chemical bonds with Ta atoms in the amorphous solid, must be the origin of the stability. The crystallization follows the out-diffusion of oxygen and sulfur from the solid at temperatures where the mobility of atoms is high enough, indicating that the crystallization is kinetically arrested.

Copyright © Materials Research Society 2014 

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Kresge, C.T., Leonowicz, M.E., Roth, W.J., Vartuli, J.C., and Beck, J.S.: Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism. Nature 359, 710 (1992).CrossRefGoogle Scholar
Johnson, S.A., Ollivier, P.J., and Mallouk, T.E.: Ordered mesoporous polymers of tunable pore size from colloidal silica templates. Science 283, 963 (1999).CrossRefGoogle ScholarPubMed
Masuda, H. and Fukuda, K.: Ordered metal nanohole arrays made by a two-step replication of honeycomb structures of anodic alumina. Science 268, 1466 (1995).CrossRefGoogle ScholarPubMed
Gong, D., Grimes, C.A., Varghese, O.K., Hu, W., Singh, R.S., Chen, Z., and Dickey, E.C.: Titanium oxide nanotube arrays prepared by anodic oxidation. J. Mater. Res. 16, 3331 (2001).CrossRefGoogle Scholar
Sieber, I., Hildebrand, H., Friedrich, A., and Schmuki, P.: Formation of self-organized niobium porous oxide on niobium. Electrochem. Comm. 7, 97 (2005).CrossRefGoogle Scholar
Tsuchiya, H., Macak, J.M., Ghicov, A., Taveira, L., and Schmuki, P.: Self-organized porous TiO2 and ZrO2 produced by anodization. Corr. Sci. 47, 3324 (2005).CrossRefGoogle Scholar
Tsuchiya, H. and Schmuki, P.: Self-organized high aspect ratio porous hafnium oxide prepared by electrochemical anodization. Electrochem. Comm. 7, 49 (2005).CrossRefGoogle Scholar
Tsuchiya, H., Macak, J.M., Sieber, I., Taveira, L., Ghicov, A., Sirotna, K., and Schmuki, P.: Self-organized porous WO3 formed in NaF electrolytes. Electrochem. Comm. 7, 295 (2005).CrossRefGoogle Scholar
Wei, W., Macak, J.M., and Schmuki, P.: High aspect ratio ordered nanoporous Ta2O5 films by anodization of Ta. Electrochem. Comm. 10, 428 (2008).CrossRefGoogle Scholar
Paramasivam, I., Jha, H., Liu, N., and Schmuki, P.: A Review of photocatalysis using self-organized TiO2 nanotubes and other ordered oxide nanostructures. Small 8, 3073 (2012).CrossRefGoogle ScholarPubMed
Chen, X., Shen, S., Guo, L., and Mao, S.S.: Semiconductor-based photocatalytic hydrogen generation. Chem. Rev. 110, 6503 (2010).CrossRefGoogle ScholarPubMed
Allam, N.K., Feng, X.J., and Grimes, C.A.: Self-assembled fabrication of vertically oriented Ta2O5 nanotube arrays, and membranes thereof, by one-step tantalum anodization. Chem. Mater. 20, 6477 (2008).CrossRefGoogle Scholar
Feng, X., LaTempa, T.J., Basham, J.I., Mor, G.K., Varghese, O.K., and Grimes, C.A.: Ta3N5 nanotube arrays for visible light water photoelectrolysis. Nano Lett. 10, 948 (2010).10.1021/nl903886eCrossRefGoogle ScholarPubMed
Barton, J.E., Stender, C.L., Li, P., and Odom, T.W.: Structural control of anodized tantalum oxide nanotubes. J. Mater. Chem. 19, 4896 (2009).CrossRefGoogle Scholar
Gonçalves, R.V., Migowski, P., Wender, H., Eberhardt, D., Weibel, D.E., Sonaglio, F.v.C., Zapata, M.J.M., Dupont, J., Feil, A.F., and Teixeira, S.R.: Ta2O5 nanotubes obtained by anodization: Effect of thermal treatment on the photocatalytic activity for hydrogen production. J. Phys. Chem. C 116, 14022 (2012).CrossRefGoogle Scholar
Allam, N.K. and El-Sayed, M.A.: Photoelectrochemical water oxidation characteristics of anodically fabricated TiO2 nanotube arrays: Structural and optical properties. J. Phys. Chem. C 114, 12024 (2010).CrossRefGoogle Scholar
Nakamura, R., Tanaka, K., Ishimaru, M., Sato, K., Konno, T.J., and Nakajima, H.: Self-elongated growth of nanopores in annealed amorphous Ta2O5 films. Scr. Mater. 66, 182 (2012).CrossRefGoogle Scholar
Hirotsu, Y., Ishimaru, M., Ohkubo, T., Hanada, T., and Sugiyama, M.: Application of nano-diffraction to local atomic distribution function analysis of amorphous materials. J. Electron Microsc. 50, 435 (2001).CrossRefGoogle ScholarPubMed
Ishimaru, M.: Electron-beam radial distribution analysis of irradiation-induced amorphous SiC. Nucl. Instrum. Methods Phys. Res., Sect. B 250, 309314 (2006).CrossRefGoogle Scholar
Roth, R.S., Waring, J.L., and Parker, H.S.: Effect of oxide additions on the polymorphism of tantalum pentoxide. IV. The system Ta2O5-Ta2WO8. J. Solid State Chem. 2, 445 (1970).CrossRefGoogle Scholar
Nakamura, R., Ishimaru, M., Sato, K., Tanaka, K., Nakajima, H., and Konno, T.J.: Formation of highly oriented nanopores via crystallization of amorphous Nb2O5 and Ta2O5. J. Appl. Phys. 114, 124308 (2013).CrossRefGoogle Scholar
Waseda, Y.: The Structure of Non-crystalline Materials (McGraw-Hill, International Book Co, New York, 1980).Google Scholar
Elliott, S.R.: Physics of Amorphous Materials, 2nd ed. (Longman Scientific & Technical, UK, 1990).Google Scholar
Ishimaru, M., Zhang, Y., and Weber, W.J.: Ion-beam-induced chemical disorder in GaN. J. Appl. Phys. 106, 053513 (2009).CrossRefGoogle Scholar
Bassiri, R., Borisenko, K.B., Cockayne, D.J.H., Hough, J., MacLaren, I., and Rowan, S.: Probing the atomic structure of amorphous Ta2O5 coatings. Appl. Phys. Lett. 98, 031904 (2011).CrossRefGoogle Scholar
Nakamura, R., Ishimaru, M., Sato, K., Tanaka, K., and Nakajima, H., and Konno, T.J.: Enhancement of nanovoid formation in annealed amorphous Al2O3 including W. J. Appl. Phys. 114, 124308 (2013).CrossRefGoogle Scholar
Jellinek, F.: The system tantalum-sulfur. J. Less Common Met. 4, 9 (1962).CrossRefGoogle Scholar
Mahy, J., Wiegers, G.A., van Bolhuis, F., Diedering, A., and Haange, R.J.: X-ray and electron diffraction study of intercalates AgxTaS2. Phys. Status Solidi A 107, 873 (1988).CrossRefGoogle Scholar
Suzuki, A., Yamashita, T., Matsui, K., and Doyama, M.: Thermal and structural measurements of the mixed crystal 1T-TaS2-xSe1-x. J. Phys. Soc. Jpn. 57, 1707 (1988).CrossRefGoogle Scholar
Xie, H., Zhang, Q., Xi, T., Wang, J., and Liu, Y.: Thermal analysis on nanosized TiO2 prepared by hydrolysis. Thermochim. Acta 381, 45 (2002).CrossRefGoogle Scholar
Filippova, S.E. and Reznitskii, L.A.: The temperature and enthalpy of crystallization of amorphous niobium oxide. Russian J. Inorganic Chem. 46, 1640 (2001).Google Scholar
Tane, M., Nakano, S., Nakamura, R., Ogi, H., Ishimaru, M., Kimizuka, H., and Nakajima, H.: Nanovoid formation by change in amorphous structure through the annealing of amorphous Al2O3 thin films. Acta Mater. 59, 4631 (2011).CrossRefGoogle Scholar
Gad-Allah, A.G., Abd El-Rahman, H.A., and Abou-Romia, M.M.: Influence of oxide bond energies on the kinetics of chemical dissolution of anodic oxides on valve metals. J. Appl. Electrochem. 18, 532 (1988).10.1007/BF01022247CrossRefGoogle Scholar