電致色變材料是近年來被大家廣泛研究的一項薄膜光學技術，它可以被應用在汽車和建築物之視窗玻璃上，以製作節省能源、調節光線及控制熱負荷之智慧型窗戶。本實驗利用直流反應磁控濺鍍法來沉積氧化鎢薄膜，並探討各種濺鍍條件對薄膜成份、微結構、和電致色變性質的影響。

　　實驗結果發現，隨著氧氣流量的增加，薄膜中的氧含量會隨之增加；在高氧氣流量下沉積氧化鎢薄膜，薄膜具有較佳的可逆性，當氧氣流量為30sccm時，在波長550nm處，其著色去色之穿透率變化可達61.4%，且其在任何波長下均具有較高的光學密度，而薄膜之著色效率CE=7.79cm2/C。當基板溫度超過300℃時，薄膜即會開始結晶化，隨著基板溫度從室溫增加到350℃時，氧化鎢薄膜的光能隙會從3.64下降至3.08eV，能隙會有窄化的情形發生，這是因為氧空缺的存在或是結晶顆粒尺寸變大等因素。結晶化的氧化鎢薄膜在近紅外光區具較強的反射性。

　　實驗中並以最佳參數(氧氣流量:30sccm、基板溫度:RT)濺鍍之氧化鎢薄膜進行可靠度測試，實驗結果發現，氧化鎢薄膜經過100次循環之後，其再現性和著去色穿透率並沒有受到影響，薄膜的穩定性仍相當良好。

　　Recent years electrochromism have been extensively investigated due to their potential applications such as smart window of architecture and automobile glazing to save energy and modulate the transmission of light and solar radiation. Therefore, the objective of this study is to investigate the effects of sputtering conditions on the composition, microstructure, electrochromic properties of tungsten oxide films prepared by d.c. reactive magnetron sputtering.
　　
　　Experimental results indicated that with increasing oxygen flow rate, oxygen content of the film was increased. For high oxygen flow rate, tungsten oxide films showed good reversibility. At the oxygen flow rate of 30sccm, the transmission change between colored and bleached states at a wavelength of 550nm was 61.4%. The film obtained high optical density, and coloration efficiency was 7.79cm2/C. It was also found that the crystallinity of films was obtained at the substrate temperature larger than 300℃. As the substrate temperature increasing from room temperature to 350℃, the optical band gap changed from 3.64 to 3.08eV due to the existence of oxygen vacancies or larger grain size. The crystalline tungsten oxide films show high reflectance in the near IR region. The reproducibility and the transmission of colored and bleached state were not affected after 100 cycles. It means the tungsten oxide films deposited by d.c. reactive magnetron sputtering had good quality stability which is important for application in smart window.

[1]焦小浣, 胡文旭, 陳玲, 光窗透明材料的實驗研究, 太陽能學報, Vol 18, No 4, p.365-370 (1997)
[2]吳永豪, 智慧窗與玻璃塗層, 工業材料雜誌, Vol. 207, p136-149, (2004).
[3]Elin Hammarberg, Arne Roos, "Antireflection treatment of low-emitting glazings for energy efficient windows with high visible transmittance", Thin Solid Films, Vol.442, p.222-226 (2003)
[4]C.M. Lampert, "Large-area smart glass and integrated photovoltaics", Solar Energy Materials & Solar Cells, Vol.76, p.489-499 (2003)
[5]G. Bräuer, "Large area glass coatings", Surface and Coatings Technology, Vol.112, p.358-365 (1999)
[6]C.G. Granqvist, E. Avendano, A. Azens, "Electrochromic coatings and devices: survey of some recent advances", Thin Solid Films, Vol.442, p.201-211 (2003)
[7]C. G. Granqvist, A. Azens, A. Hjelm, L. Kullman, G. A. Niklasson, D. Rönnow, M. Strømme Mattsson, M. Veszelei, G. Vaivars, "RECENT ADVANCES IN ELECTROCHROMICS FOR SMARTWINDOWS APPLICATIONS", Solar Energy, Vol.63, No. 4, p. 199-216 (1998)
[8]D. N. Buckley, L. D. Burke, J. K. Mukahy, J. Chem. Soc., Faraday 72 (1) (1976) 1896
[9]L. D. Burke, E. J. M. O’sakan, J. Electroanal. Chem., Vol. 93 (1978) 11
[10]Y. A. Yang, Y. W. Cao, B. H. Loo, J. N. Yao, J. Phys. Chem. B, Vol.102 (1998) 9392
[11]Z. S. Guan, J. N. Yao, Y. A. Yang, B. H. Loo, J. Electroanal. Chem., Vol. 443 (1998) 175
[12]A. Azens, L. Kullman, G. Vaivars, H. Nordborg, C. G. Granqvist, "Sputter -deposited nickel oxide for electrochromic applications", Solid State Ionics, Vol.113-115, p.449-456 (1998)
[13]L.D. Burke ,T. A. M. Thomey, D. P. Whelan, J. Electroanal. Chem., Vol 107 (1980) 201
[14]T. Ohtasuka, M. Masuda and N. Sato, J. Electrochem. Soc, Vol.134 (1987) 804
[15]Nilgün, Özer, "Optical and electrochemical characteristics of sol-gel deposited tungsten oxide films: a comparison", Thin Solid Films, Vol 304, p.310-314 (1997)
[16]C.W. Ong, H.Y. Wong, G.K.H. Pang, K.Z. Baba-Kishi, and C.L. Choy, "Relationship between the microstructure and nanoindentation hardness of thermally evaporated and magnetron-sputtered electrochromic tungsten oxide films", J. Mater. Res., Vol.16(6), p.1541-1548 (2001)
[17]J. L. He, M. C. Chiu, "Effect of oxygen on the electrochromism of RF reactive magnetron sputter deposited tungsten oxide", Surface and Coatings Technology, Vol.127, p.43-51 (2000)
[18]Lamartine Meda, Richard C. Breitkopf, Terry E. Haas, Rein U Kirss, "Investigation of electrochromic properties of nanocrystalline tungsten oxide thin film", Thin Solid Films, Vol.402, p.126-130 (2002)
[19]G. Leftheriotis, S. Papaefthimiou, P. Yianoulis, "The effect of water on the electrochromic properties of WO3 films prepared by vacuum and chemical methods", Solar Energy Materials & Solar Cells, Vol.83, p.115-124 (2004)
[20]M. Deepa, A. K. Srivastava, S. Singh, S. A. Agnihotry, "Structure-property correlation of nanostructured WO3 thin films produced by electrodeposition", J. Mater. Res., Vol.19(9), p.2576-2585 (2004)
[21]A. Rougier, F. Portemer, A. Quédée, M. El Marssi, "Characterization of pulsed laser deposited WO3 thin films for electrochromic devices", Applied Surface Science, Vol.153, p.1-9 (1999)
[22]M. Regragui, M. Addou, A. Outzourhit, J.C. Bernéde, Elb. El Idrissi, E. Benseddik, A. Kachouane, "Preparation and characterization of pyrolytic spray deposited electrochromic tungsten trioxide films", Thin Solid Films, Vol.358, p.40-45 (2000)
[23]何國川, 電化學與無窗時代, 化工, Vol 37, No 3, p.32-42
[24]何主亮, 邱明傑, 反應磁控濺鍍氧化鎢薄膜氧含量對其電致色變性質之影響, 真空科技, Vol 12, No 3, p.4-15 (1999)
[25]Prakash R. Somani, S. Radhakrishnan, "Electrochromic materials and devices: present and future", Materials Chemistry and Physics, Vol.77, p.117-133 (2002)
[26]楊明長, 電致色變系統簡介, 化工, Vol 40, No 2, p.64-67 (1993)
[27]謝育忠, 電漿濺鍍電致色變氧化鎳薄膜特性研究與節能評估, 中原大學化學工程系, 碩士論文, 民國九十一年.
[28]S. K. Deb, "A Novel Electrophotographic System", Appl. Optics, Suppl. 3, p.192 (1969)
[29]B. W. Faughnan, R. S. Crandall, P. M. Heyman, "Electrochromism in WO3 Amorphous Films", RCA Review, Vol 36, p.177-197 (1975)
[30]C. G. Granqvist, A. Azens, J. Isidorsson, M. Kharrazi, L. Kullman, T. Lindström, G.A. Niklasson, C.-G. Ribbing, D. Rönnow, M. Strømme Mattson, M. Veszelei, "Towards the smart windows: progress in electrochromics", Journal of Non-Crystalline Solids, Vol.218, p.273-279 (1997)
[31]李淑端, 有機固態電解質電致色變元件之製作, 逢甲大學材料與製造工程研究所, 碩士論文, 民國九十二年
[32]S.H. Lee, H. M. Cheong, J. G. Zhang, A. Mascarenhas, D. K. Benson, S. K. Deb, "Electrochromic mechanism in a-WO3-y thin films", Applied Physics Letters, Vol 74, No 2, p.242-244 (1999)
[33]S. K. Deb, "Optical and Photoelectric Properties and Color Centers in Thin Films of Tungsten Oxide", Philosophical Magazine, Vol 27, No 4, p.801-822 (1973)
[34]J.M. Honig, in: S. Trasatti (Ed), Electrodes of Conductive Metallic Oxides, Elsevier, Amsterdam, 1980
[35]O. F. Schirmer, V. Wittwer, G. Baur, G. Brandt, "Dependence of WO3 Electrochromic Absorption on Crystallinity", Journal of the Electrochemical Society, Vol.124, No.5, p.749-753 (1977)
[36]C.G. Granqvist, "Handbook of Inorganic Electrochromic Materials ", Elsevier, Amsterdam, Lausanne, New York, Oxford, Shannon, Tokyo, 1995 p.181
[37]K. Bange, " Colouration of tungsten oxide films: A model for optically active coatings", Solar Energy Materials & Solar Cells, Vol.58, p.1-131 (1999)
[38]B. Chapman, "Glow Discharge Processes ", John Wiley & Sons, Inc., New York, (1980)
[39]S. M. Rossnagel et al., "Handbook of Plasmas Processing Technology ", Noyes Publications, Park Ridge, New Jersey, U.S.A, (1982)
[40]莊達人 編著, "VLSI製造技術", 高立圖書有限公司, p.146-158, (1995)
[41]J. A. Thornton, "Influence of Apparatus Geometry and Deposition Conditions on the Structure and Topography of Thick Sputtered Coatings", J. Vac. Sci. Technol., Vol.11, p.666-670 (1974)
[42]H. T. G. Hentzell, C. R. M. Grovenor, and D. A. Smith, "Grain Structure Variation with Temperature for Evaporated Metal Films", J. Vac. Sci. Technol., A2, p.218-219 (1984)
[43]P. B. Barna, and M. Adamik, "Fundamental Structure Forming Phenomena of Polycrystalline Films and The Structure Zone Models", Thin Solid Films, Vol.317, p.27-33 (1998)
[44]Walter H. Class, 楊錦章 譯, "基礎濺鍍電流", 電子發展月刊, Vol. 68, p.13-40 (1983)
[45]A. SioKou, S. Ntais, S. Papaefthimiou, G. Leftheriotis, P. Yianoulis, " Influence of the substrate on the electrochromic characteristics of lithiated a-WO3 layers ", Surface Science, Vol.566-568, p.1168-1173 (2004)
[46]Se-Hee Lee, Hyeonsik M. Cheong, C. Edwin Tracy, Angelo Mascarenhas, David K. Benson, Satyen K. Deb, " Raman spectroscopic studies of electrochromic a-WO3", Electrochimica Acta, Vol.44, p.3111-3115 (1999)
[47]Takuro Nanba, Tadashi Takahashi, Jun Takada, Akiyoshi Osaka, Yoshinari Miura, Itaru Yasui, Akira Kishimoto, Tetsuichi Kudo, " Characterization of amorphous tungsten trioxide thin films prepared by rf magnetron sputtering method ", Journal of Non-Crystalline Solids, Vol.178, p.233-237 (1994)
[48]D. Yang, L. Xue, "Structures and electrochromic properties of Ta0.1W0.9Ox thin films deposited by pulsed laser ablation", Thin Solid Films, Vol.469-470, p.54-58 (2004)
[49]MG Hutchins, NA Kamel, Abdel-Hady, " Effect of oxygen content on the electrochromic properties of sputtered tungsten oxide films with Li+ insertion ", Vacuum, Vol.51, No.3, p.433-439 (1998)
[50]C. Brigouleix, P. Topart, E. Bruneton, F. Sabary, G. Nouhaut, G. Campet, " Roll to roll dc magnetron sputtering deposition of WO3 for electrochromic windows ", Electrochimica Acta, Vol.46, p.1931-1936 (2001)
[51]P.V. Ashrit, G. Bader, Vo-Van Truong, "Electrochromic properties of nanocrystalline tungsten oxide thin films", Thin Solid Films, Vol.320 p.324-328 (1998)
[52]Lars Berggren, Gunnar A. Niklasson, "Influence of sputtering condition on the solar and luminous optical properties of amorphous LixWOy thin films", Solar Energy Materials & Solar Cells, Vol.85, p.573-586 (2005)
[53]Gunnar A. Niklasson, Lars Berggren, Anna-Lena Larsson, " Electrochromic tungsten oxide: the role of defects", Solar Energy Materials & Solar Cells, Vol.84 p.315-328 (2004)
[54]Hideo Yamada, Osamu Tsuji, Peter Wood, "Stress reduction for hard amorphous hydrogenated carbon thin films deposited by self-bias method", Thin Solid Films, Vol.270, p.220-225 (1995)
[55]R. Sivakumar, M. Jayachandran, C. Sanjeeviraja, "Studies on the effect of substrate temperature on (Ⅵ-Ⅵ) textured tungsten oxide (WO3) thin films on glass, SnO2:F substrates by PVD:EBE technique for electrochromic devices ", Materials Chemistry and Physics, Vol.87, p.439-445 (2004)
[56]Yin-Song Huang, Yu-Zhi Zhang, Xian-Ting Zeng, Xing-Fang Hu, "Study on Raman spectra of electrochromic c-WO3 films and their infrared emittance modulation characteristics", Applied Surface Science, Vol.202, p.104-109 (2002)
[57]P.R. Bueno, F.M. Potes, E.R. Leite, L.O.S. Bulhões, P.S. Pizani, P.N. Lisboa-Filho, W.H. Schreiner, "Structural analysis of pure and LiCF3SO3-doped amorphous WO3 electrochromic films and discussion on coloration kinetics", Journal of Applied Physics, Vol. 96, No.4, p.2102-2109 (2004)
[58]L. Gupta, A. Mansingh, P.K. Srivastava, "Band Gap Narrowing and the Band Structure of Tin-Doped Indium Oxide Films", Thin Solid Films, Vol.176, p.33-44 (1989)
[59]Takaya Kubo and Yoshinori Nishikitani, "Deposition Temperature Dependence of Optical Gap and Coloration Efficiency Spectrum in Electrochromic Tungsten Oxide Films ", Journal of the Electrochemical Society, Vol.145, p.1729-1734 (1998)
[60]X.G. Wang, Y.S. Jiang, N.H. Yang, L. Yuan, S.J. Pang, "Crystallinity and morphology changes of a-WO3 films", Applied Surface Science, Vol.143, p.135-141 (1999)
[61]H. Kamal, A.A. Akl, K. Abdel-Hady, "Influence of proton insertion on the conductivity, structural and optical properties of amorphous and crystalline electrochromic WO3 films", Physica B, Vol.349, p.192-205 (2004)