Influence of substrate and annealing temperatures on optical properties of RF-sputtered TiO2 thin films
Document Type
Article
Publication Date
1-1-2010
Abstract
TiO2 thin films were deposited on unheated and heated glass substrates at an elevated sputtering pressure of 3 Pa by radio frequency (RF) reactive magnetron sputtering. TiO2 films deposited at room temperature were annealed in air for 1 h at various temperatures ranging from 300 to 600 °C. The structural and optical properties of the thin films were investigated using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and ultraviolet–visible–near infrared (UV–VIS–NIR) spectrophotometry. XRD results show that as-grown and post-annealed TiO2 films have anatase crystal structure. Higher substrate and annealing temperatures result in a slight increase of crystallinity. TiO2 films deposited at different substrate temperatures exhibit high visible transmittance and the transmittance decreases slightly with an increase in annealing temperature. The refractive indices (at λ = 550 nm) of the as-deposited and annealed films are found to be in the range of 2.31–2.37 and 2.31–2.35, respectively. Extinction coefficient decreases slightly with increasing substrate and annealing temperatures. The indirect and direct optical band gap of the as-grown films increases from 3.39 to 3.42 eV and 3.68 to 3.70 eV, respectively, with the increase of substrate temperatures. Annealed TiO2 films also exhibit an increase in the values of indirect and direct optical band gap.
Keywords
Optical properties, RF reactive sputtering, Structure, Titanium dioxide, Anatase crystals, Annealed films, Annealing temperatures, As-grown, As-grown films, Crystallinities, Different substrates, Extinction coefficients, Field emission scanning electron microscopy, Heated glass substrates, Near Infrared, Radio frequencies, Reactive magnetron sputtering, Room temperature, Sputtering pressures, Structural and optical properties, Substrate temperature, TiO, UV-vis-NIR, Visible transmittance, XRD, Annealing, Crystal structure, Energy gap, Field emission, Field emission microscopes, Infrared devices, Near field scanning optical microscopy, Optical band gaps, Organic polymers, Oxides, Refractive index, Scanning electron microscopy, Structural properties, Thin films, Titanium, X ray diffraction, X ray diffraction analysis, Substrates.
Divisions
fac_eng
Publication Title
Optical Materials
Volume
32
Issue
6
Publisher
Elsevier
Additional Information
Cited By (since 1996): 10 Export Date: 6 December 2012 Source: Scopus CODEN: OMATE Language of Original Document: English Correspondence Address: Hasan, M.M.; Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur, Malaysia; email: mmhasan92@yahoo.com References: Pulker, H.K., (1999) Coatings on Glass, , Elsevier, Amsterdam; Euvananont, C., Junin, C., Inpor, K., Limthongkul, P., Thanachayanont, C., (2008) Ceram. Int., 34, p. 1067; Kawasaki, H., Ohshima, T., Yagyu, Y., Suda, Y., Khartsev, S.I., Grishin, A.M., (2008) J. Phys.: Conf. Ser., 100, p. 012038; Ray, S., Dutta, U., Das, R., Chatterjee, P., (2007) J. Phys. D: Appl. Phys., 40, p. 2445; Sung, Y.M., Kim, H.J., (2007) Thin Solid Films, 515, p. 4996; Yang, W., Wolden, C.A., (2006) Thin Solid Films, 515, p. 1708; Tavares, C.J., Vieira, J., Rebouta, L., Hungerford, G., Coutinho, P., Teixeira, V., Carneiro, J.O., Fernandes, A.J., (2007) Mater. Sci. Eng. B, 138, p. 139; Okada, M., Tazawa, M., Jin, P., Yamada, Y., Yoshimura, K., (2006) Vacuum, 80, p. 732; Wang, Z., Chen, Q., Cai, X., (2005) Appl. Surf. Sci., 239, p. 262; Jin, P., Miao, L., Tanemura, S., Xu, G., Tazawa, M., Yoshimura, K., (2003) Appl. Surf. Sci., 212-213, p. 775; Ye, Q., Liu, P.Y., Tang, Z.F., Zhai, L., (2007) Vacuum, 81, p. 627; Habibi, M.H., Talebian, N., Choi, J.H., (2007) Dyes Pigm., 73, p. 103; Yang, C., Fan, H., Xi, Y., Chen, J., Li, Z., (2008) Appl. Surf. Sci., 254, p. 2685; Amor, S.B., Baud, G., Jacquet, M., Pichon, N., (1998) Surf. Coat. Technol., 102, p. 63; Ghamsari, M.S., Bahramian, A.R., (2008) Mater. Lett., 62, p. 361; Wang, Z., Helmersson, U., Käll, P.O., (2002) Thin Solid Films, 405, p. 50; Sun, H., Wang, C., Pang, S., Li, X., Tao, Y., Tang, H., Liu, M., (2008) J. Non-Cryst. Solids, 354, p. 1440; Hou, Y.Q., Zhuang, D.M., Zhang, G., Zhao, M., Wu, M.S., (2003) Appl. Surf. Sci., 218, p. 98; Sawanepoel, R., (1983) J. Phys. E: Sci. Instrum., 16, p. 1214; Karuppasamy, A., Subrahmanyam, A., (2007) J. Appl. Phys., 101, p. 064318; Wang, T.M., Zheng, S.K., Hao, W.C., Wang, C., (2002) Surf. Coat. Technol., 155, p. 141; Saini, K.K., Sharma, S.D., Chanderkant, Kar, M., Singh, D., Sharma, C.P., (2007) J. Non-Cryst. Solids, 353, p. 2469; Tauc, J., (1974) Amorphous and Liquid Semiconductors, , Plenum, London; Yoo, D., Kim, I., Kim, S., Hahn, C.H., Lee, C., Cho, S., (2007) Appl. Surf. Sci., 253, p. 3888; Ting, C.C., Chen, S.Y., Liu, D.M., (2000) J. Appl. Phys., 88 (8), p. 4628