Correlations between the optical properties and the microstructure of TiO2 thin films prepared by reactive electron-beam evaporation
- 65 Downloads
High refractive index TiO2 thin films were deposited on BK7 glass by reactive electron—beam (REB) evaporation at pressure of 2×10−2 Pa, deposition rate of 0.2 nm/s and at various substrate temperatures from 120°C to 300°C. The refractive index and the thickness of the films were measured by visible spectroscopic ellipsometry (SE) and determined from transmission spectra. Optical properties and structure features were characterized by UV-VIS, SEM and XRD, respectively. The measurement and analysis on transmission spectra of all samples show that with the substrate temperature increasing from 120°C to 300°C, the refractive indices of thin films increase from 1.7 to 2.1 and the films after heat treatment have higher refractive indices due to its crystallizing. The XRD analysis results indicate that the structure of TiO2 thin films deposited on BK7 glass at substrate temperatures of 120°C, 200°C and 300°C is amorphous, after post-annealing under air condition at 400°C for 1 hour, the amorphous structure is crystallized, the crystal phase is of 100% anatase with strong preferred orientation (004) and the grain size of crystalline is within 3.6–8.1 nm, which is consistent with results from SEM observation.
Key wordsthin film titania XRD SEM reactive evaporation
Unable to display preview. Download preview PDF.
- 1.Wei Jianhong, Xiao Jing, Zhao Xiujian,et al. Preparation of Ag−TiO2 Thin Film by Sol-gel Method.J. Wuhan Univ. of Tech.-Mater. Sci. Ed., 2001, 16(4): 27–30Google Scholar
- 2.Yu Jiaguo, Zhao Xiujian, Zhang Gaoke et al. Grain Size and Photocatalytic Activity of Nanometer TiO2.J. Wuhan Univ. of Tech.-Mater. Sci. Ed. 2001, 16(2): 1–5Google Scholar
- 3.He Feng, Li Qiantao, Hu Wangkai,et al. Preparation of Nanometer Structured TiO2 Thin Films by Sol-Gel Meth.J. Wuhan Univ. of Tech.-Mater. Sci. Ed., 2002, 17(4): 20–22Google Scholar
- 4.Wang X H, Xue Y Y, Zhao L,et al. Optical Thin Films and Its New Status.Journal of Wuhan University of Technology, 2002, 24(2): 20–23 (in Chinese)Google Scholar
- 5.Brady G S, Clauser H R.Materials Handbook, 13th Ed. Mc Graw-Hill, New York, 1991: 948Google Scholar
- 6.Palik E D.Handbook of Optical Cons tants of Solids II, New York, Academic Press, 1991: 795Google Scholar
- 7.Wang X H, Xue Y Y, Zhao L,et al. Study on the Structure and Optical Properties of TiO2 Thin Films Deposited by Reactive Electron Beam Evaporation.Journal of Wuhan University of Technology, 2002, 24(11): 30–33 (in Chinese)Google Scholar
- 8.Macleod H A.Thin-film Optical Filters. Institute of Physics Publishing, P. A., 2001: 40–43Google Scholar
- 11.Wang Y L, Souche D, Zhang K Y,et al. Relations between the Optical Properties and Microstructure and of TiO2 Thin Films Prepared by Ion-assisted Depos-ition.Thin Solid Films, 1997, 307(1,2): 38–42Google Scholar
- 12.Milton Ohring.Materials Science of Thin Films Deposition and Structure, 2nd Ed., New York, Academic Press, 2001: 498–501Google Scholar
- 14.Klugm H P, Alexander L E.X-ray Diffraction Procedures. New York, Wiley Intersci. 2nd edition (1974).Google Scholar