Abstract:

TiO₂ thin films were deposited on low temperature on poly（methylmethacrylate） （PMMA） by DC pulse magnetron sputtering. The effects of oxygen ratio， vacuum degree and other parameters on the structure and optical properties of TiO₂ thin films were studied. With the help of elliptic polarizing light tester， X⁃ray diffraction （XRD） tester， spectrophotometer and atomic force microscope （AFM）， the optical properties， element composition， crystallization properties and microstructure of the thin films were analyzed. The experimental result shows that with the increases of oxygen ratio， the deposition rate of the film decreases， the particle size of the film becomes larger， and the film tend to be looser. In term of optical properties， the refractive index deceases with the increase of oxygen proportion，but visible light transmittance increases，the reflectance appears redshift. The films packing densities calculated according to the refractive index are 0.95，0.93，0.87，0.88 and 0.78 respectively， changes inversely with the proportion of oxygen. The band gap of the films calculated according to the spectrum is between 3.12~3.14 eV， changes inversely with the proportion of oxygen. With the decreases of vacuum， the deposition speed of the film first increased and then decreased. The films tend to be looser， and the refractive index decreased. The packing density of the film calculated according to the refractive index are 0.96，0.95，0.89，0.88，0.88，0.87， the vacuum degree has an positive effect on the visible light transmittance of the film， and has an negative effect on the band gap width of the film， which is between 3.13~3.16 eV， The TiO₂ thin films deposited in this paper are amorphous，and the oxygen tatio and vacuum degree has little effect on their crystallinity.

Key words: poly（methylmethacrylate）, titanium dioxide, thin film, magnetron sputtering, optical property, microstructure