Electrical and optical properties of TiOx thin films deposited by reactive magnetron sputtering

The present study of the electronic properties of titanium monoxide thin films is centered on the electrical and optical properties of nano-grain material. TiOx thin films with x ranging from 0.75 to 1.45 have been deposited by r.f. reactive magnetron sputtering in a mixed Ar/O2 or Ar/H2O atmosphere. All films show a negative temperature coefficient of the resistivity. Spectroscopic ellipsometry measurements were performed in the Vis-UV spectral range. The free carrier and interband contributions to the dielectric function have been sorted out. The most striking feature of the free carrier optical response is the very short scattering time of the order of 10−15 s. Such an intense impurity scattering is beyond the validity range of the semi-classical Boltzmann equation and remains an open problem.