Electrical transport properties of Ru1-xTixO2 films deposited by magnetron sputtering technique

Abstract The optical and electrical properties of Ru1-xTixO2 (0 ≤ x ≤ 0.13) thin films deposited by hybrid HiPIMS/DCMS process have been investigated as function of Ti content. The optical properties were studied by specular reflectivity and spectroscopic ellipsometry in the photon energy range 1.3–6.3 eV. The electrical resistivity was measured by the van der Pauw method in the temperature range from 20 K to 300 K and Hall effect was examined at 300 K. Pure RuO2 and Ru1-xTixO2 films with x ≤ 0.026 exhibit reflectivity and dielectric functions comparable to those of the RuO2 single crystals reported in the literature. For 0.62 ≤ x ≤ 0.13 important modifications in the optical and electrical properties of Ru1-xTixO2 films were noticed. The optical properties of the films are well described by the Drude-Lorentz model. The resistivity vs temperature variation of all the Ru1-xTixO2 thin films revealed a metallic behavior. Hall measurements indicated that these films are p-type conductors. The results are interpreted by considering the modifications of RuO2 band structure induced by the substitution of Ru4+ with Ti4+.