Abstract:

Perovskite-structured SrSnO₃ has attracted considerable attention in recent years because of its unusual dielectric and semiconducting properties. Certain dopants can be used to modify and improve the properties of these materials. Epitaxial SrSn_1-xCo_xO₃ (x = 0, 0.16, 0.33, 0.5) (SSCO) thin films were deposited on single crystal SrTiO₃(001) substrates via the pulsed laser deposition method. The crystallinity, microstructure, optical, and electrical properties of the films were investigated. The results indicated that SrSn_1-xCo_xO₃ films were epitaxially grown on SrTiO₃(001) substrate with both a perovskite structure and high crystallinity irrespective of the Co doping level. The films exhibited a smooth and dense morphology with a root-mean-square roughness of 0.44 nm and a film thickness of ~200 nm. As the'x' value increased from 0 to 0.5, the optical transmittance decreased from 90%to 25%, and the band gap dropped from 4.24 to 2.44 eV. Moreover, the doped film exhibited a high dielectric constant of 70.1 at 10⁶ Hz, 57% higher than the control SrSnO₃ film. The SSCO film displayed surface resistivity of 172 MΩ at room temperature and high stability at temperature up to 1000℃.

Key words: Alkaline earth stannate, Physical vapour deposition, Thin film, Epitaxial growth, Optical band gap