Structural and optical properties of Ba_0.9Sr_0.1TiO₃ thin films prepared by chemical solution routes

Ba_0.9Sr_0.1TiO₃ (BST) thin films were deposited on LaNiO₃ thin films by modified chemical solution routes. X-ray diffraction investigation shows that BST thin films are highly preferential (100) -orientation. Atomic force microscopy shows that BST thin films have large grain size of 80-200 nm. The optical properties were measured by spectroscopic ellipsometry in the photon energy range of 0.7-3.4 eV. Cauchy model was used to express the optical properties. Optical constants (refractive index and extinction coefficient) were obtained. The band gap of the BST thin films is 3.36 eV.