Structural and optical properties of Ba0.9Sr0.1TiO3 thin films prepared by chemical solution routes

Ba0.9Sr0.1TiO3 (BST) thin films were deposited on LaNiO3 thin films by modified chemical solution routes. Xray diffraction investigation shows that BST thin films are highly preferential ( 100)-orientation. Atomic force microscopy shows that the films have large size of 80 similar to 200 nm. The optical properties of the films were measured by spectroscopic ellipsometry in the photon energy range of 0.7 similar to 3.4eV. Cauchy model was used to express the optical properties of BST thin films. Optical constants (refractive index k and extinction coefficient k) of the BST films were obtained. The band gap E-g of the BST films was determined to be 3. 36 eV.