The Comparison of Optical Properties Between Ba_0.25Sr_0.75TiO₃ and Ba_0.75Sr_0.25TiO₃ Thin Films As The Light Sensors Application

An investigation has been carried out to determine the optical properties of Barium Strontium Titanate (BST) thin films, with different chemical composition, namely Ba0.25Sr₀.75TiO₃ and Ba0.₇₅Sr0.₂₅TiO3. BST thin films that were prepared by the Chemical Solution Deposition (CSD) method and was coated on an Indium Tin Oxide (ITO) substrate using the Spin Coating method at a speed of 3000 rpm for 30 seconds. BST thin films have been characterized using optical microscopy, UV-vis spectrophotometer and X-Ray Diffraction (XRD). The results obtained that the thickness of BST thin films with the composition of Ba_0.25Sr_0.75TiO₃ and Ba0.₇₅Sr0.₂₅TiO3 were 42.7 μm and 28.152 μm respectively, the refractive index value of 2.31 and 2.30 respectively, and they had the gap energy of 3.4 eV and 3.3 eV respectively. From the data obtained data with notes using the same method and treatment, thin film with the chemical structure composition of Ba0.₇₅Sr_0.25TiO3 was declared superior for the usageas photodiode sensors. (paper)