Optical and Gas sensing properties of BaxSr1-xTiO3 (with x=0.5 and x=0.7) thin films grown using Pulse Laser Deposition

Abstract

Abstract Thin films of Barium Strontium Titanate (BST) have been fabricated using Pulse Laser Deposition (PLD) technique. Two stoichiometries of BaxSr1-xTiO3 with x=0.5 and x=0.7 are deposited on well cleaned quarts substrates in high vacuum chamber with oxygen pressure of 0.13mbar at 700˚C. XRD pattern shows perovskite structure of the films. Energy Dispersive X-ray (EDX) is used to determine the element concentration of both the films. Transmittance spectra of UV characterization shows decrement in transparency of the film as Barium (Ba) concentration increase and sharp cut-offs are observed at the band edge. Refractive Index (n), absorption coefficient (α), extinction coefficient (k), optical conductivity (σ) and optical band gap (Eg) are derived from UV-Vis spectroscopy. The calculated parameters for Ba0.5Sr0.5TiO3 and Ba0.7Sr0.3TiO3 are presented in this work. The present work also includes study of BST thin films as gas sensors.