Structural and Electrical Properties of Nanostructured Ba_0.8Sr_0.2TiO₃ Films Deposited by Pulsed Laser Deposition

Abstract

Barium Strontium Titanate Ba0.8Sr0.2TiO3 (BST) thin films have been deposited on Pt/Ti/SiO2/Si substrates by pulsed laser deposition technique. The X-ray diffraction (XRD) shows that the films crystallize in a perovskite phase. XRD and Atomic Force Microscopy (AFM) characterization reveal that the grains are nano-sized. Rutherford Backscattering Spectrometry (RBS) analysis shows the stoichiometry of the films to be close to the stoichiometry of the target. The Raman spectroscopy shows that the films exhibit the tetragonal structure by the presence of the Raman active modes at 301 cm(-1) and 729 cm(-1), at room temperature. Leakage current measurements of Au/ Ba0.8Sr0.2TiO3/Pt capacitors have been done, at room temperature, to investigate the conduction mechanisms of the films. We found that there are two different conduction regions in the capacitors, namely, an ohmic behavior at low voltages and a Schottky emission mechanism at high voltages. The Schottky barrier height has been estimated to be 0.99 eV.