Investigation of structural, optical and electric properties of silver and iron doped barium titanate thin films deposited by spray pyrolysis

Abstract

In this work, undoped Barium Titanate (BTO), Silver (Ag) and Iron (Fe) doped BTO thin films have been deposited using the spray pyrolysis method onto plain glass substrates at 300 ℃. The surface morphology, structural, optical and electrical properties of Ag and Fe doped BTO thin films have been investigated with doping concentrations of 2, 4, 6 and 8at.% of Ag and Fe. The surface morphology of these films has been observed by scanning electron microscopy (SEM). The stoichiometry of the thin films was confirmed using Energy Dispersive Analysis of X-rays (EDAX). X-ray diffraction (XRD) was used to study the structure and crystallite size of BTO nanoparticles. The XRD pattern of undoped BTO and Ag doped BTO thin films revealed that the different types of the grain of hexagonal phase have been formed for undoped BTO and Ag doped BTO thin films. The optical properties were studied using UV-Visible spectroscopy in the wavelength range of 200-1100 nm. The calculated band gap for undoped BTO is found at 2.80 eV and for 2, 4, 6 and 8 at. % Ag doped BTO thin films are 2.30, 2.26, 2.22 and 2.0 eV, respectively. The hexagonal phase for BTO turned into a tetragonal phase for Fe doped BTO thin films. The evaluated band gaps are 2.79, 2.77, 2.57 and 2.51 eV for 2, 4, 6 and 8 at. % Fe doped BTO thin films. The metallic and semiconducting nature of the undoped BTO, Ag and Fe doped BTO thin films were found using the four-probe method.