Investigation of structural, optical dielectrical and optical conductivity properties of BaTiO3, Al0.01Ba0.99TiO3 and La0.01Ba0.99TiO3 thin films prepared by pulsed laser deposition

The pulsed laser deposition technique was used to prepare BaTiO3 (BTO), Al0.01Ba0.99TiO3 (ABTO) and La0.01Ba0.99TiO3 (LBTO) thin films. The structures of these films were determined using x-ray diffraction, while the surface topography was examined by scanning electron microscopy. This study shows that these films have a nanopolycrystalline structure. The optical properties of these samples were studied. The optical parameters such as optical energy gap, refractive index, extinction coefficient, dielectric loss and dielectric tangent loss were determined for these films. The values of oscillating energy (E-o) and dispersion energy (E-d) increase for the BTO, ABTO and LBTO thin films, respectively. While the values of both effective mass/carrier concentration (N/m*) and infinite permittivity (epsilon(infinity)) decrease for the BTO, ABTO and LBTO films, respectively. On the other hand, both terms of optical conductivity (the real part sigma(1) and the imaginary part sigma(2)) and the ratio of the surface energy loss function to the volume energy loss function were determined optically for these films.