OPTICAL PROPERTIES OF BMN-BT FERROELECTRIC THIN FILMS PREPARED BY SPRAY PYROLYSIS DEPOSITION

Abstract

By using spray pyrolysis method, 0.65 Ba ( Mg 1/3, Nb 2/3) O 3-0.35 BaTiO 3 thin films were deposited on glass/aluminum substrates. The effect of annealing temperature on perovskite phase and crystalline structure analysis of the BMN-BT films performed on an X-ray diffraction (XRD). The optical properties of the resultant materials have been characterized as a function of substrate's temperature. The absorption coefficient (α) and extinction coefficient (k) of the films are obtained by using UV-vis spectroscopy. The band gap energy values of the films using analysis of the absorption coefficient and Tauc's formula have also been determined. For films deposited at different substrate temperatures, direct transitions occur with energies varying from 4.57 eV to 4.21 eV.