Abstract
Molybdenum trioxide (MoO3) thin films have been prepared by the spray pyrolysis technique on glass substrates at 460°C using (NH4)6Mo7O24·4H2O (ACROS pure more than 99.0%) as precursor in the starting solution. X-ray analysis shows that MoO3 thin film crystallizes in orthorhombic structure with a preferred orientation of the crystallites along (020) and (040) directions. The surface topography of these films was performed by atomic force microscopy and the optical properties were investigated through reflectance and transmittance measurements. The optical band gap energy value is about 3.46eV and the Urbach energy is of the order of 191meV. Raman spectroscopy shows the bands׳ positions corresponding to α-MoO3 phase. PL measurements show two large bands located at 375nm and 575nm respectively. Finally, the electric conductivity of MoO3 thin film was investigated using impedance spectroscopy technique in the frequency range 5Hz–13MHz at various temperatures (300–500°C). The variation of the conductivity in terms of the temperature is characterized by the existence of two ranges with activation energy of 1.00, and 0.42eV. AC conductivity of MoO3 thin films is investigated through Jonsher law.