Effect of substrate temperature on the structural and optical properties of MoO3 thin films prepared by spray pyrolysis technique

Thin films of Molybdenum oxide were prepared by spray pyrolysis technique on glass substrates, by using 0.1 M of molybdenum chloride (MoCl5) dissolved in deionized water. Influence of substrate temperature on structural and optical properties is studied in the range from 200 to 300 °C. The prepared samples correspond to MoO3 phase with orientation and crystallites size which are modified by deposition temperature, the films prepared at 200 °C are monoclinic and the films prepared in the range from 250 to 300 °C are polycrystalline with orthorhombic symmetry. The samples present transmission coefficient and optical gap which vary as function of substrate temperature. Gap energy is located between 3.14 and 3.34 eV depending on the substrate temperature.