Morphological and optical evolution of different organic acids used MoO3 thin films by spin coating method

Abstract

Molybdenum trioxide (MoO3) thin films were prepared at room temperature (RT) and at different annealing temperatures of 250, 350, 450 and 550°C. We also prepared MoO3 films using additives of water-soluble and water-insoluble organic acids. The thin films were coated using the spin coating technique and annealed at 350°C temperature. The effects of different annealing temperatures and different organic acid additives on MoO3 films were characterized by structural and optical studies. From the XRD pattern, the structure of the MoO3 films is found to vary with respect to increase in the annealing temperature. For RT and 250°C, the hexagonal structure was observed and for 350, 450 and 550°C, the orthorhombic structure was observed. The XRD pattern for all the organic acid additive used MoO3 films exposed the orthorhombic structure. SEM images show hasty variations in the surface morphology for different annealed MoO3 films and different additive used MoO3 films. The EDX analysis confirmed the presence of Mo and O elements for all the films. The UV–vis results show the absorbance and transmittance values. The band gap energy was found to be around 3.8eV for all the MoO3 films.