Simple route deposition and some physical investigations on nanoflower NiMoO4 sprayed thin films

Nickel molybdate (NiMoO4) thin film has been prepared by the spray pyrolysis method, using nickel chloride hexahydrate (NiCl2·6H2O) and ammonium molybdate tetrahydrate [(NH4) 6Mo7O24·4H2O] as precursors in the aqueous starting solution. First, the structure and the surface morphology characterizations were carried out by scanning electron spectroscopy (SEM), Raman and X-ray diffraction (XRD) techniques. Structural analysis by using XRD technique shows that the NiMoO4 thin film crystallizes in the monoclinic phase, mainly orientation along (110), (021), ( $${\bar{2}}04$$ ), (220), (150) and ( $${\bar{1}}52$$ ), directions. In addition to these studies, the stoichiometric composition has been reached by the energy dispersion analysis technique. Second, the optical properties have been studied by means of the reflectance and the transmittance spectra, in the wavelength range of 300–1800 nm. This study shows a direct transition of this ternary oxide with an optical bandgap about 3.12 eV and Urbach energy EU in the order of 663 meV. Finally, the photoluminescence emission spectrum of the NiMoO4 thin film showed emissions peaks in the violet and blue regions and others emission related to some defects in the prepared film.