Morphological, structural and optical properties of MoO2 films electrodeposited on SnO2∣glass plate

Abstract

Abstract MoO2 films were prepared by electrodeposition under potential controlled conditions from an aqueous alkaline solution of sodium molybdate. Optical microscopy showed that films of different morphology were deposited. The surface roughness and grain size were determined by atomic force microscopy. The characterization of as-deposited films by X-ray diffraction analysis revealed their amorphous nature. The optical constants of films were derived from transmittance spectra recorded in the 310–1100 nm wavelength range. All films were highly absorptive and showed a direct band to band transition. From the absorption edge data, the values of the optical band gap E g and the Urbach energy E U were determined based on Tauc’s model. The influence of film thickness on the extinction coefficient k, refractive index n, absorption coefficient a and the band gap energy E g was studied.