Unveiling the nature of adsorbed species onto the surface of MgO thin films during prolonged annealing

Present work investigates the nature of adsorbed species onto the surface of MgO thin films during prolonged annealing. The prolonged annealing (300 °C, 24 h) was performed on MgO thin films of different thicknesses ranging from 6.5 to 56.2 nm in order to exactly identify the related effect. Deposited films of different thicknesses exhibited local electronic structure very much analogues to the bulk MgO as investigated through near edge X-ray absorption fine structure measurements. These measurements further revealed that local electronic structure was significantly modified by prolonged annealing. It was contemplated that oxygen molecules were adsorbed on the surface of MgO thin films during prolonged annealing. Apart from this, onset of H2O adsorption was also identified using Fourier transform infrared spectroscopy. [Display omitted] •Deposition of MgO thin films using radio-frequency sputtering method.•Preferred (220) orientation of films were confirmed using X-ray diffraction.•Near edge fine structure and FTIR measurements reveals oxygen and water adsorption on MgO thin films.