Effect of oxygen partial pressure on the properties of NiO–Ag composite films grown by DC reactive magnetron sputtering

Abstract

• NiO–Ag films were deposited using DC reactive magnetron sputtering technique. • Surface morphology was highly influenced by reactive gas of oxygen. • The resistivity values exhibited a decreasing tendency with partial pressure of oxygen. • The electrical properties of p-NiO films were enhanced by Ag doping. NiO–Ag composite thin films were grown on Corning 7059 glass substrates at 200 °C by DC reactive magnetron sputtering technique. The effect of the oxygen partial pressure on the properties of the deposited films was investigated by X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), optical and Hall measurements. X-ray diffraction analysis revealed that the deposited films were polycrystalline nature with cubic structure along (2 2 0) and (1 1 1) orientations. X-ray photo electron spectroscopy confirmed the surface presence of Ag ions, indicated that Ag ions were oxidized in the NiO matrix. Morphological studies showed that the grain size and root mean square (RMS) roughness were increased with increasing the oxygen partial pressure. The optical transmittance and band gap values were found to be increased with increasing oxygen partial pressure up to 5 × 10 − 4 mbar, beyond this the values were decreased. The electrical resistivity showed decreasing tendency with increasing the oxygen partial pressure.