Structural, spectroscopic and electrical properties of dc magnetron sputtered NiO thin films and an insight into different defect states

In this article, we report a detailed study on the influence of sputter power on physical properties of the NiO films grown by DC magnetron sputtering. Structural studies carried out by Grazing Incidence X-ray diffraction (XRD) reveals the polycrystalline nature of the films with FCC phase. The crystallographic orientation (111) plane followed by (200), (220), and (311) plane were evident from the XRD spectra. The average crystallites sizes were estimated from the spectra, and the values were compared using three different plots such as Scherrer, Williamson–Hall and size–strain plot. The surface morphology was carried out by atomic force microscopy. The deposited samples show semitransparent behavior in the visible region and the estimated band gap increased from 2.70 to 3.34 eV with an increase in sputter power. Furthermore, X-ray photoelectron spectroscopy (XPS) core-level Ni2p spectra were deconvoluted and the observed Ni 2 p _3/2, Ni 2 p _{1 / 2} domain along with their satellite’s peaks were analyzed. Most importantly, XPS quantification data and Raman spectra confirm the presence of both Ni ^{2 +} and Ni ^{3 +} states in the NiO films. The electrical properties carried at room temperature revealed that the resistivity of the film significantly increased and a mobility of ~ 84 cm ²V ^{- 1}s^{- 1} was obtained.