Characteristics of nickel doped zinc oxide thin films prepared by sputtering

Nickel-doped zinc oxide thin films were prepared by the magnetron sputtering method. We have studied the structure and optical properties of the samples by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and optical transmittance. The chemical ingredients were examined by energy dispersive X-ray spectroscopy (EDS), and the charge state of Ni ions in the ZnO:Ni films was characterized by X-ray photoelectronic spectrometry (XPS). From the XRD spectra of the samples, it was obvious that there was no second phase, but the doping can disturb the ZnO crystal lattice and change the lattice parameters. All the films prepared have a wurtzite structure and grow mainly along the c-axis orientation. The magnetic measurments showed that the samples exhibit no ferromagnetism above room temperature.