XPS study of nitrogen-implanted ZnO thin films obtained by DC-Magnetron reactive plasma

We have synthesized pure and N-doped ZnO films by reactive plasma in a DC-Magnetron sputtering system. Nitrogen was implanted by using an ion gun attached to an electron spectrometer. The films were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM) to investigate their composition and microstructure. XPS revealed the presence of two well-resolved peaks in N 1s spectra at about 396.2 and 404.3 eV. The peak at 404.3 eV has been assigned to zinc nitrite while the peak at 396.2 eV to zinc nitride. After annealing the sample at 250 °C in air for 1 h, one single peak, located at 399.1 eV, was observed. We suggest that this is due to the decomposition of nitrite and the formation of oxynitride.