Characterization of ZnO:N films prepared by annealing sputtered zinc oxynitride films at different temperatures

N-doped ZnO films were prepared by annealing zinc oxynitride films deposited by rf reactive sputtering. Two Raman peaks were observed at 274 and 580 cm-1. According to the variation of the integral intensity of these two peaks, the nitrogen activation at 500 °C [the activation temperature (AT)] has been obtained. Below the AT, the integral intensities of them show a different variation trend. X-ray photoelectron spectroscopy (XPS) indicates the N chemical state variation for them and finds the activated Zn-N bond. Further analyses by photoluminescence (PL) spectra and spectroscopic ellipsometry (SE) have been carried out. The activated sample exhibits a symmetric emission peak at 3.22 eV assigned to be the A X0 emission at room temperature. SE investigation takes account of samples within the different temperature span divided by the AT. Different factors, such as nitrogen dopant (N) O and the nanocrystal growth, which affect the redshift of the absorption edges, have been discussed.