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 A0X 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. [ABSTRACT FROM AUTHOR]