Structure and Properties of ZnO: (Cr, N) Film Prepared by Thermal Oxidation Method

The ZnO: (Cr, N) films were fabricated by annealed Zn3N2: Cr films in flowing O-2 ambient, while the Zn3N2: Cr films were deposited on quartz substrates by RF-sputtering of Zn target and DC-sputtering of Cr target. The variation of structure, optical bandgap, and third nonlinear optical properties with a different Cr sputtering power is investigated. X-ray diffraction (XRD) spectra were used to examine the microstructure of the thin films. Optical bandgap of the thin films was determined by UV/Visible spectroscopy. The third-order nonlinear optical properties were measured by a standard Z-scan device. The analyzed results indicate that the obtained films are of good crystal quality, which have a pure hexagonal wurtzite ZnO structure without any Cr related phases. The optical bandgaps are 3.35 eV and 3.40 eV for Cr sputtering power of 12 W and 16 W, respectively. The TZ-scan experiment and analysis results show that the films are a self-defocusing material with saturation absorption properties. The ZnO: (Cr, N) film have good third-order nonlinear optical properties when the film prepared by Cr sputtering power is 12 W and annealed temperature was 400 degrees C.