Structural, optical and electrical properties of N-doped ZnO thin films prepared by thermal oxidation of pulsed filtered cathodic vacuum arc deposited ZnxNy films

In this study, N-doped ZnO thin films were fabricated by oxidation of ZnxNy films. The ZnxNy thin films were deposited on glass substrates by pulsed filtered cathodic vacuum arc deposition (PFCVAD) using metallic zinc wire (99.999%) as a cathode target in pure nitrogen plasma. The influence of oxidation temperature, on the electrical, structural and optical properties of N-doped ZnO films was investigated. P-type conduction was achieved for the N-doped ZnO obtained at 450 °C by oxidation of ZnxNy, with a resistivity of 16.1 Ω cm, hole concentration of 2.03 × 1016 cm−3 and Hall mobility of 19 cm2/V s. X-ray photoelectron spectroscopy (XPS) analysis confirmed the incorporation of N into the ZnO films. X-ray diffraction (XRD) pattern showed that the films as-deposited and oxidized at 350 °C were amorphous. However, the oxidized films in air atmosphere at 450–550 °C were polycrystalline without preferential orientation. In room temperature photoluminescence (PL) spectra, an ultraviolet (UV) peak was seen for all the samples. In addition, a broad deep level emission was observed.

Figure optionsDownload as PowerPoint slideHighlights▶ Thermal oxidation of ZnxNy method is used to obtain N doped ZnO. ▶ N acceptors in ZnO is not sufficiently activated at oxidation temperature below 350 °C. ▶ Oxidation treatment at 450 °C activates more N acceptors in ZnO. ▶ Oxidation treatment at high temperatures above 550 °C reduces the N concentration in the ZnO thin film.