Preparation of Nitrogen Doped ZnO Dilute Ferromagnetic Semiconductor by Magnetron Sputtering
ZnO/Zn3N2 multilayer films were synthesized on slide glass substrates by radio-frequency (RF) magnetron sputtering technology with RF powers of 100 W. After annealing in oxygen atmosphere for 3 hours at the temperature changed from 473 K to 873 K, the multilayer films were changed to be single-layer films of nitrogen doped ZnO dilute ferromagnetic semiconductor. The structural, elementary constituents, carrier concentration and magnetic properties of the films were investigated with X-ray diffraction (XRD), X-ray photoemission spectroscopy (XPS), hall-effect measurements and vibrating sample magnetometer (VSM) magnetization measurements, respectively. The XRD measurements revealed that the nitrogen doped ZnO films had a wurtzite structure with their crystal (002) directions oriented along the c-axis of the substrate. Hall-effect measurements indicated that nitrogen doped ZnO thin film, annealed at 673 K for 3 hour, had the best p-type properties. Carrier concentration and resistivity of the film was 3.12 × 1017 cm-3 and 93 Ωcm, respectively. A Lakeshore 7407 vibrating sample magnetometer was employed for magnetization (M) versus applied field strength (H) investigations of these thin films. A typical hysteresis loop was found in the observed M–H curve of the samples, demonstrated that the films annealed at 673 K for 3 hour were ferromagnetic at 300 K. The XPS analysis revealed the presence of Zn-N chemical bonding in the films. It suggested that nitrogen atoms are substituted at the oxygen sites of the ZnO films and mediate the ferromagnetic properties of the films.
Yansheng Yin and Xin Wang
W. S. Lin et al., "Preparation of Nitrogen Doped ZnO Dilute Ferromagnetic Semiconductor by Magnetron Sputtering", Advanced Materials Research, Vols. 79-82, pp. 1827-1830, 2009