Influence of Annealing Temperature on Mn-doped ZnO Diluted Magnetic Semiconductor Thin Films

In this paper, we report the effects of Mn2+ and the defect on ferromagnetism in Mn-doped ZnO thin films prepared by radio frequency magnetron sputtering at different annealing temperature below 600 °C. The result of superconducting quantum interference device reveals that the sample which annealed at 500 °C realized ferromagnetism till room temperature. The X-ray diffraction results shows that the samples are wurtzite structure and the sample annealed at optimum temperature gets relatively better crystallinity. X-ray photoelectron spectroscopy results show clear evidence of oxygen vacancy increment for the samples which annealed at 500 °C. Our results indicate that Mn2+ ions replace the Zn sites and no evidence for either metallic Mn or Mn-related oxide in the samples. It was concluded that the existence of ferromagnetism was closely related to the concentration of Mn2+ and the defect of the ZnO matrix.