The structural, magnetic, and optical properties of ZnO (0001) wafers implanted with Co ions

The ion implantation technique was employed to study the structural, magnetic, and optical properties of Co-doped crystalline ZnO. The photoluminescence measurements indicated that the center of green emission of implanted samples shifts gradually from 510 nm to 531 nm with an increase of Co concentrations. All implanted samples are ferromagnetic at room temperature with a saturation magnetization from 6.89×10−5 to 2.31×10−4 emu. The possible mechanisms on the observed ferromagnetism were discussed.