Fabrication and Study on Magnetic-Optical Properties of Ni-Doped ZnO Nanorod Arrays

Zn_1-xNi_xO nanorod arrays were prepared on Si substrates by magnetron sputtering and hydrothermal methods at 100 °C. We studied the effects of doped concentration and hydrothermal growth conditions on the crystal structure, morphology, photoluminescence, and magnetic properties of Zn_1-xNi_xO nanorod arrays. The research results show that the Zn_1-xNi_xO nanorod have the hexagonal wurtzite structure without the appearance of the second phase, and all samples have a highly preferred orientation of a (002) crystal face. The Zn_1-xNi_xO nanorod arrays exhibit obvious room temperature ferromagnetism with saturation magnetization at 4.2 × 10^-4 emu/g, the residual magnetization is 1.3 × 10^-4 emu/g and the coercive field is 502 Oe, and also excellent luminescent properties with seven times greater luminous intensity than that of ZnO nanorod arrays. The redshift of the ultraviolet emission peak was found by Ni²⁺ doping. We further explained the source and essence of the magnetic properties of Zn_1-xNi_xO nanorod arrays and deemed that the magnetic moment mainly comes from the hybrid electron exchange of O 2p and Ni 3d state.