Microwave-Assisted Hydrothermal Synthesis of Cu-Doped ZnO Single Crystal Nanoparticles with Modified Photoluminescence and Confirmed Ferromagnetism

Abstract

Single crystal ZnO- and Cu-doped ZnO nanoparticles were synthesized by microwave assisted hydrothermal method. The effects of Cu concentration on the optical and magnetic properties of the nanoparticles were investigated. Cu doping did not lead to the formation of a second phase, but slightly reduced the particle size. The valence state of Cu in ZnO was confirmed to be + 2. With the increase of Cu doping concentration, the photoluminescence intensity decreased under the excitation by the light with a wavelength of 325 nm. Intrinsic ferromagnetic behavior was confirmed in Cu-doped ZnO nanoparticles and the saturation magnetization can be enhanced by increasing doping concentration. The origin of ferromagnetism can be interpreted by both effects of Cu doping and the defects.