Structural, optical and magnetic properties of Co-doped ZnO nanoparticles prepared via a wet chemical route

In this paper, ZnO nanoparticles doped with varying amount of Co contents (i.e., 0, 2, 4, 6, 8, and 10 at.%) have been prepared by wet chemical route. X-ray diffraction (XRD) results reveal the successful substitution of Co2+ ions on to sites of Zn2+ ions without forming any secondary phase. Furthermore, a linear increase in d-spacing of the ZnO lattice is found with the increase in Co content. SEM images demonstrate the formation of homogeneously distributed spherical nanoparticles with average size of 50-70 nm. It is observed from optical investigations that band gap energy of ZnO nanoparticles is significantly decreased with the increase in Co doping level. Interestingly, it is found that the high Co dopant concentration can lead to room temperature ferromagnetism in ZnO nanoparticles.