Structural and Optical Properties of Co-Doped ZnO Nanoparticles Synthesized by Precipitation Method

This article deals with the synthesis and characterization of cobalt-doped zinc oxide nanopowder prepared by precipitation method. Prepared nanopowders were analyzed for morphological, structural and optical properties. X-ray diffraction study confirmed the substitution of cobalt ion without disturbing the basic wurtzite structure of zinc oxide. The average particle size was found to increase on cobalt doping as compared to undoped zinc oxide. The lattice constants increased with composition. Scanning electron microscope study also confirmed the existence of particles in nanometer size. Furthermore, scanning electron micrograph confirmed the increase of particle size on cobalt doping. Optical transmittance spectrum shows that cobalt dopant decreases the transmittance of zinc oxide less than 60%. Energy gap of the samples determined from the absorption spectrum shows that it decreases with the increase of cobalt content. The blue and green emission lines of photoluminescence spectrum also confirmed the substitution of cobalt ion in zinc oxide.