Optical and nonlinear optical properties of Cobalt doped ZnO nanostructures

Cobalt doped zinc oxide nanostructures were prepared in room temperature through a wet chemical method. X-Ray diffraction studies confirm that the prepared particles have a hexagonal wurtzite structure. The morphology of the particles is found from Scanning Electron Microscopy. Optical absorption measurements reveal the presence of an exciton peak at 375 nm (3.31 eV). Excitation at 330 nm shows photoluminescence arising from exciton recombination and oxygen vacancies. Open aperture z-scan measurements using 5 ns laser pulses at 532 nm reveal an optical limiting behavior arising from three-photon absorption, which gets enhanced for higher concentrations of Co.