Co doped ZnO nanowires with different Co contents have been fabricated by a chemical vapor deposition method. X-ray diffraction results show that all the samples are of single phase and crystallize in wurtzite ZnO structure. The lattice parameter a increases with increasing Co content, while the parameter c has no obvious change with increasing Co. Raman spectra show that the nonpolar E2(High) mode becomes broad and weak with the doping of Co, which indicates that the incorporation of Co causes structural disorder in the crystalline columnar ZnO lattice. The photoluminescence spectra exhibit that the position of the ultraviolet emission shifts to short wavelength and the intensity decreases with increasing Co. The green emission is affected by two contrary factors. It is increased by the introduced defects, but suppressed by the interaction between Co doping and native defects and the later affects it more significantly.
Large-scale flower-shaped Mn doped ZnO nanostructures have been grown on silicon substrates by simple thermal evaporation at atmospheric pressure.The flower-shaped nanostructure makes up of many nanorods,which are rooted in one center.Analysis of X-ray diffraction,high-resolution transmission electron microscopy and Raman spectra results reveal that the products are of single phase with wurtzite structure.Elemental mapping results show that no impurity clusters exist in the doped materials.The photoluminescence spectra demonstrate that many oxygen vacancies exist in the doped materials,and the crystal quality is improved and the content of oxygen vacancies is decreased by annealing treatment.The flower-shaped Mn doped ZnO nanostructures exhibit ferromagnetic ordering above room temperature,and its magnetization is decreased by the annealing treatment,which indicates that the magnetic behavior of the doped materials may be related to the interaction between Mn doping and the oxygen vacancies.
