Cobalt-doped ZnO films were grown on the glass substrates using sol–gel/spin-coating technique to investigate the effect of annealing on the structural and magnetic properties. The X-ray diffraction (XRD) patterns of the Co-doped ZnO films are dominated by the (002) peak, suggesting an up-standing array of ZnO structure hexagonal (wurtzite) with a good crystalline quality, however, the secondary phases of Co3O4 and Co are present in the samples. With the annealing temperature increased, the secondary phases tend to disappear completely and the intensity of the (002) peak increased, indicating a high crystallinity of the samples. For the ZnO majority phase, the lattice constant ([Formula: see text] decreases (from 5.232 [Formula: see text] to 5.224 [Formula: see text]), while the crystallite size increases (from 22.040[Formula: see text]nm to 24.018[Formula: see text]nm) as the annealing temperature varies from 380∘C to 600∘C. Significant changes in the dislocation density ([Formula: see text], strain [Formula: see text] and stress [Formula: see text] of the Co-doped ZnO films were also observed, by increasing the annealing temperature. All samples display a ferromagnetic behavior with variations in the saturation magnetization ([Formula: see text], [Formula: see text] and [Formula: see text] emu/cm[Formula: see text] and coercive field ([Formula: see text], 104 and 75 Oe) for the temperatures of 380∘C, 500∘C and 600∘C, respectively. The magnetic behavior of Co-doped ZnO films confirms the exchange interaction between the local spin moments produced by the oxygen vacancy. In addition, the ferromagnetic existence of the samples (380∘C, 500∘C and 600∘C) can be attributed to certain nanoparticles or to the binding of Co[Formula: see text] ions at the Zn[Formula: see text] location in the ZnO lattice. Finally, it appears that the ferromagnetism at room temperature found in these films, is consistent with endogenous defects (oxygen vacancies) and magnetic ions insertion along the same lines.

To study the effect of Cu concentration on morphological, structural, linear and nonlinear optical properties, copper-doped ZnO thin films are grown by sol-gel/ spin-coating technique on the glass substrates. Scanning electron microscopy (SEM) images reveal that the surface morphology is homogeneous with good adhesion to the glass substrate. The energy dispersive X-ray spectroscopy (EDS) spectra confirm that Zn, O, and Cu elements are present in ZnO films. The X-ray diffraction (XRD) pattern of Cu-doped ZnO is dominated by (002) peak, indicating an upstanding ZnO nanorods array growing along the c-axis. The optical bandgap of Cu-doped ZnO thin films, calculated from optical transmission spectra, is found to decrease with the increase in copper concentration. The refractive index dispersion curve of ZnO films is subjected to the single-oscillator model. The optical dispersion parameters E o , E d , and n ∞ , the nonlinear refractive index, and nonlinear optical susceptibility are calculated and interpreted.

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Thin films of Nickel-doped ZnO have been prepared by sol-gel spin coating process. The doping concentration of Ni by weight has been adjusted as 0%, 2% and 5% .In order to examine the effect of doping on the optical properties , ZnO thin films has been characterized by UV-Vis spectroscopy, this shows Nickel doping affects the transmission in regards to the thin films and the band gap. The observed value of gap energy for 2% of Ni by weight is 3.25eV; also, the urbach energy value of “EU” is contrast with the values of energy gap.For ZnO powder nanostructures, we studied the microstructural and morphological properties, it have been characterized by optical microscope and first-principals computing. The ZnO replicas were clearly observed, the band structure and density of states of phase of crystal ZnO computed using Ab Initio methods, confirmed that pure ZnO is a direct band gap semiconductor for B3 phase, whose phase B3 is of ZnS type Blende.