| Low-dimensional ZnO nanomaterials have wide range of potential applications inoptoelectronic devices due to their excellent structure and performance. Doping withtransition metal ions or rare earth elements can induce dramatic changes in the optical,electrical and magnetic properties, so for the preparation and research of intrinsic anddoped ZnO nanomaterials has important significance. In this paper, well-aligned ZnOnanorod arrays and ZnO nanomaterials with Cu doping were grown by hydrothermalmethod and the effect of Cu ions on the morphology, structure and luminescenceproperties of ZnO nanomaterials were also studied.ZnO nanocrystal thin film consisted of dense and uniform nano-particles wereobtained on quarts under different sputtering conditions using RF magnetron sputteringmachine.The preparing conditions including growth time and deposition temperaturenot only played a main role in govering the rod diameter but also greatly effects the rodorientation. The average grain size of the sputtered ZnO nucleation layer was found tobe approximately10-30nm, but when the temperature of substrate increasd from roomtemperature to450℃, the film grain refined and the film structure tended to becomplete. The roughness of the thin film surface decreased as the sputtering timeprolonged. At the beginning of sputtering, the thickness of the thin film was30nm-40nm which increased slowly, but when sputtering time prolonged to15min, thethickness increased to115nm, then the change of which tended to be stable.Well-aligned intrinsic ZnO nanorod arrays with different morphologies andproperties were prepared by hydrothermal method in HMTA and Zn(CH3COO)2.2H2Osystem.The effect of preparing conditions such as deposition time, growth tempertureand subsequent annealing process had great influence on the morphology and thealignment ording of ZnO nanorod arrays. Typical XRD patterns of ZnO rods preparedwith all diffraction peaks well indexd to the standard diffraction pattern of hexagonalphase ZnO, indicating a wurtzite structure with high crystallinity. With the growth timeincreased from30min to120min, the average length of increased dramatically from0.2μm to2μm. As for the nanorods grown in higher temperature, large number of ZnOnanoparticals served as crystal seeds, which promoteed the rate of relievingsupersaturation, reduced the possibility of forming a new nucleus, lower the growth rateon the single rod and, therefore, lead to small diameter, short length and high intensity of ZnO rods. The Pl spectra of ZnO nanorods prepared at different annealingatmosphere show the similar features, in which there are two obvious peaks emissionbands, including the stronger UV emission band and a weak visible emission. Afterannealing treatment in air and O2atmosphere, the intensity of UV emission decreased,but the visible emission inchanced and red-shift from “yellow-green” emission to“yellow-orange” emission, but which was in contrast when annealing in N2atmosphere.The explanation of this phenomenon mainly due to different annealing atmospherechanged the density of defects associated with O.ZnO nanomaterials with different Cu doping concentration were prepared bysolution method. With the concentration of Cu increased from1%to9%, the surfacemorphology of ZnO nanomaterials changed from nanorod arrays to leaf shape, finallybecome mutually nested. Compared with the XRD pattern of pure ZnO, the much lowerintensity of the002diffraction peak for Cu doped ZnO namomaterials indicated thepreferential orientation were destroyed dramatically as the Cu doping concentrationincreased, which can be explained by the increase of the lattice constant "a" and "c"caused by Cu ions. The Pl spectra of Cu doped ZnO nanomaterials prepared exhibitedthe features that the intensity of the UV emission became weaker and redshift which ismainly caused by the change of lattice stress, but a stronger “yellow-green” emissionwhich is caused by new impurity level formed by Cu ions in the ZnO band gap was alsoobtained, as the doping concentration increased. |
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