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The synthesis of Cu-doped ZnO nanosheets at room temperature was reported in our previous paper.The effects of annealing temperature on Cu-doped ZnO nanosheets were studied in this paper.Cu-doped ZnO nanosheets were annealed at 200e500 C in air.The annealed specimens were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and transmission electron microscopy(TEM).The results show that Cu concentration in Cu-doped ZnO nanosheets reduced with increasing annealing temperature.When annealing temperature was lower than Zn melting point(410 C),the morphologies of the Cu-doped ZnO nanosheets remained nearly the same as that before annealing.However,when the annealing temperature was over Zn melting point,Cu-doped ZnO nanosheets changed to nanowires,wormlike nanosheets or did not change.The change of Cu concentration in Cu-doped ZnO nanosheets is explained by oxidation thermodynamics.A physical model is suggested to explain the morphology changes of Cu-doped ZnO nanosheets,based on the existence of Cu-rich layer beneath Cu-doped ZnO nanosheets.
The synthesis of Cu-doped ZnO nanosheets at room temperature was reported in our previous paper. The effects of annealing temperature on Cu-doped ZnO nanosheets were studied in this paper. Cu-doped ZnO nanosheets were annealed at 200e500 C in air. The annealed specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that Cu concentration in Cu-doped ZnO nanosheets reduced with increasing annealing temperature. Temperature annealing was lower than Zn melting point (410 C), the morphologies of the Cu-doped ZnO nanosheets remain nearly the same as that before before. However when the annealing temperature was over Zn melting point, Cu-doped ZnO nanosheets changed to nanowires, wormlike nanosheets or did not change. The change of Cu concentration in Cu-doped ZnO nanosheets is explained by oxidation thermodynamics. A physical model is suggested to explain the morphology changes of Cu-doped ZnO nanosheet s, based on the existence of Cu-rich layer beneath Cu-doped ZnO nanosheets.