Abstract: ZnO:Dy3+ nanocrystals have been synthesized by solid state reaction.X-ray diffraction (XRD),transmission electron microscopy (TEM),and selected area electronic diffraction (SAED) demonstrate that the nanocrystals can be indexed as hexagonal wurtzite polycrystalline.The photoluminescence spectra (PL) and photoluminescence excitation spectra (PLE) of the nanocrystals were measured at room temperature.The grain size of the nanocrystals is about 50nm as calculated using the Debye-Scherrer formula.We have found that in the PL of ZnO:Dy3+ nanocrystals,besides sharp lines from the 4f→4f transition of Dy3+,two broad bands appear from the Dy defects A and B in ZnO,with peaks at 600 and 760nm and full widths at half maximum (FWHM) of about 200 and 100nm,respectively.Under the exciton excitation (385nm),the intensity of the peak at 760nm is far stronger than that of the peak at 600nm.The relative intensity of each peak in the emission spectrum depends on the excitation wavelength and the concentration of the Dy3+.Under the excited state of Dy3+ (454nm),the emission of broad bands with peaks at 600 and 760nm is lost.Only the 4f→4f transitions of Dy3+ remain.

Key words: ZnO:Dy, photoluminescence, solid state reaction