Preparation And Photoluminescence Properties Of ZnO:Eu³⁺ In Films

In this paper, ZnO:Eu³⁺films were prepared on the silicon （Si） substrate and on thesapphire （Al₂O₃） substrate by RF magnetron sputtering,using Ar gas as the working gasand O₂gas as reaction gas. The characterize structure, surface morphologymicrostructures and luminescent performance of the ZnO:Eu³⁺films were analyzed byX-ray diffraction （XRD）,scanning electron microscopy （SEM）, atomic force microscopy（AFM）, and fluorescence spectrophotometer.The results are listed as follows:（1） The characterize structure of the ZnO:Eu³⁺filmsThe XRD patterns of ZnO:Eu³⁺films having a hexagonal wurtzite structure show aC-axis oriented growth of polycrystalline thin films.There are no impure phase in theZnO:Eu³⁺films. It shows that rare earth Eu³⁺ions may be doped into the ZnO lattice.The crystal plane spacing and lattice constant of the annealed ZnO:Eu³⁺films are largerthan the as-grown films. The result indicates that annealing can improve the crystallinequality of ZnO:Eu³⁺thin film.（2） The surface morphology microstructures of the ZnO:Eu³⁺filmsThe surface morphology of ZnO:Eu³⁺films are dense relatively, and the grain sizeof ZnO:Eu³⁺films is about30nm.It is reflected that the films are nanoscale ZnO:Eu³⁺thin films.By comparison with the ZnO:Eu³⁺thin films on the silicon （Si） substrate,theZnO:Eu³⁺thin films on the sapphire （Al₂O₃） substrate have a better C-axis orientedstructrue.（3） The luminescent performance of the ZnO:Eu³⁺filmsThe excitation spectra and emission spectra of ZnO:Eu³⁺films on the silicon （Si）substrate and on the sapphire （Al₂O₃） substrate are employed by fluorescencespectrophotometer, respectively.It shows the characteristic emission spectra of Eu³⁺ions under the direct excitation. The emission peak of ZnO:Eu³⁺thin films are differentas this change of the excitation wavelength.Annealing can improve the luminescenceintensity of Eu³⁺,and are beneficial to the618nm red-emission of Eu³⁺ions. Theluminescence intensity of ZnO:Eu³⁺thin films on the Al₂O₃substrate is larger than thefilms on the Si substrate. Under the direct excitation, the red-emission of ZnO:Eu³⁺films annealed in O₂ambient can also indicates that the charge state of the Eu ions is trivalent in the ZnO.