Luminescent Properties Of Rare Earth Doped ZnO Thin Films With Electron Beam Evaporation

ZnO：Eu³⁺films were prepared on the sapphire（Al2O3） substrate by electron beamevaporation. The material of the target is ceramics, which is a mixture of ZnO andEu₂O₃in an atomic ratio, and O2is the reacting gas. Using the X-raydiffraction（XRD）,scanning electron microscopy（SEM） and fluorescence spectrometer,the research studied the effect of the technological parameters in the electron beamevaporation, such as electron beam,substrate,temperature,reaction gas flow rate,dopingconcentration and annealing process,to the structure, appearance and luminescentproperties of ZnO：Eu³⁺films.The experience got the results as followed:（1） The ZnO：Eu³⁺films prepared by electron beam evaporation has a structure ofthe six corners of the wurtzite structure without the emergence of other impurities, andthe films can grow to polycrystalline film along the C-axis. All of these indicate thatEu³⁺ions probably have been mixed into the lattice of ZnO, and high-temperatureannealing increased lattice constant of ZnO：Eu³⁺films and the size of grain, whichmeans temperature annealing can improve the crystallization quality of films.（2） The appearance of prepared ZnO：Eu³⁺films is basically compact and uniform,and the size of simple grain is about30nm, measured by SEM. The comparison of twodoping concentration shows that in the condition of chosen parameters,0.5%Eu-dopedZnO films has better C-axis oriented growth.（3） Using fluorescence spectrometer, the experience tested the excitation andemission spectra of the films by annealed and unannealed. The result of analysis showedthat being direct excitation, ZnO：Eu³⁺films under different excitation wavelengthgenerated different characteristic emission peaks of emission spectrum. And theincrease of Eu³⁺characteristic emission peaks by annealing showed that temperatureannealing can improve the illumination intensity of Eu³⁺. Besides, the appearance ofEu³⁺characteristic emission peaks in the excitation spectrum proved Eu³⁺had mixedinto the lattice of ZnO successfully.