Li doping effect on the luminescent characteristics of YVO4:Eu thin films grown by pulsed laser deposition

Influence of Li doping on the crystallization, surface morphology and luminescent properties of YVO4:Eu3+ films has been investigated. The films have been grown using pulsed laser deposition method on Al2O3 (0001) substrates under different oxygen pressures. The substrate temperature was fixed at 600 deg C and the range of oxygen pressure was 20.00-46.66Pa. The crystallinity and surface morphology of the films were investigated using X-ray diffraction (XRD) and atomic force microscope (AFM), respectively. The emitted radiation at 312nm excitation was dominated by a red emission peak at 620nm radiated from the transition of 5D0-7F2 of Eu3+ ions. In particular, the incorporation of Li+ ions into YVO4 lattice could induce the increase of the intensity of the photoluminescence. The enhanced luminescence may be resulted not only from the improved crystallinity, but also from the reduced internal reflections caused by rougher surfaces. The luminescent intensity and surface roughness exhibited similar behavior as a function of oxygen pressure.