Sol–gel deposition and luminescence properties of LiYF4:Tb3+ thin films

Tb3+ -doped LiYF4 films were deposited on quartz glass by a simple sol–gel method. X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), photoluminescence spectra, and lifetimes were used to characterize the resulting films. The results of XRD indicated that the films began to crystallize at 300 °C and fully crystallized at 400 °C. AFM and FESEM images of singly coated LiY0.95Tb0.05F4 annealed at 400 °C indicated that the film is uniform and crack-free films with average grain size of 90 nm, root mean square roughness of 11 nm and thickness of 120 nm. The doped Tb3+ ions showed its characteristic emission in crystalline LiYF4 films, i.e., 5D3, 4-7FJ (J=6, 5, 4, 3) emissions. The optimum doping concentration of the Tb3+ was determined to be 5.0 mol% of Y3+ in LiYF4 films.