Fabrication, structure and luminescence properties of polycrystalline Tb-doped Lu2SiO5 films by Pechini sol–gel method

Tb³⁺-doped lutetium oxyorthosilicate (Tb:Lu₂SiO₅, LSO) films have been successfully fabricated on carefully cleaned silicon (1 1 1) substrates by Pechini sol–gel method combined with the spin-coating technique. X-ray diffraction (XRD), photoluminescence (PL) spectra and atomic force microscopy (AFM) were employed to characterize the resultant films. XRD patterns indicated that the films were crystallized into A-type LSO phase at 1000 °C, followed by a phase transition from A-type LSO to B-type LSO occurred at 1100 °C. The AFM observation revealed that the phosphor films were uniform and crack-free, consisting of closely packed grains with an average size of 200–300 nm. The PL spectra showed the characteristic emission ⁵D₄ → ⁷F_J (J = 3–6) for Tb³⁺, The lifetime of Tb³⁺ in Tb:LSO films was 2.33 ms. The effect of heat-treatment temperature on the luminescent properties was also investigated.