Influence of europium oxide doping on the structural and optical properties of pulsed laser ablated barium tungstate thin films

Nanostructured Eu₂O₃ doped Barium tungstate (BaWO₄) crystallites are successfully synthesized using pulsed laser deposition (PLD) technique. The influence of different Eu₂O₃ doping concentrations (1,2,3 & 5 wt.%) on the structural, surface morphological and optical properties are systematically studied using XRD, micro-Raman, SEM, AFM, UV-vis and photoluminescence spectroscopy. All the films are polycrystalline with tetragonal scheelite structure. The vibrational analysis of the atoms in BaWO₄ is studied by micro-Raman spectra using factor group analysis. The surface morphological analysis by SEM and AFM reveals the presence of fine nanoparticles with distinct grain boundaries in all the films. The band gap energy variation in the Eu₂O₃ doped BaWO₄ films is in accordance with the variation of the sizes of nano particles in the films. The films with higher Eu³⁺ doping concentrations (≥2 wt.%) show a PL emission peak centered around 614 nm when excited at 394 nm which can be attributed to the ⁵D₀ → ⁷F₂ (0-2) transition of Eu³⁺ ion.