Preparation and Luminescence of Europium-doped Yttrium Oxide Thin Films

Thin films of europium-doped yttrium oxide (Y2O3:Eu) were prepared on Si (100) substrates by using a radio frequency (RF) magnetron sputtering. After the deposition, the films were annealed at 1000 degrees C in an air ambient for 1 hour. X-ray diffraction analysis revealed that the Y2O3:Eu films had a polycrystalline cubic alpha-Y2O3 structure. The as-deposited films showed no photoluminescence (PL), which was due to poor crystalline quality of the films. The crystallinity of the Y2O3:Eu films was significantly improved by annealing. The strong red PL emission was observed from the annealed Y2O3:Eu films and the highest intensity peak was centered at around 613 nm. This emission peak originated from the D-5(0)-> F-7(2) transition of the trivalent Eu ions occupying the C-2 sites in the cubic alpha-Y2O3 lattice. The broad PL excitation band was observed at wavelengths below 280 nm, which was attributed to the charge transfer transition of the trivalent Eu ion.