Temperature dependence of structural and luminescence properties of Eu3+-doped Y2O3 red-emitting phosphor thin films by pulsed laser deposition

Abstract

Pulse laser deposition was used to obtain nanocrystalline red-emitting Y2O3:Eu3+ thin-film phosphors. X-ray diffraction measurements show that the un-annealed thin film was amorphous, while those annealed were crystalline. At lower annealing temperature of 600–700 °C, cubic bixbyite Y2O3:Eu3+ was formed. As the annealing temperatures were increased to 800 °C, hexagonal phase emerged. The average crystallite size of the film was 64 nm. Photoluminescence measurement indicates intense red emission around 612 nm due to the 5D0 → 7F2 transition. Scanning electron microscopy indicated that agglomerates of non-crystalline particles with spherical shapes were present for the un-annealed films. After annealing at high temperature, finer morphology was revealed. Atomic force microscopy further confirmed the formation of new morphology at the higher annealing temperatures. UV–Vis measurement indicated a band gap in the range of 4.6–4.8 eV. It was concluded that the annealing temperature played an important role in the luminescence intensity and crystallinity of these films.