Luminescent properties of SrAl2O4:Eu thin films deposited by intense pulsed ion-beam evaporation

SrAl2O4 activated with Eu, a long-phosphorescence material with high brightness, has been successfully deposited on Si substrates using intense pulsed ion-beam evaporation. Efficient preparation of long-phosphorescence thin films has been achieved using a high-density ablation plasma produced by the interaction of an intense pulsed ion-beam with the SrAl2O4:Eu target. The prepared SrAl2O4:Eu thin films had a polycrystalline structure without annealing and showed a typical photoluminescence of SrAl2O4:Eu at around 520 nm. Thermoluminescence (TL) measurements were carried out in order to obtain the lifetimes of the phosphorescence. In particular, TL spectra in the higher temperature region, which contributed to the long phosphorescence, were examined by the partial heating technique to evaluate the distributed trap depths and the lifetimes. The phosphorescence lifetime at 300 K for the prepared film was found to be about 180 min.