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

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