Thermoluminescence properties of SrAl2O4:Eu sputtered films with long phosphorescence

SrAl₂O₄ activated with Eu, one of new long phosphorescent materials with high brightness, was deposited on Si substrates using an RF sputtering technique with facing targets. The photoluminescence (PL) was not observed for the as-deposited SrAl₂ O₄:Eu films. However, a PL peak at about 520 nm was observed after annealing in a reducing H₂+Ar gas. The thermoluminescence (TL) measurements were carried out, and the lifetimes of the phosphorescence were obtained from the peaks. TL spectra in higher temperature region which contribute for the long phosphorescence, were examined by the partial heating technique to evaluate the distributed trap depths and lifetimes. The results in this work are useful for the development of phosphors