Surface characterization and luminescent properties of SrAl2O4:Eu2+, Dy3+ nano thin films

SrAl2O4:Eu2+, Dy3+ thin films were grown on Si (1 0 0) substrates in different atmospheres using the pulsed laser deposition (PLD) technique. The effects of vacuum, oxygen (O2) and argon (Ar) deposition atmospheres on the structural, morphological and photoluminescence (PL) properties of the films were investigated. The films were ablated using a 248 nm KrF excimer laser. Improved PL intensities were obtained from the unannealed films prepared in Ar and O2 atmospheres compared to those prepared in vacuum. A stable green emission peak at 520 nm, attributed to 4f65d1→4f7 Eu2+ transitions was obtained. After annealing the films prepared in vacuum at 800 °C for 2 h, the intensity of the green emission (520 nm) of the thin film increased considerably. The amorphous thin film was crystalline after the annealing process. The diffusion of adventitious C into the nanostructured layers deposited in the Ar and O2 atmospheres was most probably responsible for the quenching of the PL intensity after annealing.