Growth by laser ablation of Y2O3 and Tm:Y2O3 thin films for optical applications

Crystalline undoped and thulium doped yttrium oxide (Y2O3) thin films have been grown by the pulsed laser deposition (PLD) technique on various single-crystal substrates heated at 700 degrees C. X-Ray diffraction (XRD) analysis showed that the orientations of the films depended on the substrate and on the oxygen pressure. The crystalline quality of Y2O3 thin films, studied by rocking-curve measurements and by Rutherford backscattering spectroscopy (RBS) in channeling geometry, and the in-plane orientations between films and substrates, determined by X-ray asymmetric diffraction, were also found to depend on the same parameters. The recording of the visible fluorescence spectra of the thulium (Tm) doped Y2O3 thin films, as well as the measurements of the fluorescence lifetimes of the D-1(2) and (1)G(4) thulium emitting levels, gave results very similar to those obtained on bulk crystals. Doping rates in Tm of 0.5 and 1% were found to limit Tm-Tm interactions inside the films and to give relatively high visible fluorescence intensities.