Effect of oxygen pressure on the structure and luminescence of Eu-doped Gd2O3 thin films

Europium-doped gadolinium oxide (Gd2O3) thin films were deposited on sapphire substrates by pulsed laser deposition (PLD). The effect of oxygen pressure during deposition on the structure of the thin films, investigated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), was correlated to photoluminescence spectra. The polycrystalline films, like the one deposited in 5 mTorr oxygen environment, were primarily monoclinic phase; however the rarer cubic phase was achieved at 50 mTorr pressure. Time-integrated and time-resolved photoluminescence (TIPL and TRPL) spectra of the bright D-5(0) to F-7(2) radiative transition revealed how the differing host material phases altered the local environment of the Eu dopants. (c) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim