Influence of deposition conditions on the optical properties of erbium-doped yttrium oxide films grown by aerosol-UV assisted MOCVD

Erbium-doped Y2O3 films were prepared by aerosol-UV assisted metal-organic chemical vapour deposition (MOCVD) at 410 degrees C. The effects of humidity of carrier gas and UV-assistance on their structure and optical properties were investigated on the as-deposited and thermal annealed films using infrared spectroscopy, X-ray diffraction and transmission electron microscopy. It was found that the as-deposited Er:Y2O3 films crystallise in the Y2O3 cubic structure and present a very low organic contamination when the deposition takes place under high air humidity and, even better, with UV-assistance. After annealing, two different structural phases are observed corresponding to the cubic and the monoclinic structures of Y2O3. The Er3+ luminescence analysed in the visible and IR regions, shows the classical green transitions. The best optical properties were obtained with as-deposited and annealed Er:Y2O3 films grown under high air humidity with UV-assistance. Under such deposition conditions, I-4(13/2) lifetimes was found to be 3.07 and 6.1 ms for films annealed at 800 and 1000 degrees C, respectively, and up-conversion phenomena were underlined. This indicates that the deposition conditions, in particular air humidity, play an important role in the luminescent properties even after annealing (C) 2011 Elsevier B.V. All rights reserved.