LUMINESCENT CHARACTERISTICS OF TB DOPED AL2O3 FILMS DEPOSITED BY SPRAY PYROLYSIS

Aluminum oxide films doped with Tb have been deposited by the spray pyrolysis technique on either plain or conductive oxide coated glass substrates at temperatures in the range of 270-450-degrees-C. The photoluminescence emission from these films shows well-defined peaks at 490 and 550 nm, which are associated with Tb transitions, and a broad peak centered at 430 nm. The relative intensity of these peaks is strongly dependent on the type of substrate, the substrate temperature during deposition, and the amount of Tb incorporated in the film. Electron microscopy and energy dispersion spectroscopy (EDS) measurements indicate that changes induced on morphology and chemical composition, as well as diffusion into the substrate, are correlated with the luminescence efficiency characteristics of these films. The role as a diffusion barrier of a thin ZnO film on the substrate is also studied using EDS. Auger electron spectroscopy has been used to estimate the stoichiometry of the films.