Structural and photoluminescent characteristics of yttrium-aluminum oxide films doped with Tb, Eu or Ce

The structural and room temperature luminescent characteristics of rare earth doped yttrium-aluminum oxide films deposited by the spray pyrolysis technique at low temperatures have been studied as a function of the deposition parameters such as substrate temperature and dopant concentration. The spraying solution is prepared by mixing yttrium and aluminum chlorides in water, and the incorporation of the rare earth dopants is achieved by adding chloride salts of these elements to this solution. The photoluminescent emission from Tb- and Eu-doped films have the spectral characteristics typical of radiative transitions among the electronic energy levels associated with the 3+ ionized states of these atoms. The Ce doped films, on the other hand, present a blue emission that is associated with transitions within the energy states of the CeCl₃ molecule used for the doping process of the film. The X-ray diffraction measurements of these films indicated poor crystallinity in general, with small crystalline peaks and a broad amorphous component that tend to be reduced as the deposition temperature is increased.