Cathodoluminescent and photoluminescent properties of Al₂O₃ powders doped with Eu

Eu-doped Al₂O₃ powders were made by a coprecipitation technique using aluminum nitrate and europium chloride as precursors at annealing temperatures of 500, 700, and 900°C. Room temperature cathodoluminescence and photoluminescence characteristics of Al₂O₃:Eu powders as a function of the dopant concentration and annealing temperature have been studied. The emissions from Eu-doped powders have the spectral characteristics typical of radiative transitions among the electronic energy levels associated with the 3⁺ ionized state of this ion. The X-ray diffraction patterns show a broad peak that tends to become narrower as the annealing temperature is raised. Energy dispersive spectroscopy indicates that the powders are oxygen-rich, which may indicate a low density or porous material. Finally, scanning electron microscopy images show a variety in the shape and size of the powder particles associated with the milling procedure implemented in order to obtain the powders.