Growth and characterization of red-green-blue cathodoluminescentceramic films

Gd 2 O 3 and Y 2 O 3 films, respectively, doped with Eu 3 + , Tb 3 + , and Tm 3 + have been grown by the electron beam physical vapor codeposition technique on optically polished quartz substrates. The film samples have been doped at different concentrations by the corresponding rare-earth oxides. The concentration range explored is from 0.9% to 9.8% on 18 samples. For each film sample an extended characterization has been performed by thin film-x-ray diffraction, scanning electron microscopy, energy dispersion spectroscopy, cathodoluminescence spectroscopy, and color coordinate analysis. Y 2 O 3 films display the most intense red-green-blue (RGB) emission and their film morphology and structure are more compact and crystalline with respect to Gd 2 O 3 monoclinic films. Eu 3 + and Tb 3 + doped Y 2 O 3 films grow oriented along the (222) direction. The ratios between the intensities of the electric dipole and magnetic dipole transitions have been also evaluated. The blue emission of Tm 3 + doped Gd 2 O 3 is lacking in the dopant concentration range from 1.6% to 7.6%, whereas it is present in Tm 3 + doped Y 2 O 3 films, at approximately the same dopant concentration range (1.9%-9.8%). Commission Internationale de l'Eclairage plot of the color coordinates of all the RGB film samples has been reported together with the RGB phosphor standard used in cathodic ray tube TV screens.