Enhanced luminescence properties of pulsed laser-deposited Eu:Y₂O₃ thin film phosphors using diamond buffer layer

Europium-activated yttrium oxide (Eu:Y₂O₃) phosphor films have been grown in-situ on (100) bare silicon and diamond-coated silicon substrates using a pulsed laser deposition technique. Diamond-coated silicon substrates were prepared by hot filament chemical vapor deposition on (100) silicon wafer. Measurements of photoluminescence and cathodoluminescence properties of Eu:Y₂O₃ films showed that the films grown on diamond-coated silicon substrates are brighter than the films grown on bare silicon substrates. The improved brightness of the Eu:Y₂O₃ films on diamond-coated silicon substrates is attributed to reduced internal reflection and enhanced scattering of incident beam with lattice. These effects are primarily brought about by the presence of a rough diamond buffer layer between the phosphor film and substrate. Oxygen environment during deposition is necessary for better crystallinity but excess oxygenation of the Eu:Y₂O₃ films during cooling degrades the brightness of the films.