Combustion chemical vapor deposition of CeO sub(2) film

Thin ceria (CeO sub(2)) films were deposited onto a-plane sapphire substrate via combustion chemical vapor deposition using toluene as a solvent and Ce(III) 2-ethylhexanoate (Ce-2EH) and tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)(IV) cerium (Ce-(TMHD) sub(4)) as chemical precursors. Depositions were made at a substrate temperature of 1000 degree C using several precursor concentrations and aerosol size distributions. Ceria assumes the fluorite (cubic) structure in the polycrystalline films. Films produced with low concentrations (approx. 0.001 M) of Ce-2EH display a preferred orientation in which the (200) axis is perpendicular to sapphire substrate. Similar low concentration of Ce-(TMHD) sub(4) yield films with (111) preferred orientation. High precursor concentrations ( > 0.002 M) and/or large aerosol size distributions yielded films containing ceria clusters that appear to have nucleated in the gas phase and adhered to the substrate in addition to material that nucleated on the substrate.