Low temperature synthesis of Y2O3–doped CeO2 layers using MOCVD

Abstract

In this work, investigations were carried out on microstructure and transparency of yttria-doped ceria (YDC) layers synthesized by Metalorganic Chemical Vapour Deposition using Ce(tmhd)4 (Cerium(IV) tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionate) and Y(tmhd)3 (Yttrium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate) as reactants on the inner surfaces of quartz glass tubes and flat plates. The YDC layers were deposited at different pressures, molar contents of reactants and temperatures. The carrier gases used in the deposition process were Ar and air. The molar content of Y(tmhd)3 in the gaseous reaction mixture was: 1 mol%, 9 mol% and 16 mol%. The obtained layers were smooth and non-porous. They were amorphous or nanocrystalline. The molar content of Y2O3 in the layers was in the range of 3–33%. It increased when the gas pressure in the CVD process was lowered, however it decreased along with the molar content of Y(tmhd)3. The reduction of gas pressure in the reactor had a beneficial influence on the synthesis of uniform in thickness layers in different transverse sample cross-sections.