MOCVD growth of gadolinium oxide layers on tubes

In the paper, non-porous and smooth gadolinium oxide layers were synthesized on the inner surfaces of quartz glass tubes using MOCVD (Metalorganic Chemical Vapour Deposition) in the temperature range of 580–800 °C. Commercial Gd(tmhd)3 (Tris(2,2,6,6-tetramethyl-3,5-heptanedionato)gadolinium(III), 99% (99.9%-Gd)) was a basic reactant. Pure argon (99.999%) was used as a carrier gas. Air was applied to eliminate the carbon. It also was a carrier gas. The magnitude of the extended Grx/Rex2 criterion did not exceed the value of 0.01. Other synthesis conditions were established in such a way that this condition was maintained. The evaporation temperature of Gd(tmhd)3 varied in the range of 170–270 °C.The influence of the synthesis conditions on microstructure, structure and transparency of the deposited layers was investigated. Oval-shaped Gd2O3 aggregates and fine crystallites were formed regardless of the synthesis conditions. The conducted research also shows that the lower deposition temperature and the higher evaporation temperature of reactant, causes smaller crystallite sizes and smaller their number.