Deposition of Gadolinia-Doped Zirconia Layers Using Metalorganic Compounds at Low Temperatures

This paper shows the results of an investigation on the synthesis of non-porous and nanocrystalline ZrO₂-Gd₂O₃ layers by metalorganic chemical vapor deposition (MOCVD) with the use of Zr(tmhd)₄ (tetrakis(2,2,6,6-tetramethyl-3,5-heptanedionato)zirconium(IV)) and Gd(tmhd)₃ (tris(2,2,6,6-tetramethyl-3,5-heptanedionato)gadolinium(III)). Argon and air were used as carrier gases. The molar content of Gd(tmhd)₃ in the gas reaction mixture was as follows: 10% and 20%. The layers were synthesized on tubular substrates made of quartz glass at the temperatures of 550-700 °C. Synthesis conditions were established using the Gr_x/Re_x² expression (Gr is the Grashof number; Re is the Reynolds number; x is the distance from the gas inflow point). The value of this criterion was below 0.01. ZrO₂-Gd₂O₃ layers synthesized at 600-700 °C were crystalline. When the molar content of Gd(tmhd)₃ in the gas reaction mixture was 10 mol.%, a relationship between the chemical composition of the gas reaction mixture and that of the deposited layer could be observed. The synthesized layers underwent scanning electron microscopy, as well as X-ray analysis. The transparency of coated and uncoated glass was tested using UV-Vis spectroscopy. Their chemical composition was examined with the use of an EDS analyzer.