Anode-supported planar solid oxide fuel cells by plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) and electrostatic spray deposition (ESD): Fabrication of dense thin layers of yttria-stabilized zirconia by PE-MOCVD

Abstract

This paper reports a study of plasma-enhanced metalorganic chemical vapor deposition (PE-MOCVD) as a suitable technique for depositing dense, crack-free thin layers of yttria-stabilized zirconia onto porous substrates, as a step in the fabrication of anode-supported planar solid oxide fuel cells (SOFC). Our objective is to present an alternative method by which an SOFC assembly may be fabricated at lower temperature than by conventional methods. PE-MOCVD using zirconium tertbutoxide (ZrTB) -and yttrium hexafluoroacetylacetonate dihydrate (Y6FA) is capable of producing the electrolyte in thin dense layers on smooth surfaces, as demonstrated for Si(110) wafers. If a porous substrate is used, the average surface pore size should not exceed 1–2 μm to obtain a dense film. The crystalline phase of the film was related to the Y6FA concentration in the gas phase using x-ray diffraction. Depth profiling, using x-ray photoelectron spectroscopy, showed that Y is present (fairly uniform) at all depths of the film. Growth rates are dependent on the applied power but independent of substrate temperature. Film density, however, shows a significant dependence on substrate temperature.