Growth of 20 mol% Gd-doped ceria thin films by RF reactive sputtering: The O2/Ar flow ratio effect

The search for optimal materials and the utilization of proper manufacturing techniques to replace conventional electrolytes are our research objectives for the operation of solid oxide fuel cells under intermediate temperatures. Furthermore, understanding the effects of process parameters will be helpful for obtaining suitable materials for applications. In this study, we investigate the O2/Ar flow ratio effect by employing RF reactive sputtering to fabricate 20 mol% Gd-doped ceria (20GDC) films on alumina substrates. The morphology of films was aggregated by nano-scale size of grains which gradually reduced in size from lower to higher O2/Ar flow ratios. The microstructure of films was transferred from incomplete oxidized materials to well-crystallized cubic fluorite structures using an increased O2/Ar flow ratio up to 0.30. The oxygen/metal ratio of films was increased gradually and saturated around 2.05 for O2/Ar flow ratios over 0.25 and remained in uniform composition through whole films for each flow ratios.