Synthesis and characterization of GDC solid electrolytes obtained by solid state sintering of multilayer thin films

Gadolinium doped cerium oxide (GDC) thin films are intensively investigated for Solid Oxide Fuel Cell (SOFC) application as a solid electrolyte layer. Classical methods that are used for synthesis of doped oxide materials are based on high temperature diffusion and solid state reactions of powder-form oxide mixtures. It is usually difficult to fabricate a thin GDC electrolyte film with a dense structure by a classical sintering technique, therefore this work was dedicated to a novel synthesis technique based on the sintering of Gd2O3/CeO2 multilayers deposited by reactive DC magnetron sputtering. The main purpose of the present investigation is to receive more information about the possibility to mix thin films of Gd2O3/CeO2 at intermediate temperatures (500–800 °C) in a relatively short period of time (1 h). Cross-section morphology of the samples was investigated by Scanning Electron Microscopy (SEM). Crystal structure and oxide stoichiometry was examined by X-ray diffraction (XRD) and Raman spectroscopy. The results revealed that crystallite size growth and layer mixing depends not only on sintering temperature, but also on bilayer period.