Synthesis of YSZ thin films by the novel aqueous sol–gel citrate-precursor method

The objective of this work is the synthesis of 20 mol% Y2O3 doped ZrO2 thin films on crystalline silicon (Si) substrate from the aqueous Y–Zr–O nitrate–citrate sols dissolved in ethanol or isopropanol using spin-coating technique and the investigation of the morphological, structural and electrical properties. All obtained samples were repeatedly annealed at 800 °C temperature after spin-coating procedure and fully characterized by X-ray diffraction (XRD) analysis. XRD data exhibited that nanosized Y0.2Zr0.8O2 (YSZ) thin films have been formed at 800 °C. Thermal decomposition mechanisms of dried Y–Zr–O were monitored by TG/DTA measurements in the dynamic 80%Ar + 20%O2 atmosphere. The morphological features of obtained coatings were investigated by scanning electron microscopy (SEM). The electrical properties were characterized by impedance spectroscopy in a temperature range from 200 °C to 450 °C. Impedance results demonstrate that the conductivity of prepared layer is one order of magnitude lower in comparison with the YSZ bulk reference conductivity and the total conductivity of the YSZ film on silicon is mostly determined by the grain conductivity.