Yttria-doped zirconia thin films deposited by atomic layer deposition ALD:: a structural, morphological and electrical characterisation

The recent development of solid oxide fuel cells is focused on a significant reduction in their operating temperature, from 850-1000 to 550-750 degreesC. One way to reach this goal is to reduce the thickness of the commonly used electrolyte, yttria stabilised zirconia, YSZ. Thin films of YSZ were prepared on soda lime glass, SnO2-coated glass, strontium-doped lanthanum manganite and Ni-YSZ cermet by atomic layer deposition. This technique is a sequentially controlled chemical vapour deposition technique, allowing the formation of the deposit monolayer by monolayer. The stoichiometry and morphology of the films were analysed by scanning electron microscopy/energy dispersive analysis of X-ray and wavelength dispersion spectroscopy. Thin (about 1-3 mum), dense and homogeneous layers were obtained with a doping content of Y2O3 of 8.5 mol%. The structural characterisation was realised by X-ray diffraction and Raman spectroscopy. It was shown by both methods that the cubic structure is predominant. Impedance spectroscopy at room temperature allowed to determine some characteristic parameters of YSZ material: capacitance and dielectric constant. (C) 2003 Elsevier Ltd. All rights reserved.