Pulsed laser deposition of yttria stabilized zirconia based heterostructure

Yttria stabilized zirconia (YSZ), nickel-doped yttria stabilized zirconia (NiYSZ) thin films and NiYSZ/YSZ anode-electrolyte heterostructure have been synthesized on Si(100) substrate by pulsed laser deposition technique. Atomic Force Microscopy, Scanning Electron Microscopy, and Variable Angle Spectroscopic Ellipsometry studies have been applied to determine the surface topography, film morphology and thickness. The X-ray diffraction measurements evidenced a highly textured growth along (111) direction for NiYSZ/YSZ heterostructure with crystallite dimension of 18 nm. The X-ray photoelectron spectroscopy analysis showed a displacement of Ni oxidation states along the depth profile, with Ni3+ oxidation state on the surface, a very thin layer containing Ni2+ associated to NiO buried under the surface, while metallic Ni is predominant in the bulk. The presence of an intermix layer at the interface between the NiYSZ and YSZ, suggested by the ellipsometric measurements, was confirmed by Secondary Neutral Mass Spectrometry data. (C) 2013 Elsevier B. V. All rights reserved.