Sol-gel fabrication and electrical property of nanocrystalline (RE2O3)(0.08)(ZrO2)(0.92) (RE = Sc, Y) thin films

Dense, crack-free, and homogeneous nanocrystalline (RE2O3)(0.08)(ZrO2)(0.92)(RE = Sc, Y) thin films (approximate to0.58-mum thick) on monocrystalline silicon (100) wafers were fabricated by a simple sol-gel spin-coating method under reduced annealing temperature and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Auger electron spectroscopy (AES), and impedance studies. Some key correlative processing parameters such as coating solution composition and gel-firing temperature have been optimized. XRD results indicate that the as-fabricated (Sc2O3)(0.08)(ZrO2)(0.92) thin films can achieve good crystallization in a pure cubic phase at a relatively low annealing temperature not exceeding 800 degreesC in 2 h and the nanocrystal size grows with elevation of the annealing temperature. AFM and SEM micrographs show that the (RE2O3)(0.08)(ZrO2)(0.92) nanocrystals after undergoing annealing at 950 degreesC for 2 h are uniform in the size range of 50-60 nm. AES profile analysis suggests that the (Sc2O3)(0.08)(ZrO2)(0.92) thin films are fairly pure with good composition homogeneity in the depth range of 75-500 nm. Impedance measurements reveal that the oxide ion conductivity of the nanocrystalline thin films is 10 times higher than that of the respective bulk material at temperatures beyond 600 degreesC. A decrease of grain boundary resistance related to interfacial effects is predominately responsible for this electrical conductivity enhancement.Chemistry, PhysicalMaterials Science, MultidisciplinarySCI(E)96ARTICLE2372-3781