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 metho d under reduced annealing temperature and were characterized by X-ray diffr action (XRD), scanning electron microscopy (SEM), atomic force microscopy ( AFM), Auger electron spectroscopy (AES), and impedance studies. Some key co rrelative processing parameters such as coating solution composition and ge l-firing temperature have been optimized. XRD results indicate that the as- fabricated (Sc2O3)(0.08)(ZrO2)(0.92) thin films can achieve good crystalliz ation in a pure cubic phase at a relatively low annealing temperature not e xceeding 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 sug gests that the (Sc2O3)(0.08)(ZrO2)(0.92) thin films are fairly pure with go od composition homogeneity in the depth range of 75-500 nm. Impedance measu rements reveal that the oxide ion conductivity of the nanocrystalline thin films is 10 times higher than that of the respective bulk material at tempe ratures beyond 600 degreesC. A decrease of grain boundary resistance relate d to interfacial effects is predominately responsible for this electrical c onductivity enhancement.