Synthesis and Characterization of Nanostructured Cerium Dioxide Thin Films Deposited by Ultrasonic Spray Pyrolysis

Authors

  • Mario F. García-Sánchez,

    Corresponding author
    1. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México; Ciudad Universitaria, Coyoacán 04510, México D.F., México
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  • Armando Ortiz,

    1. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México; Ciudad Universitaria, Coyoacán 04510, México D.F., México
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  • Guillermo Santana,

    1. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México; Ciudad Universitaria, Coyoacán 04510, México D.F., México
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  • Monserrat Bizarro,

    1. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México; Ciudad Universitaria, Coyoacán 04510, México D.F., México
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  • Juan Peña,

    1. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México; Ciudad Universitaria, Coyoacán 04510, México D.F., México
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  • Francisco Cruz-Gandarilla,

    1. Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional; Edif. 9, U.P.A.L.M. 07738, México D.F., México
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  • Miguel A. Aguilar-Frutis,

    1. Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Instituto Politécnico Nacional; Irrigación 11500, México D.F., México
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  • Juan C. Alonso

    1. Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México; Ciudad Universitaria, Coyoacán 04510, México D.F., México
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  • M. P. Paranthaman—contributing editor

  • This research was partially supported by the Projects PUNTA-UNAM, DGAPA IN-115708, and CONACYT-48970.

†Author to whom correspondence should be addressed. e-mail: mf@iim.unam.mx

Abstract

Nanostructured thin films of cerium dioxide have been prepared on single-crystalline silicon substrates by ultrasonic spray pyrolysis using cerium acetylacetonate as a metal–organic precursor dissolved in anhydrous methanol and acetic acid as an additive. The morphology, structure, optical index, and electrical properties were studied by X-ray diffraction, scanning electron microscopy, atomic force microscopy, ellipsometry, and impedance spectroscopy. The use of additives is very important to obtain crack-free films. The substrate temperature and flow rate was optimized for obtaining smooth (Ra<0.4 nm), dense (n>2), and homogeneous nanocrystalline films with grain sizes as small as 10 nm. The influence of thermal annealing on the structural properties of films was studied. The low activation energy calculated for total conductivity (0.133 eV) is attributed to the nanometric size of the grains.

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