Articles producció científica> Enginyeria Electrònica, Elèctrica i Automàtica

Hafnium-Oxide 3‑D Nanofilms via the Anodizing of Al/Hf Metal Layers

  • Identification data

    Identifier: imarina:4079943
    Authors:
    Mozalev, AlexanderBendova, MariaGispert-Guirado, FrancescLlobet, Eduard
    Abstract:
    Hafnium-oxide films with self-organized nanostructured 3-D architectures and variable dimension (10 to 400 nm) are synthesized via the high-current anodizing of thin aluminum-on-hafnium layers in phosphoric, malonic, and oxalic acid electrolytes. In the approach, the self-organized growth of a porous anodic alumina (PAA) film is immediately followed by the fast PAA-assisted reanodizing of the hafnium underlayer. The PAA-dissolved films consist of arrays of upright-standing hafnium-oxide nanorods held on the substrate by the tiny needle-like "nanoroots" widespread over a continuous hafnium-oxide bottom layer. The roots are amorphous Hf2O3, while the rods are amorphous HfO2-Hf2O3-Al2O3 mixed oxides, the bottom layer being, however, highly textured nanocrystalline HfO2. The calculated transport numbers for O2- and Hf4+(3)+ ions are, respectively, ∼0.55 and ∼0.45, which is a unique situation for anodic hafnium oxide, which normally grows by O2- transport only. Annealing the films in air at 600 °C oxidizes the remaining Hf metal to polycrystalline HfO2, still leaving the roots and rods amorphous. The annealing in vacuum results in partial oxide reduction and crystallization of the roots and rods to stable orthorhombic and monoclinic HfO2 phases. A model of the anodic film growth and solid-state ionic transport is proposed and experimentally justified. Potential applications of the 3-D hafnium-oxide nanofilms are in advanced electronic, photonic, or magnetic micro- and nanodevices.
  • Others:

    Author, as appears in the article.: Mozalev, Alexander; Bendova, Maria; Gispert-Guirado, Francesc; Llobet, Eduard
    Department: Enginyeria Electrònica, Elèctrica i Automàtica
    URV's Author/s: Gispert Guirado, Francesc / GUIRADO PAGÉS, FRANCISCO / Llobet Valero, Eduard
    Keywords: Metals Oxides
    Abstract: Hafnium-oxide films with self-organized nanostructured 3-D architectures and variable dimension (10 to 400 nm) are synthesized via the high-current anodizing of thin aluminum-on-hafnium layers in phosphoric, malonic, and oxalic acid electrolytes. In the approach, the self-organized growth of a porous anodic alumina (PAA) film is immediately followed by the fast PAA-assisted reanodizing of the hafnium underlayer. The PAA-dissolved films consist of arrays of upright-standing hafnium-oxide nanorods held on the substrate by the tiny needle-like "nanoroots" widespread over a continuous hafnium-oxide bottom layer. The roots are amorphous Hf2O3, while the rods are amorphous HfO2-Hf2O3-Al2O3 mixed oxides, the bottom layer being, however, highly textured nanocrystalline HfO2. The calculated transport numbers for O2- and Hf4+(3)+ ions are, respectively, ∼0.55 and ∼0.45, which is a unique situation for anodic hafnium oxide, which normally grows by O2- transport only. Annealing the films in air at 600 °C oxidizes the remaining Hf metal to polycrystalline HfO2, still leaving the roots and rods amorphous. The annealing in vacuum results in partial oxide reduction and crystallization of the roots and rods to stable orthorhombic and monoclinic HfO2 phases. A model of the anodic film growth and solid-state ionic transport is proposed and experimentally justified. Potential applications of the 3-D hafnium-oxide nanofilms are in advanced electronic, photonic, or magnetic micro- and nanodevices.
    Thematic Areas: Química Medicina ii Materials science, multidisciplinary Materials science Materials chemistry Materiais Interdisciplinar Geociências General chemistry General chemical engineering Farmacia Engenharias iv Engenharias iii Engenharias ii Engenharias i Ciências biológicas i Ciências ambientais Chemistry, physical Chemistry (miscellaneous) Chemistry (all) Chemical engineering (miscellaneous) Chemical engineering (all) Biotecnología Biodiversidade Astronomia / física
    licence for use: https://creativecommons.org/licenses/by/3.0/es/
    ISSN: 08974756
    Author's mail: eduard.llobet@urv.cat
    Author identifier: 0000-0001-6164-4342
    Record's date: 2024-10-12
    Papper version: info:eu-repo/semantics/acceptedVersion
    Link to the original source: https://pubs.acs.org/doi/10.1021/acs.chemmater.8b00188
    Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
    Papper original source: Chemistry Of Materials. 30 (8): 2694-2708
    APA: Mozalev, Alexander; Bendova, Maria; Gispert-Guirado, Francesc; Llobet, Eduard (2018). Hafnium-Oxide 3‑D Nanofilms via the Anodizing of Al/Hf Metal Layers. Chemistry Of Materials, 30(8), 2694-2708. DOI: 10.1021/acs.chemmater.8b00188
    Article's DOI: 10.1021/acs.chemmater.8b00188
    Entity: Universitat Rovira i Virgili
    Journal publication year: 2018
    Publication Type: Journal Publications
  • Keywords:

    Chemical Engineering (Miscellaneous),Chemistry (Miscellaneous),Chemistry, Physical,Materials Chemistry,Materials Science,Materials Science, Multidisciplinary
    Química
    Medicina ii
    Materials science, multidisciplinary
    Materials science
    Materials chemistry
    Materiais
    Interdisciplinar
    Geociências
    General chemistry
    General chemical engineering
    Farmacia
    Engenharias iv
    Engenharias iii
    Engenharias ii
    Engenharias i
    Ciências biológicas i
    Ciências ambientais
    Chemistry, physical
    Chemistry (miscellaneous)
    Chemistry (all)
    Chemical engineering (miscellaneous)
    Chemical engineering (all)
    Biotecnología
    Biodiversidade
    Astronomia / física
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