Hafnium-Oxide 3-D Nanofilms via the Anodizing of Al/Hf Metal Layers
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F18%3APU127829" target="_blank" >RIV/00216305:26620/18:PU127829 - isvavai.cz</a>
Result on the web
<a href="http://dx.doi.org/10.1021/acs.chemmater.8b00188" target="_blank" >http://dx.doi.org/10.1021/acs.chemmater.8b00188</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1021/acs.chemmater.8b00188" target="_blank" >10.1021/acs.chemmater.8b00188</a>
Alternative languages
Result language
angličtina
Original language name
Hafnium-Oxide 3-D Nanofilms via the Anodizing of Al/Hf Metal Layers
Original language description
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.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10405 - Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)
Result continuities
Project
Result was created during the realization of more than one project. More information in the Projects tab.
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
CHEMISTRY OF MATERIALS
ISSN
0897-4756
e-ISSN
1520-5002
Volume of the periodical
30
Issue of the periodical within the volume
8
Country of publishing house
US - UNITED STATES
Number of pages
15
Pages from-to
2694-2708
UT code for WoS article
000431088400026
EID of the result in the Scopus database
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