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RESEARCH PRODUCT
Physico-Chemical Characterization of Anodic Oxides on Hf as a Function of the Anodizing Conditions
G. TranchidaAndrea ZafforaMonica SantamariaFrancesco Di QuartoFrancesco Di Francosubject
Materials Chemistry2506 Metals and AlloysMaterials scienceRenewable Energy Sustainability and the EnvironmentAnodizingElectronic Optical and Magnetic MaterialMetallurgySurfaces Coatings and FilmCondensed Matter Physic02 engineering and technologyFunction (mathematics)010402 general chemistry021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciences0104 chemical sciencesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsCharacterization (materials science)AnodeSettore ING-IND/23 - Chimica Fisica ApplicataMaterials ChemistryElectrochemistry0210 nano-technologydescription
Anodic films were grown to 5 V (Ag/AgCl) on mechanically polished Hf in 0.1 M ammonium biborate and 0.1 M NaOH. Independent of the anodizing conditions, the photoelectrochemical characterization allowed the observation of optical transitions at 3.25 eV, i.e. at photon energy lower than the bandgap of HfO2. They are attributed to localized states inside the gap of the oxide induced by the presence of oxygen vacancies. From the cathodic photocurrent spectra, it was possible to estimate an energy threshold of ∼2.15 eV for internal electron photoemission phenomena. The impedance measurements proved the formation of insulating oxides with ϵ =19. The anodizing occurs under a high field regime with an activation energy of 1.1 eV and an activation distance of 3.8 Å.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2016-01-01 | Journal of The Electrochemical Society |