Understanding the Intrinsic Rectification Properties of Nanoporous Anodic Alumina by Selective Chemical Etching

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dc.contributor.authorWang, J.
dc.contributor.authorLaw, C.S.
dc.contributor.authorGunenthiran, S.
dc.contributor.authorLim, S.Y.
dc.contributor.authorVu, K.N.
dc.contributor.authorNgo, V.T.
dc.contributor.authorNielsch, K.
dc.contributor.authorAbell, A.D.
dc.contributor.authorSantos, A.
dc.date.issued2023
dc.description.abstractThe distribution of oxygen and aluminum vacancies across the hemispherical barrier oxide layer (BOL) of nanoporous anodic alumina (NAA) relies intrinsically on the electric field-driven flow of electrolytic species and the incorporation of electrolyte impurities during the growth of anodic oxide through anodization. This phenomenon provides new opportunities to engineer BOL's inherited ionic current rectification (ICR) fingerprints. NAA's characteristic ICR signals are associated with the space charge density gradient across BOL and electric field-induced ion migration through hopping from vacancy to vacancy. In this study, we engineer the intrinsic space charge density gradient of the BOL of NAA under a range of anodizing potentials in hard and mild anodization regimes. Real-time characterization of the ICR fingerprints of NAA during selective etching of the BOL makes it possible to unravel the distribution pattern of vacancies through rectification signals as a function of etching direction and time. Our analysis demonstrates that the space charge density gradient varies across the BOL of NAA, where the magnitude and distribution of the space charge density gradient are revealed to be critically determined by anodizing the electrolyte, regime, and potential. This study provides a comprehensive understanding of the engineering of ion transport behavior across blind-hole NAA membranes by tuning the distribution of defects across BOL through anodization conditions. This method has the potential to be harnessed for developing nanofluidic devices with tailored ionic rectification properties for energy generation and storage and sensing applications.
dc.description.statementofresponsibilityJuan Wang, Cheryl Suwen Law, Satyathiran Gunenthiran, Siew Yee Lim, Khanh Nhien Vu, Van Truc Ngo, Kornelius Nielsch, Andrew D. Abell, and Abel Santos
dc.identifier.citationACS applied materials & interfaces, 2023; 15(39):45981-45996
dc.identifier.doi10.1021/acsami.3c08745
dc.identifier.issn1944-8244
dc.identifier.issn1944-8252
dc.identifier.orcidLaw, C.S. [0000-0002-3276-8052]
dc.identifier.orcidGunenthiran, S. [0000-0002-8505-6104]
dc.identifier.orcidLim, S.Y. [0000-0002-5677-9039]
dc.identifier.orcidVu, K.N. [0000-0001-8150-7409]
dc.identifier.orcidNgo, V.T. [0000-0003-3455-2236]
dc.identifier.orcidAbell, A.D. [0000-0002-0604-2629]
dc.identifier.orcidSantos, A. [0000-0002-5081-5684]
dc.identifier.urihttps://hdl.handle.net/2440/139681
dc.language.isoen
dc.publisherAmerican Chemical Society
dc.relation.granthttp://purl.org/au-research/grants/arc/DP200102614
dc.relation.granthttp://purl.org/au-research/grants/arc/DP220102857
dc.rights© 2023 American Chemical Society.
dc.source.urihttps://doi.org/10.1021/acsami.3c08745
dc.subjectnanoporous anodic alumina
dc.subjectbarrier oxide layer
dc.subjectionic current rectification
dc.subjectselective etching
dc.subjectdefect vacancies
dc.titleUnderstanding the Intrinsic Rectification Properties of Nanoporous Anodic Alumina by Selective Chemical Etching
dc.typeJournal article
pubs.publication-statusPublished

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