Hydrogen Diffusion and Stabilization in Single-Crystal VO2 Micro/Nanobeams by Direct Atomic Hydrogenation

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dc.citation.firstpage5445
dc.citation.issueNumber9
dc.citation.journalTitleNano Letters
dc.citation.lastpage5451
dc.citation.volumeNumber14
dc.contributor.authorLin, Jian
dc.contributor.authorJi, Heng
dc.contributor.authorSwift, Michael W.
dc.contributor.authorHardy, Will J.
dc.contributor.authorPeng, Zhiwei
dc.contributor.authorFan, Xiujun
dc.contributor.authorNevidomskyy, Andriy H.
dc.contributor.authorTour, James M.
dc.contributor.authorNatelson, Douglas
dc.contributor.orgSmalley Institute for Nanoscale Science and Technology
dc.date.accessioned2016-06-27T14:14:27Z
dc.date.available2016-06-27T14:14:27Z
dc.date.issued2014
dc.description.abstractWe report measurements of the diffusion of atomic hydrogen in single crystalline VO2 micro/nanobeams by direct exposure to atomic hydrogen, without catalyst. The atomic hydrogen is generated by a hot filament, and the doping process takes place at moderate temperature (373 K). Undoped VO2 has a metal-to-insulator phase transition at ∼340 K between a high-temperature, rutile, metallic phase and a low-temperature, monoclinic, insulating phase with a resistance exhibiting a semiconductor-like temperature dependence. Atomic hydrogenation results in stabilization of the metallic phase of VO2 micro/nanobeams down to 2 K, the lowest point we could reach in our measurement setup. Optical characterization shows that hydrogen atoms prefer to diffuse along the c axis of rutile (a axis of monoclinic) VO2, along the oxygen “channels”. Based on observing the movement of the hydrogen diffusion front in single crystalline VO2 beams, we estimate the diffusion constant for hydrogen along the c axis of the rutile phase to be 6.7 × 10–10 cm2/s at approximately 373 K, exceeding the value in isostructural TiO2 by ∼38×. Moreover, we find that the diffusion constant along the c axis of the rutile phase exceeds that along the equivalent a axis of the monoclinic phase by at least 3 orders of magnitude. This remarkable change in kinetics must originate from the distortion of the “channels” when the unit cell doubles along this direction upon cooling into the monoclinic structure. Ab initio calculation results are in good agreement with the experimental trends in the relative kinetics of the two phases. This raises the possibility of a switchable membrane for hydrogen transport.
dc.identifier.citationLin, Jian, Ji, Heng, Swift, Michael W., et al.. "Hydrogen Diffusion and Stabilization in Single-Crystal VO2 Micro/Nanobeams by Direct Atomic Hydrogenation." <i>Nano Letters,</i> 14, no. 9 (2014) American Chemical Society: 5445-5451. http://dx.doi.org/10.1021/nl5030694.
dc.identifier.doihttp://dx.doi.org/10.1021/nl5030694
dc.identifier.urihttps://hdl.handle.net/1911/90571
dc.language.isoeng
dc.publisherAmerican Chemical Society
dc.rightsThis is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the American Chemical Society.
dc.subject.keywordVO2
dc.subject.keywordatomic hydrogenation
dc.subject.keywordhydrogen diffusion
dc.subject.keywordMIT
dc.titleHydrogen Diffusion and Stabilization in Single-Crystal VO2 Micro/Nanobeams by Direct Atomic Hydrogenation
dc.typeJournal article
dc.type.dcmiText
dc.type.publicationpost-print
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