Optical and electrical switching in nanostructured coatings of VO 2

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dc.contributor.author Gentle, AR
dc.contributor.author Maaroof, AI
dc.contributor.author Cortie, MB
dc.contributor.author Smith, GB
dc.date.accessioned 2009-06-26T04:16:22Z
dc.date.issued 2007
dc.date.issued 2007
dc.identifier.citation Proceedings of SPIE - The International Society for Optical Engineering, 2007, 6647
dc.identifier.citation Proceedings of SPIE - The International Society for Optical Engineering, 2007, 6647
dc.identifier.isbn 9780819467959
dc.identifier.isbn 9780819467959
dc.identifier.issn 0277-786X
dc.identifier.other E1 en_US
dc.identifier.uri http://hdl.handle.net/10453/788
dc.description.abstract Vanadium dioxide undergoes a reversible metal-insulator phase transition at about 68°C. Coatings of this compound are reflective in the infrared above this temperature, and transmissive or absorptive below it, while resistivity changes by several orders of magnitude. We present a convenient method for depositing films with nano-size grains, which are then optically and electrically characterised. Emphasis in this study is the impact of aluminum doping and grain structure. The optical hysteresis is presented and its switching range is not altered at different doping levels but the value of transition temperature Tc does shift. In contrast hysteresis in dc resistance does change with a strong correlation between the fall in resistance in the semiconductor state with doping, the drop in Tc and the electrical properties in the metal state. For grain sizes under about 180 nm the conductivity in the metal phase is not linear in temperature but is thermally activated, with activation energies AE dependent on both grain size G and doping level. Simple mathematical relationships are found connecting ΔE with G and with carrier density in the semiconductor state. ΔE ranges in our samples from 0.15 eV in the smallest grain sizes to around 0.06 eV. This anomalous low frequency metal response is linked to excitations that arise in the metal phase associated with transient singlet pairing on neighbouring sites. Such pairing is weakened by doping, and in large grains appears to be present but incoherent.
dc.description.abstract Vanadium dioxide undergoes a reversible metal-insulator phase transition at about 68°C. Coatings of this compound are reflective in the infrared above this temperature, and transmissive or absorptive below it, while resistivity changes by several orders of magnitude. We present a convenient method for depositing films with nano-size grains, which are then optically and electrically characterised. Emphasis in this study is the impact of aluminum doping and grain structure. The optical hysteresis is presented and its switching range is not altered at different doping levels but the value of transition temperature Tc does shift. In contrast hysteresis in dc resistance does change with a strong correlation between the fall in resistance in the semiconductor state with doping, the drop in Tc and the electrical properties in the metal state. For grain sizes under about 180 nm the conductivity in the metal phase is not linear in temperature but is thermally activated, with activation energies AE dependent on both grain size G and doping level. Simple mathematical relationships are found connecting ΔE with G and with carrier density in the semiconductor state. ΔE ranges in our samples from 0.15 eV in the smallest grain sizes to around 0.06 eV. This anomalous low frequency metal response is linked to excitations that arise in the metal phase associated with transient singlet pairing on neighbouring sites. Such pairing is weakened by doping, and in large grains appears to be present but incoherent.
dc.relation.isbasedon 10.1117/12.733200
dc.title Optical and electrical switching in nanostructured coatings of VO 2
dc.title Optical and electrical switching in nanostructured coatings of VO 2
dc.type Conference Proceeding
dc.description.version Published
dc.parent Proceedings of SPIE - The International Society for Optical Engineering
dc.parent Proceedings of SPIE - The International Society for Optical Engineering
dc.journal.volume 6647
dc.journal.number en_US
dc.publocation Washington, USA en_US
dc.identifier.startpage 1 en_US
dc.identifier.endpage 8 en_US
dc.cauo.name SCI.Physics and Advanced Materials en_US
dc.conference Verified OK en_US
dc.conference Conference on Nanocoatings
dc.conference.location San Diego California USA en_US
dc.for 1007 Nanotechnology
dc.personcode 730312
dc.personcode 020302
dc.personcode 000307
dc.personcode 010727
dc.percentage 100 en_US
dc.classification.name Optical Physics en_US
dc.classification.type FOR-08 en_US
dc.custom SPIE en_US
dc.date.activity 20070826 en_US
dc.date.activity 2007-08-26
dc.location.activity San Diego, California, USA en_US
dc.location.activity San Diego, CA
dc.description.keywords Coherent fluctuations
dc.description.keywords Coherent fluctuations
dc.description.keywords Metal insulator transition
dc.description.keywords Metal insulator transition
dc.description.keywords Thermochromic
dc.description.keywords Thermochromic
dc.description.keywords Thin film
dc.description.keywords Thin film
dc.description.keywords Vanadium dioxide
dc.description.keywords Vanadium dioxide
pubs.embargo.period Not known
pubs.organisational-group /University of Technology Sydney
pubs.organisational-group /University of Technology Sydney/Faculty of Science
pubs.organisational-group /University of Technology Sydney/Strength - Materials and Technology for Energy Efficiency
pubs.organisational-group /University of Technology Sydney/Strength - Materials and Technology for Energy Efficiency
utslib.copyright.status Closed Access
utslib.copyright.date 2015-04-15 12:17:09.805752+10
pubs.consider-herdc true
utslib.collection.history School of Physics and Advanced Materials (ID: 343)
utslib.collection.history General Collection (ID: 346) [2015-05-15T14:11:26+10:00]
utslib.collection.history Closed (ID: 3)


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