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Viability of a reversible femtosecond VO2 based single optoelectronic nano-gating and mapping of carriers density thermal variation in 1-D VO2 nanosystems by ultrafast Terahertz spectroscopy

English title Viability of a reversible femtosecond VO2 based single optoelectronic nano-gating and mapping of carriers density thermal variation in 1-D VO2 nanosystems by ultrafast Terahertz spectroscopy
Applicant Feurer Thomas
Number 149164
Funding scheme Bilateral programmes
Research institution Institut für angewandte Physik Universität Bern
Institution of higher education University of Berne - BE
Main discipline Condensed Matter Physics
Start/End 01.03.2014 - 28.02.2017
Approved amount 204'000.00
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Keywords (2)

Nano-technology; THz spectroscopy

Lay Summary (German)

Lead
Vanadiumdioxid ist ein stark korreliertes Material, welches bei 340.8K einen Metall-Isolator Phasenuebergang aufweist. Dieser ist reversibel und extrem schnell, weswegen VO2 als (i) intelligentes Fenstermaterial, (ii) als aktive Beschichtung bei Satelliten, (iii) als ultraleichtes und kompaktes Bolometer, (iv) als schneller optischer Schalter und (v) in der Nanoplasmonik eingesetzt wird. In diesem Projekt versuchen wir nun herauszufinden, ob Vanadiumdioxid Nanopartikel aehnliche Eigenschaften besitzen und welche Parameter wie von deren Groesse abhaengen.
Lay summary

Vanadiumdioxid ist ein vielversprechendes Material fuer schnelle optische Schalter und andere opto-elektronische Elemente. Dieses Material zeigt eine starke Korrelation zwischen elektronischen und strukturellen Freiheitsgraden. Als Konsequenz weist VO2 bei einer Temperatur von 340.8K einen Phasenuebergang erster Ordnung auf. Der Metall-Isolator Phasenuebergang ist von einer Strukturaenderung begleitet bei der die bei tiefen Temperaturen vorherrschende monoklinische Phase in eine rutile Phase bei hohen Temperaturen uebergeht. Dabei kommt es zu einer Aenderung in der Leitfaehigkeit von viele Groessenordnungen. Dieser reversible Phasenuebergang ist auch mit einer starken und ultraschnellen Aenderung des optischen Brechungsindex verknuepft, was das Material fuer photonische Anwendungen interessant macht. So wird VO2 bisher schon als (i) intelligentes Fenstermaterial, (ii) aktive Beschichtung bei Satelliten, (iii) ultraleichtes und kompaktes Bolometer, (iv) schneller optischer Schalter und (v) in der Nanoplasmonik eingesetzt.  

Im dieser binationalen Zusammenarbeit (Schweiz-Sued Afrika) untersuchen wir erstmals die Eigenschaften von Vanadiumdioxid Nanopartikeln, speziell ihre Ladungstraegerdichte und -dynamik.

Direct link to Lay Summary Last update: 17.02.2014

Responsible applicant and co-applicants

Employees

Name Institute

Project partner

Publications

Publication
Nonlinear THz spectroscopy and simulation of gated graphene
Gäumann G, Crassee I, Numan N, Tamagnone M, Mosig J R, Poumirol J-M, Wolf J-P, Feurer T (2018), Nonlinear THz spectroscopy and simulation of gated graphene, in Journal of Physics Communications, 2(6), 065016-065016.
Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging
Hack Erwin, Valzania Lorenzo, Gäumann Gregory, Shalaby Mostafa, Hauri Christoph P., Zolliker Peter (2016), Comparison of Thermal Detector Arrays for Off-Axis THz Holography and Real-Time THz Imaging, in Sensors, 16, 221.
Phase transition in a single VO2 nano-crystal: potential femtosecond tunable optoelectronic nano-gating
Maaza M., Simo A., Itani B.M., Kana J.B., El Harthi S., Bouziane K., Saboungi T.B., Doyl T.B. (2014), Phase transition in a single VO2 nano-crystal: potential femtosecond tunable optoelectronic nano-gating, in Elsevier, J Nanopart Res, 16, 2397.

Collaboration

Group / person Country
Types of collaboration
National Laser Centre-CSIR South Africa (Africa)
- Research Infrastructure
- Exchange of personnel
iThemba labs South Africa (Africa)
- Research Infrastructure
- Exchange of personnel
University of Cape Town-UCT South Africa (Africa)
- Research Infrastructure
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
5th EOS TST 2016 Meeting Talk given at a conference High field terahertz spectroscopy on gated single layer graphene 08.05.2016 Pecs, Hungary Feurer Thomas; Gäumann Gregory;
Ultrafast Phenomena in Cooperative Systems Poster THz spectroscopy of Vo2 thin films 14.02.2016 Lucca (Barga), Italy Feurer Thomas;
Ultrafast Phenomena in Cooperative Systems Poster Nonlinear THz spectroscopy of graphen 14.02.2016 Lucca (Barga), Italy Gäumann Gregory; Feurer Thomas;
Ultrafast Phenomena in Cooperative Systems (Gordon Research Conference) Poster Linear and nonlinear time domain THz spectroscopy of VO2 thin films 14.02.2016 Lucca, Italy Gäumann Gregory;


Awards

Title Year
Swiss government PhD fellowship awarded to Mrs. Nagla Numan Schweizerische Bundes-Exzellenz-Stipendium 2015

Abstract

Vanadium dioxide VO2 belongs to a class of materials including ferroelectrics, which hold great promise for future high-speed optical switches and other opto-electronic devices. In such materials, it is established that there is a strong relationship between structural and electronic effects, yet a much better understanding of the fundamental physics behind these effects is needed before they can be technologically exploited at the commercial level. Being a smart oxide, transiting at a temperature of Tc~340.8K, stoichiometric VO2 undergoes an exclusive and a unique 1st order metal-insulator electronic transition, which is accompanied by a sharp structural crystallographic transition from a low-temperature monoclinic phase to a high-temperature rutile phase. The latter result causes a sharp change in the resistivity over several orders of magnitude induced by the band gap closing. From photonics point of view, this reversible metal-insulator electronic transition is accompanied by a significant and reversible variation of the refractive index under an external stimulus such as temperature. Hence, VO2 based coatings have been attracting considerable interest both from fundamental & technological grounds. The sound technological potentialities include applications such as (i) smart windows for solar heat modulation, (ii) active coating for heat management in satellites, (iii) ultralight compact bolometry, (iv) ultrafast optical limiting and (v) femtosecond tunable nanoplasmonics. While it took a half-century since the pioneering works of Morin and Sir Neville Mott to measure the duration of the singular 1st order metal-insulator electronic transition of VO2 which was found to be in the femtosecond regime by Cavalleri et al [11], this Swiss-South African research proposal is aiming to map for the first time the thermal variation of the carriers’ density and its dynamic in nano-scaled VO2 1-D type nanorods by Terahertz spectroscopy as well as to demonstrate the feasibility of a femtosecond photo-induced optoelectronic nano-gating. The established and complementary track records of the South African and Swiss teams in the fields of VO2 nanoscaled material and Terahertz spectroscopy respectively would guarantee the full finalization of this joint project in view of technological applications in opto-electronic femtosecond single nano-gating. In parallel to the targeted scientific and technological objectives which are at the forefront of the current science status, and in view of the human capital development aspect, an identified cohort of postgraduate fellows will be trained and mentored by both PIs in the field of VO2 smart coatings physics and Terahertz spectroscopy respectively.
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