Journal ArticleDOI
Thermal hysteresis measurement of the VO 2 dielectric function for its metal-insulator transition by visible-IR ellipsometry
J. A. Ramirez-Rincon,J. A. Ramirez-Rincon,C. Gomez-Heredia,C. Gomez-Heredia,A. Corvisier,Jose Ordonez-Miranda,Thierry Girardeau,F. Paumier,Corinne Champeaux,Frédéric Dumas-Bouchiat,Younès Ezzahri,Karl Joulain,O. Arés,Juan Jose Alvarado-Gil,Juan Jose Alvarado-Gil +14 more
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In this article, the real and imaginary parts of the dielectric function of VO2 thin films, deposited on rplane sapphire via pulsed laser deposition, are measured by means of visible-infrared ellipsometry for wavelengths ranging from 0.4 to 15μm and temperatures within its phase transition.Abstract:
The real and imaginary parts of the dielectric function of VO2 thin films, deposited on r-plane sapphire via pulsed laser deposition, are measured by means of visible-infrared ellipsometry for wavelengths ranging from 0.4 to 15 μm and temperatures within its phase transition. For both the insulator-to-metal (heating) and metal-to-insulator (cooling) transitions, it is shown that the two ellipsometric signals exhibit three temperature-driven behaviors, which are well described by appropriate combinations of the Tauc-Lorentz, Gaussian, and Drude oscillator models. By fitting Bruggeman's effective medium model for the dielectric function to the corresponding measured experimental values, using the volumetric fraction of the VO2 metallic domains as a fitting parameter for different temperatures within the VO2 phase transition, we have found that this model is suitable for describing the dielectric function in visible and near-infrared wavelengths (∼0.4 to ∼3.0 μm), but it generally fails for longer infrared ones. Furthermore, the hysteresis loop of the VO2 emissivity averaged over a relevant interval of wavelengths is determined and shown to vary from ∼0.49, in the insulator phase, to ∼0.16, in the metallic one. These values, based on the VO2 dielectric function, are consistent with previous measurements reported in the literature, and therefore, our measured data are expected to be useful for describing the behavior of VO2 films involved in optical and radiative applications.read more
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Journal ArticleDOI
On the Optical Properties of Thin‐Film Vanadium Dioxide from the Visible to the Far Infrared
Chenghao Wan,Zhen Zhang,David Woolf,Colin M. Hessel,Jura Rensberg,Joel M. Hensley,Yuzhe Xiao,Alireza Shahsafi,Jad Salman,Steffen Richter,Yifei Sun,M. Mumtaz Qazilbash,Rüdiger Schmidt-Grund,Rüdiger Schmidt-Grund,Carsten Ronning,Shriram Ramanathan,Mikhail A. Kats +16 more
TL;DR: In this article, the complex refractive index of VO2 thin films across the IMT for free-space wavelengths from 300 nm to 30 µm was characterized using broadband spectroscopic ellipsometry, reflection spectroscopy, and the application of effective medium theory.
Journal ArticleDOI
VO2-based switchable radiator for spacecraft thermal control.
Heung Soo Kim,Kwok Cheung,Raymond C. Y. Auyeung,Donald E. Wilson,Kristin M. Charipar,Alberto Piqué,Nicholas A. Charipar +6 more
TL;DR: Direct calorimetric measurements of a solid state passive switchable radiator for spacecraft thermal control have been performed in a simulated space environment and the measured radiated power difference was 480 W/m2 corresponding to a 7× difference in radiative cooling power.
Journal ArticleDOI
Radiative Thermal Memristor
TL;DR: The analogy of the proposed memristor to its electrical counterpart makes it promising to lay the foundations of the thermal computing with photons.
Journal ArticleDOI
Optical properties of thin-film vanadium dioxide from the visible to the far infrared
Chenghao Wan,Zhen Zhang,David Woolf,Colin M. Hessel,Jura Rensberg,Joel M. Hensley,Yuzhe Xiao,Alireza Shahsafi,Jad Salman,Steffen Richter,Yifei Sun,M. Mumtaz Qazilbash,Rüdiger Schmidt-Grund,Carsten Ronning,Shriram Ramanathan,Mikhail A. Kats +15 more
TL;DR: In this article, the complex refractive index of vanadium dioxide thin films across the IMT for free-space wavelengths from 300 nm to 30 µm was characterized using broadband spectroscopic ellipsometry, reflection spectroscopy, and the application of effective medium theory.
Journal ArticleDOI
Thermophysical characterisation of VO2 thin films hysteresis and its application in thermal rectification.
Georges Hamaoui,Nicolas Horny,Cindy Lorena Gomez-Heredia,J. A. Ramirez-Rincon,J. A. Ramirez-Rincon,Jose Ordonez-Miranda,Corinne Champeaux,Frédéric Dumas-Bouchiat,Juan Jose Alvarado-Gil,Juan Jose Alvarado-Gil,Younès Ezzahri,Karl Joulain,Mihai Chirtoc +12 more
TL;DR: Hysteresis loops exhibited by the thermophysical properties of VO2 thin films deposited on either a sapphire or silicon substrate have been experimentally measured using a high frequency photothermal radiometry technique, obtaining new insights on the control of heat currents.
References
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TL;DR: In this article, the Berechnung der dielektrizitatatkonstanten and der Leitfahigkeiten fur Elektriatitat and Warme der Mischkorper aus isotropen Bestandteilen behandelt.
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Metal-insulator transitions
TL;DR: A review of the metal-insulator transition can be found in this article, where a pedagogical introduction to the subject is given, as well as a comparison between experimental results and theoretical achievements.
Journal ArticleDOI
Oxides Which Show a Metal-to-Insulator Transition at the Neel Temperature
Journal ArticleDOI
Mott Transition in VO2 Revealed by Infrared Spectroscopy and Nano-Imaging
M. Mumtaz Qazilbash,M. Brehm,Byung-Gyu Chae,Pei-Chun Ho,Gregory O. Andreev,Bong-Jun Kim,Sun Jin Yun,Alexander V. Balatsky,M. B. Maple,Fritz Keilmann,Hyun-Tak Kim,Dimitri Basov +11 more
TL;DR: The electronic properties of a prototypical correlated insulator vanadium dioxide in which the metallic state can be induced by increasing temperature is reported, setting the stage for investigations of charge dynamics on the nanoscale in other inhomogeneous correlated electron systems.
Book
Handbook of Ellipsometry
TL;DR: Polarized Light and Ellipsometry: Optical Physics of Materials- Data Analysis for Spectroscopic Ellipsometers- Optical Components and the Simple PCSA (polarizer, compensator, sample, analyzer) Ellipsometer as mentioned in this paper.