Download or read book Near field Optical Investigation of Vanadium Dioxide Thin Films written by Raul Torrico and published by . This book was released on 2014 with total page 491 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Vanadium Dioxide (VO2) has been garnering a lot of attention because of its ability to undergo a phase transition from insulator to metal when heated and to switch back to insulator when cooled. Here we use the scattering-type Near-Field Optical Microscope to study the changes caused in the optical properties by the phase transition in near-field regime of VO2 . We observe the growth of metallic VO2 puddles at varying temperatures from room temperature up to a critical temperature around 358 K. The insulator to metal transition causes the optical constants in VO2 to drastically change. Taking advantage of the change, coupling VO2 with plasmonic structures has the interesting effect of combining to form optical metamaterials. These man-made materials exhibit behaviors not found in nature. Using the Lumerical Solutions software, it is possible to model and simulate those optical behaviors for different types of noble metal plasmonic structures using insulating and metallic VO2 at different light sources. These metamaterials can be categorized as hybrid-tunable metamaterials which can be designed to filter certain resonance frequencies without having to change plasmonic structure.

Download or read book Insulator to Metal Transition Dynamics of Vanadium Dioxide Thin Films written by Scott Eric Madaras and published by . This book was released on 2020 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vanadium Dioxide (VO2) is a strongly correlated material which has been studied for many decades. VO2 has been proposed for uses in technologies such as optical modulators, IR modulators, optical switches and Mott memory devices. These technologies are taking advantage of VO2’s insulator to metal transition (IMT) and the corresponding changes to the optical and material properties. The insulator to metal transition in VO2 can be accessed by thermal heating, applied electric field, or ultra-fast photo induced processes. Recently, thin films of VO2 grown on Titanium Dioxide doped with Niobium (TiO2:Nb), have shown promise as a possible UV photo detector with high quantum efficiency which utilizes a heterostructure between these two materials. In this work, the dynamics of the IMT on thin films of VO2 is explored. We show that surface plasmons generated in an Au thin film can induce the insulator to metal transition in a thin film of VO2 due to the enhanced electric field as well as help detect the IMT via changes in its resonance condition. Time resolved pump probe studies were also done on thin films of VO2 grown on TiO2 and TiO2:Nb, using UV photon energy of 3.1 eV (400nm wavelength). The fluence threshold of the IMT at 3.1 eV was significantly lower than published values for the 1.55 eV pump fluence. The time response of the IMT shows uncommon reflectivity dynamics in these samples. The response was partially attributed to internal interference of the reflected probe beam from the inhomogeneous layers formed inside the film by different phases of VO2, and can be elucidated by a diffusion model with respect to its optical properties. Finally, the photocurrent generation time constants for the sample with highest quantum efficiency are given and compared to its ultrafast photo induced IMT time constants.

Download or read book Optical Investigation of Metal oxide Thin Films written by Valter Kiisk and published by . This book was released on 2006 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Principles of Nano Optics written by Lukas Novotny and published by Cambridge University Press. This book was released on 2012-09-06 with total page 583 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fully revised and in its second edition, this standard reference on nano-optics is ideal for graduate students and researchers alike.

Download or read book Shining Light on the Phase Transitions of Vanadium Dioxide written by Tyler J. Huffman and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The salient feature of the familiar structural transition accompanying the thermally-driven metal-insulator transition in bulk vanadium dioxide (VO2) is a pairing of all the vanadium ions in the monoclinic M¬1 insulating phase. Whether this pairing (unit cell doubling) alone is sufficient to open the energy gap has been the central question of a classic debate which has continued for almost sixty years. Interestingly, there are two less familiar insulating states, monoclinic M2 and triclinic, which are accessible via strain or chemical doping. These phases are noteworthy in that they exhibit distinctly different V-V pairing. With infrared and optical photon spectroscopy, we investigate how the changes in crystal structure affect the electronic structure. We find that the energy gap and optical inter-band transitions are insensitive to changes in the vanadium-vanadium pairing. This result is confirmed by DFT+U and HSE calculations. Hence, our work conclusively establishes that intra-atomic Coulomb repulsion between electrons provides the dominant contribution to the energy gap in all insulating phases of VO2. VO2 is a candidate material for novel technologies, including ultrafast data storage, memristors, photonic switches, smart windows, and transistors which move beyond the limitations of silicon. The attractiveness of correlated materials for technological application is due to their novel properties that can be tuned by external factors such as strain, chemical doping, and applied fields. For advances in fundamental physics and applications, it is imperative that these properties be measured over a wide range of regimes. Towards this end, we study a single domain VO2 crystal with polarized light to characterize the anisotropy of the optical properties. In addition, we study the effects of compressive strain in a VO2 thin film in which we observe remarkable changes in electronic structure and transition temperature. Furthermore, we find evidence that electronic correlations are active in the metallic rutile phase as well. VO2 films exhibit phase coexistence in the vicinity of the metal-insulator transition. Using scanning near-field infrared microscopy, we have studied the patterns of phase coexistence in the same area on repeated heating and cooling cycles. We find that the pattern formation is reproducible each time. This is an unexpected result from the viewpoint of classical nucleation theory that anticipates some degree of randomness. The completely deterministic nature of nucleation and growth of domains in a VO2 film with imperfections is a fundamental finding. This result also holds promise for producing reliable nanoscale VO2 devices.

Download or read book Near Field Radiative Heat Transfer across Nanometer Vacuum Gaps written by Soumyadipta Basu and published by William Andrew. This book was released on 2016-05-30 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: Near-Field Radiative Heat Transfer across Nanometer Vacuum Gaps provides an in-depth description of fundamentals and application of near-field radiative heat transfer. When the vacuum gap between two media is on the order of nanometers, heat transfer can exceed that between blackbodies. This book investigates near-field heat transfer between different materials and geometries highlighting interplay between optics, material thermophysical properties and electromagnetism. The book also highlights the application of near-field thermal radiation in the field of power generation, imaging, and thermal systems as an analog of electronic devices. - Brings together research in near-field radiative heat transfer in a focused and comprehensive manner, allowing those new to the topic to gain a thorough understanding of the science and how it can be used - Offers focused coverage of heat transfer in near-field radiation, which other books do not - Outlines the interplay between optics, electromagnetics, basic thermodynamics, and thermophysical properties of materials during near-field heat transfer

Download or read book A Study of Phase Transition Mechanisms in Vanadium Dioxide Thin Films for Flat Panel Display Appliciations written by Scott H. Beasor and published by . This book was released on 2000 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Optical Loss Mechanisms in Oxide Thin Films written by and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preparation and Property Investigation of Vanadium Oxide Thin Films written by Siew Ping Lim and published by . This book was released on 2006 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electron Microscopy Characterization of Vanadium Dioxide Thin Films and Nanoparticles written by Felipe Rivera and published by . This book was released on 2012 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vanadium dioxide (VO_2) is a material of particular interest due to its exhibited metal to insulator phase transition at 68°C that is accompanied by an abrupt and significant change in its electronic and optical properties. Since this material can exhibit a reversible drop in resistivity of up to five orders of magnitude and a reversible drop in infrared optical transmission of up to 80%, this material holds promise in several technological applications. Solid phase crystallization of VO_2 thin films was obtained by a post-deposition annealing process of a VO_{x, x approx 2} amorphous film sputtered on an amorphous silicon dioxide (SiO_2) layer. Scanning electron microscopy (SEM) and electron-backscattered diffraction (EBSD) were utilized to study the morphology of the solid phase crystallization that resulted from this post-deposition annealing process. The annealing parameters ranged in temperature from 300°C up to 1000°C and in time from 5 minutes up to 12 hours. Depending on the annealing parameters, EBSD showed that this process yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. In addition to these films on SiO_2, other VO_2 thin films were deposited onto a-, c-, and r-cuts of sapphire and on TiO_2(001) heated single-crystal substrates by pulsed-laser deposition (PLD). The temperature of the substrates was kept at ~500°C during deposition. EBSD maps and orientation imaging microscopy were used to study the epitaxy and orientation of the VO_2 grains deposited on the single crystal substrates, as well as on the amorphous SiO_2 layer. The EBSD/OIM results showed that: 1) For all the sapphire substrates analyzed, there is a predominant family of crystallographic relationships wherein the rutile VO_2{001} planes tend to lie parallel to the sapphire's {10-10} and the rutile VO_2{100} planes lie parallel to the sapphire's {1-210} and {0001}. Furthermore, while this family of relationships accounts for the majority of the VO_2 grains observed, due to the sapphire substrate's geometry there were variations within these rules that changed the orientation of VO_2 grains with respect to the substrate's normal direction. 2) For the TiO_2, a substrate with a lower lattice mismatch, we observe the expected relationship where the rutile VO_2 [100], [110], and [001] crystal directions lie parallel to the TiO_2 substrate's [100], [110], and [001] crystal directions respectively. 3) For the amorphous SiO_2 layer, all VO_2 crystals that were measurable (those that grew to the thickness of the deposited film) had a preferred orientation with the the rutile VO_2[001] crystal direction tending to lie parallel to the plane of the specimen. The use of transmission electron microscopy (TEM) is presented as a tool for further characterization studies of this material and its applications. In this work TEM diffraction patterns taken from cross-sections of particles of the a- and r-cut sapphire substrates not only solidified the predominant family mentioned, but also helped lift the ambiguity present in the rutile VO_2{100} axes. Finally, a focused-ion beam technique for preparation of cross-sectional TEM samples of metallic thin films deposited on polymer substrates is demonstrated.

Download or read book Spectroscopic Ellipsometry written by Hiroyuki Fujiwara and published by John Wiley & Sons. This book was released on 2007-09-27 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ellipsometry is a powerful tool used for the characterization of thin films and multi-layer semiconductor structures. This book deals with fundamental principles and applications of spectroscopic ellipsometry (SE). Beginning with an overview of SE technologies the text moves on to focus on the data analysis of results obtained from SE, Fundamental data analyses, principles and physical backgrounds and the various materials used in different fields from LSI industry to biotechnology are described. The final chapter describes the latest developments of real-time monitoring and process control which have attracted significant attention in various scientific and industrial fields.

Download or read book Nano Microscale Heat Transfer written by Zhuomin M. Zhang and published by Springer Nature. This book was released on 2020-06-23 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt: This substantially updated and augmented second edition adds over 200 pages of text covering and an array of newer developments in nanoscale thermal transport. In Nano/Microscale Heat Transfer, 2nd edition, Dr. Zhang expands his classroom-proven text to incorporate thermal conductivity spectroscopy, time-domain and frequency-domain thermoreflectance techniques, quantum size effect on specific heat, coherent phonon, minimum thermal conductivity, interface thermal conductance, thermal interface materials, 2D sheet materials and their unique thermal properties, soft materials, first-principles simulation, hyperbolic metamaterials, magnetic polaritons, and new near-field radiation experiments and numerical simulations. Informed by over 12 years use, the author’s research experience, and feedback from teaching faculty, the book has been reorganized in many sections and enriched with more examples and homework problems. Solutions for selected problems are also available to qualified faculty via a password-protected website.• Substantially updates and augments the widely adopted original edition, adding over 200 pages and many new illustrations;• Incorporates student and faculty feedback from a decade of classroom use;• Elucidates concepts explained with many examples and illustrations;• Supports student application of theory with 300 homework problems;• Maximizes reader understanding of micro/nanoscale thermophysical properties and processes and how to apply them to thermal science and engineering;• Features MATLAB codes for working with size and temperature effects on thermal conductivity, specific heat of nanostructures, thin-film optics, RCWA, and near-field radiation.

Download or read book Solid Phase Crystallization of Vanadium Dioxide Thin Films and Characterization Through Scanning Electron Microscopy written by Felipe Rivera and published by . This book was released on 2007 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crystalline films of vanadium dioxide were obtained through thermal annealing of amorphous vanadium dioxide thin films sputtered on silicon dioxide. An annealing process was found that yielded polycrystalline vanadium dioxide thin films, semi-continuous thin films, and films of isolated single-crystal particles. Orientation Imaging Microscopy (OIM) was used to characterize and study the phase and the orientation of the vanadium dioxide crystals obtained, as well as to differentiate them from other vanadium oxide stoichiometries that may have formed during the annealing process. There was no evidence of any other vanadium oxides present in the prepared samples. Indexing of the crystals for the orientation study was performed with the Kikuchi patterns for the tetragonal phase of vanadium dioxide, since it was observed that the Kikuchi patterns for the monoclinic and tetragonal phases of vanadium dioxide are indistinguishable by OIM. It was found that a particle size of 100 nm was in the lower limit of particles that could be reliably characterized with this technique. It was also found that all VO2 crystals large enough to be indexed by OIM had a preferred orientation with the C axis of the tetragonal phase parallel to the plane of the specimen.

Download or read book Recent Advances in Thin Films written by Sushil Kumar and published by Springer Nature. This book was released on 2020-08-27 with total page 721 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume comprises the expert contributions from the invited speakers at the 17th International Conference on Thin Films (ICTF 2017), held at CSIR-NPL, New Delhi, India. Thin film research has become increasingly important over the last few decades owing to the applications in latest technologies and devices. The book focuses on current advances in thin film deposition processes and characterization including thin film measurements. The chapters cover different types of thin films like metal, dielectric, organic and inorganic, and their diverse applications across transistors, resistors, capacitors, memory elements for computers, optical filters and mirrors, sensors, solar cells, LED's, transparent conducting coatings for liquid crystal display, printed circuit board, and automobile headlamp covers. This book can be a useful reference for students, researchers as well as industry professionals by providing an up-to-date knowledge on thin films and coatings.

Download or read book Hard X ray Photoelectron Spectroscopy HAXPES written by Joseph Woicik and published by Springer. This book was released on 2015-12-26 with total page 576 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides the first complete and up-to-date summary of the state of the art in HAXPES and motivates readers to harness its powerful capabilities in their own research. The chapters are written by experts. They include historical work, modern instrumentation, theory and applications. This book spans from physics to chemistry and materials science and engineering. In consideration of the rapid development of the technique, several chapters include highlights illustrating future opportunities as well.

Download or read book Fundamentals and Applications of Nanophotonics written by Joseph W. Haus and published by Woodhead Publishing. This book was released on 2016-01-09 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals and Applications of Nanophotonics includes a comprehensive discussion of the field of nanophotonics, including key enabling technologies that have the potential to drive economic growth and impact numerous application domains such as ICT, the environment, healthcare, military, transport, manufacturing, and energy. This book gives readers the theoretical underpinnings needed to understand the latest advances in the field. After an introduction to the area, chapters two and three cover the essential topics of electrodynamics, quantum mechanics, and computation as they relate to nanophotonics. Subsequent chapters explore materials for nanophotonics, including nanoparticles, photonic crystals, nanosilicon, nanocarbon, III-V, and II-VI semiconductors. In addition, fabrication and characterization techniques are addressed, along with the importance of plasmonics, and the applications of nanophotonics in devices such as lasers, LEDs, and photodetectors. - Covers electrodynamics, quantum mechanics and computation as these relate to nanophotonics - Reviews materials, fabrication and characterization techniques for nanophotonics - Describes applications of the technology such as lasers, LEDs and photodetectors

Download or read book Submicron Porous Materials written by Paolo Bettotti and published by Springer. This book was released on 2017-02-21 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the latest research on porous materials at the submicron scale and inspires readers to better understand the porosity of materials, as well as to develop innovative new materials. A comprehensive range of materials are covered, including carbon-based and organic-based porous materials, porous anodic alumina, silica, and titania-based sol-gel materials. The fabrication, characterization, and applications of these materials are all explored, with applications ranging from sensors, thermoelectrics, catalysis, energy storage, to photovoltaics. Also of practical use for readers are chapters that describe the basics of porous silicon fabrication and its use in optical sensing and drug delivery applications; how thermal transport is affected in porous materials; how to model diffusion in porous materials; and a unique chapter on an innovative spectroscopic technique used to characterize materials' porosity. This is an ideal book for graduate students, researchers, and professionals who work with porous materials.