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 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 Transmission Electron Microscopy Characterization of Nanomaterials written by Challa S.S.R. Kumar and published by Springer Science & Business Media. This book was released on 2013-12-09 with total page 718 pages. Available in PDF, EPUB and Kindle. Book excerpt: Third volume of a 40volume series on nanoscience and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Transmission electron microscopy characterization of nanomaterials. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

Download or read book Characterization of Surfaces and Interfaces in Nanoparticles Using Transmission Electron Microscopy written by Julia Deneen Nowak and published by . This book was released on 2007 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book MBE Growth and Scanning Transmission Electron Microscopy Characterization of Group III Nitride Compound Semiconductor Thin Films written by Tyler Joe Eustis and published by . This book was released on 2004 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Group III nitride Semiconductor Thin Films by High Resolution Electron Microscopy written by Durvasulu Chandrasekhar and published by . This book was released on 1994 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Nanocomposites written by Boreddy Reddy and published by BoD – Books on Demand. This book was released on 2011-04-19 with total page 984 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Nanocomposites - Synthesis, Characterization and Industrial Applications was conceived as a comprehensive reference volume on various aspects of functional nanocomposites for engineering technologies. The term functional nanocomposites signifies a wide area of polymer/material science and engineering, involving the design, synthesis and study of nanocomposites of increasing structural sophistication and complexity useful for a wide range of chemical, physicochemical and biological/biomedical processes. "Emerging technologies" are also broadly understood to include new technological developments, beginning at the forefront of conventional industrial practices and extending into anticipated and speculative industries of the future. The scope of the present book on nanocomposites and applications extends far beyond emerging technologies. This book presents 40 chapters organized in four parts systematically providing a wealth of new ideas in design, synthesis and study of sophisticated nanocomposite structures.

Download or read book EMC 2008 written by Silvia Richter and published by Springer Science & Business Media. This book was released on 2008-09-20 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the14th European Microscopy Congress, held in Aachen, Germany, 1-5 September 2008. Jointly organised by the European Microscopy Society (EMS), the German Society for Electron Microscopy (DGE) and the local microscopists from RWTH Aachen University and the Research Centre Jülich, the congress brings together scientists from Europe and from all over the world. The scientific programme covers all recent developments in the three major areas of instrumentation and methods, materials science and life science.

Download or read book Oxide Ultrathin Films written by Gianfranco Pacchioni and published by John Wiley & Sons. This book was released on 2012-09-19 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wealth of information in one accessible book. Written by international experts from multidisciplinary fields, this in-depth exploration of oxide ultrathin films covers all aspects of these systems, starting with preparation and characterization, and going on to geometrical and electronic structure, as well as applications in current and future systems and devices. From the Contents: Synthesis and Preparation of Oxide Ultrathin Films Characterization Tools of Oxide Ultrathin Films Ordered Oxide Nanostructures on Metal Surfaces Unusual Properties of Oxides and Other Insulators in the Ultrathin Limit Silica and High-K Dielectrics Thin Films in Microelectronics Oxide Passive Films and Corrosion Protection Oxide Films as Catalytic Materials and as Models of Real Catalysts Oxide Films in Spintronics Oxide Ultrathin Films in Solid Oxide Fuel Cells Transparent Conducting and Chromogenic Oxide Films as Solar Energy Materials Oxide Ultrathin Films in Sensor Applications Ferroelectricity in Ultrathin Film Capacitors Titania Thin Films in Biocompatible Materials and Medical Implants Oxide Nanowires for New Chemical Sensor Devices

Download or read book Strongly Strained Growth of Vanadium Dioxide Thin Films on Microscale Ruthenium Dioxide Islands written by Simon Fischer and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vanadium dioxide exhibits a metal-insulator transition (MIT) which comprises an electronic and a structural component. Accordingly, it is often understood as a cooperative effect of a structure-induced Peierls transition and a electron correlations-induced Mott transition. The structural transition can be exploited by subjecting VO2 thin films to epitaxial stress, which stabilizes either the low temperature insulating or the high temperature metallic phase. Through this strain engineering approach, the transition temperature can be tuned from its bulk value of 68 °C, tailoring the material towards technological applications. In the present thesis, massively strained thin films of VO2 on micron-sized RuO2 islands are grown and analyzed. This is done, in large parts, in a low energy electron microscope (LEEM) instrument. The instrument allows for following surface processes in situ during oxidation and deposition experiments, giving microscopic and structural information on the material. First, the RuO2 islands are fabricated by oxidizing a Ru(0001) surface using atomic oxygen from a thermal cracker. The resulting complex island morphology, which encompasses four different phases of RuO2, is studied during and after growth, assessing the kinetic and thermodynamic aspects that lead to their formation. It is found that a microcrystalline oxide phase serves as a nucleation hub for adjacent (110)- and (101)-oriented RuO2 structures, which then outgrow the incubator phase. The structural registry of a separate RuO2(100) phase to the substrate has been resolved and is found to lead to the distinct growth behavior that this phase exhibits compared to the others. On samples prepared in this way, VO2 was grown, again with the aid of atomic oxygen. This, as confirmed by x-ray absorption spectroscopy (XAS) and x-ray photoelectron spectroscopy (XPS), ensures that the stoichiometry of the films is correct. In situ low energy electron diffraction (LEED) measurements showed that during the growth of VO2 on RuO2(110), the lattice parameters stay constant. This indicates a very high strain near the pseudomorphic case (8.78 %). The VO2(110) surface was also found to exhibit a (2 × 2) reconstruction due to an oxygen-rich surface termination. Conversely, VO2 was found to grow relaxed on the (100)-oriented islands. Its VO2(100) surface is heavily faceted, indicating a high surface energy. Complementary measurement of the x-ray linear dichroism in these films finds that the VO2(110)/RuO2(110) islands exhibit spectra that are characteristic for the metallic phase. This may indicate that the MIT is suppressed in high-strain conditions. On VO2(100)/RuO2(100) islands, indications of a MIT are found. However, the VO2 films experience reduction due to the synchrotron beam, which can also induce the transition into the metallic state. Alongside a deeper understanding of Ru oxidation kinetics using atomic oxygen, this work opens up a remarkably high window of accessible strain for VO2 thin film growth and gives important insights into the surface of VO2, which until recently was often neglected.

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 Electrochromic Properties of Vanadium Pentoxide Nanostructured Thin Films written by Afaf Almoabadi and published by . This book was released on 2015 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT Electrochromic Properties of Vanadium Pentoxide Nanostructured Thin Films Afaf Almoabadi The focus of this work is the improvement of the electrochromic properties of vanadium pentoxide thin films in order to expand its use. Indeed, because of its rather poor electrochromic properties, until now, vanadium pentoxide has only been used as a storage material in an electrochromic device, in conjunction with tungsten oxide, molybdenum oxide etc. To this purpose, vanadium pentoxide thin films were prepared under different conditions and characterized by using optical and electrochemical methods. Films were deposited on indium tin oxide (ITO) substrates by dip-coating at both room- and sub-zero temperature (-100C) and porosity in the sol-gel prepared vanadium pentoxide film was created by using templating methods. The morphology, optical and electrochromic properties of the macro- and mesoporous films, prepared in the presence of structure-directing agents such as polystyrene microspheres and triblock copolymer, have been compared with those of dense films. By using various methods to remove the template material, it was shown that the morphology of the vanadium pentoxide film can be controlled and new nanostructures can be created. The transformation of the lamellar into a nanorod structure, observed when the film is heated at 425-500◦C for several hours, resulted in the development of an elegant method for the synthesis of vanadium oxide nanostructures. The electrochromic performance of the nanorods prepared through the thermal treatment was found to be superior to that of the vanadium pentoxide with the layered structure, especially in the near-infrared region, demonstrating their potential for electrochromic applications. The structure, morphology, optical and electrochromic properties of dense and porous vanadium oxide films, coated at low temperature were also determined and compared to those of the corresponding films, deposited under room-temperature conditions. The results indicated that in the films coated at -100C, a residual compressive stress exists that originates from a non-uniformity in depth of the film, most probably, due to the formation of micro voids during the deposition. The micro voids are preserved during the heat-treatment of the films. The "micro void" morphology was found to account for the considerably improved electrochromic properties of the sub-zero dip-coated films. Low-temperature coated films, heated at 4500C for several hours, undergo the transformation from a layered to a highly uniform nanorod structure with important potential optoelectronic applications. The overall aim of this work is thus to evaluate how the morphology of vanadium pentoxide thin films is instrumental in obtaining a material with a high lithium ion intercalation capacity. With an appropriate morphology, the performance of vanadium oxide as electrochromic material and as cathode in lithium ion batteries can be improved significantly. For this purpose, both layered (dense and porous) and nanorod films were prepared and characterized. Scanning electron microscopy, cyclic voltammetry and electrical impedance spectroscopy measurements were used for the characterization of the different V2O5 films.

Download or read book PULSED ELECTRON DEPOSITION AND CHARACTERIZATION OF NANOCRYSTALLINE DIAMOND THIN FILMS written by Omar Alshekhli and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Colloidal Metal Oxide Nanoparticles written by and published by Elsevier. This book was released on 2019-10-16 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Colloidal Metal Oxide Nanoparticles: Synthesis, Characterization and Applications is a one-stop reference for anyone with an interest in the fundamentals, synthesis and applications of this interesting materials system. The book presents a simple, effective and detailed discussion on colloidal metal oxide nanoparticles. It begins with a general introduction of colloidal metal oxide nanoparticles, then delves into the most relevant synthesis pathways, stabilization procedures, and synthesis and characterization techniques. Final sections discuss promising applications, including bioimaging, biosensing, diagnostic, and energy applications—i.e., solar cells, supercapacitors and environment applications—i.e., the treatment of contaminated soil, water purification and waste remediation. Provides the most comprehensive resource on the topic, from fundamentals, to synthesis and characterization techniques Presents key applications, including biomedical, energy, electronic and environmental Discusses the most relevant techniques for synthesis, patterning and characterization

Download or read book Scandium Oxide Thin Films and Their Optical Properties in the Extreme Ultraviolet written by Guillermo Acosta, 1974- and published by . This book was released on 2007 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study reports on the physical and optical characterization of scandium oxide thin films. Thin films of scandium oxide, 20-40 nm thick, were deposited on silicon wafers, quartz slides, and silicon photodiodes by reactively sputtering scandium in an oxygen environment. These samples were characterized using ellipsometry, high-resolution transmission electron microscopy, scanning transmission electron microscopy, and energy dispersive x-ray analysis. A 28.46 nm thick scandium oxide thin film was measured in the Extreme Ultraviolet (EUV) from 2.7 to 50 nm (459.3 to 24.8 eV) using synchrotron radiation at the Advanced Light Source Beamline 6.3.2 at the Lawrence Berkeley National Laboratory. In these measurements, a new method for data collection was used, in which the reflection and transmission data were collected simultaneously. Analysis of the EUV reflection and transmission data was performed using a front-side reflection, matrix-multiplication technique, which is novel among EUV analytical practice. During data analysis, a new weighting scheme was used, named "adaptive weighting". This analysis provides the first experimentally determined optical constants n and k for scandium oxide thin films from 4.5-30 nm. Also, the positions of the L2 and L3 electronic transitions of scandium oxide have been measured, at 3.069 and 3.101 nm (404.0 and 399.9 eV), respectively, while the measurements near the M transition suggest it to be at approximately 31.5 nm (39.4 eV). Comparing the electronic transition positions of scandium oxide to those of scandium show that the oxidation of scandium shifts the positions to lower energies. For L2 the shift is about 1.8 eV, for L3 the shift is about 1.4 eV, and for M the shift is about 1.9 eV. The binding energies of scandium oxide are greater than those of scandium, as is expected for an oxide compared to its parent metal. This trend in the shift of the transition positions is unexpected, and warrants further investigation.

Download or read book Synthesis and Characterization of Iron Oxide Thin Films for Use in Electrical Devices written by and published by . This book was released on 2013 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have developed a novel method of preparation of homogeneous transparent iron oxide thin films based on the thermal decomposition of iron tris-2,2'-bipyridine complexes. The resulting films were characterized with optical spectroscopy, optical and scanning electron microscopy and their crystal structure was established with X-ray powder diffraction and Raman spectroscopy. The film morphology is defined by the choice of the iron precursor and the method allows for both mono- and multilayer deposition, effectively providing control over film thickness. Addition of tris-2,2'-bipyridine complexes of other metals on the stage of film deposition provides a convenient path towards film doping. Obtained iron oxide films were also tested as photoanodes in dye-sensitized solar cells.

Download or read book The Solid solid Phase Transition in Vanadium Dioxide Thin Films written by Joyeeta Nag and published by . This book was released on 2011 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: