Download or read book Preparation of Atomically Flat Rutile TiO2 001 Surfaces for Oxide Film Growth written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The availability of low-index rutile TiO2 single crystal substrates with atomically flat surfaces is essential for enabling epitaxialgrowth of rutile transition metal oxide films. The high surface energy of the rutile (001) surface often leads to surface faceting, which precludes the sputter and annealing treatment commonly used for the preparation of clean and atomically flat TiO2(110) substrate surfaces. In this work, we reveal that stable and atomically flat rutile TiO2(001) surfaces can be prepared with an atomically ordered reconstructedsurface already during a furnace annealing treatment in air. We tentatively ascribe this result to the decrease in surface energy associated with the surface reconstruction, which removes the driving force for faceting. Despite the narrow temperature window where this morphology can initially be formed, we demonstrate that it persists in homoepitaxialgrowth of TiO2(001) thin films. The stabilization of surface reconstructions that prevent faceting of high-surface-energy crystal faces may offer a promising avenue towards the realization of a wider range of high quality epitaxial transition metal oxide heterostructures.
Download or read book The Surface Chemistry of Rutile in Technologically Relevant Environments written by Anqi Song and published by . This book was released on 2016 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The surface science of titanium dioxide, TiO2, has attracted great amount of attention due to its high profile applications. This dissertation shows the development of well-controlled rutile (110) surfaces that provide a platform for studying the chemical and photochemical reactivity of rutile in technologically relevant environments, including air and solutions. Near-perfect rutile (110) surfaces characterized by atomically flat terraces and straight steps were produced using basic peroxide solutions. The reaction produced straight steps with a different orientation, different structure, and different reactivity from those prepared in ultrahigh vacuum. The morphology was explained by a site-specific model of rutile (110) etching based on metal oxo coordination chemistry. This work shows that one of the important roles of peroxo ligands in etching and growth reactions is to destabilize neighboring bonds and increase their lability. The peroxo ligands add a degree of reversibility to the growth reaction, leading to the formation of well-ordered crystals. In addition, this near-perfect rutile (110) surface is an ideal starting point for studying surface chemistry of rutile in technologically relevant environments. Under ambient conditions atmospheric CO2 reacted with adsorbed H2O and produced a selfassembled monolayer of HCO3 on rutile (110) surfaces. The monolayer was formed on the nearperfect rutile surfaces prepared by basic peroxide etching, indicating that surface defects, such as Ti interstitials and O vacancies, were not required. DFT calculations suggested that the nanoscale water film adsorbed on the surface solvated the adsorbates and changed the reaction energetics. The HCO3 monolayer was very stable, even in vacuum, which was a result of the strong bidentate bonding of HCO3. The formation of the strongly bound bicarbonate monolayer suggests that HCO3, instead of CO2, plays a key role in the photoreduction of CO2. A high-quality, self-assembled benzoate monolayer was prepared on the near-perfect rutile (110) surfaces using simple solution chemistry. The monolayer remained free of contamination in air for tens of minutes. Surface science techniques combined with computations revealed that the phenyl rings adopted an edge-to-face tetrameric geometry with their four nearest neighbors. Adjacent molecules tilted towards each other across Ti atom rows, leading to the formation of a paired structure as observed in scanning tunneling microscopy images. The stability of the monolayer is a result of the strong bidentate bonding to unsaturated Ti atoms and the [pi]-[pi] interactions between the benzoate molecules.
Download or read book Japanese Journal of Applied Physics written by and published by . This book was released on 2005 with total page 1176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxygen Induced Restructuring of Rutile TiO 2 110 written by and published by . This book was released on 1999 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: The rutile TiO2 (110) (1x1) surface is considered the prototypical ''well-defined'' system in the surface science of metal oxides. Its popularity results partly from two experimental advantages: bulk-reduced single crystals do not exhibit charging, and stoichiometric surfaces--as judged by electron spectroscopes--can be prepared reproducibly by sputtering and annealing in oxygen. We present results that show that this commonly-applied preparation procedure may result in a surface structure that is by far more complex than generally anticipated. Flat, (1x1) terminated surfaces are obtained by sputtering and annealing in ultrahigh vacuum. When re-annealed in oxygen at moderate temperatures (470 K to 660 K), irregular networks of partially-connected, pseudohexagonal rosettes (6.5 x 6 Å wide), one-unit cell wide strands, and small ((approximately) tens of Å) (1x1) islands appear. This new surface phase is formed through reaction of oxygen gas with interstitial Ti from the reduced bulk. Because it consists of an incomplete, kinetically-limited (1x1) layer, this phenomenon has been termed restructuring. We report a combined experimental and theoretical study that systematically explores this restructuring process. The influence of several parameters (annealing time, temperature, pressure, sample history, gas) on the surface morphology is investigated using STM. The surface coverage of the added phase as well as the kinetics of the restructuring process are quantified by LEIS and SSIMS measurements in combination with annealing in 18O-enriched gas. Atomic models of the essential structural elements are presented and are shown to be stable with first-principles density functional calculations. The effect of oxygen-induced restructuring on surface chemistry and its importance for TiO2 and other bulk-reduced oxide materials is briefly discussed.
Download or read book Preparation and Characterization of Sol gel Derived Metal Oxide Thin Films and Powders for Coatings and Catalysts written by Per A. Askeland and published by . This book was released on 1997 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Oxide Materials at the Two Dimensional Limit written by Falko P. Netzer and published by Springer. This book was released on 2016-04-01 with total page 403 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes the current knowledge of two-dimensional oxide materials. The fundamental properties of 2-D oxide systems are explored in terms of atomic structure, electronic behavior and surface chemistry. The concept of polarity in determining the stability of 2-D oxide layers is examined, charge transfer effects in ultrathin oxide films are reviewed as well as the role of defects in 2-D oxide films. The novel structure concepts that apply in oxide systems of low dimensionality are addressed, and a chapter giving an overview of state-of-the-art theoretical methods for electronic structure determination of nanostructured oxides is included. Special emphasis is given to a balanced view from the experimental and the theoretical side. Two-dimensional materials, and 2-D oxides in particular, have outstanding behavior due to dimensionality and proximity effects. Several chapters treat prototypical model systems as illustrative examples to discuss the peculiar physical and chemical properties of 2-D oxide systems. The chapters are written by renowned experts in the field.
Download or read book Scanning Probe Microscopy and Spectroscopy written by Dawn Bonnell and published by John Wiley & Sons. This book was released on 2000-12-05 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: A practical introduction to basic theory and contemporary applications across a wide range of research disciplines Over the past two decades, scanning probe microscopies and spectroscopies have gained acceptance as indispensable characterization tools for an array of disciplines. This book provides novices and experienced researchers with a highly accessible treatment of basic theory, alongside detailed examples of current applications of both scanning tunneling and force microscopies and spectroscopies. Like its popular predecessor, Scanning Probe Microscopy and Spectroscopy, Second Edition features contributions from distinguished scientists working in a wide range of specialties at university, commercial, and government research labs around the world. Chapters have been edited for clarity, conciseness, and uniformity of presentation to provide professionals with a concise working reference to scanning probe microscopic and spectroscopic principles, techniques, and practices. This Second Edition has been substantially revised and expanded to reflect important advances and new applications. In addition to numerous examples, the Second Edition features expanded coverage of electrostatic and magnetic force microscopies, near-field optical microscopies, and new applications of buried interfaces in nanomechanics, electrochemistry, and biology. Scanning Probe Microscopy and Spectroscopy, Second Edition is an indispensable working resource for surface scientists, microscopists, and spectroscopists in materials science, chemistry, engineering, biochemistry, physics, and the life sciences. It is also an unparalleled reference text for advanced undergraduates and graduate students in those fields.
Download or read book Encyclopedia of Interfacial Chemistry written by and published by Elsevier. This book was released on 2018-03-29 with total page 5276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry, Seven Volume Set summarizes current, fundamental knowledge of interfacial chemistry, bringing readers the latest developments in the field. As the chemical and physical properties and processes at solid and liquid interfaces are the scientific basis of so many technologies which enhance our lives and create new opportunities, its important to highlight how these technologies enable the design and optimization of functional materials for heterogeneous and electro-catalysts in food production, pollution control, energy conversion and storage, medical applications requiring biocompatibility, drug delivery, and more. This book provides an interdisciplinary view that lies at the intersection of these fields. Presents fundamental knowledge of interfacial chemistry, surface science and electrochemistry and provides cutting-edge research from academics and practitioners across various fields and global regions
Download or read book Handbook of Thin Films Five Volume Set written by Hari Singh Nalwa and published by Elsevier. This book was released on 2001-11-17 with total page 3451 pages. Available in PDF, EPUB and Kindle. Book excerpt: This five-volume handbook focuses on processing techniques, characterization methods, and physical properties of thin films (thin layers of insulating, conducting, or semiconductor material). The editor has composed five separate, thematic volumes on thin films of metals, semimetals, glasses, ceramics, alloys, organics, diamonds, graphites, porous materials, noncrystalline solids, supramolecules, polymers, copolymers, biopolymers, composites, blends, activated carbons, intermetallics, chalcogenides, dyes, pigments, nanostructured materials, biomaterials, inorganic/polymer composites, organoceramics, metallocenes, disordered systems, liquid crystals, quasicrystals, and layered structures. Thin films is a field of the utmost importance in today's materials science, electrical engineering and applied solid state physics; with both research and industrial applications in microelectronics, computer manufacturing, and physical devices. Advanced, high-performance computers, high-definition TV, digital camcorders, sensitive broadband imaging systems, flat-panel displays, robotic systems, and medical electronics and diagnostics are but a few examples of miniaturized device technologies that depend the utilization of thin film materials. The Handbook of Thin Films Materials is a comprehensive reference focusing on processing techniques, characterization methods, and physical properties of these thin film materials.
Download or read book Metals Abstracts written by and published by . This book was released on 1996 with total page 1622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Growth of Rutile TiO2 written by Louis J. Vernon and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: TiO2 is a well investigated material due to its vast array of applications, from the most common white food colouring, to usage as an optical coating due to its high refractive index. When deposited as a thin?lm for use in solar control coatings using a magnetron sputtering device, TiO2 is found to form in rutile, anatase and amorphous phases, with the rutile (1 1 0) and anatase (1 0 0) crystal surfaces occurring most frequently. While the in?uence of deposition rate, substrate bias voltage, oxygen partial pressure and temperature have all been investigated experimentally, there are fewer simulated results. This seems to be primarily due to the lack of a suitable empirical potential through which dynamics can be accurately modelled. In this research project, the short-comings of the leading?xed and variable charge TiO2 potentials were revealed through comparison of binding energies and transition barriers for simple ad-clusters and interstitials to DFT. This led to the development of an improved variable charge potential, particularly when modelling the rutile (1 1 0) surface. It has been experimentally demonstrated that rutile growth results in a reduced surface due to the formation of large numbers of Ti interstitials and this was also suggested due to low Ti interstitial formation barriers found using DFT and the variable charge empirical potentials. The high interstitial formation probability was con?rmed when performing large numbers of Tix Oy depositions at typical industrial energies. Correlations between impact site and numbers of interstitials and vacancies formed were found along with insight into typical penetration depths and common defect structures. Multilayer growth was successfully modelled using classical MD by accelerating the deposition rate. The large numbers of formed interstitials coupled with a high escape barrier resulted in defective growth and so it was necessary to increase the substrate temperature such that atoms were mobile on the computational time-scale. Multilayer growth was investigated as a function of deposition energy, cluster composition and stoichiometry on the rutile (1 1 0), anatase (1 0 0) and amorphous surfaces. The optimum conditions for forming defect free rutile were found along with more limited insight into the ideal growth conditions when depositing on anatase and amorphous substrates. Finally a long time-scale dynamics technique, the?on-?y-kinetic Monte Carlo? method, was developed, and using an e?cient bespoke transition search algorithm, rutile TiO2 growth was successfully modelled at 350 K, with some caveats to avoid becoming entrenched in low activation di?usion processes. The?nal conclusion being that low energy depositions of large clusters with an oxygen excess would produce optimum?lm growth.
Download or read book 22nd Annual Conference of the German Crystallographic Society March 2014 Berlin Germany written by and published by Walter de Gruyter GmbH & Co KG. This book was released on 2014-09-11 with total page 475 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zeitschrift für Kristallographie. Supplement Volume 34 presents the complete Abstracts of all contributions to the 22nd Annual Conference of the German Crystallographic Society in Berlin 2014: - Celebration of the “International Year of Crystallography 2014” - Plenary Talks - Microsymposia - Poster Session Supplement Series of Zeitschrift für Kristallographie publishes Abstracts of international conferences on the interdisciplinary field of crystallography.
Download or read book The Surface Science of Metal Oxides written by and published by Royal Society of Chemistry. This book was released on 2000 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: The surface science of metal oxides is studied using a variety of experimental and theoretical techniques, allowing the geometry, electronic structure, dynamics and the behaviour of the metal oxide-metal interface to be explored. Faraday Discussions documents a long-established series of Faraday Discussion meetings which provide a unique international forum for the exchange of views and newly acquired results in developing areas of physical chemistry, biophysical chemistry and chemical physics. The papers presented are published in the Faraday Discussion volume together with a record of the discussion contributions made at the meeting. Faraday Discussions therefore provide an important record of current international knowledge and views in the field concerned.
Download or read book Atomic Layer Deposition for Semiconductors written by Cheol Seong Hwang and published by Springer Science & Business Media. This book was released on 2013-10-18 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offering thorough coverage of atomic layer deposition (ALD), this book moves from basic chemistry of ALD and modeling of processes to examine ALD in memory, logic devices and machines. Reviews history, operating principles and ALD processes for each device.
Download or read book Oxide Surfaces written by and published by Elsevier. This book was released on 2001-05-21 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is a multi-author survey (in 15 chapters) of the current state of knowledge and recent developments in our understanding of oxide surfaces. The author list includes most of the acknowledged world experts in this field. The material covered includes fundamental theory and experimental studies of the geometrical, vibrational and electronic structure of such surfaces, but with a special emphasis on the chemical properties and associated reactivity. The main focus is on metal oxides but coverage extends from 'simple' rocksalt materials such as MgO through to complex transition metal oxides with different valencies.
Download or read book Handbook of Thin Film Materials Characterization and spectroscopy of thin films written by Hari Singh Nalwa and published by . This book was released on 2002 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vol.1: Deposition and processing of thin films; Vol.2: Characterization and spectroscopy of thin films; Vol.3: Ferroelectric and dielectric thin films; Vol.4: Semiconductor and superconductor thin films; Vol.5: Nanomaterials and magnetic thin flims
