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Showing 1 to 20 of 33 for “"Ultra High Vacuum (UHV)"”.
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Scanning tunneling microscopy of silicon(100) 2 x 1
… studies of this surface. To this end, an ultra-high vacuum (UHV) STM/surface science system has been designed and constructed to study semiconductor surfaces. Clean Si(100) 2 x 1 surfaces have been prepared and imaged with the STM. Atomic resolution images probing both the filled states …
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Coadsorption of anions and ultra-thin metal films on single crystal electrodes
This thesis describes results of a combined ultra-high vacuum (UHV)-electrochemistry instrument for structual and compositional surface analysis of anions and ultra-thin metallic films of copper and silver deposited on single crystal electrodes. The anion and metal coverages from the Auger electron …
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Cross-Sectional Scanning Tunneling Microscopy Investigations of Cleaved Iii-V Heterostructures
… of XSTM to III-V heterostructures. An ultra-high vacuum (UHV) system dedicated to XSTM has been specifically designed and constructed as part of this work. Reported for the first time are XSTM cross-sections of self-assembled InAs quantum dots, XSTM cross-sections of quantum wires …
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IR Spectroscopy Study of silver and Copper Nano-films
… the metal films at low temperatures (< 100 K) in Ultra High Vacuum (UHV), infrared spectra were captured in situ in transmission or reflection geometry. Afterwards the surface morphology of the films was examined ex situ by atomic force microscopy (AFM). For the first time, an infrared reflectance …
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Scanning tunneling microscopy investigations of transition metal dichalcogenide 1t-tantalum disulfide and zigzag-shape graphene nanoribbons in ultra-high vacuum
… layered materials onto a desired substrate under ultra-high vacuum (UHV), to largely prevent potential solvent and atmospheric contamination. STM imaging and scanning tunneling spectroscopy (STS) measurements provide preliminary results on lattice structure of possibly monolayer or few- layer …
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Activity Studies of NI-AU And CO-AU Bimetallic Clusters on TIO2 (110)
… on a TiO2 (titania) support was examined under ultra-high vacuum (UHV) conditions, to determine the mechanism of oxidation. On a pure gold surface, the O-H bond is broken, and the methoxy intermediate binds to the Au-titania interface. A C-H bond is broken and the resulting product is …
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Deposition and Characterization of Ceramic Thin Films and a New Experimental Approach to Evaluate the Mechanical Integrity of Film/Substrate Interfacial Layers
Due to their corrosion resistance, high temperature stability, high strength, and high hardness, refractory ceramic thin films and coatings have been utilized for surface engineering of mechanical components and mechanical fabrication tools. Adhesion between ceramic thin films and coatings and the …
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Integration of Trapped Ion System and Sympathetic Cooling with Multi-isotope Ions
… trapped ion system is presented, comprising an ultra-high vacuum (UHV) package, a micro-fabricated surface trap, and a small form-factor ion pump, demonstrating trapping of 174Yb+ ions and achieving a suitable vacuum level. A detailed ion chain cooling model based on sympathetic cooling …
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Coexistence of surface diffusion mechanisms: jump and exchange for W on W(100)
… using a Field Ion Microscope (FIM) under Ultra-High Vacuum (UHV) conditions (~ 10-11 Torr). The activation energy for the exchange in a W on W(100) system was found to be 1.6 ± 0.24 eV. For the jump, the activation energy was estimated as ~2.1 eV. These values are in very good agreement …
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Two-dimensional molecular self-assemblies on surfaces studied by low-temperature scanning tunneling microscopy
… scanning tunneling microscopy (LT-STM) in ultra-high vacuum (UHV) environments. Intensive effort had been devoted to construct mono- and bi-component organic molecular networks via various intermolecular interactions and molecule-substrate interactions. A comprehensive understanding of the …
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A Single-Stage Passive Vibration Isolation System for Scanning Tunneling Microscopy
… vibration isolation system (VIS) stays inside an Ultra High Vacuum (UHV) environment. This research aims to analyze and build a single-stage passive VIS for an STM. The VIS consists of a mass-spring system staying inside an aluminum hollow tube. The mass-spring system is comprised of a circular …
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Temperature-dependent structures of heteroepitaxial metallo-phthalocyanine (Mpc, M = Cu, Fe) thin films on silver.
… formed on Ag(111) surface by vapor deposition in ultra high vacuum (UHV). The morphology and structure of the MPcs were studied by scanning tunneling microscope (STM). Submonolayer (sub-ML) MPcs deposited at room temperature (RT) without subsequent annealing did not form ordered film regions. …
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Bose-Fermi mixtures of ultracold gases of dysprosium
… the laser systems at 421, 741, and 1064 nm, the ultra-high vacuum (UHV) chamber, and the computer control that has produced a magneto-optically (MOT) and magneto-statically (MT) trapped Dy gas (Chapters 3, 4, 5). Despite the fact that Dy has a complex energy level structure with nearly 140 …
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The Chemistry of Metal Oxyhydroxides and their 3D Porous Hybrid Materials for the Capture, Transport and Degradation of Toxic Chemicals
… (FTIR) spectroscopy were performed under ultra-high vacuum (UHV) and revealed unconventional binding sites and assisted in the successful characterization of missing linker defects. Here, our research helped in identification of a new class of binding sites, via NH-π interactions, in …
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Process Evaluation and Characterization of Tungsten Nitride as a Diffusion Barrier for Copper Interconnect Technology
… desorption spectroscopy (TDS) under controlled ultra high vacuum (UHV) conditions. At room temperature, the Auger intensity ratio vs. time plots demonstrates layer by layer Cu growth for the clean tungsten (W) surface and three-dimensional nucleation for the nitride overlayer. Auger intensity …
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Adhesion/Diffusion Barrier Layers for Copper Integration: Carbon-Silicon Polymer Films and Tantalum Substrates
… have been formed by electron beam bombardment or ultraviolet (UV) radiation of molecularly adsorbed vinyl silane precursors on metal substrates under ultra-high vacuum (UHV) conditions. Temperature programmed desorption (TPD) studies show that polymerization is via the vinyl groups, while Auger …
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Study of semiconductor and metal surfaces using a novel scanning Kelvin probe.
… Scanning Kelvin probe (SKP) compatible with the Ultra-High-Vacuum (UHV) environment - the first automatic, high resolution, UHV-SKP in the UK. The Kelvin Probe is a capacitor device used to measure the work function phi between a vibrating reference electrode (the tip) and the surface under …
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Squeezed states for advanced gravitational wave detectors
Quantum vacuum fluctuations impose strict limits on precision displacement measurements, those of interferometric gravitational-wave detectors among them. Introducing squeezed states into an interferometer's readout port can improve the sensitivity of the instrument, leading to richer astrophysical …
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Getting to the Point: Bridging the Gap between Simple and Complex Catalytic Systems using Temporal Analysis of Products (TAP)
… means operating pressures of one atmosphere or higher. Under these conditions, it is difficult to extract intrinsic kinetic properties of the catalyst which are properties that are directly related to the catalyst structure and composition. To find these intrinsic kinetic properties, scientists …
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Mechanical Stiffness and Dissipation in Ultrananocrystalline Diamond Films
Tetragonal sp3-bonded diamond has the highest known atomic density. The nature of the bond and its high density enable diamond to have superior physical properties such as the highest Young’s modulus and acoustic velocity of all materials, and excellent tribological properties. Recently, conformal …
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