New Preparation Method For Liquid Alloy Surfaces and Their Characterization by Electron Spectroscopy

1986 ◽  
Vol 83 ◽  
Author(s):  
G. Indlekofer ◽  
P. Oelhafen ◽  
H.- J. Güntherodt
Keyword(s):  
Photoelectron Spectroscopy ◽  
Liquid State ◽  
Electron Spectroscopy ◽  
Surface Composition ◽  
Liquid Metals ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Valence Electron Structure ◽  
Composition Segregation ◽  
Liquid Surfaces

ABSTRACTSurface investigations of liquid metals in ultra-high vacuum are scarce as compared with solid state studies, mainly because of experimental difficulties of preparing atomically clean liquid surfaces. A new technique has been developed in order to prepare clean liquid metal surfaces. According to the characterization with electron spectroscopy it proved to be an effective way to obtain high purity liquid surfaces and hence offers the possibility to study a variety of metals and alloys in the liquid state.Information about the surface composition, segregation properties and its purity in the liquid state and the valence electron structure has been obtained by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS, respectively). Exciting new insights in the electronic structure of various liquid alloys such as Au-Si, Cu-Sn, Ga-Sn and TI-Bi have been obtained from these measurements.

Novel Morphology of Voids in Single-Quasicrystalline Icosahedral Al70.5Pd21.0Mn8.5

1998 ◽  
Vol 53 (8) ◽  
pp. 679-683 ◽  
Author(s):  
Y. Waseda ◽  
S. Suzuki ◽  
K. Urbanb
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Composition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Chemical Surface ◽  
Habit Planes ◽  
Scanning Electron

Abstract This paper deals with the morphology and surface chemistry of faceted voids existing in singlequasicrystalline icosahedral Al70.5Pd21.0Mn8.5. By observation with a scanning electron microscope of surfaces obtained by cleavage of the quasicrystal, the habit planes of the dodecahedral voids were identified. The chemical surface composition of the void surface was determined by Auger electron spectroscopy after cleavage in ultra-high vacuum.

Thermodynamically Stable Conducting Films of Intermetallic PtGa2 on Gallium Arsenide

1988 ◽  
Vol 144 ◽  
Author(s):  
Larry P. Sadwick ◽  
Kang L. Wang ◽  
David K. Shuh ◽  
Young K. Kim ◽  
R. Stanley Williams
Keyword(s):  
Gallium Arsenide ◽  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gaas Substrates ◽  
Suitable Temperature

ABSTRACTThe first epitaxial platinum gallium two (PtGa2) films have been grown on gallium arsenide (GaAs) (100) by co-evaporation of the elements under ultra-high vacuum conditions. An electron beam evaporator and a Knudsen cell were used to produce the platinum and gallium beams, respectively. The resulting films and bulk PtGa2 have been characterized by x-ray diffraction, Auger electron spectroscopy, and x-ray photoelectron spectroscopy. The data confirm the PtGa2 stoichiometry and crystal structure of the films, and demonstrate their chemical stability on GaAs (100). This study supports the contention that PtGa2 can be a suitable, temperature stable contact material on GaAs substrates.

Atomic Structure and Spectra

2021 ◽  
pp. 68-146
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Rays ◽  
X Ray ◽  
Spatially Resolved ◽  
Excitation Processes ◽  
Shell Ionization

We review the structure of atoms to describe allowed intra-atomic electronic transitions following dipole selection rules. Inner shell ionization is followed by characteristic X-ray emission or non-radiative de-excitation processes leading to Auger electrons that involve three atomic levels. Photon incidence also results in characteristic photoelectron emission, reflecting the energy distribution of the electrons in the solid. We present details of laboratory and synchrotron sources of X-rays, and discuss their detection by wavelength or energy-dispersive spectrometers, as well as microanalysis with X-ray (XRF), or electron (EPMA) incidence. Characteristic X-ray intensities are quantified in terms of composition using corrections for atomic number (Z), absorption (A), and fluorescence (F). Electron detectors use electrostatic or magnetic dispersing fields; two common designs are electrostatic hemispheric or mirror analyzers. Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS), used for surface analysis, require ultra-high vacuum. AES is a weak signal, best resolved in a derivative spectrum, shows sensitivity to the chemical state and the atomic environment, provides a spatially-resolved signal for composition mapping, and can be quantified for chemical analysis using sensitivity factors. Finally, we introduce the basics of XPS, a photon-in, electron-out technique, discussed further in §3.

Nanowire Reconstruction on the 4H-SiC(1102) Surface

2007 ◽  
Vol 556-557 ◽  
pp. 529-532 ◽  
Author(s):  
M. Hetzel ◽  
Charíya Virojanadara ◽  
Wolfgang J. Choyke ◽  
Ulrich Starke
Keyword(s):  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Composition ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Intrinsic Structure ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

Ordered reconstruction phases on the 4H-SiC(1102) surface have been investigated using low-energy electron diffraction (LEED), Auger electron spectroscopy (AES) and scanning tunneling microscopy (STM). After initial hydrogen etching, the samples were prepared by Si deposition and annealing in ultra-high vacuum (UHV). Two distinct reconstruction phases develop upon annealing, first with a (2×1), and at higher temperatures with a c(2×2) LEED pattern. After further annealing the fractional order LEED spots vanish and a (1x1) pattern develops. For the (2×1) phase, STM micrographs show that adatom chains develop on large flat terraces, which in view of AES consist of additional Si. These highly linear and equidistant chains represent a self-assembled well-ordered pattern of nanowires developing due to the intrinsic structure of the 4H-SiC(1102) surface. For the c(2×2) phase AES indicates a surface composition close to the bulk stoichiometry. For the (1×1) phase a further Si depletion is observed.

Interaction of Copper With Single Crystal Sapphire

1985 ◽  
Vol 60 ◽  
Author(s):  
A. G. Schrott ◽  
R. D. Thompson ◽  
K. N. Tu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Electron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Initial State ◽  
Xps Spectra ◽  
Similar Treatment ◽  
X Ray ◽  
Energy Location ◽  
Single Crystal Sapphire

AbstractThe effect of small coverages of Cu evaporated in ultra-high vacuum (UHV) on A12O3 (0001) surfaces has been investigated by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). These surfaces were cleaned either by annealing at 1000°C in O2 or by Ar sputtering. They differ both in their initial state and their interaction with Cu. The XPS spectra from as-deposited Cu on sputtered samples exhibit small shifts in the energy location of the various peaks as compared to those from a Cu standard. Annealing the Cu/sputtered A12O3 structure at 500°C produces a shoulder on the Cu 3d peak as well as a new Cu (L3 M4.5 M4.5) Auger feature. Neither of these effects are observed after similar treatment of the Cu/annealed A12O3 structure. An influence of this different bonding situation on the Cu-sapphire interfacial energy is observed.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

scholarly journals A New Measurement and Evaluation of Wettability between Solid and Liquid Metals in Ultra-High Vacuum.

1998 ◽  
Vol 64 (5) ◽  
pp. 753-757 ◽  
Author(s):  
Hiromichi TOYOTA ◽  
Takashi IDE ◽  
Hidetsugu YAGI ◽  
Yuzo MORI ◽  
Kikuji HIROSE
Keyword(s):  
Liquid Metals ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Measurement And Evaluation

scholarly journals Investigations of the Deuterium Permeability of As-Deposited and Oxidized Ti2AlN Coatings

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2085 ◽  
Author(s):  
Lukas Gröner ◽  
Lukas Mengis ◽  
Mathias Galetz ◽  
Lutz Kirste ◽  
Philipp Daum ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Physical Vapor Deposition ◽  
Protective Coatings ◽  
High Vacuum ◽  
Barrier Properties ◽  
Reduction Factor ◽  
Ultra High Vacuum ◽  
Max Phase ◽  
Self Healing ◽  
Α Al2o3

Aluminum containing Mn+1AXn (MAX) phase materials have attracted increasing attention due to their corrosion resistance, a pronounced self-healing effect and promising diffusion barrier properties for hydrogen. We synthesized Ti2AlN coatings on ferritic steel substrates by physical vapor deposition of alternating Ti- and AlN-layers followed by thermal annealing. The microstructure developed a {0001}-texture with platelet-like shaped grains. To investigate the oxidation behavior, the samples were exposed to a temperature of 700 °C in a muffle furnace. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) depth profiles revealed the formation of oxide scales, which consisted mainly of dense and stable α-Al2O3. The oxide layer thickness increased with a time dependency of ~t1/4. Electron probe micro analysis (EPMA) scans revealed a diffusion of Al from the coating into the substrate. Steel membranes with as-deposited Ti2AlN and partially oxidized Ti2AlN coatings were used for permeation tests. The permeation of deuterium from the gas phase was measured in an ultra-high vacuum (UHV) permeation cell by mass spectrometry at temperatures of 30–400 °C. We obtained a permeation reduction factor (PRF) of 45 for a pure Ti2AlN coating and a PRF of ~3700 for the oxidized sample. Thus, protective coatings, which prevent hydrogen-induced corrosion, can be achieved by the proper design of Ti2AlN coatings with suitable oxide scale thicknesses.

Fundamental study of the interaction of Ti atoms with spruce surfaces

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 523-527 ◽  
Author(s):  
Lothar Klarhöfer ◽  
Florian Voigts ◽  
Dominik Schwendt ◽  
Burkhard Roos ◽  
Wolfgang Viöl ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Strong Interactions ◽  
Titanium Oxide Film ◽  
Fundamental Study ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Atoms

Abstract Metastable induced electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were applied to study the interaction of Ti metal atoms with spruce surfaces. Spruce surfaces were produced by planing splints from a spruce bar. Ti atoms were adsorbed from a metal evaporator under ultra-high vacuum conditions. The amount adsorbed corresponds to 10 monolayer equivalents. Strong interactions between the spruce surface and metals atoms occurred. Impinging Ti atoms were oxidized by the spruce surface. No Ti agglomeration or particle formation was observed. The surface was smoothed by the Ti applied and was completely covered by a titanium oxide film.

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