scholarly journals Поверхностное соединение при адсорбции Be на W(100): определение абсолютной концентрации и свойства

2022 ◽  
Vol 48 (3) ◽  
pp. 21
Author(s):  
Е.В. Рутьков ◽  
Е.Ю. Афанасьева ◽  
Н.Р. Галль
Keyword(s):  
Activation Energy ◽  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
High Vacuum ◽  
Surface Concentration ◽  
Ultra High Vacuum ◽  
Absolute Concentration ◽  
Adsorption State ◽  
The Absolute

Be adsorption and T = 900 - 1100 K results in formation of a stable adsorption state; it drops the activation energy of atomic Be dissolution in the substrate bulk, and all newly deposited Be dissolves in the substrate. The absolute concentration of atomic Be has been measured by Auger electron spectroscopy using specially designed ultra high vacuum getter Be source. The concentration is (1 ± 0.1)•1015 сm-2 , and corresponds to WBe stoichiometry relative to W surface concentration. The layer is destroyed at T > 1100 K, the atomic Be dissolves in the bulk with the activation energy ~ 3,5 eV.

Auger electron spectroscopy and microscopy in STEM

1991 ◽  
Vol 49 ◽  
pp. 464-465
Author(s):  
Gary G. Hembree ◽  
Frank C. H. Luo ◽  
John A. Venables
Keyword(s):  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
High Vacuum ◽  
Low Energy ◽  
Energy Electron ◽  
Ultra High Vacuum ◽  
Secondary Electrons ◽  
Excitation Beam ◽  
Low Energy Electron

Spatial resolution in Auger electron spectroscopy (AES) is primarily a function of the excitation beam current distribution. For highest resolution the question of how to produce such a small probe of electrons is coupled with how to extract the secondary electrons efficiently from the sample. Kniit and Venables have shown the optimum configuration for highest resolution AES is a combination of a magnetic immersion lens, additional solenoids (“parallelizers“) to shape the weak magnetic field in the low energy electron transport region and a concentric hemispherical analyzer (CHA) to disperse and detect the secondary electrons. This combination has been incorporated into a new ultra-high vacuum STEM at ASU, along with the low energy electron optics required to interface the magnetic collection system with the CHA.

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.

Novel Methods of Microanalysis Employing Secondary- and Auger-Electron Spectroscopy in Stem

1990 ◽  
Vol 48 (1) ◽  
pp. 214-215
Author(s):  
P. Kruit
Keyword(s):  
Magnetic Field ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Electrostatic Energy ◽  
Objective Lens ◽  
Secondary Beam ◽  
Specimen Preparation ◽  
The Magnetic Field

Introduction: Electron spectroscopy is a well established technique in physics and material science and merely adding the spatial resolution of a STEM would already open a new field of applications. However, by using the specific advantages of electron microscope optics and the expertise in thin specimen preparation of microscopists, electron spectroscopy in the STEM can yield information that cannot be obtained in any other way.Instrumentation: The feasibility of extracting a large portion of the Auger and secondary electrons from the magnetic field of an immersion condenser objective lens has now been demonstrated. The scheme involves a careful shaping of the magnetic field through which the electrons are guided to a deflector which separates the secondary beam from the primary beam. The parallelizing action of this field forces the electrons into a beam of small opening angle which can be accepted by traditional optics including an electrostatic energy analyser. Results reported in this paper are from a prototype instrument; energy analysers mounted on fully ultra high vacuum microscopes are now also in operation or will become operational very soon. To detect the secondary or Auger electron together with the primary electron which was responsible for its emission requires only small additions to the instrumentation. Single electron sensitivity in both the secondary electron detector and the EELS detector are of course necessary, but this can be done with standard detectors with a timing resolution of better than 5 ns. Commercial electronic equipment can then sort the coincident events.

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.

Mev Ion Induced Modification of The Native Oxide of Silicon

1985 ◽  
Vol 51 ◽  
Author(s):  
R.L. Headrick ◽  
L.E. Seiberling
Keyword(s):  
Auger Electron Spectroscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Surface Concentration ◽  
Native Oxide ◽  
Elastic Recoil ◽  
Elastic Recoil Detection Analysis ◽  
Elastic Recoil Detection ◽  
Ion Channeling ◽  
Detection Analysis

ABSTRACTWe have studied the native oxide of silicon (110) and the changes roduced by MeV ion bombardment using transmission ion channeling of 5.9 MeV 9Be, and Elastic Recoil Detection Analysis (ERDA). Transmission channeling was used to measure interfacial nonregistered Si and adsorbed C and 0. ERDA was used to measure the surface concentration of H. MeV ions were found to cause an increase in the interfacial nonregistered silicon which saturates at approximately one monolayer. Rapid desorption of hydrogen was observed. The effect of 2 keV electrons on the silicon native oxide was also studied by Auger Electron Spectroscopy.

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