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  • 1
    Electronic Resource
    Electronic Resource
    Determination of the local Al concentration in AlxGa1−xAs-GaAs quantum well structures using the (200) diffraction intensity obtained with a 10 A(ring) electron beam (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 1454-1456 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A novel method for determining the local concentration of Al in the AlxGa1−xAs layer of AlxGa1−xAs-GaAs multiple quantum well structures is reported. By scanning a 10 A(ring) electron beam across the interface, the (200) dark-field scanning transmission electron microscopy (STEM) image shows the contrast of the AlxGa1−xAs-GaAs multilayer since the intensity of the (200) diffraction is sensitive to the Al concentration. The line scan intensity profile of the (200) diffraction, along a uniform specimen region of known thickness, shows the intensity variation of the (200) diffraction and reflects the local content of Al in each region. The simulation of the nanodiffraction patterns produces a chart of the (200) diffraction intensity versus the Al concentration for the determination of the local change of the Al concentration. A molecular beam epitaxy grown AlxGa1−xAs-GaAs specimen (x=0.57 as determined from Raman spectroscopy) is tested and the dark-field STEM studies show two thin layers of x=0.46 at the 1/3 and 2/3 height level within every AlxGa1−xAs layer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100695
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  • 2
    Electronic Resource
    Electronic Resource
    Improved instrument for medium energy electron diffraction and microscopy of surfaces (1985)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 56 (1985), S. 1215-1219 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: The REMEDIE system for reflection electron microscopy and electron diffraction at intermediate energies (0.5–20 keV) has been rebuilt with an improved imaging resolution of better than 10 nm, a convenient and versatile system for observation diffraction patterns and provision for specimen preparation and treatment suitable for surface structural studies. The current capabilities of the instrument are illustrated by results obtained from cleaved and annealed silicon (111) surfaces with or without thin deposited silver and gold layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1137978
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  • 3
    Electronic Resource
    Electronic Resource
    High Resolution Electron Microscopy (1987)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physical Chemistry 38 (1987), S. 57-88 
    Details
    ISSN: 0066-426X
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.pc.38.100187.000421
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  • 4
    Electronic Resource
    Electronic Resource
    Microdiffraction from stacking faults and twin boundaries in F.c.c. crystals (1983)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 16 (1983), S. 171-175 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Electron microdiffraction patterns have been obtained from regions of diameter about 15 Å in thin crystals of stainless steel containing twin boundaries and stacking faults. The diffraction spots show splittings which are characteristic of the type of defect present as a result of interference effects in the coherent convergent electron beam. The observations of spot splitting are in good agreement with calculations based on simple theoretical models. In conjunction with previous work on antiphase domain boundaries [Zhu & Cowley (1982). Acta Cryst. A38, 718–724] these results suggest that the observation of spot splitting is of general relevance for the study of all planar faults in thin crystals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889883010213
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  • 5
    Electronic Resource
    Electronic Resource
    The structure of Pt particles on γ-Al2O3 support (1987)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 20 (1987), S. 300-305 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Samples of the catalyst Pt/γ-Al2O3 have been examined by high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) and microdiffraction techniques. An epitaxic relationship of metallic Pt crystals on the γ-Al2O3 has been established. In both calcined and reduced samples, the crystalline oxide α-PtO2 was found along with metallic Pt. The oxide has a hexagonal lattice with unit-cell dimensions about 6% smaller than those previously reported. Microdiffraction from areas less than 20 Å in diameter, combined with HRTEM, STEM and secondary electron microscopy (SEM), has proved to be a very powerful technique for the study of the structures of particles less than 50 Å in size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889887086631
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  • 6
    Electronic Resource
    Electronic Resource
    High-voltage transmission scanning electron microscopy (1970)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 3 (1970), S. 49-59 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: The use of scanning electron microscopy for the study of thin specimens by transmission has advantages over conventional transmission electron microscopy in terms of simplicity and cheapness, reduction in damage to irradiation-sensitive specimens and convenience for electron diffraction, energy analysis and the electronic measurement and recording of images. These advantages are specially important for microscopes operating in the range 200 kV to 1 MeV. The design of a 600 kV instrument to exploit these advantages is described. The possible modes of operation employing deflexion systems and an energy analyser are discussed with reference to light- and dark-field microscopy, convergent beam diffraction and conventional focused diffraction patterns. The reciprocity principle is invoked to relate both image contrast and instrument design in scanning electron microscopy to that in conventional transmission electron microscopy. Examples are given of light- and dark-field images and diffraction patterns obtained with the instrument.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889870005642
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  • 7
    Electronic Resource
    Electronic Resource
    Line patterns in wide-angle convergent beam electron diffraction (1971)
    Copenhagen : International Union of Crystallography (IUCr)
    Applied crystallography online 4 (1971), S. 482-487 
    Details
    ISSN: 1600-5767
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Geosciences , Physics
    Notes: Wide-angle convergent-beam electron diffraction patterns from thin single crystals show sets of parallel lines somewhat similar to Kikuchi or Kossel lines. In some cases, each line separates into a black and white line pair when the electron beam is defocused. It is shown that this separation depends on the curvature of the crystal. A method for analysis of the line geometry is proposed which takes into account the aberrations of the electron lens. Using a high-voltage transmission scanning electron microscope, through-focus series of patterns from graphite crystals have been obtained and analyzed to give values for the radius of curvature of the crystal. In defocussed patterns the distortions of the lattice by defects are clearly visible.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0021889871007507
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  • 8
    Electronic Resource
    Electronic Resource
    Microdiffraction from antiphase domain boundaries in Cu3Au (1982)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 38 (1982), S. 718-724 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Electron diffraction patterns have been obtained from regions of a thin crystal of partially ordered copper-gold alloy, Cu3Au, which have a diameter of about 15 Å and contain an antiphase domain boundary. The superlattice diffraction spots show a characteristic splitting similar to the splitting which appears in all spots, both fundamental and superlattice, when the beam irradiates a region at the edge of a crystal. By observing which of the superlattice spots are split and which are not, it is possible to deduce immediately whether the antiphase domain boundary is of the 'good' type or is one of the 'bad' types or whether more than one boundary is illuminated by the beam. The observations of split spots are in good agreement with the results of calculations made on the basis of kinematic theory. It is shown that these results remain valid in the presence of strong dynamical scattering for small specimen thicknesses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0567739482001442
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  • 9
    Electronic Resource
    Electronic Resource
    Errors arising from numerical use of the Mott formula in electron image simulation (1988)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 44 (1988), S. 1-6 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The Mott formula relating the electron scattering factor to that for X-rays is inaccurate in its numerical form in the small-angle region. Effects of the inaccuracy on both kinematic and dynamical diffraction have been investigated. Some artifacts arising from the inaccuracy have been found in simulated electron microscopy images. A modified form for the Mott formula, which minimizes the error, is proposed. However, for any accurate and reliable calculation only those electron scattering factors derived directly from the atomic potential can be used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108767387006858
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  • 10
    Electronic Resource
    Electronic Resource
    Electron microscopy of crystals with time-dependent perturbations (1988)
    [S.l.] : International Union of Crystallography (IUCr)
    Acta crystallographica 44 (1988), S. 847-853 
    Details
    ISSN: 1600-5724
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The electron microscope image intensity of a thin crystal is described as a time average of the image of a crystal perturbed by time-dependent fluctuations corresponding to thermal motion of the atoms or low-energy electronic excitations. For very thin crystals the phase-object approximation indicates that images having atomic resolution may be obtained from the inelastically scattered electrons. It is shown that the use of suitable approximations allows estimates to be made of the contribution of the inelastically scattered electrons to the high-resolution images of thicker crystals. The resolution of images formed by inelastically scattered electrons is not affected by the non-localization of the inelastic scattering process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0108767388004751
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