scholarly journals Precise Evaluation of Specimen Thickness by Convergent-beam Electron Diffraction Technique and Electron Energy-loss Spectroscopy

2001 ◽  
Vol 65 (5) ◽  
pp. 427-433 ◽  
Author(s):  
Ryota Uemichi ◽  
Yoichi Ikematsu ◽  
Daisuke Shindo
Keyword(s):  
Electron Diffraction ◽  
Energy Loss ◽  
Electron Energy Loss Spectroscopy ◽  
Convergent Beam Electron Diffraction ◽  
Specimen Thickness ◽  
Beam Electron ◽  
Precise Evaluation ◽  
Electron Diffraction Technique ◽  
Convergent Beam ◽  
Electron Energy Loss

A library of convergent-beam electron diffraction patterns

1986 ◽  
Vol 44 ◽  
pp. 688-691
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Diffraction ◽  
Materials Science ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Transmission Electron ◽  
Yield Information ◽  
Analytical Electron ◽  
Diffraction Patterns ◽  
Convergent Beam ◽  
Electron Energy Loss

One of the most important advancements of the transmission electron microscopy (TEM) in recent years has been the development of the analytical electron microscope (AEM). The microanalytical capabilities of AEMs are based on the three major techniques that have been refined in the last decade or so, namely, Convergent Beam Electron Diffraction (CBED), X-ray Energy Dispersive Spectroscopy (XEDS) and Electron Energy Loss Spectroscopy (EELS). Each of these techniques can yield information on the specimen under study that is not obtainable by any other means. However, it is when they are used in concert that they are most powerful. The application of CBED in materials science is not restricted to microanalysis. However, this is the area where it is most frequently employed. It is used specifically to the identification of the lattice-type, point and space group of phases present within a sample. The addition of chemical/elemental information from XEDS or EELS spectra to the diffraction data usually allows unique identification of a phase.

scholarly journals Sensitivity of quantitative symmetry measurement algorithms for convergent beam electron diffraction technique

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Hyeongsub So ◽  
Ro Woon Lee ◽  
Sung Taek Hong ◽  
Kyou-Hyun Kim
Keyword(s):  
Electron Diffraction ◽  
Cross Correlation ◽  
Structural Changes ◽  
Small Strain ◽  
Convergent Beam Electron Diffraction ◽  
Digital Microscopy ◽  
Beam Electron ◽  
R Factor ◽  
Electron Diffraction Technique ◽  
Convergent Beam

AbstractWe investigate the sensitivity of symmetry quantification algorithms based on the profile R-factor (Rp) and the normalized cross-correlation (NCC) coefficient (γ). A DM (Digital Micrograph©) script embedded in the Gatan digital microscopy software is used to develop the symmetry quantification program. Using the Bloch method, a variety of CBED patterns are simulated and used to investigate the sensitivity of symmetry quantification algorithms. The quantification results show that two symmetry quantification coefficients are significantly sensitive to structural changes even for small strain values of < 1%.

scholarly journals Influence of Doping on the Crystal Potential of Silicon investigated by the Convergent Beam Electron Diffraction Technique

1980 ◽  
Vol 35 (9) ◽  
pp. 973-984 ◽  
Author(s):  
R. Voss ◽  
G. Lehmpfuhl ◽  
P. J. Smith
Keyword(s):  
Electron Diffraction ◽  
Excellent Agreement ◽  
Convergent Beam Electron Diffraction ◽  
Index Structure ◽  
Beam Electron ◽  
X Ray ◽  
Crystal Potential ◽  
Small Crystal ◽  
Electron Diffraction Technique ◽  
Convergent Beam

Abstract Low index structure potentials of silicon were determined by convergent beam electron diffraction (Kossel-Möllenstedt technique) from very small crystal areas of about 100 Å in diameter. The values of 111, 222, 220, 113 and 004, determined to an accuracy of ±0.03 volts, are in excellent agreement with the accurate X-ray results of Aldred and Hart (see [6], p. 239). Heavy arsenic or phosphorous doping was found to cause a shift of 0.15 volts in the 111 structure potential. Absorption potentials were also determined and found to be 1/3 of the theoretical values published by Radi [20].

Thickness dependence of the intensities of the 200 forbidden reflections in the TiBe2 diamond type structure

1988 ◽  
Vol 46 ◽  
pp. 826-827
Author(s):  
Dang-Rong Liu ◽  
D. B. Williams
Keyword(s):  
Electron Diffraction ◽  
Diffraction Pattern ◽  
Convergent Beam Electron Diffraction ◽  
Type Structure ◽  
Beam Electron ◽  
Space Group ◽  
X Ray ◽  
Electron Diffraction Technique ◽  
Convergent Beam ◽  
Diamond Type

It is interesting to note that for the diamond type structure of Si, Ge and diamond, the forbidden {200} reflections in the exact <100> orientation diffraction pattern cannot be seen. In contrast, we also note a standing controversy over the structure of the MgAl2O4, spinel. Its structure was determined long ago by x-ray powder method as Fd3m (the diamond type). However, its electron diffraction pattern taken in the <100> orientation shows weak {200} reflections, which are taken as evidence that the spinel should have the space group F43m (the blende type), rather than Fd3m. Others speculate that these {200} reflections result from the high order Laue zone (HOLZ) reflections, and the spinel should be Fd3m. Nevertheless, still others think that these analyses are not conclusive. We have carefully studied the space group of TiBe2 using the convergent beam electron diffraction technique, and unambiguously demonstrated that its space group must be Fd3m.

Advantages of FE-TEM for convergent-beam electron diffraction

1993 ◽  
Vol 51 ◽  
pp. 1206-1207
Author(s):  
T. Kaneyama ◽  
T. Tomita ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
Electron Diffraction ◽  
Spatial Resolution ◽  
Convergent Beam Electron Diffraction ◽  
Lens System ◽  
Beam Electron ◽  
X Ray ◽  
Small Probe ◽  
Electron Microscopes ◽  
Convergent Beam ◽  
Electron Energy Loss

Many electron microscopes equipped with a field-emission gun (FE-TEMs) are now used for the purpose of improving the spatial and the energy resolution in energy dispersive x-ray spectroscopy and electron energy loss spectroscopy. For the convergent-beam electron diffraction techniques, FE-TEMs have greater advantages than conventional electron microscopes with a thermal LaB cathode. We discussed these advantages using JEM2010F and JEM2010, which have equivalent specifications except for the electron source and the condenser lens system.High spatial resolutionThe brightness of an FE-gun (∽ 5 × 108A cm-2 sr-1) is about 100 times that a conventional LaB6 cathode. The gun can obtain enough current for taking CBED patterns in an exposure time of a few seconds even with an electron probe less than 1 nm in diameter (FIG. 1). Steep wedge shapes and rapid bends within the illuminated area deteriorate the accuracy of quantitative CBED analysis. Improvement of the spatial resolution by a small probe reduces these inevitable averaging effects.

Computer experiments for coherent convergent-beam electron diffraction

1983 ◽  
Vol 41 ◽  
pp. 304-305
Author(s):  
William Krakow
Keyword(s):  
Electron Diffraction ◽  
Amorphous Materials ◽  
Three Dimensional ◽  
Computer Experiments ◽  
Convergent Beam Electron Diffraction ◽  
Specimen Thickness ◽  
Beam Electron ◽  
Wide Range ◽  
Stem Type ◽  
Convergent Beam

Considerable effort has been expended to use convergent beam electron diffraction (CBED) from small specimen areas with an incoherent thermionic source. Here space group classification and even three dimensional analysis have proven to be possible by observing the diffraction disks and the fine detail seen within these disks. The use of a coherent convergent beam has been attempted for a field emission STEM type instrument and a number of novel interference effects have recently been observed in both crystalline and amorphous materials. Preliminary CBED computer calculations were performed for a dislocation in Si3 however no structural detail was observed in the diffraction disks because the computation only considered a 30Å thick crystal. Computations covering a wide range of materials, specimen thickness values and STEM type probe conditions has been obtained by the present author. In these papers only results for zone axis patterns and 100kV electrons were given. It is now the intent to present some new results at high voltages (200kV) and for non-symmetric crystal orientations and with larger reciprocal space sampling distributions

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