Determination of composition in Cd x Hg1−x Te 1by measurement of the [111] zone axis critical voltage

2020 ◽  
pp. 153-158
Author(s):  
P Spellward ◽  
D Cherns
Keyword(s):  
Zone Axis ◽  
Critical Voltage

Determination of arsenic atom distribution arsenic doped silicon using HOLZ-line analysis

1996 ◽  
Vol 54 ◽  
pp. 976-977
Author(s):  
Y. Kikuchi ◽  
N. Hashikawa ◽  
F. Uesugi ◽  
E. Wakai ◽  
K. Watanabe ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Zone Axis ◽  
Experimental Result ◽  
Background Intensity ◽  
Crystal Thickness ◽  
Arsenic Atom ◽  
Doped Silicon ◽  
P Type ◽  
Line Analysis

In order to measure the concentration of arsenic atoms in nanometer regions of arsenic doped silicon, the HOLZ analysis is carried out underthe exact [011] zone axis observation. In previous papers, it is revealed that the position of two bright lines in the outer SOLZ structures on the[011] zone axis is little influenced by the crystal thickness and the background intensity caused by inelastic scattering electrons, but is sensitive to the concentration of As atoms substitutbnal for Siatomic site.As the result, it becomes possible to determine the concentration of electrically activated As atoms in silicon within an observed area by means of the simple fitting between experimental result and dynamical simulatioan. In the present work, in order to investigate the distribution of electrically activated As in silicon, the outer HOLZ analysis is applied using a nanometer sized probe of TEM equipped with a FEG.Czodiralsld-gown<100>orientated p-type Si wafers with a resistivity of 10 Ώ cm are used for the experiments.TheAs+ implantation is performed at a dose of 5.0X1015cm-2at 25keV.

On the Characterisatiopn of Order-Disorder in Ion-Irradiated Pyrochlore Compounds by Electron Scattering Methods

2008 ◽  
Vol 1122 ◽  
Author(s):  
Gregory R. Lumpkin ◽  
Karl R. Whittle ◽  
Mark G. Blackford ◽  
Katherine L. Smith ◽  
Nestor J. Zaluzec
Keyword(s):  
Electron Scattering ◽  
Diffuse Scattering ◽  
Zone Axis ◽  
Irradiation Damage ◽  
Nuclear Materials ◽  
Crystalline Fraction ◽  
Selected Area Electron Diffraction ◽  
Pyrochlore Compounds ◽  
Diffraction Patterns

AbstractSelected area electron diffraction patterns are routinely used to determine the effects of irradiation damage in nuclear materials. Using zone axis orientations, the intensities of Bragg beams change from a dynamical to kinematic-like state due to the presence of amorphous domains in the material. Such changes in beam intensities, together with the increased diffuse scattering from the increasing amorphous fraction, present a major obstacle to the determination of cation or anion disorder in the crystalline fraction.

Determination of Atomic Scattering Factors of B.C.C. Metals by the Critical-Voltage Method

1975 ◽  
Vol 39 (5) ◽  
pp. 1277-1281 ◽  
Author(s):  
Osamu Terasaki ◽  
Yūji Uchida ◽  
Denjiro Watanabe
Keyword(s):  
Critical Voltage ◽  
Atomic Scattering

Space group determination by CBED: G-M lines and holz interactions

1992 ◽  
Vol 50 (2) ◽  
pp. 1186-1187
Author(s):  
Vinayak P. Dravid
Keyword(s):  
Diffuse Scattering ◽  
Zone Axis ◽  
Translational Symmetry ◽  
Screw Axis ◽  
Careful Choice ◽  
Space Group ◽  
Exact Location ◽  
Unambiguous Determination ◽  
Crystal Space

Symmetry determination remains as a powerful and fascinating application of CBED techniques. As pointed out by Gjønnes & Moodie and later developed by Steeds & Vincent, the appearance of lines of missing intensity (G-M lines) in certain kinematically forbidden reflections in CBED patterns can be analyzed to obtain information about the presence and type of translational symmetry elements in the crystal space group, such as screw axis and glide planes. However, the microscopist must be aware of numerous pitfalls in analyzing G-M lines as they can be confused with other diffuse scattering (2-D diffraction) present in most CBED patterns. Furthermore, unambiguous determination of exact translational symmetry elements and their orientation requires careful choice of zone axis, voltage and analysis of indices of the forbidden reflections. When done properly, such experiments reveal the exact location and type of translational symmetry elements, e.g. whether the glide plane is a, b, c, n or d type.

Some practical aspects of CBED applications in materials science

1989 ◽  
Vol 47 ◽  
pp. 508-509
Author(s):  
D. R. Liu ◽  
D. B. Williams
Keyword(s):  
Materials Science ◽  
Theoretical Foundation ◽  
Point Group ◽  
Convergent Beam Electron Diffraction ◽  
Zone Axis ◽  
X Ray ◽  
Unambiguous Determination ◽  
Convergent Beam ◽  
Electron Energy Loss

The paper by Buxton et al. has firmly laid down the theoretical foundation for the point group determination of a crystal structure with convergent beam electron diffraction (CBED). Numerous examples of successful applications of this theory to materials science problems have been published. However, it has also been observed that, for an unambiguous determination of some crystal structures, more zone axis CBED patterns are needed than it is indicated by the tables in the paper. Yet sometimes ambiguity can still exist as in the case of the point group determination of the MgAl2O4 spinel, where CBED is unable to detect an alleged Al3+ ion displacement of Δb=0.0002∼0.0006 nm along a <111> direction and thus unable to determine whether its point group should be m3m or m. This difficulty might be attributed to the fact that, as for microanalysis, such as x-ray energy dispersive spectroscopy and electron energy-loss spectroscopy, the CBED technique must have its detection limit beyond which the detail in an acquired CBED pattern is not adequate enough to permit an unambiguous determination of its diffraction group.

The Critical Voltage Effect in Zone Axis Patterns. A Theoretical Study

1980 ◽  
Vol 98 (1) ◽  
pp. 349-364
Author(s):  
R. Gevers ◽  
M. David ◽  
W. Herremans
Keyword(s):  
Theoretical Study ◽  
Zone Axis ◽  
Critical Voltage

The interpretation of the zone axis critical voltage effect

1978 ◽  
Vol 36 (1) ◽  
pp. 194-195
Author(s):  
B. F. Buxton
Keyword(s):  
Structural Information ◽  
Incident Beam ◽  
Beam Theory ◽  
High Energy ◽  
Zone Axis ◽  
Critical Voltage ◽  
High Symmetry ◽  
Brillouin Zone Boundary ◽  
Extinction Length ◽  
Thickness Parameter

In cross-grating high energy electron diffraction, the scattering of the incident beam by the atomic string potentials is often so strong that there are many zone axis critical voltages below 1 MV. Steeds et al. (1976, 1977) have therefore explored the possibility of obtaining structural information from these critical voltages. In particular, for simple zone axes of high symmetry with only one string of atoms in each unit cell of the projected potential, they were able to characterize zone axis patterns by the critical voltage Ec and a thickness parameter ξ24 defined as the (2)-(4) extinction length at an orientation approximately midway between the zone axis and the first Brillouin zone boundary. Here a simple model atomic string potential will be used to investigate the information which can be gleaned from these parameters.The atomic string approximation (ASA) developed by Buxton and Tremewan (1977) will be used in order to avoid the large matrices encountered in the conventional many-beam theory.

Determination of crystal polarity in the Electron Microscope

1994 ◽  
Vol 52 ◽  
pp. 560-561
Author(s):  
W. Mader ◽  
A. Recnik
Keyword(s):  
Electron Microscope ◽  
Zone Axis ◽  
Mirror Plane ◽  
Polar Crystal ◽  
Transmission Electron ◽  
Polarity Determination ◽  
Extinction Length ◽  
Zero Layer ◽  
Convergent Beam

A few methods were proposed for the determination of crystal polarity using electron diffraction. The method by Taftø and Spence is based on the coupling between ZOLZ and FOLZ reflections, requiring exact tilting to excite weak high- and odd-indexed reflections. The method by Spellward and James relies on the comparison of experimentally observed and calculated CBED patterns of fairly thick crystals, where the features in the CBED discs are compared. In this paper we present a method for polarity determination readily evident from ZOLZ reflections in zone-axis microdiffraction patterns. The method is based on zero-layer interactions from thin crystals with thickness t smaller than the extinction length of the primary beam. Then the diffraction discs appear homogeneous, and the breakdown of Friedel's law is noticable in a difference of the intensities of the reflections g and -g which are not related to a mirror plane (Bijvoet-related reflections).The method can be applied using any transmission electron microscope which is designed for obtaining convergent-beam microdiffraction patterns and in principle, specimen-cooling is not necessary. The crystals have to be oriented to a low-indexed zone axis, where the diffraction plane contains a polar crystal axis.

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