Analysis of Grain Boundaries, Twin Boundaries and Te Precipitates in Cd1−xZnxTe Grown by High-Pressure Bridgman Method

1997 ◽  
Vol 484 ◽  
Author(s):  
J. R. Heffelfinger ◽  
D. L. Medlin ◽  
R. B. James
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Light Microscopy ◽  
Grain Boundaries ◽  
Local Density ◽  
Infrared Light ◽  
High Angle ◽  
Twin Boundaries ◽  
Transmission Electron ◽  
Te Precipitates

AbstractGtain boundaries and twin boundaries in commercial Cd1−xZnxTe, which is prepared by a high-pressure Bridgeman technique, have been investigated with transmission electron microscopy, scanning electron microscopy, infrared-light microscopy and visible-light microscopy. Boundaries inside these materials were found to be decorated with Te precipitates. The shape and local density of the precipitates were found to depend on the particular boundary. For precipitates that decorate grain boundaries, their microstructure was found to consist of a single, saucer-shaped grain of hexagonal Te (space group P3,2 1). Analysis of a Te precipate by selected-area diffraction revealed the Te to be aligned with the surrounding Cd1−xZnxTe grains. This alignment was found to match the (111) Cd1−xZxTe planes with the (0 111) planes of hexagonal Te. Crystallographic alignments between the Cd1−xZnxTe grains were also observed for a high-angle grain boundary. The structures of the grain boundaries and the Te/Cd1−xZnxTe interface are discussed.

Analysis of Grain Boundaries, Twin Boundaries and Te Precipitates in Cd1−xZnxTe Grown bY High-Pressure Bridgman Method

1997 ◽  
Vol 487 ◽  
Author(s):  
J. R. Heffelfinger ◽  
D. L. Medlin ◽  
R. B. James
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Light Microscopy ◽  
Grain Boundaries ◽  
Local Density ◽  
Infrared Light ◽  
High Angle ◽  
Twin Boundaries ◽  
Transmission Electron ◽  
Te Precipitates

AbstractGrain boundaries and twin boundaries in commercial Cd1−xZnxTe, which is prepared by a high-pressure Bridgeman technique, have been investigated with transmission electron microscopy, scanning electron microscopy, infrared-light microscopy and visible-light microscopy. Boundaries inside these materials were found to be decorated with Te precipitates. The shape and local density of the precipitates were found to depend on the particular boundary. For precipitates that decorate grain boundaries, their microstructure was found to consist of a single, saucer-shaped grain of hexagonal Te (space group P3121). Analysis of a Te precipate by selected-area diffraction revealed the Te to be aligned with the surrounding Cd1−xZnxTe grains. This alignment was found to match the (111) Cd1−xZnxTe planes with the (0111) planes of hexagonal Te. Crystallographic alignments between the Cd1−xZnxTe grains were also observed for a high-angle grain boundary. The structures of the grain boundaries and the Te/C1−xZnxTe interface are discussed.

Electron microscopy of ceramic superconductors

1993 ◽  
Vol 51 ◽  
pp. 934-935
Author(s):  
M. Grant Norton ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Grain Boundaries ◽  
Analytical Techniques ◽  
Atomic Scale ◽  
Weak Links ◽  
Chemical Information ◽  
High Angle ◽  
Ceramic Superconductors ◽  
Transmission Electron ◽  
Current Densities

The microstructure of ceramic superconductors plays a crucial role in the transport properties of these materials. For example, it has been shown that high-angle grain boundaries can act as weak links and atomic scale defects can act as pinning centers. The nature and spatial distribution of such defects is related to the way in which the material is processed. Transmission electron microscopy (TEM) is an essential technique for understanding the relationship between microstructure, processing, and properties and for defect characterization. The advantage of TEM is that it is possible to combine various imaging modes with electron diffraction and other analytical techniques such as x-ray energy dispersive spectroscopy in order to obtain both structural and chemical information.Early measurements of critical current densities (Jc) across individual tilt grain boundaries in YBa2Cu3O7-δ (YBCO) thin films demonstrated that Jc decreased with increasing misorientation angle. More recently, however, it has been observed that this phenomenon may not be the case for all high-angle grain boundaries.

Structure of Low- And High-Angle Grain Boundaries In YBCO/MgO Films

1998 ◽  
Vol 4 (S2) ◽  
pp. 676-677
Author(s):  
S. Oktyabrsky ◽  
R. Kalyanaraman ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Boundary Plane ◽  
Dislocation Model ◽  
High Angle ◽  
Transmission Electron

Grain boundaries (GBs) in laser deposited YB2Cu3O7-δ/MgO(001) thin films have been investigated by high-resolution transmission electron microscopy (TEM) and scanning TEM (STEM). We report both statistics and atomic structure of low-angle and high-angle [001] tilt grain boundaries resulting from almost perfect c-axis textured YBCO films.Atomic structure of low-angle GBs was analyzed using a dislocation model. These boundaries have been found to be aligned primarily along (100) and (110) interface planes. For (100) boundary plane, the GB consists of a periodic array of [100] dislocations (Fig.l). For (110) boundary plane, the array is also periodic but every [110] dislocation is split by ∼ 1.5 nm into two [100] and [010] dislocations (Fig.2). We have calculated energy of various configurations and shown that the energy of the (110) boundary with dissociated dislocations is comparable to that of (100) boundary, which explains the coexistence of (100) and (110) interface facets along the boundary.

Investigation of Grain Boundaries in an Al-Mg-Si-Cu Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 951-956 ◽  
Author(s):  
Jon Holmestad ◽  
Martin Ervik ◽  
Calin D. Marioara ◽  
John Charles Walmsley
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Solution Heat Treatment ◽  
High Angle ◽  
Corrosion Properties ◽  
X Ray ◽  
Cu Alloy ◽  
Transmission Electron

The grain boundaries of a fibrous Al-Mg-Si-Cu alloy have been investigated with Transmission Electron Microscopy. The compositions have been mapped by Energy Dispersive X-ray Spectroscopy. The alloy has been aged for 12 hours at 155°C after solution heat treatment and is in a slightly underaged condition. The precipitates nucleated on the high angle grain boundaries are coarse, while the precipitates on the low angle grain boundaries are smaller and more numerous. The precipitates on both types of grain boundaries has been identified as Q'-type. Copper is segregated to both the low and high angle grain boundaries. The effect of this segregation will be discussed with regards to the corrosion properties of the alloy.

Structure, Thermal Stability and Properties of Grain Boundaries of Submicrocrystalline Mo Obtained by Severe Plastic Deformation

2012 ◽  
Vol 326-328 ◽  
pp. 674-681 ◽  
Author(s):  
Vladimir V. Popov ◽  
Galina P. Grabovetskaya ◽  
A.V. Sergeev ◽  
I.P. Mishin
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Grain Boundaries ◽  
High Pressure Torsion ◽  
Emission Mössbauer Spectroscopy ◽  
Transmission Electron

The structure of submicrocrystalline Mo, obtained by high pressure torsion, its thermal stability and the state of grain boundaries have been studied by transmission electron microscopy and emission Mössbauer spectroscopy.

On the Roles of Temperature and Interfaces in Irradiation and Thermally Induced Solid State Amorphization

1995 ◽  
Vol 398 ◽  
Author(s):  
L.M. Wang ◽  
W.L. Gong ◽  
R.C. Ewing ◽  
W.J. Webert
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Grain Boundaries ◽  
Irradiation Temperature ◽  
Free Surfaces ◽  
Thermally Induced ◽  
Transmission Electron ◽  
Increasing Temperature ◽  
State Amorphization

ABSTRACTThe roles of irradiation temperature and interfaces (free surfaces and grain boundaries) in irradiation- and thermally- induced amorphization of ceramics (coesite, apatite, olivines and spinels) have been studied by transmission electron microscopy (TEM). The irradiations were performed with 1.5 MeV Kr+, 200 keV and 1 MeV electrons over a wide temperature range (20-700 K). The critical amorphization dose at which amorphization is complete, Dc, increased with increasing irradiation temperature for most materials except coesite (a high pressure polymorph of Si02) which showed a decreasing Dc with increasing temperature under 1 MeV electron irradiation. Although amorphization may occur directly within a displacement cascade or by cascade overlap, this study shows that free surfaces and grain boundaries are favorable sites for nucleation of amorphous volumes. Once the amorphous volume is formed at interfaces, it may grow rapidly under continued irradiation. Coesite which has a glass transition temperature higher than its melting temperature underwent spontaneous amorphization during thermal annealing at 1200 K. This thermally-induced amorphization also started at free surface and grain boundaries and propagated into the interior of the crystal. The interface-mediated amorphization is analogous to the process of thermodynamic melting.

Image Analysis and Fourier Transform Infrared Light Microscopy and Transmission Electron Microscopy of Mercerized Cotton Yarns

1999 ◽  
Vol 5 (S2) ◽  
pp. 924-925
Author(s):  
Eileen K. Boylston
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Image Analysis ◽  
Light Microscopy ◽  
Cotton Fiber ◽  
Infrared Light ◽  
Transmission Electron ◽  
Microscopy Image ◽  
Cotton Yarns ◽  
Microscopy Image Analysis

Renewed interest in mercerization as a pre-treatment for textile finishing has led to research on the effects of temperature on this process. Mercerization, the swelling of cotton in caustic soda, causes changes in crystallinity from a Cellulose I structure to a Cellulose II structure, along with changes in fiber physical dimensions, increased dyeability, luster and tensile strength. These changes are differentiated by light microscopy, image analysis and FT-IR, and transmission electron microscopy. Cotton yarns were mercerized with an aqueous solution of 23% NaOH and 1% wetting agent. The yarns were treated for 1 hour at 0, 20, 60, 80, and 110° C, and washed in distilled water at the same temperature as the treatment bath. Rapid embeddment procedures have been developed for analyzing the effects of treatments on cotton fiber structure. Cotton fiber cross-sections were prepared for light microscopy/image analysis by encasing the fibers in a tube,1 embedding in mefhacrylate plastic (Fig. la), polymerizing for 30 minutes with UV, and sectioning.

Two- or three-way observations of the identical cell elements within the same sections by LM, TEM and/or SEM

1978 ◽  
Vol 36 (2) ◽  
pp. 82-83 ◽  
Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Fine Structure ◽  
Light Microscopy ◽  
Thin Sections ◽  
Transmission Electron ◽  
Identical Cell ◽  
Electron Microscopes ◽  
Scanning Electron

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).

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