Anti-Site Bonds and the Structure of Interfaces in SiC

AbstractHigh resolution electron microscopy has been used to study the structure of the 3C/6H interface, Σ,=3 {111}and Σ.=3 {112}grain boundaries in 3C-SiC. In SiC, as in other compound semiconductors, anti-site bonds occur in a variety of defects. These are high energy bonds comparable to that of dangling bonds. But, while dangling bonds at the grain boundaries may be eliminated by reconstruction just as in elemental semiconductors, it may not be possible to avoid anti-site bonds.These problems are discussed for the Σ=3 {112} grain boundary, where the structures proposed for Ge and Si are used as starting models for SiC.

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An investigation of grain boundaries in submicrometer-grained Al-Mg solid solution alloys using high-resolution electron microscopy

Journal of Materials Research ◽

10.1557/jmr.1996.0239 ◽

1996 ◽

Vol 11 (8) ◽

pp. 1880-1890 ◽

Cited By ~ 273

Author(s):

Zenji Horita ◽

David J. Smith ◽

Minoru Furukawa ◽

Minoru Nemoto ◽

Ruslan Z. Valiev ◽

...

Keyword(s):

Electron Microscopy ◽

Solid Solution ◽

High Resolution ◽

Grain Boundaries ◽

Boundary Migration ◽

Boundary Energy ◽

High Resolution Electron Microscopy ◽

High Energy ◽

Structural Features ◽

Resolution Electron

High-resolution electron microscopy was used to examine the structural features of grain boundaries in Al–1.5% Mg and Al–3% Mg solid solution alloys produced with submicrometer grain sizes using an intense plastic straining technique. The grain boundaries were mostly curved or wavy along their length, and some portions were corrugated with regular or irregular arrangements of facets and steps. During exposure to high-energy electrons, grain boundary migration occurred to reduce the number of facets and thus to reduce the total boundary energy. The observed features demonstrate conclusively that the grain boundaries in these submicrometer-grained materials are in a high-energy nonequilibrium configuration.

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Grain Boundary Transformations in Bi-Doped Copper

MRS Proceedings ◽

10.1557/proc-238-201 ◽

1991 ◽

Vol 238 ◽

Cited By ~ 3

Author(s):

Elsie C. Urdaneta ◽

David E. Luzzi ◽

Charles J. McMahon

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Grain Boundaries ◽

Treatment Time ◽

High Resolution Electron Microscopy ◽

Transmission Electron ◽

Resolution Electron

ABSTRACTBismuth-induced grain boundary faceting in Cu-12 at ppm Bi polycrystals was studied using transmission electron microscopy (TEM). The population of faceted grain boundaries in samples aged at 600°C was observed to increase with heat treatment time from 15min to 24h; aging for 72h resulted in de-faceting, presumably due to loss of Bi from the specimen. The majority of completely faceted boundaries were found between grains with misorientation Σ=3. About 65% of the facets of these boundaries were found to lie parallel to crystal plane pairs of the type {111}1/{111]2- The significance of these findings in light of recent high resolution electron microscopy experiments is discussed.

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Observations of grain boundary structure in submicrometer-grained Cu and Ni using high-resolution electron microscopy

Journal of Materials Research ◽

10.1557/jmr.1998.0057 ◽

1998 ◽

Vol 13 (2) ◽

pp. 446-450 ◽

Cited By ~ 132

Author(s):

Zenji Horita ◽

David J. Smith ◽

Minoru Nemoto ◽

Ruslan Z. Valiev ◽

Terence G. Langdon

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Grain Boundaries ◽

Nonequilibrium State ◽

High Resolution Electron Microscopy ◽

High Energy ◽

Typical Feature ◽

Boundary Structure ◽

Grain Boundary Structure ◽

Resolution Electron

Submicrometer-grained (SMG) structures were produced in Cu and Ni using an intense plastic straining technique, and the grain boundaries and their vicinities were observed by high-resolution electron microscopy. The grain boundaries exhibited zigzag configurations with irregular arrangements of facets and steps, and thus they were found to be in a high-energy nonequilibrium state. A similar conclusion was reached earlier for SMG Al–Mg solid solution alloys which have much lower melting points than Cu and Ni, suggesting that nonequilibrium grain boundaries are a typical feature of metals processed by intense plastic straining.

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Structure of the ∑=3 (111) Grain Boundary in Cu-1.5%Sb

MRS Proceedings ◽

10.1557/proc-295-161 ◽

1992 ◽

Vol 295 ◽

Author(s):

Richard W. Fonda ◽

David E. Luzzi

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Grain Boundaries ◽

Auger Electron ◽

Preliminary Investigation ◽

High Resolution Electron Microscopy ◽

Transmission Electron ◽

Resolution Electron

AbstractGrain boundaries in quenched and aged Cu-i.5%Sb were examined with Auger electron microscopy, transmission electron microscopy, and high resolution electron microscopy. The ∑=3 grain boundaries are strongly faceted, with the facets lying primarily along the coincident (111) planes of the two grains. The grain boundaries are enriched in antimony, as demonstrated by both AES and HREM. HREM images of the ∑=3 (111) ║ (111) grain boundary differ from those of the Cu-Bi ∑ =3 (111) ║ (111) grain boundary in the lack of a significant grain boundary expansion to accommodate the excess solute at the boundary. A preliminary investigation of the atomic structure of the ∑=3 (111) ║ (111) facet by HREM and multislice calculations is presented.

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Time-resolved high-resolution electron microscopy of grain migration process in MgO films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100165835 ◽

1996 ◽

Vol 54 ◽

pp. 674-675

Author(s):

T. Kizuka ◽

M. Iijima ◽

N. Tanaka

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Grain Boundaries ◽

Boundary Migration ◽

High Resolution Electron Microscopy ◽

Video Tape ◽

Grain Boundary Migration ◽

Time Resolved ◽

Resolution Electron

High-resolution electron microscopy (HREM) has been employed intensively to analyze the atomic structures of grain boundaries and interfaces having two dimensional structures inside polycrystalline and composite materials. Furthermore time-resolved HREM (TRHREM) is required to analyze the behavior of grain boundaries and interfaces at atomic scale. The grain boundary migration, which is a typical grain boundary behavior, is a fundamental process relating to structural stability of polycrystalline materials. The mechanism of the migration has been still unknown.In the present study, the variation of atomic arrangement at the grain boundary migration of a MgO [001]Σ5 boundary was analyzed by TRHREM.Magnesium oxide polycrystalline films were prepared by vacuum-deposition on air-cleaved (001) surfaces of sodium chloride at 300°C. TRHREM was carried out at room temperature using a 200-kV electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder. The spatial resolution of the system was 0.2 nm at 200 kV and the time resolution was 1/60 s. Electron beam density was 30 A/cm2.

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High Resolution Electron Microscopy of Grain Boundaries in Nanophase Palladium

MRS Proceedings ◽

10.1557/proc-153-13 ◽

1989 ◽

Vol 153 ◽

Cited By ~ 24

Author(s):

G. J. Thomas ◽

R. W. Siegel ◽

J. A. Eastman

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Grain Boundaries ◽

Lattice Structure ◽

High Resolution Electron Microscopy ◽

Coarse Grained ◽

Resolution Electron ◽

The Individual ◽

Individual Grains

AbstractUsing high resolution electron microscopy, consolidated nanophase palladium samples were examined following electrolytic thinning after a hydriding - dehydriding cycle at 310 K. Due to the small size and random orientations of the individual grains, a large number of grain boundaries were available for examination. Some of these yielded adequate imaging conditions to allow observation of the lattice structure in the grain boundary regions. Image simulations were performed to determine the sensitivity of the technique to lattice disorder. The results of these studies suggest that grain boundary structures in nanophase palladium are similar to those in conventional coarse-grained polycrystals.

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High-resolution electron microscopy of nanostructured materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100137239 ◽

1995 ◽

Vol 53 ◽

pp. 172-173

Author(s):

M. José-Yacamán

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Grain Boundaries ◽

Nanostructured Materials ◽

High Resolution Electron Microscopy ◽

Hrem Image ◽

Small Particles ◽

Resolution Electron ◽

Nanophase Materials

Electron microscopy is a fundamental tool in materials characterization. In the case of nanostructured materials we are looking for features with a size in the nanometer range. Therefore often the conventional TEM techniques are not enough for characterization of nanophases. High Resolution Electron Microscopy (HREM), is a key technique in order to characterize those materials with a resolution of ~ 1.7A. High resolution studies of metallic nanostructured materials has been also reported in the literature. It is concluded that boundaries in nanophase materials are similar in structure to the regular grain boundaries. That work therefore did not confirm the early hipothesis on the field that grain boundaries in nanostructured materials have a special behavior. We will show in this paper that by a combination of HREM image processing, and image calculations, it is possible to prove that small particles and coalesced grains have a significant surface roughness, as well as large internal strain.

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Structural Transformation of a Germanium Σ=13 (510) [001] Tilt Grain Boundary under the Electron Beam

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100179014 ◽

1990 ◽

Vol 48 (1) ◽

pp. 52-53 ◽

Cited By ~ 1

Author(s):

Jean-Luc Rouvière ◽

Alain Bourret

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Structural Transformation ◽

Mirror Symmetry ◽

High Resolution Electron Microscopy ◽

Structural Transformations ◽

Covalent Bonds ◽

Resolution Electron ◽

Tilt Grain Boundary

The possible structural transformations during the sample preparations and the sample observations are important issues in electron microscopy. Several publications of High Resolution Electron Microscopy (HREM) have reported that structural transformations and evaporation of the thin parts of a specimen could happen in the microscope. Diffusion and preferential etchings could also occur during the sample preparation.Here we report a structural transformation of a germanium Σ=13 (510) [001] tilt grain boundary that occurred in a medium-voltage electron microscopy (JEOL 400KV).Among the different (001) tilt grain boundaries whose atomic structures were entirely determined by High Resolution Electron Microscopy (Σ = 5(310), Σ = 13 (320), Σ = 13 (510), Σ = 65 (1130), Σ = 25 (710) and Σ = 41 (910), the Σ = 13 (510) interface is the most interesting. It exhibits two kinds of structures. One of them, the M-structure, has tetracoordinated covalent bonds and is periodic (fig. 1). The other, the U-structure, is also tetracoordinated but is not strictly periodic (fig. 2). It is composed of a periodically repeated constant part that separates variable cores where some atoms can have several stable positions. The M-structure has a mirror glide symmetry. At Scherzer defocus, its HREM images have characteristic groups of three big white dots that are distributed on alternatively facing right and left arcs (fig. 1). The (001) projection of the U-structure has an apparent mirror symmetry, the portions of good coincidence zones (“perfect crystal structure”) regularly separate the variable cores regions (fig. 2).

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Interaction Between Basal Stacking Faults and Prismatic Inversion Domain Boundaries in GaN

MRS Proceedings ◽

10.1557/proc-639-g3.44 ◽

2000 ◽

Vol 639 ◽

Cited By ~ 1

Author(s):

Philomela Komninou ◽

Joseph Kioseoglou ◽

Eirini Sarigiannidou ◽

George P. Dimitrakopulos ◽

Thomas Kehagias ◽

...

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Stacking Faults ◽

High Resolution Electron Microscopy ◽

High Energy ◽

Low Energy ◽

Inversion Domain ◽

Resolution Electron ◽

Domain Boundaries ◽

Inversion Domain Boundaries

ABSTRACTThe interaction of growth intrinsic stacking faults with inversion domain boundaries in GaN epitaxial layers is studied by high resolution electron microscopy. It is observed that stacking faults may mediate a structural transformation of inversion domain boundaries, from the low energy types, known as IDB boundaries, to the high energy ones, known as Holt-type boundaries. Such interactions may be attributed to the different growth rates of adjacent domains of inverse polarity.

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