Characterization of Dislocations and Interfaces in Semiconductors by High Resolution Electron Microscopy

1980 ◽  
Vol 2 ◽  
Author(s):  
J.C.H. Spence ◽  
A. Olsen
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Local Symmetry ◽  
Partial Dislocations ◽  
Resolution Electron ◽  
Lattice Images ◽  
Diffraction Patterns ◽  
The Individual

ABSTRACTIt is not presently possible to resolve the individual atoms in any semiconductor by high resolution electron microscopy (HREM). However symmetry arguments may be used to allow near-atomic resolution lattice images to be interpreted in rare favorable cases. This method is applied to the problem of distinguishing shuffle and glide set partial dislocations in silicon. It is also proposed that two dimensional characteristic loss energy selected diffraction patterns be used to reveal the local symmetry about selected substitutional species implanted in semiconductor lattices.

Characterization of Cross-Sections of Tibacacuo Thin Films on Ceramic Substrates by Analytical and High Resolution Electron Microscopy

1989 ◽  
Vol 169 ◽  
Author(s):  
J. Mayer ◽  
M. Lanham ◽  
T.W. James ◽  
A.G. Evans ◽  
M. RÜHle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Sections ◽  
High Resolution Electron Microscopy ◽  
Amorphous Layer ◽  
Superconducting Film ◽  
Ceramic Substrates ◽  
Resolution Electron ◽  
Lattice Images

AbstractCross-sectioned TEM specimens of thin TIBaCaCuO superconducting films on MgO and LaAlO3 substrates have been obtained using special ceramic holders. The superconductor/substrate interface as well as grain boundaries and defects in the superconductor have been characterized by means of analytical and high-resolution electron microscopy. EDX analysis and lattice images confirm that interdiffusion and the formation of an amorphous layer takes place at the interface between the LaA1O3 substrate and the superconducting film, while no indication for such reactions has been found in the case of the MgO substrates. The presence of intergrowth and defects in the superconducting film have been demonstrated by high-resolution electron microscopy. The chemical nature of such defects has been determined by a quantitative evaluation of high-resolution micrographs.

Atomic structural images of crystalline cholesterol monohydrate in human atheroma

1990 ◽  
Vol 48 (3) ◽  
pp. 206-207
Author(s):  
Ying-Shiung Lee
Keyword(s):  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Crystal Lattices ◽  
Resolution Electron ◽  
Lattice Images ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns ◽  
Cholesterol Monohydrate ◽  
Human Atheroma

To gain further insight regarding the micromechanisms of progression and regression of human atherosclerotic plaques the present study was designed for characterization of crystal lattices of cholesterol monohydrate, demonstration of cholesterol crystallization processes, and identification of crystal disorders of cholesterol monohydrate by means of high resolution electron microscopy (HREM).Clusters of cholesterol clefts containing crystalline cholesterol monohydrate were obtained from atherosclerotic human aortas under a dissecting microscope at autopsy. Cholesterol clefts were milled to a powder with a porcelain pestle. The powdered samples without staining dispersed in distilled water were spread on the copper-grid and dried at room temperature. The air-dried specimens were directly examined by a Hitachi H-9000 high resolution electron microscope operated at 300 KV. High resolution lattice images were taken under an optimal defocus condition. Selected area images and electron diffraction patterns were simultaneously taken for the analysis of crystalline characteristics.

High-resolution electron microscopy of nanostructured materials

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.

HRTEM simulation of interfacial structure in amorphous multilayers

1989 ◽  
Vol 47 ◽  
pp. 466-467
Author(s):  
Margaret L. Sattler ◽  
Michael A. O'Keefe
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Cross Section ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Multilayer Sample ◽  
Resolution Electron ◽  
Multilayered Materials ◽  
Simulated Images

Multilayered materials have been fabricated with such high perfection that individual layers having two atoms deep are possible. Characterization of the interfaces between these multilayers is achieved by high resolution electron microscopy and Figure 1a shows the cross-section of one type of multilayer. The production of such an image with atomically smooth interfaces depends upon certain factors which are not always reliable. For example, diffusion at the interface may produce complex interlayers which are important to the properties of the multilayers but which are difficult to observe. Similarly, anomalous conditions of imaging or of fabrication may occur which produce images having similar traits as the diffusion case above, e.g., imaging on a tilted/bent multilayer sample (Figure 1b) or deposition upon an unaligned substrate (Figure 1c). It is the purpose of this study to simulate the image of the perfect multilayer interface and to compare with simulated images having these anomalies.

The ultrastructure of coccoliths from the marine alga Emiliania huxleyi (Lohmann) Hay and Mohler: an ultra-high resolution electron microscope study

1983 ◽  
Vol 219 (1215) ◽  
pp. 111-117 ◽  
Keyword(s):  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Emiliania Huxleyi ◽  
Growth Patterns ◽  
Lattice Image ◽  
Nucleation Sites ◽  
Resolution Electron ◽  
Lattice Images ◽  
High Resolution Electron Microscope ◽  
Diffraction Patterns

The calcite coccoliths from the alga Emiliania huxleyi (Lohmann) Hay and Mohler have been studied by ultra-high resolution electron microscopy. This paper describes the two different types of structure observed, one in the upper elements, the other in the basal plate, or lower element. The former consisted of small, microdomain structures of 300-500 Å (1 Å = 10 -10 m) in length with no strong orientation. At places along these elements, and particularly in the junction between stem and head pieces, triangular patterns of lattice fringes were observed indicating multiple nucleation sites in the structure. In contrast, the lower element consisted of a very thin single crystalline sheet of calcite which could be resolved into a two dimensional lattice image, shown by a computer program that is capable of simulating electron diffraction patterns and lattice images to be a [421] zone of calcite. A possible mechanism for these growth patterns in the formation of coccoliths is discussed, together with the relevance of such mechanisms to biomineralization generally.

Atomic structure of YB56 studied by digital high-resolution electron microscopy and electron diffraction

2001 ◽  
Vol 16 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Takeo Oku ◽  
Jan-Olov Bovin ◽  
Iwami Higashi ◽  
Takaho Tanaka ◽  
Yoshio Ishizawa
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
High Resolution Electron Microscopy ◽  
Charge Coupled Device ◽  
X Ray ◽  
Resolution Electron ◽  
High Resolution Images ◽  
Diffraction Patterns ◽  
Simulated Images

Atomic positions for Y atoms were determined by using high-resolution electron microscopy and electron diffraction. A slow-scan charge-coupled device camera which had high linearity and electron sensitivity was used to record high-resolution images and electron diffraction patterns digitally. Crystallographic image processing was applied for image analysis, which provided more accurate, averaged Y atom positions. In addition, atomic disordering positions in YB56 were detected from the differential images between observed and simulated images based on x-ray data, which were B24 clusters around the Y-holes. The present work indicates that the structure analysis combined with digital high-resolution electron microscopy, electron diffraction, and differential images is useful for the evaluation of atomic positions and disordering in the boron-based crystals.

Sign in / Sign up

Export Citation Format

Share Document