Origin of Threefold Periodicity in High-Resolution Transmission Electron Microscopy Images of Thin Film Cubic SiC

1999 ◽  
Vol 5 (6) ◽  
pp. 420-427 ◽  
Author(s):  
U. Kaiser ◽  
A. Chuvilin ◽  
P.D. Brown ◽  
W. Richter

Abstract: High-resolution transmission electron microscopy (HRTEM) images of the [1–10] zone of cubic SiC layers grown by molecular beam epitaxy (MBE) often reveal regions of material exhibiting an unusual threefold periodicity. The same contrast was found in earlier works of Jepps and Page, who attributed this contrast in HRTEM images of polycrystalline SiC to the 9R-SiC polytype. In this report we demonstrate by HRTEM image simulations that the model of the 9R polytype and an alternative twinning model can fit qualitatively the experimental HRTEM images. However, by comparing the fast Fourier transform (FFT) patterns of the experiments and the simulations, as well as by using dark-field imaging, we show unambiguously that only the model of overlapping twinned 3C-SiC crystals fully agrees with the experiments.

2009 ◽  
Vol 15 (S2) ◽  
pp. 1082-1083
Author(s):  
D Masiel ◽  
B Reed ◽  
T LaGrange ◽  
ND Browning

Extended abstract of a paper presented at Microscopy and Microanalysis 2009 in Richmond, Virginia, USA, July 26 – July 30, 2009


1987 ◽  
Vol 103 ◽  
Author(s):  
W. M. Stobbs

ABSTRACTT.E.M. methods are described for the quantitative characterisation of the compositional and structural changes at interfaces and in homo- and hetero-phase multilayer structures. Many of the newer approaches described including the Fresnel and Centre Stop Dark Field Imaging Methods were developed specifically for such characterisations. The range of applications of each of the techniques is assessed as is the importance of delineating the limiting effects of inelastic and inelastic/elastic multiple scattering.


1997 ◽  
Vol 04 (04) ◽  
pp. 687-694 ◽  
Author(s):  
KUNIO TAKAYANAGI ◽  
YOSHITAKA NAITOH ◽  
YOSHIFUMI OSHIMA ◽  
MASANORI MITOME

Surface transmission electron microscopy (TEM) has been used to reveal surface steps and structures by bright and dark field imaging, and high resolution plan view and/or profile view imaging. Dynamic processes on surfaces, such as step motion, surface phase transitions and film growths, are visualized by a TV system attached to the electron microscope. Atom positions can precisely be detected by convergent beam illumination (CBI) of high resolution surface TEM. Imaging of the atomic positions of surfaces with truncation is briefly reviewed in this paper, with recent development of a TEM–STM (scanning tunneling microscope) system.


1999 ◽  
Vol 14 (4) ◽  
pp. 1645-1652 ◽  
Author(s):  
Toshiki Shimizu ◽  
Masaki Tsuji ◽  
Shinzo Kohjiya

Thin films of polychloroprene (CR; Neoprene-W) were made by casting its solution (2.0 wt%) in benzene onto the water surface, and some of them were stretched by a desired amount of strain (ε) in their “molten” state. The specimens thus prepared were then crystallized and examined by transmission electron microscopy. Morphological observations in bright- and dark-field imaging modes and selected-area electron diffraction analysis revealed directly that filamentous entities observed in the bright-field image are the edge-on lamellar crystals. It was, therefore, confirmed that the morphological results obtained from the thin specimens of CR without any electron staining are basically in accord with those reported so far for the OsO4-stained thin films of CR.


2011 ◽  
Vol 17 (5) ◽  
pp. 788-798 ◽  
Author(s):  
Mitsuhiro Okuda ◽  
Nobuhiro Ogawa ◽  
Masaki Takeguchi ◽  
Ayako Hashimoto ◽  
Motohiro Tagaya ◽  
...  

AbstractThe mineralized structure of aligned collagen fibrils in a tilapia fish scale was investigated using transmission electron microscopy (TEM) techniques after a thin sample was prepared using aqueous techniques. Electron diffraction and electron energy loss spectroscopy data indicated that a mineralized internal layer consisting of aligned collagen fibrils contains hydroxyapatite crystals. Bright-field imaging, dark-field imaging, and energy-filtered TEM showed that the hydroxyapatite was mainly distributed in the hole zones of the aligned collagen fibrils structure, while needle-like materials composed of calcium compounds including hydroxyapatite existed in the mineralized internal layer. Dark-field imaging and three-dimensional observation using electron tomography revealed that hydroxyapatite and needle-like materials were mainly found in the matrix between the collagen fibrils. It was observed that hydroxyapatite and needle-like materials were preferentially distributed on the surface of the hole zones in the aligned collagen fibrils structure and in the matrix between the collagen fibrils in the mineralized internal layer of the scale.


2016 ◽  
Vol 30 (20) ◽  
pp. 1650269 ◽  
Author(s):  
Thi Giang Le ◽  
Minh Tuan Dau

High-resolution transmission electron microscopy (HR-TEM) has been used to investigate the structural properties of GeMn/Ge nanocolumns multilayer samples grown on Ge(001) substrates by means of molecular beam epitaxy (MBE) system. Four bilayers with the spacer thickness in the range between 6 nm and 15 nm and 10 periods of bilayers of Ge[Formula: see text]Mn[Formula: see text]/Ge nanocolumn are presented. A simplified 2D model based on the theory of elastic constant interactions has been used to provide reasonable explanations to the vertical self-organization of GeMn nanocolumns in multilayers.


2017 ◽  
Vol 46 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Uschi M. Graham ◽  
Robert A. Yokel ◽  
Alan K. Dozier ◽  
Lawrence Drummy ◽  
Krishnamurthy Mahalingam ◽  
...  

This is the first utilization of advanced analytical electron microscopy methods, including high-resolution transmission electron microscopy, high-angle annular dark field scanning transmission electron microscopy, electron energy loss spectroscopy, and energy-dispersive X-ray spectroscopy mapping to characterize the organ-specific bioprocessing of a relatively inert nanomaterial (nanoceria). Liver and spleen samples from rats given a single intravenous infusion of nanoceria were obtained after prolonged (90 days) in vivo exposure. These advanced analytical electron microscopy methods were applied to elucidate the organ-specific cellular and subcellular fate of nanoceria after its uptake. Nanoceria is bioprocessed differently in the spleen than in the liver.


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