High Resolution Transmission Electron Microscopy of GaAs/AlAs Hetero-Structures in the Projection

1990 ◽  
Vol 183 ◽  
Author(s):  
N. Ikarashi ◽  
A. Sakai ◽  
T. Baba ◽  
K. Ishida ◽  
J. Motohisa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Atomic Scale ◽  
Transmission Electron ◽  
Interfacial Structures ◽  
Focus Condition ◽  
Lattice Images ◽  
The Difference ◽  
Imaging Conditions

AbstractHigh resolution transmission electron microscopy (HRTEM) of GaAs/AlAs hetero-structures grown by molecular beam epitaxy (MBE) is carried out in the <110> projection. It is shown that GaAs and AlAs are distinguished clearly by the difference in their lattice images at the samples thicknesses of about 15–30 nm under near Scherzer focus condition. Under these imaging conditions, very thin films consist of single monolayer AlAs are observed. Vicinal interfaces of GaAs/AlAs which were grown on (001) substrate misoriented toward [110] are also examined in the [110] projection. The interfacial structures are imaged edgeon, so that the fluctuations of terrace width, and the roughness of step-edges at these interfaces are observed on an atomic scale.

Atomistic Visualization of Mechanical Interaction in Gold Crystalline Boundaries by Time-Resolved High Resolution Transmission Electron Microscopy

1998 ◽  
Vol 05 (03n04) ◽  
pp. 739-745
Author(s):  
Tokushi Kizuka
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Atomic Layer ◽  
Mechanical Tests ◽  
Atomic Scale ◽  
Mechanical Interaction ◽  
Time Resolved ◽  
Specimen Holder ◽  
Transmission Electron

The atomic processes in mechanical interaction were visualized by time-resolved high resolution transmission electron microscopy at a spatial resolution of 0.2 nm and a time resolution of 1/60 s. Nanometer-sized tips of gold were approached, contacted, bonded, deformed and fractured inside a 200 kV electron microscope using a piezo-driving specimen holder. The crystallographic boundary formed after the contact. A few layers near the surfaces and bonding boundaries were responsible for the approach, contact and bonding processes. Atomic scale mechanical tests, such as the friction test, compressing, tensile and shear deformation tests, were proposed. A new type of mechanical processing at one-atomic-layer resolution was demonstrated. Atomic scale contact or noncontact type surface scanning similar to that in atomic force microscopy was also performed with the gold tips.

Structural study of Cd(S,Se) doped glasses. High-resolution transmission electron microscopy (HRTEM) assisted by image processing

1990 ◽  
Vol 23 (5) ◽  
pp. 418-423 ◽  
Author(s):  
M. Allais ◽  
M. Gandais
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Bulk Material ◽  
Optical Filters ◽  
Characteristic Size ◽  
Transmission Electron ◽  
Doped Glasses ◽  
Lattice Images ◽  
Average Size

High-resolution transmission electron microscopy (HRTEM) was used for examining Cd(S,Se) nanocrystals grown in silicate glasses commercially available as optical filters. The lattice images of the nanocrystals were numerated and submitted to filtering through Fourier transformation in order to sweep off the background signal originating mainly from glass. Optical filters from several firms were examined. The nanocrystals have been identified with Cd(S,Se) compounds crystallized in the wurzite structure, as in bulk material. The lattice images indicate crystallites having the shape of hexagonal prisms a little elongated along the c axis. The distribution of grain size differs according to the filter: the smallest size being about 1.5 nm (threshold for detection), the largest size varies from 7 to 10 nm, the average size sa , from 3–4 to 5–6 nm and the characteristic size sc from 5–6 to 7–8 nm (sc is the size of grains occupying the main part of the crystallized volume).

Preparation of vermiculites for HRTEM

Clay Minerals ◽  
1989 ◽  
Vol 24 (1) ◽  
pp. 23-32 ◽  
Author(s):  
CH. Marcks ◽  
H. Wachsmuth ◽  
H. Graf V. Reichenbach
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Computer Simulation ◽  
High Resolution ◽  
Alkyl Chains ◽  
Transmission Electron ◽  
Lattice Images ◽  
Silicate Layers

AbstractA technique for preparing vermiculites for examination by high-resolution transmission electron microscopy (HRTEM) has been developed. A TEM-stable expanded phase can be obtained by intercalating n-alkylammonium ions between the silicate layers of a parent biotite. The vermiculite particles were embedded in Spurr resin and centrifuged to improve orientation. Ultra-thin specimens were prepared using an ultramicrotome, the quality and thickness of the sections being monitored by TEM. Lattice images of biotite, Ba-vermiculite and octylammonium-vermiculite, the latter showing a perpendicular arrangement of the alkyl chains relative to the silicate layers, were obtained with a resolution ∼2 Å. The reliability of these images was confirmed by computer simulation.

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