The Observation Of Mg)-Al Interface By Hrem and Microdiffraction

1985 ◽  
Vol 43 ◽  
pp. 240-241
Author(s):  
S.Y. Zhang ◽  
J.M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Materials Science ◽  
Incident Beam ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Resolution Electron ◽  
Powerful Means ◽  
Interface Structures

The combination of high resolution electron microscopy (HREM) and nanodiffraction techniques provided a powerful means for characterizing many of the interface structures which are of fundamental importance in materials science. In this work the interface structure between magnesium oxide and aluminum has been examined by HREM (with JEM-200CX) and nanodiffraction (with HB-5). The interfaces were formed by evaporating Al on freshly prepared cubic MgO smoke crystals under various vacuum conditions, at 10 -4, 10-5 10-6 and 10-7 torr. The Al layers on the MgO (001) surface are about 100Å thick. TEM observations were performed with the incident beam along the MgO [100] direction so that the interface could be revealed clearly. The nanodiffraction patterns were obtained with the electron beam of 15Å diameter parallel to the interface.

Voltage-center COMA-free alignment for high-resolution Electron Microscopy

1994 ◽  
Vol 52 ◽  
pp. 410-411
Author(s):  
K. Ishizuka ◽  
K. Shirota
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Incident Beam ◽  
Chromatic Aberration ◽  
High Resolution Electron Microscopy ◽  
Beam Deflection ◽  
Objective Lens ◽  
Main Magnetic Field ◽  
Beam Direction ◽  
Resolution Electron

In a conventional alignment for high-resolution electron microscopy, the specimen point imaged at the viewing-screen center is made dispersion-free against a voltage fluctuation by adjusting the incident beam direction using the beam deflector. For high-resolution works the voltage-center alignment is important, since this alignment reduces the chromatic aberration. On the other hand, the coma-free alignment is also indispensable for high-resolution electron microscopy. This is because even a small misalignment of the incident beam direction induces wave aberrations and affects the appearance of high resolution electron micrographs. Some alignment procedures which cancel out the coma by changing the incident beam direction have been proposed. Most recently, the effect of a three-fold astigmatism on the coma-free alignment has been revealed, and new algorithms of coma-free alignment have been proposed.However, the voltage-center and the coma-free alignments as well as the current-center alignment in general do not coincide to each other because of beam deflection due to a leakage field within the objective lens, even if the main magnetic-field of the objective lens is rotationally symmetric. Since all the proposed procedures for the coma-free alignment also use the same beam deflector above the objective lens that is used for the voltage-center alignment, the coma-free alignment is only attained at the sacrifice of the voltage-center alignment.

Quantitative high-resolution electron microscopy (HREM) of defects in ordered polymers

1996 ◽  
Vol 54 ◽  
pp. 166-167
Author(s):  
Patricia M. Wilson ◽  
David C. Martin
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Liquid Crystalline ◽  
High Resolution Electron Microscopy ◽  
Polymer Materials ◽  
Scattered Electron ◽  
Crystalline Polymers ◽  
Resolution Electron ◽  
Beam Damage

Efforts in our laboratory and elsewhere have established the utility of low dose high resolution electron microscopy (HREM) for imaging the microstructure of crystalline and liquid crystalline polymers. In a number of polymer systems, direct imaging of the lattice spacings by HREM has provided information about the size, shape, and relative orientation of ordered domains in these materials. However, because of the extent of disorder typical in many polymer microstructures, and because of the sensitivity of most polymer materials to electron beam damage, there have been few studies where the contrast observed in HREM images has been analyzed in a quantitative fashion.Here, we discuss two instances where quantitative information about HREM images has been used to provide new insight about the organization of crystalline polymers in the solid-state. In the first, we study the distortion of the polymer lattice planes near the core of an edge dislocation and compare these results to theories of dislocations in anisotropic and liquid crystalline solids. In the second, we investigate the variations in HREM contrast near the edge of wedge-shaped samples. The polymer used in this study was the diacetylene DCHD, which is stable to electron beam damage (Jc = 20 C/cm2) and highly crystalline. The instrument used in this work was a JEOL 4000 EX HRTEM with a beam blanidng device. More recently, the 4000 EX has been installed with instrumentation for dynamically recording scattered electron beam currents.

Atomic Scale Study of Cosi/Si (111) and CoSi2/Si (111) Interfaces

1989 ◽  
Vol 159 ◽  
Author(s):  
A. Catana ◽  
M. Heintze ◽  
P.E. Schmid ◽  
P. Stadelmann
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Orientation Relationship ◽  
Cross Sections ◽  
High Resolution Electron Microscopy ◽  
Atomic Scale ◽  
Type B ◽  
Initial Stage ◽  
Resolution Electron

ABSTRACTHigh Resolution Electron Microscopy (HREM) was used to study microstructural changes related to the CoSi/Si-CoSi/CoSi2/Si-CoSi2/Si transformations. CoSi is found to grow epitaxially on Si with [111]Si // [111]CoSi and < 110 >Si // < 112 >CoSi. Two CoSi non-equivalent orientations (rotated by 180° around the substrate normal) can occur in this plane. They can be clearly distinguished by HRTEM on cross-sections ( electron beam along [110]Si). At about 500°C CoSi transforms to CoSi2. Experimental results show that the type B orientation relationship satisfying [110]Si // [112]CoSi is preserved after the initial stage of CoSi2 formation. At this stage an epitaxial CoSi/CoSi2/Si(111) system is obtained. The atomic scale investigation of the CoSi2/Si interface shows that a 7-fold coordination of the cobalt atoms is observed in both type A and type B epitaxies.

Direct structure analysis of advanced nanomaterials by high-resolution electron microscopy

2012 ◽  
Vol 1 (5) ◽  
pp. 389-425 ◽  
Author(s):  
Takeo Oku
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Nanostructured Materials ◽  
Structure Analysis ◽  
Incident Beam ◽  
High Resolution Electron Microscopy ◽  
Structure Model ◽  
Resolution Electron ◽  
Correction Technique ◽  
Resolution Imaging

AbstractHigh-resolution electron microscopy (HREM) analysis has contributed to the direct structure analysis of advanced nanostructured materials, of which the properties of these materials are strongly dependent on the atomic arrangements. In the present article, the direct structure analysis of nanostructured materials such as boride and oxide materials was described and the high-resolution imaging methods were applied to boron nitride nanomaterials such as nanotubes and nanoparticles. An aberration correction technique is also expected as an advanced nanostructure analysis with higher resolution. The HREM image of TlBa2Ca3Cu4O11 was taken with the incident beam parallel to the a axis together with a structure model after image processing.

High Resolution Electron Microscopy Observations About The Interface Structure In A Ti/TiN Multilayer Material

1991 ◽  
Vol 238 ◽  
Author(s):  
X. G. Ning ◽  
L. P. Guo ◽  
R. F. Huang ◽  
J. Gong ◽  
B. H. Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Orientation Relationship ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Multilayer Material ◽  
Transition Layers ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Specific Orientation

ABSTRACTThe interface structure in a Ti/TiN multilayer material has been investigated by high resolution transmission electron microscopy (HRTEM). It was shown that the α-Ti and β-TiN layers consisted of many cylindrical crystals growing along the close packed directions normal to the surface of a stainless steel. There existed specific orientation relationship at the Ti/TiN interfaces without transition layers: (111)TiN ‖ (001)Ti, [110]TiN ‖ [100]Ti. However there was no such orientation relationship at the Ti/TiN interfaces with TixN (x >1) transition layers.

A HREM study of V/Al2O3 interface

1992 ◽  
Vol 50 (1) ◽  
pp. 146-147
Author(s):  
Y. Ikuhara ◽  
P. Pirouz ◽  
A. H. Heuer ◽  
S. Yadavalli ◽  
C. P. Flynn
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
High Resolution ◽  
Substrate Temperature ◽  
Molecular Beam ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Cross Sectional ◽  
Plan View ◽  
Resolution Electron

The interface structure between vanadium and the R-plane of sapphire (α-Al2O3) was studied by conventional and cross-sectional high resolution electron microscopy (HREM) to clarify the atomic structure of the interface.A 57 nm thick vanadium film was deposited on the (1102) (R) plane of sapphire by molecular beam epitaxy (MBE) at a substrate temperature of 920 K in a vacuum of 10-10torr. The HREM observations of the interface were done from three directions: two cross-sectional views (parallel to [0221]Al2O3 and [1120]Al2O3) and a plan view (parallel to [2201]Al2O3) by a top-entry JEOL 4000EX electron microscope (400 kV).

Small-Spot Illumination For High-Resolution Electron Microscopy of Beam-Sensitive Specimens

1985 ◽  
Vol 43 ◽  
pp. 320-321
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
High Resolution ◽  
Electron Diffraction ◽  
High Resolution Electron Microscopy ◽  
Photographic Emulsion ◽  
Lateral Motion ◽  
Small Spot ◽  
Resolution Electron ◽  
Diffraction Patterns

The contrast observed in images of beam-sensitive, crystalline specimens is found to be significantly less than one would predict based on observations of electron diffraction patterns of the specimens. Factors such as finite coherence, inelastic scattering, and the limited MTF of the photographic emulsion account for some decrease in contrast. It appears, however, that most of the loss in signal is caused by motion of the specimen during exposure to the electron beam. The introduction of point and other defects in the crystal, resulting from radiation damage, causes bending and lateral motion, which degrade the contrast in the image. We have therefore sought to determine whether the beam-induced specimen motion can be reduced by reducing the area of the specimen which is illuminated at any one time.

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