High Resolution Electron Microscopy and Computer Simulation Studies of the Atomic Structure of Tilt Boundaries in TiO2

1994 ◽  
Vol 357 ◽  
Author(s):  
Yaping Liu ◽  
Imtiaz Majid ◽  
John B. Vander Sande
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
High Resolution ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Symmetric Plane ◽  
Tilt Boundaries ◽  
Computer Simulation Studies ◽  
Simulated Images

AbstractThe atomic structure of [001] tilt grain boundaries of Σ25 (210), Σ5 (310), Σ213 (320) and Σ217 (410) in TiO2 (rutile) were studied using high resolution electron microscopy and computer simulation. Regularly separated small steps (1/2 [120] high) and big steps (3/2 [120] high) which contain secondary dislocations were found in the (210) boundary as a result of deviation from the exact Σ5 misorientation and (210) symmetric plane. Similar steps were also found in (310) and (320) boundaries. Flat segments between the steps were found to have very accurate misorientation of their, Σ's and a nearly symmetric boundary plane. Their rigid body translation, volume expansion and relaxed structures were determined by comparing HRTEM images with computer calculated structures and simulated images. An irregular core structure was found in the (410) boundary when its misorientation deviated 2° from the exact Σ17 misorientation.

Atomic structure imaging of the Si/SiO2 interface with high-resolution electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 390-391
Author(s):  
J.L. Batstone ◽  
J.M. Gibson ◽  
Alice.E. White ◽  
K.T. Short
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Medium Voltage ◽  
Voltage Electron ◽  
Resolution Electron ◽  
Structural Image ◽  
Electron Microscopes ◽  
Point To Point

High resolution electron microscopy (HREM) is a powerful tool for the determination of interface atomic structure. With the previous generation of HREM's of point-to-point resolution (rpp) >2.5Å, imaging of semiconductors in only <110> directions was possible. Useful imaging of other important zone axes became available with the advent of high voltage, high resolution microscopes with rpp <1.8Å, leading to a study of the NiSi2 interface. More recently, it was shown that images in <100>, <111> and <112> directions are easily obtainable from Si in the new medium voltage electron microscopes. We report here the examination of the important Si/Si02 interface with the use of a JEOL 4000EX HREM with rpp <1.8Å, in a <100> orientation. This represents a true structural image of this interface.

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.

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.

scholarly journals Vitrification of Y zeolite and its effects on HREM images

1986 ◽  
Vol 44 ◽  
pp. 774-775
Author(s):  
R. Csencsits
Keyword(s):  
Electron Microscopy ◽  
Computer Simulation ◽  
Electron Microscope ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Systematic Investigation ◽  
Y Zeolite ◽  
Y Zeolites ◽  
Transmission Electron ◽  
Resolution Electron

High resolution electron microscopy (HREM) is a valuable technique for studying catalytic zeolite systems because it gives direct information about the structure and defects present in the structure. The difficulty with doing an HREM study on zeolites is that they become amorphous under electron irradiation. This work is a systematic investigation of the damage of Y zeolites in the transmission electron microscope (TEM); the goals of this study are to determine the mechanism for electron damage and to access the effects of damage in Y zeolites on their HREM images using computer simulation.

Atomic Structure of Interfaces: Link of Atomistic Calculations with High Resolution Electron Microscopy

1998 ◽  
Vol 4 (S2) ◽  
pp. 762-763
Author(s):  
V. Vitek
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Computer Modeling ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Interfacial Structure ◽  
Embedded Atom ◽  
Resolution Electron ◽  
Atomic Interactions ◽  
Atomistic Calculations

Since interfaces and grain boundaries affect critically many properties of materials, their atomic structure has been investigated very extensively using computer modeling. Most of these calculations have been made using semi-empirical central-force descriptions of atomic interactions, recently primarily the embedded-atom type many-body potentials. Owing to the approximate nature of such schemes, a connection with experimental observations that can validate the calculations is essential. The high resolution electron microscopy (HREM) is such experimental technique and it has, indeed, been frequently combined with calculations of interfacial structure and chemistry. In fact such a link is not only important for verification of the results of computer modeling but also crucial for meaningful interpretation of HREM observations. Hence, coupling the atomistic modeling with HREM is a synergistic procedure. It not only leads to better understanding of interfacial structures but may contribute significantly to the validation and assessment of limits of the schemes used for the description of atomic interactions.

Sign in / Sign up

Export Citation Format

Share Document