Atomic Structure of Si-SiO2 Interface

1997 ◽  
Vol 3 (S2) ◽  
pp. 459-460
Author(s):  
G. Duscher ◽  
F. Banhart ◽  
H. Müllejans ◽  
S.J. Pennycook ◽  
M. Rühle
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Structure ◽  
Phase Contrast ◽  
Thermally Grown Oxide ◽  
Interface Roughness ◽  
Spatial Difference ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Z Contrast

Investigations of the atomic structure of Si-SiO2 interfaces have mostly been performed with high resolution transmission electron microscopy. However, the interpretation of the phase contrast in the amorphous phase at the interface is not unique. While Ourmazd et al. concluded on a crystalline phase at the Si-SiO2 interface, Akatsu and Ohdomari attributed the same contrast to an interface roughness parallel to the incident electrons.We investigated the Si-SiO2 interface by studying the ELNES of the O-K edge with the spatial difference technique with a dedicated STEM with l00kV (VG HB501 UX). Also the interface was studied by Z-contrast imaging with a 300 kV dedicated STEM (VG HB603 U). Silicon wafers (110) were first thermally oxidised to produce a SiO2 layer. The thermally grown oxide was used as a substrate for liquid phase epitaxy of silicon, given two {111} Si-SiO2 interfaces in the sample grown by two different techniques (see fig. 1).

Atomic Structure and Property Correlation in Pulsed Laser Deposited High -Tc Films

1998 ◽  
Vol 526 ◽  
Author(s):  
R. Kalyanaraman ◽  
S. Oktyabrsky ◽  
K. Jagannadham ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Boundaries ◽  
Atomic Structure ◽  
Substrate Surface ◽  
Pulsed Laser ◽  
Structure And Property ◽  
Transmission Electron ◽  
Tilt Boundaries ◽  
Z Contrast

AbstractThe atomic structure of grain boundaries in pulsed laser deposited YBCO/MgO thin films have been studied using transmission electron microscopy. The films have perfect texturing with YBCO(001)//MgO(001), giving rise to low-angle [001] tilt boundaries from the grains with the c-axis normal to substrate surface. Low angle grain boundaries have been found to be aligned preferentially along (100) and (110) interface planes. The energy of (110) boundary planes described by an alternating array of [100] and [010] dislocation is found to be comparable to the energy of a (100) boundary. The existence of these split dislocations is shown to further reduce the theoretical current densities of these boundaries indicating that (110) boundaries carry less current as compared to (100) boundaries of the same misorientation angle. Further, Z-contrast transmission electron microscopy of a 42° asymmetric high-angle grain boundary of YBCO shows evidence for the existence of boundary fragments and a reduced atomic density along the boundary plane

scholarly journals Multiscale X-ray phase contrast imaging of human cartilage for investigating osteoarthritis formation

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Annie Horng ◽  
Johannes Stroebel ◽  
Tobias Geith ◽  
Stefan Milz ◽  
Alexandra Pacureanu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Synchrotron Radiation ◽  
Phase Contrast ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
Human Cartilage ◽  
X Ray ◽  
Transmission Electron ◽  
Architectural Organization

Abstract Background The evolution of cartilage degeneration is still not fully understood, partly due to its thinness, low radio-opacity and therefore lack of adequately resolving imaging techniques. X-ray phase-contrast imaging (X-PCI) offers increased sensitivity with respect to standard radiography and CT allowing an enhanced visibility of adjoining, low density structures with an almost histological image resolution. This study examined the feasibility of X-PCI for high-resolution (sub-) micrometer analysis of different stages in tissue degeneration of human cartilage samples and compare it to histology and transmission electron microscopy. Methods Ten 10%-formalin preserved healthy and moderately degenerated osteochondral samples, post-mortem extracted from human knee joints, were examined using four different X-PCI tomographic set-ups using synchrotron radiation the European Synchrotron Radiation Facility (France) and the Swiss Light Source (Switzerland). Volumetric datasets were acquired with voxel sizes between 0.7 × 0.7 × 0.7 and 0.1 × 0.1 × 0.1 µm3. Data were reconstructed by a filtered back-projection algorithm, post-processed by ImageJ, the WEKA machine learning pixel classification tool and VGStudio max. For correlation, osteochondral samples were processed for histology and transmission electron microscopy. Results X-PCI provides a three-dimensional visualization of healthy and moderately degenerated cartilage samples down to a (sub-)cellular level with good correlation to histologic and transmission electron microscopy images. X-PCI is able to resolve the three layers and the architectural organization of cartilage including changes in chondrocyte cell morphology, chondrocyte subgroup distribution and (re-)organization as well as its subtle matrix structures. Conclusions X-PCI captures comprehensive cartilage tissue transformation in its environment and might serve as a tissue-preserving, staining-free and volumetric virtual histology tool for examining and chronicling cartilage behavior in basic research/laboratory experiments of cartilage disease evolution.

Image resolution in conventional transmission electron microscopy

1991 ◽  
Vol 49 ◽  
pp. 468-469
Author(s):  
Mehmet Sarikaya ◽  
James M. Howe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Contrast ◽  
Spherical Aberration ◽  
Dark Field ◽  
Image Resolution ◽  
Objective Lens ◽  
Contrast Imaging ◽  
Conventional Transmission Electron Microscopy ◽  
Transmission Electron

The image resolution in bright-field (BF) and dark-field (DF) conventional transmission electron microscopy (TEM) is given by: r = 0.66 CS¼¾¾, where Cs and ¾ are the spherical aberration coefficient of the objective lens and electron wavelength, respectively. Based on this formula, it should be possible to resolve single atoms or clusters of atoms by phase contrast imaging with a highly coherent electron beam and a properly defocused objective lens; this has been demonstrated for both BF and DF imaging. However, for most situations encountered in conventional TEM, the type of information that can be obtained about the specimen is the most important, rather than the instrumental resolution. Atomicresolution microscopy of crystalline specimens relies on phase contrast produced when two or more beams interfere to form an image and this is discussed elsewhere in this symposium. This paper discusses the contrast and resolution when either a single beam or diffuse scattering is used to form an image.

TEM Z-contrast imaging with wide-angle hollow-cone illumination

1990 ◽  
Vol 48 (4) ◽  
pp. 400-401
Author(s):  
J. Bentley ◽  
K. B. Alexander ◽  
Z. L. Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dark Field ◽  
Wide Angle ◽  
Hollow Cone ◽  
Contrast Imaging ◽  
Field Mode ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Z Contrast

High resolution scanning transmission electron microscopy (STEM) images with contrast sensitive to atomic number (Z-contrast) have been obtained with the use of a high-angle annular detector. The equivalent conventional transmission electron microscopy (TEM) dark-field mode reciprocally related to Z-contrast STEM is wide-angle hollow-cone illumination with an on-axis objective aperture. There are two ways to obtain hollow cone illumination; with an annular condenser aperture or by conically scanning the beam tilt coils. As in the case of STEM Z-contrast imaging, resolution with hollow-cone illumination should theoretically be higher than for phase contrast imaging in the same instrument.Philips CM30/STEM, CM12/STEM, and EM400T/FEG/STEM instruments have been used to investigate this imaging technique. The conical illumination dark-field mode is standard on the CM series and was implemented with a hybrid diffraction unit on the EM400. Commercial (SPI Supplies #1780) copper annular apertures with inner and outer diameters of 600 and 900 μm, respectively, spot welded to suitable supports for use as condenser apertures, resulted in cone angles too small to give good Z-contrast in the microprobe mode, because there is still a large diffraction contrast contribution.

scholarly journals Four-Dimensional Scanning Transmission Electron Microscopy (4D-STEM): From Scanning Nanodiffraction to Ptychography and Beyond

2019 ◽  
Vol 25 (3) ◽  
pp. 563-582 ◽  
Author(s):  
Colin Ophus
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Phase Contrast ◽  
Real Space ◽  
Contrast Imaging ◽  
Strain Mapping ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractScanning transmission electron microscopy (STEM) is widely used for imaging, diffraction, and spectroscopy of materials down to atomic resolution. Recent advances in detector technology and computational methods have enabled many experiments that record a full image of the STEM probe for many probe positions, either in diffraction space or real space. In this paper, we review the use of these four-dimensional STEM experiments for virtual diffraction imaging, phase, orientation and strain mapping, measurements of medium-range order, thickness and tilt of samples, and phase contrast imaging methods, including differential phase contrast, ptychography, and others.

New Frontiers in Cryo-electron Tomography with Zernike Phase Contrast Imaging for Transmission Electron Microscopy

2008 ◽  
Vol 14 (S2) ◽  
pp. 1072-1073
Author(s):  
B Armbruster ◽  
J Brink ◽  
H Furukawa ◽  
TC Isabell ◽  
M Kawasaki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
New Mexico ◽  
Phase Contrast ◽  
Electron Tomography ◽  
Phase Contrast Imaging ◽  
Contrast Imaging ◽  
Transmission Electron ◽  
Cryo Electron Tomography

Extended abstract of a paper presented at Microscopy and Microanalysis 2008 in Albuquerque, New Mexico, USA, August 3 – August 7, 2008

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