scholarly journals Study of Point Spread in the Aberration-Corrected Transmission Electron Microscopy

2014 ◽  
Vol 20 (5) ◽  
pp. 1447-1452 ◽  
Author(s):  
Binghui Ge ◽  
Yumei Wang ◽  
Yunjie Chang ◽  
Yuan Yao
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atomic Number ◽  
Spherical Aberration ◽  
Peak Width ◽  
Small Width ◽  
Point Spread ◽  
Transmission Electron ◽  
Aberration Corrected

AbstractHigh precision determination of atomic position is necessary for quantitative electron microscopy so that small width of peaks, which represent atoms in structural images, adequate resolution, and sufficiently strong image contrast are needed. The width of peak is usually determined by the point spread (PS) of instruments, but the PS of objects should also be taken into consideration in aberration-corrected transmission electron microscopy when point resolution of a microscope reaches the sub-angstrom scale, and thus the PS of the instrument is comparable with that of the object. In this article, PS is investigated by studying peak width with variation of atomic number, sample thickness, and spherical aberration coefficients in both negative Cs (NCSI) and positive Cs imaging (PCSI) modes by means of dynamical image simulation. Through comparing the peak width with various atomic number, thickness, and values of spherical aberration, NCSI mode is found to be superior to PCSI considering the smaller width.

The New Paradigm of Transmission Electron Microscopy

MRS Bulletin ◽  
2007 ◽  
Vol 32 (11) ◽  
pp. 946-952 ◽  
Author(s):  
Knut W. Urban
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Materials Science ◽  
Spherical Aberration ◽  
High Temperature Superconductors ◽  
Research Society ◽  
New Paradigm ◽  
Point Spread ◽  
Transmission Electron ◽  
Aberration Corrected

AbstractThe following article is based on the Von Hippel Award address given by Knut W. Urban, chair of experimental physics at RWTH Aachen University and director of the Institute of Microstructure Research within the Department of Solid-State Research at the Jülich Research Center. Urban presented his award talk on November 29, 2006, during the 2006 Materials Research Society Fall Meeting in Boston. He was recognized with MRS's highest honor, the Von Hippel Award, for his “sustained contributions to the development and use of electron microscopy, and for major discoveries in the defect physics of quasicrystals and high-temperature superconductors.” The Von Hippel Award honors those qualities most prized by materials scientists and engineers—brilliance and originality of intellect, combined with vision that transcends the boundaries of conventional scientific disciplines, as exemplified by the life of Arthur von Hippel (http://vonhippel.mrs.org).In this article, Urban describes the advances in spherical-aberration-corrected electron optics that have set transmission electron microscopy on an entirely new track in materials science. The new imaging theory for aberration-corrected instruments is based on exploiting both lens focus and spherical aberration as variable parameters to optimize contrast, resolution, and point spread. The novel negative-spherical-aberration imaging technique makes it possible to image low-nuclear-charge atoms, which were previously inaccessible directly by electron microscopy. This technique has proven particularly successful for research on oxides. Due to negligible point spread, quantitative measurements of atomic-site occupancies, which are equivalent to local concentrations, have become feasible. These improvements are dramatically expanding the potential of electron microscopy for quantitative studies in materials science.

From Nanoparticles to Process: An Aberration-Corrected TEM Study of Fischer-Tropsch Catalysts at Various Steps of the Process

2011 ◽  
Vol 324 ◽  
pp. 197-200 ◽  
Author(s):  
Nadi Braidy ◽  
Carmen Andrei ◽  
Jasmin Blanchard ◽  
Nicolas Abatzoglou
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Amorphous Carbon ◽  
Spherical Aberration ◽  
Fischer Tropsch ◽  
Ft Synthesis ◽  
Transmission Electron ◽  
Treatment Step ◽  
Aberration Corrected

χThe nanostructure of Fischer-Tropsch (FT) Fe carbides are investigated using aberration-corrected high-resolution transmission electron microscopy (TEM). The plasma-generated Fe carbides are analyzed just after synthesis, following reduction via a H2 treatment step and once used as FT catalyst and deactivated. The as-produced nanoparticles (NPs) are seen to be abundantly covered with graphitic and amorphous carbon. Using the extended information limit from the spherical aberration-corrected TEM, the NPs could be indexed as a mixture of NPs in the θ-Fe3C and χ–Fe5C2 phases. The reduction treatment exposed the NPs by removing most of the carbonaceous speSubscript textcies while retaining the χ–Fe5C2. Fe-carbides NPs submitted to conditions typical to FT synthesis develop a Fe3O4 shell which eventually consumes the NPs up to a point where 3-4 nm residual carbide is left at the center of the particle. Subscript textVarious mechanisms explaining the formation of such a microstructure are discussed.

scholarly journals Atomic-Scale Characterization of Metals and Alloys Using Spherical-Aberration Corrected Scanning Transmission Electron Microscopy

2006 ◽  
Vol 12 (S02) ◽  
pp. 1344-1345
Author(s):  
D Williams ◽  
M Watanabe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Spherical Aberration ◽  
Atomic Scale ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Scale Characterization ◽  
Aberration Corrected

Extended abstract of a paper presented at Microscopy and Microanalysis 2006 in Chicago, Illinois, USA, July 30 – August 3, 2006

Fine structural features of nanoscale zero-valent iron characterized by spherical aberration corrected scanning transmission electron microscopy (Cs-STEM)

The Analyst ◽  
2014 ◽  
Vol 139 (18) ◽  
pp. 4512-4518 ◽  
Author(s):  
Airong Liu ◽  
Wei-xian Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Spherical Aberration ◽  
Zero Valent Iron ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Nanoscale Zero Valent Iron ◽  
Scanning Transmission ◽  
Aberration Corrected

An angstrom-resolution physical model of nanoscale zero- valent iron (nZVI) is generated with a combination of spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) and energy-dispersive X-ray spectroscopy (EDS).

Negative spherical aberration ultrahigh-resolution imaging in corrected transmission electron microscopy

2009 ◽  
Vol 367 (1903) ◽  
pp. 3735-3753 ◽  
Author(s):  
Knut W. Urban ◽  
Chun-Lin Jia ◽  
Lothar Houben ◽  
Markus Lentzen ◽  
Shao-Bo Mi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Phase Contrast ◽  
State Of The Art ◽  
Spherical Aberration ◽  
Transmission Electron ◽  
Resolution Imaging ◽  
Physical Background ◽  
Structure Of Matter ◽  
Aberration Corrected

Aberration-corrected transmission electron microscopy allows us to image the structure of matter at genuine atomic resolution. A prominent role for the imaging of crystalline samples is played by the negative spherical aberration imaging (NCSI) technique. The physical background of this technique is reviewed. The especially high contrast observed under these conditions owes its origin to an enhancing combination of amplitude contrast due to electron diffraction channelling and phase contrast. A number of examples of the application of NCSI are reviewed in order to illustrate the applicability and the state-of-the-art of this technique.

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