Understanding the structure of Si nanoclusters in a/nc-Si:H films using spherical aberration-corrected transmission electron microscopy

2004 ◽  
Vol 808 ◽  
Author(s):  
Christopher R. Perrey ◽  
Siri S. Thompson ◽  
Markus Lentzen ◽  
Uwe Kortshagen ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spherical Aberration ◽  
Objective Lens ◽  
Transmission Electron ◽  
Si Nanoparticles ◽  
Twin Defects ◽  
Si Films ◽  
Hydrogenated Amorphous ◽  
Aberration Corrected

ABSTRACTRecent work has shown that the electrical properties of hydrogenated amorphous Si films with nanocrystalline inclusions (a/nc-Si:H) make this material a promising candidate for applications in solar cells. The present study applies the technique of spherical aberration-corrected high-resolution transmission electron microscopy for the identification and analysis of the crystalline content of an a/nc-Si:H film. By varying both the spherical aberration of the objective lens and the defocus, regions of crystallinity in the a/nc-Si:H film can be identified. This study reports the analysis of Si nanoparticles of approximately 1.5 nm in size. Some of these nanoparticles contain planar defects, such as twin defects and stacking faults. All particles observed were the same crystal structure as bulk Si, which agrees with theoretical cluster calculations. Beam damage was observed in the amorphous matrix for long electron–beam exposures.

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.

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.

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