Materials analysis by aberration-corrected STEM

2004 ◽  
Vol 839 ◽  
Author(s):  
Ondrej L. Krivanek ◽  
Neil J. Bacon ◽  
George C. Corbin ◽  
Niklas Dellby ◽  
Andrew McManama-Smith ◽  
...  
Keyword(s):  
Spherical Aberration ◽  
Dark Field ◽  
Optical Aberration ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Powerful Research Tool ◽  
Electron Microscopes ◽  
Electron Energy Loss ◽  
Aberration Corrected

ABSTRACTElectron-optical aberration correction has recently progressed from a promising concept to a powerful research tool. 100–120 kV scanning transmission electron microscopes (STEMs) equipped with spherical aberration (Cs) correctors now achieve sub-Å resolution in high-angle annular dark field (HAADF) imaging, and a 300 kV Cs-corrected STEM has reached 0.6 Å HAADF resolution. Moreover, the current available in an atom-sized probe has grown by about 10x, allowing electron energy loss spectroscopy (EELS) to detect single atoms. We summarize the factors that have made this possible, and outline likely future progress.

Design of a new objective lens for an HB-501A STEM

1991 ◽  
Vol 49 ◽  
pp. 416-417
Author(s):  
Earl J. Kirkland ◽  
Robert J. Keyse
Keyword(s):  
High Resolution ◽  
Spherical Aberration ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Objective Lens ◽  
Specimen Holder ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
High Resolution Microscopy

An ultra-high resolution pole piece with a coefficient of spherical aberration Cs=0.7mm. was previously designed for a Vacuum Generators HB-501A Scanning Transmission Electron Microscope (STEM). This lens was used to produce bright field (BF) and annular dark field (ADF) images of (111) silicon with a lattice spacing of 1.92 Å. In this microscope the specimen must be loaded into the lens through the top bore (or exit bore, electrons traveling from the bottom to the top). Thus the top bore must be rather large to accommodate the specimen holder. Unfortunately, a large bore is not ideal for producing low aberrations. The old lens was thus highly asymmetrical, with an upper bore of 8.0mm. Even with this large upper bore it has not been possible to produce a tilting stage, which hampers high resolution microscopy.

scholarly journals Atomic structural catalogue of defects and vertical stacking in 2H/3R mixed polytype multilayer WS2 pyramids

Nanoscale ◽  
2019 ◽  
Vol 11 (22) ◽  
pp. 10859-10871
Author(s):  
Gyeong Hee Ryu ◽  
Jun Chen ◽  
Yi Wen ◽  
Si Zhou ◽  
Ren-Jie Chang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Aberration Corrected

We examine the atomic structure of chemical vapour deposition grown multilayer WS2 pyramids using aberration corrected annular dark field scanning transmission electron microscopy coupled with an in situ heating holder.

Microstructure and interdiffusion behaviour of β-FeSi2 flat islands grown on Si(111) surfaces

2013 ◽  
Vol 46 (4) ◽  
pp. 1076-1080
Author(s):  
Sung-Pyo Cho ◽  
Yoshiaki Nakamura ◽  
Jun Yamasaki ◽  
Eiji Okunishi ◽  
Masakazu Ichikawa ◽  
...  
Keyword(s):  
Scanning Transmission Electron Microscopy ◽  
Single Phase ◽  
Spherical Aberration ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Abrupt Interface ◽  
Average Size ◽  
20 Nm

β-FeSi2 flat islands have been fabricated on ultra-thin oxidized Si(111) surfaces by Fe deposition on Si nanodots. The microstructure and interdiffusion behaviour of the β-FeSi2/Si(111) system at the atomic level were studied by using spherical aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and energy dispersive X-ray spectroscopy. The formed β-FeSi2 flat islands had a disc shape with an average size of 30–150 nm width and 10–20 nm height, and were epitaxically grown on high-quality single-phase Si with a crystallographic relationship (110)β-FeSi2/(111)Si and [001]β-FeSi2/[1\bar 10]Si. Moreover, the heterojunction between the β-FeSi2(110) flat islands and the Si(111) substrate was an atomically and chemically abrupt interface without any irregularities. It is believed that these results are caused by the use of ultra-thin SiO2 films in our fabrication method, which is likely to be beneficial particularly for fabricating practical nanoscaled devices.

Aberration-Corrected STEM: the Present and the Future

2001 ◽  
Vol 7 (S2) ◽  
pp. 896-897
Author(s):  
O.L. Krivanek ◽  
N. Dellby ◽  
P.D. Nellist ◽  
P.E. Batson ◽  
A.R. Lupini
Keyword(s):  
Spherical Aberration ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Objective Lens ◽  
High Angle ◽  
Successful Operation ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Full Speed ◽  
Aberration Corrected

Surprising as it may seem, aberration correction for the scanning transmission electron microscope (STEM) is now a practical proposition. The first-ever commercial spherical aberration corrector for a STEM was delivered by Nion to IBM Research Center in June 2000, and other deliveries have taken place since or are imminent. At the same time, the development of corrector hardware and software is still proceeding at full speed, and our understanding of what are the most important factors for the successful operation of a corrector is deepening continuously.Fig. 1 shows two high-angle dark field (HADF) images of [110] Si obtained with the IBM VG HB501 STEM operating at 120 kV, about 2 weeks after we fitted a quadrupole-octupole corrector into it. Fig. 1(a) shows the best HADF image that could be obtained with the corrector's quadrupoles on but its octupoles off. Sample structures were captured down to about 2.5 Å detail, easily possible in a STEM with a high resolution objective lens with a spherical aberration coefficient (Cs) of 1.3 mm. Fig. 1(b) shows a HADF image obtained after the Cs-correcting octupoles were turned on and the corrector tuned up. The resolution has now improved to 1.36 Å. This is sufficient to resolve the correct separation of the closely-spaced Si columns.

Atomic Ordering and Disordering of Amorphous CoNiP Alloy

2018 ◽  
Vol 386 ◽  
pp. 377-382
Author(s):  
Evgenii V. Pustovalov ◽  
Alexander F. Fedorets ◽  
Vladimir V. Tkachev ◽  
Vladimir S. Plotnikov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electron Energy Loss ◽  
Temperature Heating ◽  
Thermal Stability Of

The structure of electrolytically deposited nanocrystalline alloys of the CoP-CoNiP systems under low-temperature heating was investigated by means of high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF STEM), and analytical methods such as energy dispersive x-ray spectroscopy (EDS) and electron energy loss spectroscopy (EELS). Structural relaxation and crystallization were investigated at temperatures from 150°C to 300°C. Structural and compositional inhomogeneities were found in the CoP-CoNiP alloys, while the local changes in composition were found to reach 15 at.%. Nanocrystals in the alloys grew most intensely in the presence of a free surface. It was determined that the local diffusion coefficient ranged from 1.2 to 2.4 10−18 m2/s, which could be explained by the surface diffusion prevalence. The data gathered in these investigations can be further used to predict the thermal stability of CoP-CoNiP alloys.

Analytical High-Resolution TEM Study on Au/TiO2 Catalysts

1999 ◽  
Vol 589 ◽  
Author(s):  
T. Akita ◽  
K. Tanaka ◽  
S. Tsubota ◽  
M. Haruta
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Transmission Electron Microscope ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
High Resolution Tem ◽  
Electron Energy Loss

AbstractHRTEM(High-Resolution Transmission Electron Microscope), HAADF-STEM (High Angle Annular Dark Field Scanning Transmission Electron Microscope) and EELS(Electron Energy Loss Spectroscopy) techniques were applied for the characterization of Au/TiO2 catalysts. HAADFSTEM provides precise size distributions for Au particles smaller than ∼2nm in diameter. It was observed that many small particles under 2nm were supported on anatase TiO2 having a large surface area. The HAADF-STEM method was examined as a way to measure the shape of Au particles. EELS measurements were also used to examine the interface between Au and TiO2 support to study electronic structure effects.

Microscopic Examination of SiO2/4H-SiC Interfaces

2011 ◽  
Vol 679-680 ◽  
pp. 330-333 ◽  
Author(s):  
Tetsuo Hatakeyama ◽  
Hirofumi Matsuhata ◽  
T. Suzuki ◽  
Takashi Shinohe ◽  
Hajime Okumura
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Scanning Transmission Electron Microscopy ◽  
Dark Field ◽  
Rich Region ◽  
Spatially Resolved ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Electron Energy Loss

SiO2/4H-SiC interfaces are examined by high-resolution transmission electron microscopy (HRTEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and spatially resolved electron energy-loss spectroscopy (EELS). HRTEM and HAADF-STEM images of SiO2/4H-SiC interfaces reveal that abrupt interfaces are formed irrespective of the fabrication conditions. Transition regions around the interfaces reported by Zheleva et al. were not observed. Using EELS, profiles of the C/Si and O/Si ratios across an interface were measured. Our measurements did not reveal a C-rich region on the SiC side of the interface, which was reported by Zheleva et al.

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