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Vanrompay H, Skorikov A, Bladt E, Béché A, Freitag B, Verbeeck J, Bals S. Fast versus conventional HAADF-STEM tomography of nanoparticles: advantages and challenges. Ultramicroscopy 2020; 221:113191. [PMID: 33321424 DOI: 10.1016/j.ultramic.2020.113191] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/30/2020] [Accepted: 12/06/2020] [Indexed: 11/24/2022]
Abstract
HAADF-STEM tomography is a widely used experimental technique for analyzing nanometer-scale structures of a large variety of materials in three dimensions. It is especially useful for studying crystalline nanoparticles, where conventional TEM tomography suffers from diffraction-related artefacts. Unfortunately, the acquisition of a HAADF-STEM tilt series can easily take up one hour or more, depending on the complexity of the experiment. It is therefore challenging to investigate samples that do not withstand long electron beam illumination or to acquire a large number of tilt series during a single TEM experiment. The latter would facilitate obtaining more statistically representative 3D data, and enable performing dynamic in situ 3D characterizations with a finer time resolution. Various HAADF-STEM acquisition strategies have been proposed to accelerate the tomographic acquisition and reduce the required electron dose. These methods include tilting the holder continuously while acquiring a projection "movie" and a hybrid, incremental, methodology which combines the benefits of the conventional and continuous technique. However, until now an experimental evaluation of these techniques has been lacking. In this paper, the different acquisition strategies will be experimentally compared in terms of speed, resolution and electron dose. This evaluation will be performed based on experimental tilt series, acquired for various metallic nanoparticles with different shapes and sizes. We discuss the necessary data processing and provide a general guideline that can be used to determine the most optimal acquisition strategy for specific electron tomography experiments.
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Affiliation(s)
- Hans Vanrompay
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Alexander Skorikov
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Eva Bladt
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Armand Béché
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Bert Freitag
- Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, The Netherlands
| | - Johan Verbeeck
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium
| | - Sara Bals
- Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Belgium.
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Isakozawa S, Baba M, Amano J, Sakamoto S, Baba N. Generalized spot auto-focusing method with a high-definition auto-correlation function in transmission electron microscopy. Microscopy (Oxf) 2019; 68:395-412. [PMID: 31504689 DOI: 10.1093/jmicro/dfz028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 05/19/2019] [Accepted: 05/20/2019] [Indexed: 11/13/2022] Open
Abstract
The spot auto-focusing (AF) method with a unique high-definition auto-correlation function (HD-ACF) proposed in the previous paper is improved and is now applicable to general specimens at a wide range of magnifications. According to the definition where the AF is defocused to obtain the highest resolution, the proposed method achieves the sharpest HD-ACF profile in the AF spot image. The relationship where the sharpest HD-ACF profile gives the highest resolution is theoretically explained, and practical AF examples for different specimens and magnifications are experimentally demonstrated. Specimens include a yeast cell thin section at 10-k magnification, a standard grating replica used as a ruler at 50-k, a crystal lattice of graphitized carbon at 400-k and a 60°-tilted thin section (yeast cell) at 10-k. Different procedures are prepared to actively identify the defocus position that gives the sharpest HD-ACF profile. Every AF result demonstrates the highest-resolution image.
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Affiliation(s)
- Shigeto Isakozawa
- Research Institute for Science and Technology, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015, Japan
| | - Misuzu Baba
- Research Institute for Science and Technology, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015, Japan
| | - Junpei Amano
- Major of Informatics, Graduate School, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015, Japan
| | - Shohei Sakamoto
- Major of Informatics, Graduate School, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015, Japan
| | - Norio Baba
- Major of Informatics, Graduate School, Kogakuin University, 2665-1 Nakano, Hachioji, Tokyo 192-0015, Japan
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Sawada H, Watanabe M, Chiyo I. Ad hoc auto-tuning of aberrations using high-resolution STEM images by autocorrelation function. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2012; 18:705-710. [PMID: 22849799 DOI: 10.1017/s1431927612001304] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A method for measurement of the aberration status from high-resolution dark-field images is developed using scanning transmission electron microscopy (STEM), called the Segmented Image Autocorrelation function Matrix (SIAM). The method employs an autocorrelation function from the segmented area in the defocused STEM images from an aligned crystalline specimen to measure the defocus and twofold astigmatism for the probe-forming system. The values measured using this method can be fed directly back to the instrument by changing the strength of the stigmator and the objective lens of the microscope. It is successfully demonstrated that the feedback system can automatically correct the defocus and twofold astigmatism of the microscope after several iterations using practical STEM images from an actual crystalline specimen.
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Affiliation(s)
- Hidetaka Sawada
- JEOL Ltd., EMBU, 3-1-2 Musashino, Akishima, Tokyo 196-8558, Japan.
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