Advanced Computing in Electron Microscopy

Kirkland, Earl J.

doi:10.1007/978-1-4757-4406-4

Cited by 563 publications

(406 citation statements)

References 0 publications

Supporting

Mentioning

399

Contrasting

Unclassified

Order By: Relevance

“…Analysis of electron diffraction data was performed by 2D-gaussian fitting of (102) diffraction spot from experiment, which showed streaking in a*-direction ( Figure 2). Comparison of fitting data with Multislice simulations [5] of electron diffraction patterns and structure factor calculations allowed us to compute the average MFI domain size and MEL content within the 2D zeolite nanosheets. In this study, we observed the prevalence of MEL-type defect in a targeted synthetic route for MFI-type framework suggesting a dynamic growth process, which requires precise control and further understanding of chemical synthesis [6].…”

mentioning

confidence: 99%

Characterization of MEL defects in 2 - Dimensional MFI nanosheets

et al. 2017

View full text Add to dashboard Cite

MFI-type zeolite is a microporous silicon-oxygen framework that has been important for several decades due to its o-/p-xylene separation properties in petroleum industry. In 1980s, significant TEM characterization work was done on large-sized MFI-type zeolite crystals, leading to imaging and electrondiffraction studies of its crystal structure, identification of defects and detection of MEL intergrowth within the MFI framework [1][2]. Since then, development of novel synthesis techniques has enabled the creation of 2-dimensional MFI nanosheets [3][4], while development of aberration corrected TEM has pushed the resolution limit of electron microscopes. Capitalizing on these scientific advancements, we revisit the problem of MEL intergrowth within MFI framework by characterizing this defect at the atomic scale in 2-dimensional nanosheets using aberration corrected TEM.Electron-diffraction and BF-TEM data was collected on [010] oriented MFI zeolite nanosheets using FEI Tecnai G2 F30 (S)TEM equipped with TWIN pole piece (Cs=2 mm) and a Schottky field emission electron gun operating at 300 kV. HAADF-STEM imaging was performed on aberration corrected FEI Titan 60-300 (S)TEM, equipped with FEI SuperX EDX detector, operating at 200 kV.Analysis of experimental data was performed by developing new image processing algorithm constituting radial weiner filtering and cross-correlation to identify the MFI and MEL unit cell in BF-TEM and HAADF-STEM mode (Figure 1a-c). These unit cell images were used as templates in a matching algorithm developed to obtain the spatial distribution of MEL within MFI framework (Figure 1d). Analysis of electron diffraction data was performed by 2D-gaussian fitting of (102) diffraction spot from experiment, which showed streaking in a*-direction (Figure 2). Comparison of fitting data with Multislice simulations [5] of electron diffraction patterns and structure factor calculations allowed us to compute the average MFI domain size and MEL content within the 2D zeolite nanosheets. In this study, we observed the prevalence of MEL-type defect in a targeted synthetic route for MFI-type framework suggesting a dynamic growth process, which requires precise control and further understanding of chemical synthesis [6].

show abstract

mentioning

confidence: 99%

Characterization of MEL defects in 2 - Dimensional MFI nanosheets

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Our image formation model includes three main steps in electron microscopy: electron-specimen interaction, the optical system, and the recording process [44][45][46].…”

Section: Image Formationmentioning

confidence: 99%

The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections

Chen¹,

Goris

Bleichrodt

et al. 2014

Ultramicroscopy

View full text Add to dashboard Cite

a b s t r a c tIn electron tomography, the fidelity of the 3D reconstruction strongly depends on the employed reconstruction algorithm. In this paper, the properties of SIRT, TVM and DART reconstructions are studied with respect to having only a limited number of electrons available for imaging and applying different angular sampling schemes. A well-defined realistic model is generated, which consists of tubular domains within a matrix having slab-geometry. Subsequently, the electron tomography workflow is simulated from calculated tilt-series over experimental effects to reconstruction. In comparison with the model, the fidelity of each reconstruction method is evaluated qualitatively and quantitatively based on global and local edge profiles and resolvable distance between particles. Results show that the performance of all reconstruction methods declines with the total electron dose. Overall, SIRT algorithm is the most stable method and insensitive to changes in angular sampling. TVM algorithm yields significantly sharper edges in the reconstruction, but the edge positions are strongly influenced by the tilt scheme and the tubular objects become thinned. The DART algorithm markedly suppresses the elongation artifacts along the beam direction and moreover segments the reconstruction which can be considered a significant advantage for quantification. Finally, no advantage of TVM and DART to deal better with fewer projections was observed.

show abstract

“…Frozen-phonon multislice code modified from Kirkland (1998) The column ratio was calculated for 16 dumbbells across the centre of the interface supercell at thicknesses of 5nm, 15nm and 30nm. Simulated parameters were chosen to match the SuperSTEM 1 probe and the experimental conditions.…”

Section: Experiments and Simulation Detailsmentioning

confidence: 99%

Characterisation of InAs/GaAs short period superlattices using column ratio mapping in aberration-corrected scanning transmission electron microscopy

Robb

Finnie

Craven

2012

Micron

View full text Add to dashboard Cite

. (2012) Characterisation of InAs/GaAs short period superlattices using column ratio mapping in aberration-corrected scanning transmission electron microscopy. Micron, 43 (10 AbstractThe image processing technique of column ratio mapping was applied to aberration-corrected high angle annular dark field (HAADF) images of short period MBE (molecular beam epitaxy) grown InAs/GaAs superlattices. This method allowed the Indium distribution to be mapped and a more detailed assessment of interfacial quality to be made. Frozen-phonon multislice simulations were also employed to provide a better understanding of the experimental column ratio values. It was established that ultra-thin InAs/GaAs layers can be grown sufficiently well by MBE. This is despite the fact that the Indium segregated over 3-4 monolayers. Furthermore, the effect of the growth temperature on the quality of the layers was also investigated. It was demonstrated that the higher growth temperature resulted in a better quality superlattice structure.

show abstract

Advanced Computing in Electron Microscopy

Cited by 563 publications

References 0 publications

Characterization of MEL defects in 2 - Dimensional MFI nanosheets

Characterization of MEL defects in 2 - Dimensional MFI nanosheets

The properties of SIRT, TVM, and DART for 3D imaging of tubular domains in nanocomposite thin-films and sections

Characterisation of InAs/GaAs short period superlattices using column ratio mapping in aberration-corrected scanning transmission electron microscopy

Contact Info

Product

Resources

About