Sample Thickness Determination by Scanning Transmission Electron Microscopy at Low Electron Energies

Volkenandt, Tobias; Müller, Erich; Gerthsen, D.

doi:10.1017/s1431927613013913

Cited by 17 publications

(14 citation statements)

References 29 publications

(35 reference statements)

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“…The thickness of the gutter layer estimated from gas permeation measurements according to Equations (3) to (16) for the studied gases corresponds well to the thickness values determined from SEM micrographs [42] as shown in Table 3: 105 nm for Stamp 1-2 and 150 nm for Stamp 2-2 (Figure 8a,b respectively). If the uncertainty of the porous layer thickness will be taken into account and the thickness δ ps will be reduced by 25% (Scenario 2) the average thickness of the gutter layer δ G will, according to our model, increase from 140 to 150 nm.…”

Section: Resultssupporting

confidence: 77%

Characteristics of Gas Permeation Behaviour in Multilayer Thin Film Composite Membranes for CO2 Separation

et al. 2019

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Porous, porous/gutter layer and porous/gutter layer/selective layer types of membranes were investigated for their gas transport properties in order to derive an improved description of the transport performance of thin film composite membranes (TFCM). A model describing the individual contributions of the different layers’ mass transfer resistances was developed. The proposed method allows for the prediction of permeation behaviour with standard deviations (SD) up to 10%. The porous support structures were described using the Dusty Gas Model (based on the Maxwell–Stefan multicomponent mass transfer approach) whilst the permeation in the dense gutter and separation layers was described by applicable models such as the Free-Volume model, using parameters derived from single gas time lag measurements. The model also accounts for the thermal expansion of the dense layers at pressure differences below 100 kPa. Using the model, the thickness of a silicone-based gutter layer was calculated from permeation measurements. The resulting value differed by a maximum of 30 nm to the thickness determined by scanning electron microscopy.

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Section: Resultssupporting

confidence: 77%

Characteristics of Gas Permeation Behaviour in Multilayer Thin Film Composite Membranes for CO2 Separation

et al. 2019

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“…They differ in the incorporated physical models, the possibilities for sample definition, data exporting, or computed physical characteristics. The principle of quantitative STEM imaging is described in more detail in [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Nanoscale Estimation of Coating Thickness on Substrates via Standardless BSE Detector Calibration

2020

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The thickness of electron transparent samples can be measured in an electron microscope using several imaging techniques like electron energy loss spectroscopy (EELS) or quantitative scanning transmission electron microscopy (STEM). We extrapolate this method for using a back-scattered electron (BSE) detector in the scanning electron microscope (SEM). This brings the opportunity to measure the thickness not just of the electron transparent samples on TEM mesh grids, but, in addition, also the thickness of thin films on substrates. Nevertheless, the geometry of the microscope and the BSE detector poses a problem with precise calibration of the detector. We present a simple method which can be used for such a type of detector calibration that allows absolute (standardless) measurement of thickness, together with a proof of the method on test samples.

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“…The initial marginal interest in low-energy STEM in SEM can be partly attributed to the fact that resolution has been limited to about 1 nm. However, the benefits of the technique have been recognized and this has led to the improvement of the BF-STEM resolution into the sub-nanometer range where lattice fringes with a distance of 0.34 nm and below were resolved (Van Ngo et al, 2007; Michael et al, 2009; Konno et al, 2014). In addition to the improvement of resolution, additional capabilities are necessary to develop STEM in a SEMs into a complete characterization technique for thin specimens.…”

Section: Introductionmentioning

confidence: 99%

On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope

et al. 2018

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Transmission electron microscopy (TEM) with low-energy electrons has been recognized as an important addition to the family of electron microscopies as it may avoid knock-on damage and increase the contrast of weakly scattering objects. Scanning electron microscopes (SEMs) are well suited for low-energy electron microscopy with maximum electron energies of 30 keV, but they are mainly used for topography imaging of bulk samples. Implementation of a scanning transmission electron microscopy (STEM) detector and a charge-coupled-device camera for the acquisition of on-axis transmission electron diffraction (TED) patterns, in combination with recent resolution improvements, make SEMs highly interesting for structure analysis of some electron-transparent specimens which are traditionally investigated by TEM. A new aspect is correlative SEM, STEM, and TED imaging from the same specimen region in a SEM which leads to a wealth of information. Simultaneous image acquisition gives information on surface topography, inner structure including crystal defects and qualitative material contrast. Lattice-fringe resolution is obtained in bright-field STEM imaging. The benefits of correlative SEM/STEM/TED imaging in a SEM are exemplified by structure analyses from representative sample classes such as nanoparticulates and bulk materials.

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Sample Thickness Determination by Scanning Transmission Electron Microscopy at Low Electron Energies

Cited by 17 publications

References 29 publications

Characteristics of Gas Permeation Behaviour in Multilayer Thin Film Composite Membranes for CO2 Separation

Characteristics of Gas Permeation Behaviour in Multilayer Thin Film Composite Membranes for CO2 Separation

Nanoscale Estimation of Coating Thickness on Substrates via Standardless BSE Detector Calibration

On the Progress of Scanning Transmission Electron Microscopy (STEM) Imaging in a Scanning Electron Microscope

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