On producing high-spatial-resolution composition profiles via scanning transmission electron microscopy

Hall, Ernest L.; Imeson, D.; Sande, J. B. Vander

doi:10.1080/01418618108239528

Cited by 51 publications

(19 citation statements)

References 15 publications

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“…Models of the probe broadening (Doig & Flewitt, 1982; Doig, et al, 1981; Hall, et al, 1981; Michael & Williams, 1987; Reed, 1982; Reimer & Kohl, 2008) often assume that the broadening can be described by the convolution of the Gaussian incident beam with another Gaussian to give a single Gaussian with the width given by the quadrature of the two Gaussian widths. The underlying thought of this hypothesis is that all electron trajectories are broadened such that the initial beam (unscattered electron) completely disappears.…”

Section: Resultsmentioning

confidence: 99%

“…For the imaging of micrometer-thick samples, the spatial resolution is not limited by the electron optics, as is the case for ultrathin amorphous substrates, but by noise or by beam broadening caused by elastic scattering of the electron beam in the specimen (de Jonge, et al, 2010; Reimer & Kohl, 2008). Analytical expressions were obtained for the lateral width, where the broadening on account of (multiple) electron scattering was regarded as a Gaussian distribution for thin films (Doig & Flewitt, 1982; Doig, et al, 1981; Gentsch, et al, 1974; Hall, et al, 1981; Reimer & Kohl, 2008). However, it is not clear if the Gaussian distribution for the lateral probe shape is still valid for samples much thicker than the mean-free-path-length for elastic scattering.…”

Section: Introductionmentioning

confidence: 99%

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The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

et al. 2012

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Lateral profiles of the electron probe of scanning transmission electron microscopy (STEM) were simulated at different vertical positions in a micrometers-thick carbon sample. The simulations were carried out using the Monte Carlo method in the CASINO software. A model was developed to fit the probe profiles. The model consisted of the sum of a Gaussian function describing the central peak of the profile, and two exponential decay functions describing the tail of the profile. Calculations were performed to investigate the fraction of unscattered electrons as function of the vertical position of the probe in the sample. Line scans were also simulated over gold nanoparticles at the bottom of a carbon film to calculate the achievable resolution as function of the sample thickness and the number of electrons. The resolution was shown to be noise limited for film thicknesses less than 1 μm. Probe broadening limited the resolution for thicker films. The validity of the simulation method was verified by comparing simulated data with experimental data. The simulation method can be used as quantitative method to predict STEM performance or to interpret STEM images of thick specimens.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

et al. 2012

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“…There is ample experimental evidence to support the existence of compositional anisotropy in GB segregation phenomena 16–22 . For example, Bi segregation to grain boundaries in Cu shows differences as large as ±100% in Bi concentration from one grain boundary to another 16 .…”

Section: Discussionmentioning

confidence: 99%

Correlation Between Grain‐Boundary Segregation and Grain‐Boundary Plane Orientation in Nb‐Doped TiO₂

Pang

Wynblatt

2005

Journal of the American Ceramic Society

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Grain‐boundary (GB) segregation has been measured in Nb‐doped TiO2 (rutile) by Auger electron spectroscopy analyses of the two surfaces exposed by inter‐granular fracture. In addition, the orientations of the exposed GB planes on both sides of the fracture surface have been determined. A strong anisotropy of GB composition is found. Measurements on 166 individual GB fracture surfaces show that boundary planes with low and high levels of segregation tend to be clustered along the (110)–(010) and (001)–(011) regions of the stereographic triangle, respectively. The matching halves of GB planes with either high or low segregation also tend to be terminated by planes in the same respective regions of orientation space. High and low levels of segregation occur in regions of GB plane orientation space estimated to correspond to high and low GB energy, respectively. This trend is consistent with qualitative arguments based on Gibbsian adsorption.

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“…The measured concentration needs to be convoluted to derive an 'actual' grain boundary concentration. Following Hall's analysis, 10 the 'actual' grain boundary concentration can be …”

Section: Tem Sample Preparation and Analysismentioning

confidence: 99%

Effect of phosphorus segregation on fracture properties of two quenched and tempered structural steels

Ding¹,

Islam²,

Wu³

et al. 2005

Materials Science and Technology

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Segregation of phosphorus to grain boundaries in commercial grade 2?25Cr1Mo and A533B steels subjected to a variety of heat treatments has been examined using field emission gun scanning transmission electron microscope (FEGSTEM) with energy dispersive X-ray microanalysis. The measured grain boundary P concentrations have been used to explain the low temperature brittle fracture behaviour, which exhibits increasing levels of intergranular embrittlement as a function of aging time at 520uC. The results show that P segregation at grain boundaries has a strong effect on the intergranular area fraction, the microscopic fracture stress, and the fracture toughness. Phosphorus peak height ratios measured using auger electron spectroscopy are shown to follow a linear relationship with the FEGSTEM/X-ray values.

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On producing high-spatial-resolution composition profiles via scanning transmission electron microscopy

Cited by 51 publications

References 15 publications

The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

Correlation Between Grain‐Boundary Segregation and Grain‐Boundary Plane Orientation in Nb‐Doped TiO₂

Effect of phosphorus segregation on fracture properties of two quenched and tempered structural steels

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On producing high-spatial-resolution composition profiles via scanning transmission electron microscopy

Cited by 51 publications

References 15 publications

The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

The Probe Profile and Lateral Resolution of Scanning Transmission Electron Microscopy of Thick Specimens

Correlation Between Grain‐Boundary Segregation and Grain‐Boundary Plane Orientation in Nb‐Doped TiO2

Effect of phosphorus segregation on fracture properties of two quenched and tempered structural steels

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Correlation Between Grain‐Boundary Segregation and Grain‐Boundary Plane Orientation in Nb‐Doped TiO₂