Application of Scanning Confocal Electron Microscopy to Nanomaterials and the Improvement in Resolution by Image Processing

2011 ◽  
Vol 675-677 ◽  
pp. 259-262
Author(s):  
X. Zhang ◽  
Masaki Takeguchi ◽  
Ayako Hashimoto ◽  
Kazutaka Mitsuishi ◽  
Masayuki Shimojo
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Spherical Aberration ◽  
Depth Resolution ◽  
Dark Field ◽  
Nanometer Scale ◽  
Bright Field ◽  
Probe Size ◽  
Annular Dark Field ◽  
Vertical Probe

Scanning confocal electron microscopy (SCEM) is a novel technique for threedimensional observation with a nanometer-scale resolution. Annular dark field (ADF) SCEM imaging has been demonstrated to have better depth resolution than bright field (BF) SCEM imaging. However, the depth resolution of ADF-SCEM images is limited by the vertical probe size determined by spherical aberration and convergence angle. Therefore, we attempted to employ a deconvolution image processing method to improve the depth resolution of SCEM images. The result of the deconvolution process for vertically sliced SCEM images showed the improvement in the depth resolution by 35-40%.

Improvement of Depth Resolution of ADF-SCEM by Deconvolution: Effects of Electron Energy Loss and Chromatic Aberration on Depth Resolution

2012 ◽  
Vol 18 (3) ◽  
pp. 603-611 ◽  
Author(s):  
Xiaobin Zhang ◽  
Masaki Takeguchi ◽  
Ayako Hashimoto ◽  
Kazutaka Mitsuishi ◽  
Meguru Tezuka ◽  
...  
Keyword(s):  
Energy Loss ◽  
Electron Energy ◽  
Spherical Aberration ◽  
Depth Resolution ◽  
Chromatic Aberration ◽  
Dark Field ◽  
Probe Size ◽  
Two Factors ◽  
Annular Dark Field ◽  
Electron Energy Loss

AbstractScanning confocal electron microscopy (SCEM) is a new imaging technique that is capable of depth sectioning with nanometer-scale depth resolution. However, the depth resolution in the optical axis direction (Z) is worse than might be expected on the basis of the vertical electron probe size calculated with the existence of spherical aberration. To investigate the origin of the degradation, the effects of electron energy loss and chromatic aberration on the depth resolution of annular dark-field SCEM were studied through both experiments and computational simulations. The simulation results obtained by taking these two factors into consideration coincided well with those obtained by experiments, which proved that electron energy loss and chromatic aberration cause blurs at the overfocus sides of the Z-direction intensity profiles rather than degrade the depth resolution much. In addition, a deconvolution method using a simulated point spread function, which combined two Gaussian functions, was adopted to process the XZ-slice images obtained both from experiments and simulations. As a result, the blurs induced by energy loss and chromatic aberration were successfully removed, and there was also about 30% improvement in the depth resolution in deconvoluting the experimental XZ-slice image.

Imaging properties of bright-field and annular-dark-field scanning confocal electron microscopy

2010 ◽  
Vol 111 (1) ◽  
pp. 20-26 ◽  
Author(s):  
K. Mitsuishi ◽  
A. Hashimoto ◽  
M. Takeguchi ◽  
M. Shimojo ◽  
K. Ishizuka
Keyword(s):  
Electron Microscopy ◽  
Dark Field ◽  
Bright Field ◽  
Annular Dark Field ◽  
Imaging Properties

Possibility of Single Atom Resolution in Single-Sideband Imaging

1977 ◽  
Vol 35 ◽  
pp. 16-17
Author(s):  
K. H. Downin
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Phase Contrast ◽  
Dark Field ◽  
Single Atom ◽  
Bright Field ◽  
Heavy Atoms ◽  
Single Atoms ◽  
Single Sideband ◽  
Light Components

The ability to distinguish between heavy and light components of a specimen, and especially to distinguish single heavy atoms, would be a great benefit in many instances. Even with the demonstrated ability of the STEM, and of the CTEM especially in dark field, to image single atoms, it is of interest to know the possibility of using bright field in a conventional microscope with subsequent image processing to obtain images of single heavy atoms separated from the image of a lighter supporting film.Single-sideband image reconstruction, involving the combination of two images obtained using opposite halves of the diffraction pattern, offers in principle the ability to separate images of heavy and light specimen components, or specimen components giving rise to amplitude and phase contrast, respectively. This has been demonstrated in electron microscopy^, but under conditions or low resolution, where inelastic scattering, as well as scattering outside the effective objective aperture, contribute heavily to the component with amplitude contrast.

Annular Dark-Field Transmission Electron Microscopy for Low Contrast Materials

2013 ◽  
Vol 19 (3) ◽  
pp. 629-634 ◽  
Author(s):  
F. Leroux ◽  
E. Bladt ◽  
J.-P. Timmermans ◽  
G. Van Tendeloo ◽  
S. Bals
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Soft Matter ◽  
Signal To Noise Ratio ◽  
Dark Field ◽  
Bright Field ◽  
Low Contrast ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Imaging Mode

AbstractImaging soft matter by transmission electron microscopy (TEM) is anything but straightforward. Recently, interest has grown in developing alternative imaging modes that generate contrast without additional staining. Here, we present a dark-field TEM technique based on the use of an annular objective aperture. Our experiments demonstrate an increase in both contrast and signal-to-noise ratio in comparison to conventional bright-field TEM. The proposed technique is easy to implement and offers an alternative imaging mode to investigate soft matter.

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.

Atomic resolution Z-contrast imaging of bulk crystal surfaces in Scanning Reflection Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 414-415
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Dark Field ◽  
Contrast Imaging ◽  
Crystal Lattices ◽  
Small Probe ◽  
Scanning Transmission ◽  
Annular Dark Field ◽  
Image Position ◽  
Z Contrast

The success of obtaining atomic-number-sensitive (Z-contrast) images in scanning transmission electron microscopy (STEM) has shown the feasibility of imaging composition changes at the atomic level. This type of image is formed by collecting the electrons scattered through large angles when a small probe scans across the specimen. The image contrast is determined by two scattering processes. One is the high angle elastic scattering from the nuclear sites,where ϕNe is the electron probe function centered at bp = (Xp, yp) after penetrating through the crystal; F denotes a Fourier transform operation; D is the detection function of the annular-dark-field (ADF) detector in reciprocal space u. The other process is thermal diffuse scattering (TDS), which is more important than the elastic contribution for specimens thicker than about 10 nm, and thus dominates the Z-contrast image. The TDS is an average “elastic” scattering of the electrons from crystal lattices of different thermal vibrational configurations,

Systematic zone-Axis orientation of NM-scale particles for microdiffraction

1990 ◽  
Vol 48 (4) ◽  
pp. 262-263
Author(s):  
E D Boyes ◽  
L Hanna
Keyword(s):  
Real Space ◽  
Dark Field ◽  
Zone Axis ◽  
High Symmetry ◽  
Lattice Imaging ◽  
Cell Level ◽  
Bright Field ◽  
Axis Orientation ◽  
Annular Dark Field ◽  
Target Designation

A VG HB501 FEG STEM has been modified to provide track whilst tilt [TWIT] facilities for controllably tilting selected and initially randomly aligned nanometer-sized particles into the high symmetry zone-axis orientations required for microdiffraction, lattice imaging and chemical microanalysis at the unit cell level. New electronics display in alternate TV fields and effectively in parallel on split [+VTR] or adjacent externally synchronized screens, the micro-diffraction pattern from a selected area down to <1nm2 in size, together with the bright field and high angle annular dark field [HADF] STEM images of a much wider [˜1μm] area centered on the same spot. The new system makes it possible to tilt each selected and initially randomly aligned small particle into a zone axis orientation for microdiffraction, or away from it to minimize orientation effects in chemical microanalysis. Tracking of the inevitable specimen movement with tilt is controlled by the operator, with realtime [60Hz] update of the target designation in real space and the diffraction data in reciprocal space. The spot mode micro-DP and images of the surrounding area are displayed continuously. The regular motorized goniometer stage for the HB501STEM is a top entry design but the new control facilities are almost equivalent to having a stage which is eucentric with nanometric precision about both tilt axes.

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