Z-contrast images acquired during a tilt-series observation, after tilt-axis correction. (a) , (b) , and (c) . The tilt series was observed sequentially from 0° to −70° and then 0° to . The reconstructed area, in size, is also indicated in Fig. 1(a). Large Cu particles are indicated by arrows in Fig. 1(b).
An original image (a), corresponding reconstructed images processed by WBP (b) and SIRT (c), viewed along the axis, which is parallel to the beam incidence direction. Arrows in (b) indicate floating dotlike artifacts. The tilt axis is the axis, about which the specimen film is sequentially tilted.
Reconstructed result of the FePd nanoparticles processed by WBP. The reconstructed volume is . Arrows in the projection indicate the artifacts (hole) inside the nanoparticles. Particle growth direction is also indicated in the projection.
Reconstructed images of the FePd nanoparticles processed by SIRT with 20 iterations. The reconstructed volume is identical to that processed by WBP shown in Fig. 3. SIRT gives a clear 3D morphology without the floating artifacts.
Oblique-view of the reconstructed volume processed by (a) WBP (upper) and (b) SIRT (lower). Large discrepancy in particle thickness (height) is apparent between these two images. Nanoparticles in the upper image show oblate 3D-shapes, while those in the lower images are prolate. The reconstructed volume is .
(a) A series of Z-contrast images taken at different tilt angles. (b) The analyzed particle length in the direction as a function of the tilt angle. The particle length decreases as the tilt angle increases toward 90°, indicating the fact that the particle height is shorter than the diameter. Extrapolation of particle length in the direction to the value expected at the tilt angle leads to an elucidation of the true particle height. Here, the extrapolation was performed by fitting the data points at angles higher than 40° using cosine of the tilt angle.
The relation between particle diameter and thickness (height) for the FePd nanoparticles estimated by using several different techniques. The large error bar for WBP indicates a possible elongation of , as suggested by Eqs. (2) and (3).
Results of the tomographic reconstruction for the as-deposited Fe/Pd nanoparticles. (a) An original Z-contrast image, (b) reconstructed volume ( plane), and (c) that of viewed in an oblique direction.
Article metrics loading...
Full text loading...