Zero-loss imaging

Angert I, Majorovits E and Schroder R R 2000 Zero-loss image formation and modified contrast transfer theory of EFTEM Ultramicroscopy 8 203-22... 

Figure 11. The HRTEM micrograph of VO2 4.(C16H33NH2)0.34 nanotubes (a rolled up superlattice of V205 layers separated by amphiphilic moities with amine head group) (39). (a) Side-on view of three nanotubes with unclosed caps and (b) cross-section of the nanotubes left zero-loss (electron energy) image, right vanadium (electron energy loss) image. [Courtesy of F. Krumeich and R. Nesper, ETH.]...

Porat et al. performed TEM (zero-loss bright field) studies of very thin Nation films that were cast from ethanol/water solutions, and some of the conclusions are as follows. It was suggested that the backbone had a planar zigzag conformation in large orthorhombic crystallites as in polyethylene, in contrast with the helical conformation found in poly(tetra-fluoroethylene). This is an interesting result, although there are no other studies that support this view. Sulfur imaging indicated the presence of sulfonate clusters that are 5 nm in size. 

Figure 14.6 Zero-loss energy-filtered transmission electron microscopy images of MDMO-PPV PCNEPV blends with low (a), medium (b), and high (c) molecular weights of PCNEPV.(Reprinted with permission from Ref [53]. Copyright 2007, Wiley-VCH VerlagCmbH.)...

Figure 1.57 Improvement of contrast and resolution of a stained 400 nm thick ABS section produced by zero-loss filtering in an EFTEM (b) compared to global mode imaging (a)...

Zero-loss filtering Both BF TEM images and diffraction patterns contain inelastically scattered electrons. The number of inelastic electrons increases with the increase of specimen thickness and they cause a diffuse background. Using a narrow sUt width (for example, 5 eV) at the ZLP, this filters out the majority of inelastic electrons and thus significantly improves the image contrast. 

Analysis of the energy distribution of electrons that have passed through the specimen (EELS) is used in an energy-filtered transmission electron microscopy (EFTEM). EFTEM offers a powerful tool for the chemical analysis of materials at the nanometer scale. On the other hand, the mode of zero-loss filtering, where only the unscattered and elastically scattered electrons contribute to the image, enhance the conttast and improve the resolution by avoiding... 

Figure 4.8 Zero-loss filtered TEM images of thin MDMO-PPV PCNEPV blend film samples, (a) Sample 1 with low (3500 g mol" ) PCNEPV derivative,...

This equation shows that only limited information is preserved. In particular, depending on the spatial frequency Mo, no information is transferred at all at the zeroes of the phase-contrast function sin(x). The loss of information is even more serious when the phase object approximation holds and for ideal imaging in that case the phase information is completely lost in the Gaussian image of the object and special methods the so-called phase-contrast [94,95] methods should be employed in order to partly recover this information. 

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