| 1. |
- Bovin, J O, et al.
(författare)
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TEM-tomography of FAU-zeolite crystals containing Pt-clusters
- 1996
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Ingår i: Ultramicroscopy. - : Elsevier BV. - 0304-3991. ; 62:4, s. 81-277
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Tidskriftsartikel (refereegranskat)abstract
- A method for preparing ultrathin sections (- 20 nm) of inorganic solids has been developed using ultramicrotomy of resin-embedded crystal fragments. Undamaged crystals, oriented along a crystallographic direction, could be imaged with transmission electron microscopy (TEM) at a resolution better than 0.5 nm. The true internal structure of the crystals could be investigated by imaging the second in a series of at least three consecutive ultrathin sections. Such TEM-tomography proved that Pt-ion exchanged FAU zeolite crystals, after reduction and oxidation, are occupied internally and randomly of large platinum clusters mainly in the {111-twin planes. TEM-tomography could be useful in man made nanostructures like semiconductors, epitaxial thin films, hard metal coatings, ceramics, catalysts, and biomaterials.
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| 2. |
- Henning, P, et al.
(författare)
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Compositional information from amorphous Si-Ge multilayers using high-resolution electron microscopy imaging and direct digital recording
- 1996
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Ingår i: Ultramicroscopy. - 0304-3991. ; 66:3-4, s. 221-235
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Tidskriftsartikel (refereegranskat)abstract
- A simple method for extracting compositional information from high-resolution electron microscopy images of an amorphous two-element system using a slow-scan CCD camera has been developed. The method has been evaluated on amorphous Si/Ge multilayers. The characterisation of the multilayers provided information about thickness of the layers, maximum concentrations within the layers and elemental profiles across the boundaries. It was shown that the intensity profiles could be corrected for the wedge shape of the specimen and that the derived compositional profile was independent of average sample thickness variation within the range of the cross-section sample thickness.The results have been compared to analysis performed by Auger electron spectroscopy depth profiling on as-prepared multilayers as well as by energy-dispersive X-ray analysis and electron energy filtered images of cross-sections. The proposed HREM image contrast evaluation method gave spatial resolution in chemical analysis across the thin layers comparable in accuracy to the other methods, whereas the oscillation amplitude for the concentration is slightly less due to specimen preparation artifacts.
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| 3. |
- Hertz, H.M, et al.
(författare)
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Optically trapped non-linear particles as probes for scanning near-field optical microscopy
- 1995
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Ingår i: Ultramicroscopy. - 0304-3991. ; 57:2-3, s. 309-312
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Tidskriftsartikel (refereegranskat)abstract
- We use the frequency doubled light from an optically trapped lithium niobate particle for non-intrusive scanning near-field optical microscopy. The detected power from this 50-100 nm diameter probe is currently tens of pW and is expected to approach nW with an improved detection system. The current experimental resolution is approximately 0.5 [mu]m, while the ultimate theoretical resolution is 70-90 nm. An acoustic trap which potentially allows higher resolution imaging is briefly described.
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| 4. |
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