Prerequisites and Specifications for Sub Ångström Low-Voltage Transmission Electron Microscopy (SALVE) operation for investigating nano-scale properties of beam-sensitive objects (SALVE III)
Zusammenfassung der Projektergebnisse
We report on advances in sample preparation, imaging theory, instrumentation and application for low-voltage microscopy and spectroscopy. We developed further sample preparation for ultra-thin lamellas of classical materials (semiconductors, layered systems, ceramics, and metal oxides) by FIB techniques as well as for low-dimensional materials by graphene-sandwiches or carbon nanotube-confining. With regard to image theory we used a modified calculation approach and showed that graphene can be treated as a weak-phase object when imaged at a voltage of 80kV, but not at 20kV. As most of our samples cannot accept an infinitely high dose, a procedure for dose-dependent calculations has been developed and can now be applied to electron-beam-sensitive materials. We also considered inelastic scattering and an improved way has been developed for energy-filtered TEM image calculation based on the mutual coherence function. We carried out specification tests of the TEM instruments including the newly developed aberration corrector. However, because of the withdrawal of Zeiss from TEM development and the SALVE project, we had to concentrate on the existing (unfinished) tool and could test only a few proposed specifications. Furthermore, we successfully developed and refined calibration methods for momentum-resolved electron energy-loss spectroscopy on the SALVE I machine. With respect to developing the SALVE application field in the range of 20 to 80 kV, we focused in two different directions: we obtained new insight in the dynamics of phase transformation, defect formation and metal-carbon bond formation as well as into the structure of the amorphous phase when operating the machine at 80kV. However, when working at 20kV, we aimed to understand the pristine structure of the material.
Projektbezogene Publikationen (Auswahl)
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“Effects of residual aberrations explored on singlewalled carbon nanotubes” Ultramicroscopy 116 (2012) 1
Biskupek J, Hartel P, Haider M, Kaiser U
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“Improved Focused Ion Beam Target Preparation of (S)TEM Specimen - A Method for Obtaining Ultrathin Lamellae”, Microsc. Microanalysis 18 (2012) 379
Lechner L, Biskupek J, Kaiser U
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“Interactions and Reactions of Transition Metal Clusters with the Interior of Single-Walled Carbon Nanotubes Imaged at the Atomic Scale" J. Am. Chem. Soc. 134 (2012) 3073
Zoberbier T, Chamberlain TW, Biskupek J, Kuganathan N, Bichoutskaia E, Eyhusen S, Kaiser U, Khlobystov AN
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“High-energy collective electronic excitations in free-standing single-layer graphene” Phys. Rev. B88 (2013) 075433
Wachsmuth P, Hambach R, Kinyanjui MK, Guzzo M, Benner G, Kaiser U
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“Imaging Atomic Rearrangements in Two-Dimensional Silica Glass: Watching Silica’s Dance” Science 342 (2013) 224
Huang PY, Kurasch S, Alden JS, Shekhawat A, Alemi AA, McEuen PL, Sethna JP, Kaiser U, Muller DA
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„Atomic scale study of the life cycle of a dislocation in graphene from birth to annihilation” Nature Communications 4 (2013) 2098
Lehtinen O, Kurasch S, Krasheninnikov AV, Kaiser U
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„The pristine atomic structure of MoS2 monolayer protected from electron radiation damage by graphene” Appl. Phys. Lett. 103 (2013) 203107
Algara-Siller G, Kurasch D, Sedighi M, Lehtinen O, Kaiser U
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„Dry cleaning of graphene”, Appl. Phys. Lett. 104 (2014) 153115
Algara-Siller G., O. Lehtinen, A. Turchanin, U. Kaiser
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„Electron dose dependence of signal-to-noise ratio, atom contrast and resolution in transmission electron microscope images” Ultramicroscopy (2014)
Lee Z, Rose H, Lehtinen O, Biskupek J, Kaiser U
