Berlin 2012 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 30: Thin film characterization: structure analysis and composition (TEM, LEED, PAS)

DS 30.2: Vortrag

Donnerstag, 29. März 2012, 09:45–10:00, H 0111

Structural investigations of ferecrystals [(SnSe)_1+x]_m[TaSe₂]₁ by transmission electron microscopy — •Corinna Grosse¹, Ryan Atkins², Holm Kirmse¹, Wolfgang Neumann², and David C. Johnson² — ¹AG TEM, Humboldt-Universität zu Berlin, 10099 Berlin, Germany — ²Department of Chemistry, University of Oregon, Eugene OR 97401-3753, USA

Ferecrystals are a new kind of layered materials with an unusual, turbostratically disordered structure. Layered materials can have structural and physical properties which differ from those of bulk compounds. Structural investigations of the materials are necessary to gain an insight into the mechanisms which can influence their physical properties. The new family of ferecrystals [(SnSe)_1+x]_m[TaSe₂]₁ with m = 1, 3, and 6 was investigated by various methods of transmission and scanning transmission electron microscopy (TEM/STEM), including selected area electron diffraction (SAED) and energy-dispersive X-ray spectroscopy (EDXS). The high-resolution TEM and STEM images show in-plane crystallinity, atomically abrupt interfaces and turbostratic disorder in the [(SnSe)_1+x]_m[TaSe₂]₁ ferecrystals. Certain layer-to-layer orientations appear prevalently, suggesting local ordering between the different types of layers in parts of the ferecrystals. The SAED patterns show an increase in ordering with increasing index m. The chemical composition of the layers was determined by means of EDXS.