Regensburg 2004 – wissenschaftliches Programm
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DS: Dünne Schichten
DS 22: Postersitzung
DS 22.62: Poster
Dienstag, 9. März 2004, 14:30–17:00, Poster B
Cu-induced nanostructures and thin layer phases on VSe2 crystals — •S. Hollensteiner, E. Spiecker, and W. Jäger — Technische Fakultät der CAU zu Kiel
Self-assembled networks of linear nanostructures formed on surfaces of transition metal dichalcogenides by metal deposition have attracted much interest because of their potential for technological applications. This contribution summarizes new results of detailed analytical TEM studies of the surface phenomena occurring for the early stages of UHV copper deposition (nominal coverage ≤ 2.5 nm) by electron beam evaporation onto cleaved layered VSe2 crystals. We found that at higher coverages (≥ 1 nm) beside uniform networks of linear nanostructures of smaller lateral dimension (∼ 20 nm) with mainly hexagonal meshes on substrate terraces in addition to the large nanostructures develop. Beside this nanostructures a thin layer phases (thickness ≈ few nm) could be detected inside the meshes. Our results reveal that the surface layers consist of a copper-rich crystalline phase with three orientation domains of a nearly commensurate superstructure with regard to the VSe2 lattice. In addition a dense network of dislocations has been found at the interface between substrate and the thin layer phases. We suppose that the copper deposition induces compressive in-plane strains in the top-most VSe2 surface layers, resulting from the formation of a Cu-rich crystalline phase by intercalation, with possible contributions of an electronic charge transfer from copper to the substrate during the earliest deposition stages.