Growth and decay of hcp-like Cu hut-shaped structures on W(100)

Autor(en): Bollmann, Tjeerd R. J.
van Gastel, Raoul
Wormeester, Herbert
Zandvliet, Harold J. W.
Poelsema, Bene
Stichwörter: AG; COPPER; DIFFRACTION; DIFFUSION; FILMS; Materials Science; Materials Science, Multidisciplinary; Physics; Physics, Applied; Physics, Condensed Matter; SI(001); SURFACE ALLOYS
Erscheinungsdatum: 2012
Volumen: 85
Ausgabe: 12
We have studied both the morphology and structure of thin Cu deposits on W(100) during growth and desorption, using low-energy electron microscopy (LEEM) and selective area low-energy electron diffraction (mu LEED). During growth at 674 K hut-shaped Cu crystallites with steep facets (>54 degrees) coexist with a pseudomorphic Cu monolayer. The mu LEED data suggest that these crystallites predominantly have a hcp structure with a high density of stacking faults and the (11 (2) over bar0) plane parallel to W(100). The boundaries run along the [(1) over bar 50] azimuth on W(100), which is explained by cancellation of shear stress exerted by Cu on the W(100) surface. Upon slow heating, Cu desorbs and the pseudomorphic wetting layer is transformed into coexisting surface alloy patches, with respectively, a Cu-rich p(2 x 2) and p(2 x 1) structure at 815 K. At about 950 K the islands are fully desorbed, leaving p(2 x 1) footprints behind. The p(2 x 2) patches disappear at about 1020 K, resulting in a homogeneous p(2 x 1) surface. Upon continued Cu desorption this surface transforms into small c(2 x 2) domains until all Cu has been desorbed at 1150 K.
ISSN: 10980121
DOI: 10.1103/PhysRevB.85.125417

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