Sj. Chey et al., Interface bonding and manipulation of Ag and Cu nanocrystals on Si(111)-(7x7)-based surfaces, PHYS REV B, 59(24), 1999, pp. 16033-16041
Clusters of pure Ag, pure Cu, and mixed Ag-Cu were grown on solid Xe at 50
K. Subsequent desorption of the Xe buffer layers delivered the nanocrystals
to pristine Si(111)-(7 x 7). Imaging with scanning tunneling microscopy sh
owed that these structures ranged in size from 100 to 40000 atoms. We inves
tigated their interactions and bonding with the surface, and attempted to m
anipulate them on the surface using the tip of the scanning tunneling micro
scope. Silver nanocrystals could be pushed by mechanical contact, and they
left behind a Ag track due to site-selective Ag-atom transfer to the surfac
e. Copper nanocrystals could not be moved but they could be sheared by tip
contact. Composite Ag-Cu nanocrystals could be pushed on Si(lll) for low Cu
contents, though adhesive interactions with the surface tended to separate
the constituents. These results are discussed in terms of the bonding with
the surface, the tendency to form necks with the tip, and the dynamics of
particle movement. For Ag nanostructures, we also examined interface format
ion and manipulation on Ag(111), on Si(111)-(root 3 x root 3) Ag, and on Br
-exposed and adsorbate-decorated Si(111)-(7 x 7). [S0163-1829(99)06224-4].