Abstract
We have used a scanning tunneling microscope to study the static and dynamic behaviour of Cu, Ag, Au, and Al deposited in situ on highly oriented pyrolytic graphite in an ultra-high vacuum chamber. We have imaged static monomers of Ag, Au, and Al, dimers of Ag and Au, and clusters of 3 or more atoms of Ag, Al, and Au. From the lifetime of the monomers, we estimate the energy barrier against diffusion to be greater than 0.65 eV. We have studied two-dimensional islands of Ag and Au, containing up to 100 atoms, which are atomically resolved against the supporting graphite substrate. The interiors of the islands contain ordered rectangular lattices separated by grain boundaries, while the atoms at the periphery are disordered. We show a small three-dimensional Cu crystal, the decoration of a grain boundary by Cu particles with an average diameter of 44 Å, and two examples of granular films. Finally, we present examples of dynamic processes: the shrinking of a small Au island, the contraction of the lattice spacing of a rectangular two-dimensional Au lattice on a time scale of minutes, and the diffusion of a Ag cluster along a graphite step edge on a time scale of seconds.
Original language | English (US) |
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Pages (from-to) | 33-67 |
Number of pages | 35 |
Journal | Surface Science |
Volume | 219 |
Issue number | 1-2 |
DOIs | |
State | Published - Sep 1 1989 |
Bibliographical note
Funding Information:This work was supported by the Deutsche Forschungsgemeinshaft (K.S.), IBM (E.G.), and the Director, Office of Energy Research, Office of Basic Energy Science, Materials Science Division of the US Department of Energy, under Contract No. DE-AC03-76SF00098.