Abstract:
A novel mechanism is described which enables the selective formation of three-dimensional Ge islands.
Submonolayer adsorption of Ga on Si(111) at high temperature leads to a self-organized two-dimensional
pattern formation by separation of the 7 7 substrate and Ga=Si 111 -
3
p
3
p
R30 domains.
The latter evolve at step edges and domain boundaries of the initial substrate reconstruction. Subsequent
Ge deposition results in the growth of 3D islands which are aligned at the boundaries between bare and
Ga-covered domains. This result is explained in terms of preferential nucleation conditions due to a
modulation of the surface chemical potential.