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Nonequilibrium Interface and Surface Dynamics 2007
Growth and Pattern Formation for Epitaxial
CSIC Building (#406),
Seminar Room 4122.
Growth and Pattern Formation for Epitaxial Surfaces
Growth of an epitaxial thin film involves physics on
both atomistic and continuum length scales. For
example, diffusion of adatoms can be coarse-grained,
but nucleation of new islands and breakup for
existing islands are best described atomistically.
The lattice properties of the film are determined by
those of the underlying substrate. In
heteroepitaxial growth, e.g., Germanium on Silicon,
mismatch between the lattice spacing of the Silicon
substrate and the Germanium film will introduce a
strain into the film, which can significantly
influence the material structure. leading for
example to the formation of quantum dots.
Technological applications of quantum dot arrays
require a degree of geometric uniformity that has
been difficult to achieve. One approach to
overcoming this difficulty is to prepattern the
system, for example with buried dislocation lines.
This talk will describe mathematical modelling,
simulation methods and computational results for
epitaxial growth, strain in thin films and pattern
formation. The growth simulations use an island
dynamics model with a level set simulation method.
Strain computations can be computationally
intensive, so that effective simulation of atomistic
strain effects relies on an accelerated method that
incorporates algebraic multigrid and an artificial
boundary condition. Simulations that combine growth
and strain will be presented showing spontaneous and
directed self-assembly of patterns (quantum dots and
wires) on thin films.