  We computed by a Monte Carlo method the thermal relaxation of a
polycrystalline thin film deposited on a Penrose lattice. The thin film was
modelled by a 2 dimensional array of elementary domains, which have each a
given height. During the Monte Carlo process, the height of each of these
elementary domains is allowed to change as well as their crystallographic
orientation. After equilibrium is reached at a given numerical temperature, all
elementary domains have changed their orientation into the same one and small
islands appear, preferentially on the domains of the Penrose lattice located in
the center of heptagons. This method is a new numerical approach to study the
influence of the substrate and its defects on the islanding process of
polycrystalline films.
