Epitaxial growth of copper phthalocyanine monolayers on Ag(111)

Monolayer growth of copper phthalocyanine on Ag(111) has been studied by STM. Three different superlattices with oblique or rectangular unit cells have been identified. The four-fold symmetry of the molecules is maintained for two of the superstructures. For the third, the observed topography indicates a deformation of the molecules, which may be attributed to the interaction with the substrate. Grain boundaries between domains of the same type of superstructure, as well as between domains of different superstructures, have been resolved. The monolayer ordering persists across monoatomic steps of the substrate surface. In some cases these are modified by the interaction with the molecules.