Highly‐Ordered Organic Adsorbates: Commensurate Superstructures, OMBE, and 1D Nanostructures

Big organic molecules deposited by vacuum sublimation on reactive surfaces form highly‐ordered superstructures which are often commensurate to the substrate if covalent, nondissociative bonding occurs. The orientation of the molecules at the interface can be varied depending on reactive groups, substrate surface, and coadsorbates. Deposition of highly‐ordered thin films, or even organic molecular beam epitaxy (OMBE), is difficult but appears possible under certain conditions. Organic nanostructures can be produced by self‐organization of covalentiy‐bound molecules and substrate steps on high‐index surfaces. Experiments with different aromatic molecules like NDCA and PTCDA as well as with oligothiophenes (α4T and EC4T) on various substrates such as Ag(111), Ag(775), Ni(111), and Si(111) are reviewed using a variety of complementary surface sensitive techniques.