Epitaxy at the organic-inorganic interface

We describe an X-ray diffraction study of the epitaxy of organic thin films on well-defined inorganic substrates. These include alkyl-thiol monolayers (''self-assembled monolayers'') and films of PTCDA (3, 4, 9, 10 perylenetetracarboxylic dianhydride) on Au(111) surfaces. Although each of these films are grown by very different methods (liquid phase self-assembly, versus molecular beam epitaxy), we find that the molecular degrees of freedom have an important impact upon the film structure and its dependence upon the him thickness. We discuss the generality of these observation for organic/inorganic growth systems.