Geometric and Electronic Structure of Templated C60 on Diindenoperylene Thin Films

The structural order of C-60 thin films is shown to be significantly improved by inserting a templating layer of diindenoperylene (DIP) between the SiO2 substrate and C-60. In contrast to growth on an amorphous substrate like SiO2, C-60 grown on DIP exhibits alignment of fcc-domains with the (111) plane parallel to the substrate and a significant increase of the coherent in-plane island size by a factor of similar to 4. Modification of the structural quality of the DIP bottom layer leads to a change in structural order in the C-60 top layer. In addition, ultraviolet photoelectron spectroscopy data from templated and nontemplated C-60 films are discussed. In contrast to other anisotropic organic molecules, for C-60 the spectral broadening and density of states of the highest occupied molecular orbital region do not depend significantly on the structural order in the C-60 film, which can be rationalized by the isotropic shape of the C-60 molecule.