Structural properties of chlorinated epitaxial C-60 films - art. no. 155401

The interaction of chlorine gas with epitaxially grown C-60 films was inves tigated by combined scanning tunneling microscopy (STM) x-ray photoelectron spectroscopy (XPS) and x-ray absorption spectroscopy (XANES). The STM meas urements of chlorinated fullerene surfaces on VSe2 reveal an inhomogeneous C-60 and chlorine coverage in an area up to 200 nm from the fullerene islan d edges but showed no influence to the fullerene (111) coordination in the inner regions of the layers. In accordance with the STM data the XPS spectr a of C 1s and Cl 2p core levels, which were taken at different emission ang les, provide evidence for chlorine aggregation on the fullerite surface. As valence band and XANES spectra show that all C-60 features derived from th e highest occupied and lowest unoccupied molecular orbitals are preserved, a noncovalent interaction between fullerene and halogen can be concluded. A s monitored by STM subsequent fullerene deposition on the chlorinated sampl es prove the perturbed island areas to serve as growth seeds so that a chlo rine incorporation into the fullerite lattice can be achieved by an alterna ting preparation sequence.