ATOMIC-FORCE MICROSCOPIC STUDY ON THE MOLECULAR ARRANGEMENT OF HIGHLYCONDUCTIVE LB FILMS OF METAL(DMIT)2

The atomic force microscope (AFM) was used to obtain the images of the LB film of tridecylmethylammonium-Au(dmit)2 complex mixed with icosan oic acid. A single-layered sample of the as-deposited LB film revealed a heterogeneous structure with very thin plate-like crystallites of t he order of mum distributed in the film surface. The height of the cry stallite was about 18 nm measured from the planar region in which a mo nolayer of icosanoic acid was assumed to be present. This thickness co rresponded to a stacking of ca. 10 molecules of Au(dmit)2 with each of the molecular plane almost parallel to the film surface, taking into account the molecular arrangement in a single crystal. No epitaxial de position was observed for a multilayered sample, which was shown by th e almost random stacking of the plate-like crystallites. The AFM image changed with the electrochemical oxidation that was necessary to make the film conductive. The blurring of the outline of the plate-like cr ystallites was observed, suggesting a structural change of the crystal lites accompanied by the electrochemical oxidation.