IMAGING OF LANGMUIR-BLODGETT-FILMS OF C60 BY SCANNING-TUNNELING-MICROSCOPY AND TRANSMISSION ELECTRON-MICROSCOPY

C60 forms very rigid insoluble films at the air-water interface (collapse Pressure The ''area per molecule'' A(o)=21.6 angstrom2 (at zero pressure) and A(c)=11.5 angstrom2 (at PI(c))are smaller than that of a single C60 molecule, and suggest 4 to 7.5 C60 molecules piled atop each other, per ''monolayer''. C60 can be transferred as Langmuir-Blodgett films on glass and HOPG, and Langmuir-Schaefer films on a Cu grid. By ellipsometry of an LB multilayer, the thickness is about 2 molecules per ''monolayer''. STM shows a slightly distorted {013} projection of an face-centered cubic (FCC) pattern of roundish, atomically unresolved peaks, with a cell constant of 14.2 angstrom. The HRTEM micrographs and a selected-area electron diffraction pattern show that, at optimum crystallinity, the C60 molecules pack in an FCC pattern with a=14.20(5) angstrom. No hexagonal structures were found.