INTERFACE STRUCTURE OF FLUORINE-GRAPHITE INTERCALATION COMPOUNDS STUDIED BY ATOMIC-FORCE MICROSCOPY

Atomic force microscopy (AFM) has been used to study the interface str ucture of stage-1 and stage-2 fluorine-graphite intercalation compound s (CXF) synthesized under the gaseous HF. The results obtained are sum marized as follows; (1) It is difficult to prepare the atomically-flat surfaces of the stage-1 CXF by cleaving. (2) We have recognized a wel l ordered 2 x root 3 and 1 x root 3 superlattice structures of fluorin e atoms with twofold symmetry on the cleaved surfaces of the stage-1 C XF synthesized from natural graphite. This suggests that the 1 x 1 ord ered structure and the new 1 x root 3 superlattice structure of fluori ne atoms coexist in the interface of the stage-1 CXF. (3) Only the gra phitic surface structure has been observed on the cleaved surfaces of the stage-2 CXF. This suggests that the cleavage occurs at the graphit e layer having the weak bonds preferentially. (4) We have found that t he force between the tip of AFM and a sample surface for the intercala nt layer of CXF is larger than that for the graphite layer.