Growth of a uniaxial incommensurate C-60 lattice on Ge(100)2x1

Room temperature adsorption of C-60 On a Gz(100)2 x 1 surface from a few molecules to a full monolayer coverage was studied using scanning tunneling microscopy and low-energy electron diffraction. The distribution of the C-60 molecules at the early stage of adsorption indicates that the molecules dissipate their in-plane kinetic energy primarily through collisions with other bound C-60 molecules, rather than steps and vacancies of the surface. Upon thermalization. the molecules reside exclusively in troughs between dimer rows of the substrate. Clustering of the molecules takes place from outset of the adsorption, and the molecules in clusters adopt either a four-dimer or a two-dimer binding site. Subsequent adsorption proceeds in an orderly fashion, leading to the growth of two-dimensional islands and finally an overlayer with a uniaxial incommensurate C-60 lattice structure. The adsorption of C-60 molecules appears to affect the buckling of the substrate dimers. (C) 1996 American Vacuum Society.