STM INVESTIGATION AND MANIPULATION OF C-60 MOLECULES ADSORBED ON AN SI(111) SURFACE

We have used an ultra-high-vacuum (UHV) scanning tunnelling microscope (STM) to image C-60 molecules adsorbed on a Si(111) 7 x 7 surface. At low coverage (similar to 0.01 monolayers) molecules are adsorbed at r andom sites. For coverages close to a monolayer they are partially ord ered in a hexagonal arrangement. Second- and higher-layer islands, in which the C-60 molecules are clearly resolved, are observed at higher coverage. These islands may be desorbed by annealing in the range 200- 300 degrees C, leaving an Si surface terminated by a C-60 monolayer. T his surface is stable to exposure to air and immersion in water. in ad dition, recent work on manipulation of C-60 molecules at various cover ages is reviewed and results relating to tip alignment in UHV are disc ussed.