Identification And Control Of Adsorption Geometry Of Indiviual Fullerene On Si Surface At Room-Temperature

The adsorption properties of individual fullerene molecules on Si(Ⅲ)-7×7 surface at room-temperature have been investigated by scanning tunneling microscopy. Statistical analysis of the images demonstrates that fullerene molecules prefer to adsorbing on five specific sites:corner hole, the middle of the faulted and unfaulted parts, and the top of the rest atoms within the faulted and unfaulted parts. High-resolution images of individual fullerene molecules on each of the adsorption sites show distinct intramolecular structures. By combining these internal fine structures with theoretical simulations, the molecular orientations at each of the adsorption sites can be unambiguously determined. Have the same orientation of the fullerene molecules adsorbed with a fixed angle, this phenomenon shows that there are many equivalent adsorption states in the specific sites for fullerenes.Controlling the adsorption geometry of single molecule has been achieved by putting metal atoms or clusters close to the location of the molecule. Our STM observations clearly show that the adsorption geometries of fullerene molecules on Si(Ⅲ)-(7×7) surface are significantly influenced by the adsorption of silver atoms or clusters close to the adsorption sites of the molecules. Such influences strongly depend on the distance between the Ag atom or cluster and the molecules and the number of silver atoms. Once the silver atom or cluster close to a molecule is stripped by STM tip, the adsorption geometry of this molecule resumes the same as that before the adsorption of Ag, further confirming the feasibility and reversibility of controlling the status of single molecule by adding metal atom or cluster.