Scanning Tunneling Microscopy of C₆₀ on the Si(111)7×7 Surface

Adsorption of C 60 molecules on the Si(111)7×7 surface was investigated using a field ion-scanning tunneling microscope. C 60 adsorbs preferentially on the faulted half of the 7×7 unit and stays still without rotation at room temperature, implying the reasonably strong interaction with the Si substrate. The internal structure of individual C 60 molecules can be understood if we assume that the C=C double bonds are imaged brightly. Unlike the case of its adsorption on the Si(100)2×1 surface, C 60 do not form ordered mono/multi layers on the 7×7 surface.