Atomic scale protection using fullerene encapsulation

The use of fullerene multilayers as a removable protective coating on a cle an, reconstructed semiconductor surface has been investigated using an ultr ahigh vacuum scanning tunneling microscope (UHV-STM). We have found that th e Ag/Si(111)-root 3x root 3R30 degrees surface, which is normally stable on ly under an UHV environment, can survive exposure to ambient conditions ben eath a protective layer of C-60. The C-60 capping layer may be removed by a nnealing after reinsertion into UHV. For optimum protection a thickness >5 monolayers is required. The protective effect lasts for times of order seve ral minutes. (C) 2001 American Institute of Physics.