Investigations of C60 molecules deposited on Si(111) by noncontact atomic force microscopy

We demonstrated the high resolution imaging of the organic molecules using noncontact atomic force microscopy in ultrahigh vacuum. The sample was C-60 molecules deposited on the Si(lll)-7 x 7 reconstructed surface. When the thickness of the C-60 film was submonolayer, we could image some isolated C-60 molecules and the reconstructed Si surface simultaneously. However, the imaging was highly unstable not only because of the large structure but also due to the large difference between the interaction forces on the molecules and on the Si surface. On the other hand, when the thickness of the C60 molecules was almost monolayer, individual molecules could be stably imaged. (C) 1999 Published by Elsevier Science B.V. All rights reserved.