Scanning force microscopic images of the Si(111) 7 x 7 surface reconstruction, obtained in the contact mode under ultra-high vacuum conditions, were presented. Topographical and lateral force data were acquired simultaneously. It was found that PTFE treatment of the sensing tip helped to overcome the strong adhesion and wear effects which normally occurred for this particular surface.

L.Howald, R.Lüthi, E.Meyer, P.Güthner, H.J.Güntherodt: Zeitschrift für Physik B, 1994, 93, 267-8