Cantilever flexure, adhesive/attractive and lateral force measurements on highly-oriented pyrolytic graphite by scanning force microscopy

Pre-existing defects in the surface of highly-oriented pyrolytic graphite (HOPG) can be etched out by reaction with oxygen at high temperature. The result of this treatment is a population of one-monolayer-deep etch pits on the surface. An etch pit edge, possessing different chemical terminations than the basal plane of HOPG, may display unique interactions with any nanometer-scale material entity (viz. clusters and molecules) located in its vicinity Since probe tips used in scanning force microscopy (SFM) can possess radii of curvature as small as 5-10 nm, it might be possible to measure the chemical uniqueness of etch pit edges with the help of SFM. In this paper, we consider possible instrumental artefacts which could hinder SPM studies of topography and friction on tailored HOPG surfaces for which there is a spatial variation in chemical properties. We conclude by discussing evidence for enhanced friction (approximate to 100%) and adhesion (approximate to 20%) at etch pit edges. (C) 1998 Elsevier Science Ltd. All rights reserved.