The observability of poorly bound powder-like material on hard surface by atomic force microscopy

Various working modes of atomic force microscopy (AFM) are compared as imag ing surfaces with poorly bound, easy-to-displace powder-like material on it . The poorly bound amorphous/turbostratical carbon structures a-re formed b y laser ablation on the top of highly oriented pyrolytic graphite (HOPG) su rface, Working in contact mode, these structures can easily be displaced by the AFM tip. Non-contact (low amplitude resonance) mode experiments proved to be adaptable to image the debris-like material, while tapping amplitude and phase detection mode measurements do not yield proper topographic info rmation of it. On the other hand, tapping modes have the advantages of foll owing the topography of a hard surface even when covered with poorly bound materials. Model calculations describing tip motion and the feedback circui t of the piezo driver confirm the observed phenomena, (C) 2001 Elsevier Sci ence B.V. All rights reserved.