Phase imaging: Deep or superficial?

Phase images acquired while intermittently contacting a sample surface with the tip of an atomic force microscope cantilever are not easy to relate to material properties. We have simulated dynamic force curves and compared s imulated with experimental results. For some cantilever-sample combinations , the interaction remains a surface effect, whereas for others, the tip pen etrates the sample significantly. Height artifacts in the "topography" imag es, and the role of the sample stiffness, work of adhesion, damping, and to pography in the cantilever response manifest themselves to different extent s depending on the indentation depth. (C) 1999 American Institute of Physic s. [S0003- 6951(99)03143-5].