Contact mode is the basis for all AFM techniques in which the probe tip is in constant physical contact with the sample surface. While the tip scans along the surface, the sample topography induces a vertical deflection of the cantilever. A feedback loop maintains this deflection at a preset load force and uses the feedback response to generate a topographic image.
Contact mode is suitable for materials science, biological applications and basic research. It also serves as a basis for further SPM techniques that require direct tip-sample contact