Atomic Force Microscopes - Tutorial Page

As described in Section 3.2, the AFM cantilever may be vibrated to measure the force between a probe and surface during an AFM scan. The magnitude of amplitude damping and the amount of phase change of the cantilever depends on the surface chemical composition and the physical properties of the surface. Thus, on an inhomogeneous sample, contrast can be observed between regions of varying mechanical or chemical composition. Typically, in the vibrating material sensing mode, if the amplitude is fixed by the feedback unit, then the contrast of the material is observed by measuring phase changes. This technique has many names including phase mode, phase detection and force modulated microscopy.