3. Atomic force microscope and force microscopies

The atomic force microscope (AFM) was developed in 1986 in response to the need to image all types of samples, not just conductors and semiconductors, by probing the forces between the tip and the surface . By measuring and controlling these forces, a suitable microscope should be able to image the surface topography and also study other physical phenomena at the nanometric scale. Based on this objective, the AFM borrows from STM technology the system of nanometric displacements and regulation of the relative tip-surface displacement at constant force (instead of current for the STM)....