Original source: Wikipedia
An atomic force microscope (AFM) is a type of very high resolution scanning probe microscope, which can measure fractions of the nanometer, more than 1000 times better than the optical diffraction limit.
The forerunner of the AFM, the tunnel effect microscope (STM), was developed by Gerd Binnig and Heinrich Rohrer in the early 1980s at the IBM Research Center – Zurich, a progress that earned them the Nobel Prize in Physics in 1986 Binnig, Quate and Gerber invented the first atomic force microscope in 1986. The first commercially available atomic force microscope appeared in 1989.
The AFM is one of the most important tools for preparing topographic maps of matter on a nanometric scale. The information is collected by scanning detecting the molecular and atomic forces that act on a tip located on the surface of the material studied. The piezoelectric elements, which allow small but exact movements in the electronic control, make very precise scanning possible. In some variations, electrical potentials can also be measured using conductive micro-levers. In newer and more advanced versions, it is even possible to measure the electrical conductivity of the underlying surface by transmitting electrical current through the tip, but this method is more difficult and there are few research groups that present reliable data with this system.