Atomic Force Microscopes(AFM)
Atomic force microscopes (AFM) are one of the most powerful tools for determining surface topography at subnanometer resolution. The technique involves imaging a sample through the use of a probe, or tip, with a radius of 20 nm. The tip is held several nanometers above the surface using a feedback mechanism that measures surface–tip interactions on the scale of nanoNewtons. Variations in tip height are recorded while the tip is scanned repeatedly across the sample, producing a topographic image of the surface.