How do Atomic Force Microscopy (AFM) and Scanning Tunneling Microscopy (STM) work?
AFM works by scanning a cantilever with a sharp tip over the surface of a sample. The forces between the tip and the sample cause the cantilever to deflect, and these deflections are measured to generate topographic maps of the surface. In contrast, STM relies on quantum tunneling; a voltage is applied between a conductive tip and the sample, allowing electrons to tunnel through the vacuum gap. The resulting tunneling current varies with the distance between the tip and the surface, providing atomic-scale resolution images.
