Atomic Force Microscopy (AFM) in the Nanotechnology Lab

Most nanotechnology labs will have two kinds of microscopes for viewing materials at the nano level — the scanning electron microscope (SEM) and the atomic force microscope (AFM).

Both the SEM and the AFM are easy to use and therefore have become ubiquitous in labs that work with nanomaterials. The AFM has higher resolution than the SEM, but the SEM can look at a much larger area of a sample, so the two types of instruments complement each other nicely.

If you need an image of the surface of a sample at atomic resolution and don’t need to look at the sample’s internal structure, the AFM is particularly handy.

The AFM contains a tip attached to a cantilever, similar to the needle used in record players. The tip in an AFM is tiny, less than a nanometer in width. You aim a laser at the cantilever and as the AFM tip moves up and down as it scans across the surface of the sample, the position of the laser beam on the detector shifts.

Diagram of an atomic force microscope.
Diagram of an atomic force microscope.

This method generates a topographical image of the surface with sufficient resolution to determine the position of individual atoms.

Topography produced using an AFM.
Topography produced using an AFM.
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