The atomic force microscope and the scanning tunneling microscope (AFM/STM) are suitable for images with particularly high resolution. The surface is scanned by means of an ultra-fine tip, with minimal force, generating a 3D image of the surface. Lateral resolutions of 1-10 nm and vertical resolutions of less than 1 nm are achieved. Monolayer samples can be resolved. AFM is particularly suitable for characterizing extremely smooth surfaces. Friction microscopy or modulation techniques can also be used to show material contrasts.
The advantage of AFM is that it provides not only a "photo" of the surface, but a complete three-dimensional data set of the surface topography. A great deal of quantitative information can be obtained from this:
The data can also be made available as a 3D data set to the customer for their own evaluations.
The figure shows nanocrystalline platinum particles in an amorphous carbon matrix. The platinum particles have a diameter of just a few nanometers, but appear somewhat enlarged in the image due to folding with the geometry of the scanning tip.
AFM tapping mode image of a polymer surface. Tapping mode is a very low-impact scanning method, with which even soft materials such as polymers can be imaged without damage.