Atomic Force Microscopy


This powerful tool is used to measure properties of a sample surface.  Properties include roughness, height, depth and force. Yields topographic images and allows structure and detail to be seen with high resolution and without the need for rigorous sample preparation.

Theory of Operation

The system uses a sharp tip on the end of a long cantilever.  In Contact Mode, tip-to-sample spacing is held fixed by maintaining a constant very low force on the cantilever, pushing the tip against the sample.  The force is in the range of inter-atomic forces (about 10E-9N), thus the name “atomic force” microscopy.  The force is low enough to usually cause no damage to the surface being measured.  With tapping mode AFM, contact of the cantilever probes with the sample is minimised, thereby damage to the sample while imaging in minimised.

The vertical motion of the tip as it slides over the sample surface is detected by a beam deflection system that uses a laser shining and reflecting off the back of the cantilever and onto a photodiode.

 Some Typical Uses of AFM in the CMI

  • Used for the microstructural characterisation of biomaterials by analyzing the topography, component distribution and architecture of composites made of collagen and elastin-like polymers.
  • Used to quantitatively study the surface of micro- and nano-structured polymers and metals that had been patterned using various laser techniques.
  • Thin film thickness measurements can pose a significant challenge and it is a parameter that can have significant importance in the microelectronic and biotechnological arenas.  AFM is used to predict the thickness of submicron scale films.

CMI AFM systems:

Dimension 3100 AFM