The Atomic Force Microscope (AFM) has come a long way in the short time since it's invention in 1986. The "atomic Force" first used to image surfaces was Born repulsion, but soon other forces were used to image surfaces, such as the attractive part of the van der walls force, magnetic and electric forces, and double layer and stearic repulsive forces in liquids. Many modifications have been done to the AFM imaging tips, such as coating with a conductive layer to measure currents or capacitance while imaging. Tips have been coated with specific molecules to give the AFM chemical sensitivity. Others have put ultra-miniature temperature sensors, and even a transistor on the AFM tip.

AFM can be used to draw patterns on surfaces. For example, by simply scratching the surface, or applying an electric field and locally oxidizing or other local chemical transformation of the surface, or by dipping the tip in an "ink" and drawing with that ink on a surface.

In addition to scanning with the tip in continuous contact with the surface, it can be oscillated so it only makes intermittent contact with the surface, or no contact at all. This mode had been used and modified to allow imaging of soft biological materials, and imaging of dopant concentration in semiconductors, just to name two of many.

In short, AFM is a very flexible tool, which seems to be limited only by the imagination of the scientist.

Prof. Manne's lab has also developed a temperature controlled fluid stage for the AFM which allows imaging in fluids from -15 C to 130 C with lattice resolution.

Contact info:
Srin Manne
Physics Dept
PAS 575
520-626-5305
smanne@physics.arizona.edu