More Than Moore
NEMS and MEMS
Atomic force microscopy (AFM) is an influential surface analysis technique used for micro/nanostructured coatings. This flexible technique can be used to obtain high-resolution nanoscale images and study local sites. The Atomic Force Microscope (AFM) is the indispensable instrument for the entire field of nanoscience and nanotechnology. The AFM enables its users coming from research and commercial nanotechnology businesses to investigate materials on an atomic scale. Therefore, whenever and wherever nanotechnology achieves a breakthrough and opens new markets, AFM technology is sure to be involved in that process.
Contact and Non-Contact Modes
There are two primary modes of operation for an atomic force microscope, namely contact mode and non-contact mode depending on whether the cantilever vibrates during the operation. In contact mode, the cantilever drags across the sample surface and it uses the deflection of the cantilever to measure the contours of the surface. To eliminate the noise and drift that can affect a static signal, low stiffness cantilevers are used, but this allows strong attractive forces to pull the tip to the surface. To eliminate this attraction, the tip is in contact with the surface where the overall force is repulsive.
In non-contact mode, the tip vibrates slightly above its resonance frequency and does not contact the surface of the sample. Any long-range forces, like van der Waals forces, decreases the resonant frequency of the cantilever. A feedback loop system helps to maintain the oscillation amplitude constant by changing the distance from the tip to the sample. Recording the distance between the tip and sample at each point allows the software to construct a topographic image of the sample surface.