Jul 20, 2010
High-speed atomic force microscope achieves large scan sizes
The atomic force microscope (AFM) is a popular instrument for investigating surfaces on the nanoscale. Despite its many advantages, the imaging speed of conventional AFMs can be slow, with a single image taking up to several minutes to acquire. This restricts applications to the investigation of quasi-static samples.
High-speed AFMs, which are based on new approaches in instrument design, have been shown to achieve about 1000× higher image rates. With image rates of several images/second, high-speed AFMs allow real-time observations of fast dynamic processes, which play an important role in the life sciences.
In a recent study, published in the journal Nanotechnology, a group from the University of Erlangen-Nuremberg, Germany, describes a novel high-speed AFM that exhibits several advantages over previous designs. The unit's main component is a high-speed scanner with a maximum scan size of 23 µm × 23 µm, which is the largest scan size reported to date for a z-feedback-controlled, high-speed AFM. A large sample stage area of 6.5 mm × 6.5 mm allows the convenient handling of larger specimens. The device's xy-piezos are easily exchangeable, allowing small piezos to be used for investigations on the atomic scale. A symmetrical arrangement of xy-piezos enables high-speed imaging at any scan angle. A small z-piezo is used for fast z-feedback control.
Image rates of up to 46 images/second in air and 13 images/second in liquid were reached, corresponding to acquisition times down to 22 ms per image. Sample velocities of 8.8 mm/s in the xy-direction and 11 mm/s in the z-direction were reached for large scan size imaging of collagen fibrils in air with a small cantilever.
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About the author
Christoph Braunsmann and Prof. Tilman E Schäffer are members of the Department of Physics at the University of Erlangen-Nuremberg, Germany.