SFU 3

SFU 3 Shear Force Unit for ElProScan

Constant distance Scan with Shear Force Unit SFU 3

For decoupling the morphology from the catalytic properties of the sample a distance control is required
which is independent from the measuring signal, the tip current. With a current independent measure
mode for the surface height we get additional information such as the z-coordinate, i. e. the height profile
of our sample.

This can be achieved by measuring the damping of a lateral oscillating tip, during a surface approach. Approaching towards the surface between the lateral oscillating tip causes a shear force between the liquid phase, the tip and the surface of the sample. The oscillation of the tip is dampened as the tip is moved closer to the surface.

A dampening of the amplitude and a shift of the phase of the oscillating tip can be observed BEFORE the
tip hits the surface of the sample. For that reason the distance between the tip and the surface can be
measured AND regulated using the shear force method.

The Shear Force Unit is fully real-time controlled and integrated in the Scan Extension of POTMASTER. All ElProScan Systems can be easily upgraded with a shear force unit. Shear force electrodes are available as an accessory.

The shear force unit is available as integrated part of the ElProScan systens and as stand alone instrument in order to upgrade SECM systems from other suppliers.