AFM Contact Mode

Atomic Force Microscopy contact mode

in the drawing, the vertical axis is deflection of tips which represents force and the other axis is sample-cantilever distance.

When the tip approaches the sample,first attractive forces act. When close enough, the tip snaps onto the surface in the equilibrium distance. when the cantilever is approached further, the tip stays in the equilibrium distance (=contact), while the beam is deflected according to its force constant.

The typical type of cantilever used in contact mode is CSC17 series(made by Mikromasch) with the following specifications :

Contilever

length

width

Thickness

Resonant FrequencyKHz Typical

Force Constant N/m Typical

 

µ

µ

µ

 

 NC15/AlBS

460

50

2.0

12 

0.15 

Osilloscope window is an additional features of Ara research software. During approach the oscilloscope can be watched in order to check approaching process is being properly performed. Any of many data channels maybe selected and watched. for instance in the figure The black line is the movement of the z-piez, the red one is T-B signal and green is L-R.

Obtained images ara TopoFwd(1), T-BFwd(2) and L-RFwd (3) are shown :

Atomic Force Microscopy contact mode