Basic Principle Of Tappingmode; Figure 7.1A Tapping Cantilever In Free Air; Figure 7.1B Tapping Cantilever On Sample Surface. Note Deflection Of Cantilever And Return Signal (Exaggerated) - Veeco 004-210-000 Instruction Manual

TappingMode AFM

Basic Principle of TappingMode

7.1 Basic Principle of TappingMode
Figure 7.1a
excites the cantilever substrate vertically, causing the tip to bounce up and down. As the cantilever
bounces vertically, the reflected laser beam is deflected in a regular pattern over a photodiode array,
generating a sinusoidal electronic signal. The signal is converted to a root mean square (RMS)
amplitude value, which is displayed in volts on the topmost (TappingMode Output Signal) meter
located on the front of the MultiMode base.
Figure 7.1b
continues to excite the cantilever's substrate with the same energy, the tip is deflected in its
encounter with the surface. The reflected laser beam (return signal) reveals information about the
vertical height of the sample surface and some characteristics of the sample material itself. These
material characteristics may include elasticity (hardness), magnetic and/or electric forces present.
Figure 7.1b Tapping cantilever on sample surface. Note deflection of cantilever and return signal (exaggerated).
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represents a cantilever oscillating in free air at its resonant frequency. A piezo stack
represents the same cantilever at the sample surface. Although the piezo stack

Figure 7.1a Tapping Cantilever in Free Air

Laser beam
Cantilever
Return signal
Laser beam
Return signal
(deflected)
MultiMode SPM Instruction Manual
Sample surface
Rev. B