TappingMode AFM

This chapter details procedures for operating the Dimension Icon SPM in TappingMode in air. For information regarding TappingMode in fluids, see Fluid Imaging.

Figure 1, below, depicts a cantilever oscillating in free air at its resonant frequency. A piezo stack excites the cantilever substrate vertically, causing the cantilever to move up and down. As the cantilever moves vertically, the reflected laser beam, or “return signal,” deflects in a regular pattern over a photodiode array, generating a sinusoidal, electronic signal.

Figure 1: Cantilever oscillating in free air

Figure 2 represents the same cantilever at the sample surface. Although the piezo stack continues to excite the cantilever substrate with the same energy, the tip deflects in its encounter with the surface. The reflected laser beam reveals information about the vertical height of the sample surface and characteristics of the sample material itself. These material characteristics include elasticity, magnetism, and presence of electrical forces.

Figure 2: Cantilever oscillating in intermittent contact with the sample surface

TappingMode Operations

• Basic TappingMode Operation
• Advanced TappingMode AFM Operation
• In addition, Interleave Scanning and LiftMode techniques most commonly make use of TappingMode

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