Instruction manual

Electric Force (EFM) Imaging

Electric Field Gradient Detection—Procedures

Rev. B MultiMode SPM Instruction Manual 257

3. Mount a metal-coated NanoProbe cantilever into the electric field cantilever holder. MFM-

style cantilevers (225µm long, with resonant frequencies around 70kHz) usually work well.

It is also possible to deposit custom coatings on model FESP silicon TappingMode

cantilevers. Make sure that any deposited metal you use adheres strongly to the silicon

cantilever.

4. Set up the AFM as usual for TappingMode operation. In the Channel panels, be certain all

Highpass and Lowpass filters are Off. Set the Rounding parameter in the Microscope >

Calibrate > Scanner window to zero (0.00).

5. Select View > Cantilever Tune.

6. Follow the instructions below for the type of electric force imaging desired, Phase Detection

or Amplitude Detection.

14.4.1 Phase Detection

Phase Detection is only available when the Basic Extender Module has been correctly conﬁgured

into the system.

• In the Cantilever Tune window, set Start frequency and End frequency to appropriate

values for your cantilever (e.g., for 225µm MFM cantilevers, set Start frequency to

40kHz and End frequency to 100kHz). Select Autotune.

•Two curves appear on the Cantilever Tune graph: the amplitude curve in white, and the

phase curve in yellow. (In Figure 14.4e, the phase curve is the dashed line and the

amplitude curve is the solid line).

Figure 14.4b Phase detection Cantilever Tune

(for systems with the Basic Extender Module installed)

The phase should decrease with increasing frequency and cross the center line (90° point) at the

peak frequency. The phase curve then correctly reﬂects the phase lag between the drive voltage and

the cantilever response. Again, gradients in the electric force will cause a shift ∆F

in the resonance

frequency. In this case, resonance shifts give rise to phase shifts ∆φ which can then give an image of

the electric force gradients; see Figure 14.4c.