User`s guide

Additional Imaging Modes 7

Agilent 5500 SPM User’s Guide 131

Choose Controls > Advanced > AC Mode. The EFM Controls

window will open (Figure 88).

Figure 88 EFM Controls window

7 In the Main tab, set up the Lock-in 1 AC signal which drives the

cantilever oscillation:

a Set the Drive% to 10 %.

b Set the Gain to x1 (the amplitude times 1).

8 Choose Controls > AC Mode Tune to open the AC Mode Tune

window.

9 Tune the drive signal to the resonance frequency of the cantilever:

a In the AC Mode Tune window, enter the Start and End

frequencies (in kHz) for the tuning sweep, typically 20-120 kHz.

b Set the Peak Amplitude to 2.5 volts.

c Enter an Off Peak value to offset the oscillation frequency from

the cantilever’s resonance frequency. A typical value is

-0.100 kHz.

d Click the Auto Tune button. The system will sweep through the

range of frequencies, locating the peak oscillation amplitude

within the range. The AC signal oscillation will be set to this

value plus the specified Offset.

NOTE

Q Control can be used with EFM Mode to improve the resonance peak

and image quality. See Chapter 6 for more on Q-Control.