Piezoelectric Scanners: How They Work
14
Scanning Probe Microscope Training Notebook
Rev. F
7.0
Piezoelectric Scanners: How They Work
SPM scanners are made from piezoelectric material, which expands and contracts proportionally to
an applied voltage.
Whether they elongate or contract depends upon the polarity of the voltage applied. All DI scanners
have AC voltage ranges of +220V to -220V for each scan axis.
Figure 7.0a
The effect of applied voltage on piezoelectric materials.
The scanner is constructed by combining independently operated piezo electrodes for X, Y, & Z
into a single tube, forming a scanner which can manipulate samples and probes with extreme
precision in 3 dimensions.
In some models (e.g. MultiMode SPM) the scanner tube moves the sample relative to the stationary
tip. In other models (e.g., STM, Dimension Series and BioScope SPM’s) the sample is stationary
while the scanner moves the tip.
Figure 7.0b
Typical scanner piezo tube and X-Y-Z configurations. AC Signals applied to conductive areas of
the tube create piezo movement along the three major axes
AC voltages applied to the different electrodes of the piezoelectric scanner produce a scanning
raster motion in X and Y. There are two segments of the piezoelectric crystal for X (X & X) and Y
(Y & Y).
0 V
+ V
- V
No applied voltage
Extended
Contracted
Electrode
Z
Y
Y
X
X
X
X
Y
Y
Z
Metal
Electrode
Piezoelectric
Material
GND
