Additional Imaging Modes
5
Keysight 5500 SPM User’s Guide
5-9
Current Sensing AFM (CSAFM)
In Current Sensing AFM (CSAFM) an ultra-sharp AFM cantilever,
coated with conducting film, probes the conductivity and topography of
the sample surface. CSAFM requires a special 10 ° nose cone
containing a pre-amp. A bias voltage is applied to the sample while the
cantilever is kept at virtual ground (
). As in Contact Mode,
the tip force is held constant throughout the scan. The current is used to
construct the Conductivity image.
Figure 7-9
CSAFM schematic
CSAFM is useful for locating defects in thin films, for molecular
recognition studies, and for resolving electronic and ionic processes
across cell membranes. It has proven useful in joint I/V spectroscopy
and contact force experiments as well as contact potential studies.
CSAFM imaging can be used in an ambient environment or under
temperature or environmental control. However, as surface
contamination (especially a moisture layer on the sample surface) can
reduce the clarity of imaging, it is strongly recommended that CSAFM
be completed in a controlled, low humidity environment.
The Keysight multi-purpose scanner can be used with the CSAFM nose
assembly (
) for CSAFM imaging. The nose assembly
includes one of three color-coded preamps for varying sensitivity:
