21-12-2012, 03:15 PM
AFM instrument system
AFM instrument system.pdf (Size: 11.28 MB / Downloads: 187)
BASIC IMAGING PROCEDURE
Acquiring an image with the Light Lever Nano-R™ AFM requires the following basic
steps, whether you are a new, occasional, or advanced user:
1. Launch the SPM Cockpit™ or InkCAD software
2. Open a configuration file (contact or close-contact) in SPM Cockpit or select type of
the probe to be used in InkCAD..
3. Retract the tip and raise the AFM scanner to provide safe clearance between the
probe tip and the sample puck.
4. Load a sample on the sample puck.
Lateral Force Microscopy (LFM): in contact mode
LFM is done while operating the system in “ ” mode. The Z(L‐R) channel, one
of the 4 channels in contact mode imaging, provide lateral force information.
1. Set the system to take the contact mode images
2. Set the scanner and feedback control based on the step 15 of the basic
operation.
3. Select Z(L‐R) channel for LFM imaging
4. In “input selects to ADC” settings, set Gin = 1, offset = 255, and filter = full
range for LFM imaging.
5. Start image scanning.
Normally, the gain and offset values for the Z(L‐R) channel should be sufficient for
most lateral force imaging situations. If a higher gain is needed, open the Red Dot
Alignment window and align the photodetector so that the red dot is to the left of
the vertical mid‐line, near the left border of the green zone. The gain, offset, and
filter can then be adjusted while scanning, for optimal image acquisition.
Phase Imaging: in close contact mode
In Close‐Contact mode, a cantilever is vibrated at a frequency near its resonance and
its amplitude is maintained constant while scanning. At the same time, monitoring
changes in phase lag between the AC voltage applied to a piezoelectric element for
vibrating a cantilever and the response of the cantilever gives an image that is
related to the localized material properties of the surface, such as adhesion and
stiffness.
Phase imaging is done in close‐contact mode. The Z(DEM) channel, one of the four
channels available in close‐contact mode, provides phase information. This channel
can be set to represent changes in either the phase or the amplitude of the
cantilever vibration, while holding the other constant.