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4.6.2 Topo Scan Tab
1.
Select scan parameters such as Scan Size, Scan Rate and the number of lines. Sam-
ples may be scanned at 0° or 90° by adjusting the Rotation parameter.
NOTE: A scan rate of 0.5 Hz and 256 scan lines will achieve a basic
low resolution scan.
2.
Select the desired images to be displayed in the Display window. The Display window
also allows for control of leveling, as well as the ability to transpose both the Left and
Right Images with the Image Add button. Some display options for contact mode scan-
ning include:
•
Z-Drive, the change in voltage through the z-piezoelectric ceramic, shows the
sample's topography. It is common to set Z-Drive to the Left Image.
•
Z-Error, the error signal, is used to help optimize the Z Feedback parameters.
When initially setting up a scan, it is common to use Z-ERR as the Right Image.
•
L-R, lateral force, detects cantilever torsion as the tip applies constant force along
the surface. This mode is unique to contact mode scanning, and can only be prop-
erly used when scanning at 90°.
3.
Begin a scan by pressing the Start button in the Scan window.
NOTE: When the GPID parameters are optimized, the Z piezoelec-
tric ceramic will more closely follow the probe tip as it scans the sur-
face. When tip movement is minimized the Z error signal is decreased.
Increasing the setpoint by small increments (50-100 mV) sharpens the
image by pushing the tip harder on the surface.
4.
While scanning, optimize the GPID and setpoint parameters (see Appendix G).
5.
Once the parameters are optimized, stop the scan by pressing the Stop button.
6.
Before beginning a new scan, check to see if Z Drive is still near the center of its
range. If not, see sections 4.6.10 - 11.
7.
Begin a new scan. When the scan is completed, the light turns green.
8.
If desired, the user can open a larger window of both the Left and Right Images by
selecting the S button to the right of the scan window. The H and C buttons allow the
user to alter the histogram and color scheme of the scans, accordingly.
9.
When finished scanning, press Tip Retract. This function lightly releases the probe
from the sample surface.
V 1.1 / LS-AFM Users Guide
Section 4-8
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