Contact AFM Mode
Initiate the Engage Command
Rev. B
MultiMode SPM Instruction Manual
97
Now adjust the
Setpoint
for imaging. Having the setpoint anywhere above the line where the tip is
off the surface will work. The farther it is above, the more force is placed onto the sample.
To adjust tip-sample force to the minimum amount, you can run in the area where the tip is actually
pulling up but the liquid layer is holding the tip on the surface. However, this is not a stable way to
image: if the tip pops free of the surface, the
Setpoint
must be increased to reattach the tip.
To minimize tip-sample forces, lower the
Setpoint
until the tip pulls free of the surface and record
the
Setpoint
value: this is the pull-off value. Increase the
Setpoint
again to regain the surface, then
lower the
Setpoint
to a point just above the pull-off value. At this point, tip-sample forces should be
at their minimum.
If
Setpoint
is the only parameter requiring adjustment, skip ahead to
go to the next section to adjust the
Sensitivity
parameter.
