Veeco Dimension 3100, Руководство пользователя

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Scanning Tunneling Microscopy (STM)
Basic STM Operation
178 Dimension 3100 Manual Rev. D
4. Plug the loaded tip holder into the end of the Dimension head, then mount the head into the
dovetail slot. Select Stage > Locate Tip to find the end of the STM probe—it will resemble
a metallic bee stinger. Once the tip has been located, proceed with using the Stage > Focus
Surface controls to position the sample beneath the probe.
Note: Using the microscope’s optical system, the tip will be difficult or impossible to
view if it is not located over a very reflective surface. Usually, the stage surface
is sufficiently reflective to accomplish this; however, most polished, silicon
wafers will work just as well. If the sample is dark in appearance, it may be
necessary to load it onto the stage AFTER the tip has been located using a
reflective background.
5. Set the Scan Controls panel parameters to the values shown below:
6. Engage the sample surface using the Motor > Engage option. The display monitor should
render an image of the sample surface immediately. Depending on the condition of the tip,
the image on the screen will be either clear or noisy. The status bar on the control monitor
shows how many microns the tip has traveled. When the tip engages with the surface and
tunneling occurs, the computer will beep and an
Engaged message will appear in the status
bar.
7. Click on a scan parameter and drag the mouse to change the parameter. Lower the Integral
gain and Proportional gain ( Feedback Controls panel) near zero and vary the Bias voltage
to see how the image changes. Vary the Scan size to observe how the image can be
magnified, then vary the X offset and Y offset to see how the image can be moved. Transfer
to the Channel panels, and instead of displaying an image using Height data, select Current
at the Data type field to observe image changes.
Note: Generally, the Data type field is set to Height whenever the Dimension is used
in STM mode to image sample surfaces with large fields of view. The Current
setting is usually selected for imaging atomic features—a more difficult feat for
the Dimension-series microscopes due to their much larger stages and frames.
Customers desiring to image atomic features should use Veeco’s dedicated
STM microscope, which is equipped with a much smaller, more rigid frame.
For more information, contact Veeco.
Scan Controls
Scan size:
X offset:
Y offset:
Scan angle:
Scan rate:
Number of samples:
Slow scan axis:
Z limit:
90.0
µ
m
0.00 nm
0.00 nm
0.00 deg
2.44 Hz
256
Enabled
440 V