Experiment 1: SPM and XRF
Introduction:
SPM: The Scanning Probe Microscope is an imaging device that shows the details of surfaces at the
atomic level. There are three types of SPM’s, the scanning tunneling microscope (STM), the atomic force
microscope (AFM), and the scanning electrochemical microscope.
XRF: The X-Ray Fluorescence uses x-rays to analyze a sample. The x-rays expel electrons that fill the
energy “gaps”. Some of the energy released is in the form of fluorescent photons, which is unique to
each element. The XRF identifies the percent composition of metals in a sample.
Purpose:
The purpose of this experiment is to become familiar with the SPM and XRF. These are the instruments
that we have to become experts on, so we can teach the other people in our lab. We have to learn how
to operate these instruments and what the data means when the results are given.
Procedure:
SPM:
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Remove blue cover and turn on laser. Startup computer and use password given, open up WIN
TV 2000 and the data acquisition program. Move microscope into position and turn optics on.
Make sure microscope is zoomed out all the way to see the image on the screen.
Using the adjustment knobs (cantilever and detector) to calibrate and position the laser on the
tip.
Use the z-bar adjustment to raise the tip away from the sample. Load sample onto sample tray,
avoid snapping sample down. Then click approach for the z-bar to go down, and the tip will
approach the sample.
Select Mode > Image Mode. In imaging mode adjust the size and rate. Go to Setup > Input
Configuration and select topography and put it in the right box by clicking Add, if it is not already
in the right box. Make sure both arrows are checked and all the other boxes are unchecked.
Close the input configuration box, click on the A button below the image box and adjust the
slope so both the red and green line is horizontal, so you can get the best image. Click the image
button and take an image. Double click the completed image to view level analysis and
histograms.
A known grating sample image was taken at 4.75m size, and 3Hz rate. An additional image was
taken of the sample at 1.00m size and 3Hz rate. Next, a sample was taken with the CD sample.
Shut down the instrument according to the standard operating procedure.
XRF:
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Fill the XRF with liquid nitrogen and allow it to cool for a half hour.
Power on the instrument and let it stabilize for 15mins.
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Open computer software, turning on x-ray lamp and allow it to warm up for a half hour.
Calibrate the instrument using the A750 calibration standard.
To run sample choose the easy system group and place the sample in the XRF chamber.
Run an unknown sample, as well as additional samples, and record the spectra and quantitative
results.
Data:
SPM: Images of samples at 4.75m and 1.00m and their histograms
Grating Sample: 4.75m
1.00m
CD Sample: 4.75m
1.00m
Sample 3: 4.75m
Sample 4: 4.75m
1.00m
1.00m
Sample 5: 4.75m
1.00m
XRF: Data of the elements that were in each sample and the percentage found in the sample.
A750 Standard
Element
Al
Sn
Si
Cu
Fe
Ni
Ca
Ho
Ti
Cr
Mn
Zn
Percentage
92.956
2.828
2.759
0.757
0.230
0.228
0.125
0.039
0.029
0.025
0.013
0.010
Unknown
Element
Fe
Cr
Ni
Mn
Cs
Cu
Mo
V
Quartzite 96% Si
Percentage
71.096
19.372
7.407
1.238
0.469
0.251
0.110
0.058
Element
Si
Al
K
Fe
Sr
Percentage
98.301
1.524
0.102
0.063
0.010
Red Rock
Element
S
Fe
Cu
White Rock
Percentage
92.699
5.308
1.993
Element
Ca
S
K
Fe
Sr
Cu
Zr
Percentage
67.051
31.991
0.478
0.274
0.166
0.035
0.005
Conclusion:
The Scanning Probe Microscope is an instrument that scans the surface of an object. This
instrument is useful when wanting to know the surface structures of an object. The SPM is helpful in
getting images of a surface at an atomic level. Each surface of an object is unique, and this instrument
can help in identifying these different surfaces.
The X-Ray Fluorometer is an instrument that breaks down the components of an object. This
instrument is useful in telling you which elements are present in a sample. The XRF is a really easy
instrument to use and it gives you results that you can understand.