Chapter 2
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Mechanical Vibrations are transmitted to the AFM stage from
mechanical contact. Sources of mechanical noise include floor
vibrations. Usually floor vibrations are greater the higher up in a
building the AFM is located. Mechanical vibrations are reduced
by putting the AFM on a vibration table. |
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FIGURE 2-44Left: Vibration tables have a transmission curve that shows the attenuation of the table to vibrations as a function of frequency. There is always a natural resonance associated with the vibration table that is typically below 5
Hz. Right: Acoustic vibrations are reduced using a vibration enclosure. |
2.6.2. Environmental Scanning |
Scanning in a controlled environment with an AFM can be advantageous
for many reasons: |
- Reactive materials are stable in an inert environment.
- Biological materials can be measured in situ.
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FIGURE 2-45 Left: A microcell is created by gluing the cantilever/substrate on to a piece of glass. Right: An environmental cell is created by making a sealed cell that completely surrounds the probe/cantilever and the sample.
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There are many ways for controlling the environment of scanning with an AFM. The first is to place the AFM in a vacuum chamber and remove all of the gasses from the microscope stage. The second is to put the AFM in a controlled environment such as a glove box. The third is to put the sample and AFM tip in a liquid environment. Figure 2-45 shows two methods for putting the sample/probe in a liquid environment. |
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