Biomedical Engineering Reference
In-Depth Information
Fig. 6.4. Examples of how images produced with broken or dirty probes show repeating patterns in
the images. Left: SEM images of damaged and dirty probes. Right: AFM images produced using the
probes shown on the left. Images with repeating patterns like these are usually due to broken or dirty
probes.
Double tips
A further example of damage or contamination of tips altering the image is the creation of
multiple tips. If the tip breaks such that it has small spikes at the end, or more commonly,
has debris attached near the tip, the sample may be imaged both by the true tip, and the
debris. This results in multiple copies of each feature appearing in the image [379]. It's not
possible to distinguish which image feature is from the 'true' tip, and double, or multiple
copies of each feature occur in the image, as shown in Figure 6.5.
When the user determines that the probe is blunt, contaminated, or broken, they must
replace the probe. Some procedures for cleaning of AFM probes have been described
[380], however, in the authors' experience, it is usually simpler and far more effective to
replace the probe than to try to clean it.
