Hello! I am investigating some force investigations using AM-AFM and after last night's scans I have noticed in the oscilloscope that the Amplitude is having a lot of noise in the signal trace. Can someone help me diagnose this in a logical way? Thank you,
Hi,
It is very difficult to answer this question without more data, specifically:
1) which samples were scanned - the presence of heterogeneous areas with different adhesion between probe and sample could have led to this;
2) was the scan performed in ambient conditions? - Could the ambient conditions - temperature, humidity etc. - have changed overnight? - this could have led to water deposition on the surface and a change in the interaction between the probe and the sample.
Hello and thank you for the response!
The samples were Si wavers containing sub micrometer level contaminants.
The scan was performed in ambient conditions but the scanning chamber has a controlled venting system that should prevent humidity accumulation.
I've noticed that the noise starts every time when I approach the sample. I then increase my gain and decrease it back to lower values and after I decrease my gain again the noise stops.
Hello George,
it is difficult to address the problem without having a look to the image you get.
Two possibilities could be:
- You have environmental noise (not rare if you are using a chamber, if you have nitrogen flowing to decrease the relative humidity, that could easily cause the noise). Remove the nitrogen flow and try again to see if you see any difference.
- The tip has something attached and is getting stuck onto the sample on every oscillation. Use higher amplitude and change gains. Ultimately try with a differente tip.
An image would defintitvely help to a better diagnose
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