Hello all,
Suppose you are visually scanning the sample surface to select a region to do AFM scan. You select a region at first sign looking good. Then you move to another region. Then you see that the first region is better that the second one.
Question 1: Could be possible to add a marker or something to facilitated returning to the first region?
Question 2: If not, how do you solve this problem?
Equipment: Park NX10
For a similar problem, I have once prestructured a sample with a checkboard grid, which was defined lithographically. This allowed me to go to reliably find point in various devices, e.g. optical microscopy, SEM or AFM. doesnt have to be a checkboard, could be any kind of recognizeable markers. Depends, however, if you can deposit or mark anything on the surface.
Another option: If in your AFM the sample or the scanning head is moved via a positioning system with a read out of the position, you may can try to note them down, e.g. first scan is 320 µm in x and 213 µm in y from the upper corner. afterwards, you can try to find them again.
I hope these simple idea help,
Regards,
Michael
My students and myself faced this situation often.
Here are some options that helped us:
1) Check the absolute XY coordinates of the first image and then move the scan area to match those coordinates.
2) Save an image from the optical microscope (I think it has a 10x objective) the field is large enough to see any features on the surface that you can use as reference markers when you want to come back to it.
3) Make a sketch on paper of the whole (macroscopic sample) and remember the orientation in which you placed it in the AFM and where the regions of interest are.
4) Depending on your sample and the stiffness of the cantilever, you could try making a large pattern with the same AFM tip so that you can identify the region of interest of the first image. If you're investigating thin films of soft materials then you could make a pattern by scanning a "+" or "X" in contact mode at full scanning range. If it is a hard material try making the pattern with electrical AFM at large tip-sample potential.
Thanks for the answers.
@ Michael Rüsing: I am not the owner of the samples, I just operate the microscope. The users use different substrates to deposit they samples (mica, glass, etc.).
@Thomas Breuer: Nope.
@Raul D. Rodriguez: I have to check for the absolute coordinates. I didn`t see anything about it. Suggestions (2) and (3) are what I have been using till now, but some times, I get loss. For (4) I have to check the hardness of my contact tips.
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