AFM can be used to observe the surface morphology, roughness, surface height histogram, and the corresponding cross section profiles. However, the curved surface can not be caculated.
As already pointed out, AFM cannot measure curvature as it typically gives surface information on the nano/micrometer scale. Instead, you can use a stress tester (e.g. Flexus) to measure the curvature of a wafer.
You have to keep in mind that images obtained by AFM are a combination of the particle dimensions and the tip size. The AFM tip typically cannot reach the region just at the edge of the particle as it is not indefinitely sharp. As a result you will get an image which is a bit wider that the actual shape of your particle.
The height measurements are kind of reliable for hard samples which are not easily squashed and deformed by the force applied with the AFM tip during imaging. You can lower these deformations by applying smaller force, but you can never be sure what is the actual impact on your sample. This is a problem especially for soft samples as biological membranes for example.
In general, AFM should be used for any quantitative measure of the sample dimensions only with caution while having all these limitations in mind. I would not recommend it as a measure of curvature for which you need precise measure of both lateral dimensions and height.
Peter Schindler Yingyi Zhang
Can you tell me how can I calculate surface roughness ? which software should I used ?
You need to import the AFM test data into the NanoScope Analysis software and automatically obtain the roughness data through the roughness mode.
Md. Nazmul Islam You need to import the AFM test data into the NanoScope Analysis software and automatically obtain the roughness data through the roughness mode.
Nanoscope Analysis is of course a tool easy to handle but the flattening agorithm sometimes produces weird artifacts when there are single high particles; if you do not have these, the two softwares are roughly identical in quality.
Jürgen Weippert Yingyi Zhang
Thanks for your support. However, can you tell me any other software where I can analysis my SEM and TEM data like as my work on bacteria sample. So I need to analyze morphological feature of bacteria like as shape, roughness, area, size etc. How can I analysis my SEM and TEM data ? do you have any idea ?
Dear Deepak
Yes, please refer to the attached article on " Measuring Surface Roughness of an Optical Thin Film With Scanning Tunneling Microscopes ".
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