Colvolutional calibration of AFM probe

Atomic force microscopy is based on the interaction of the examined surface with a probe of a pyramidal shape, tipped with a sharp end with a radius of curvature ranging from single nanometers to hundreds of nanometers. The resolution of the obtained image is of course dependent on the above-mentioned geometric size, and the resulting image is a convolutional image of the shape of the probe tip and topographic details of the surface. In the case of the tip size, which is negligible compared to the size of the measured effects, it is possible to treat the resulting convolution as a good approximation of the topographic characteristics of the test sample. However, if the probe tip degrades due to mechanical deformation, this fact can be expected to be visualized in the form of image artifacts. This can lead to very confusing results because the convolution artifacts reflect the shape of the blade and thus look like interesting, ordered nanostructures present on the surface of the material. In order to avoid misinterpretation of the obtained images, periodic validation of the probe blade quality is recommended. It is performed using calibration standards in the form of silicon blades with a small radius of curvature. Scanning this structure allows you to see deformation and damage to the AFM probe tip. The described set includes convolutional images of this type made with the use of probes which were suspected to have been deformed as a result of long-term use. The scan includes 10 sample images taken with the NSG30 probes in the semi-contact mode. [1] J. Shen, D. Zhang, F. Zhang, Y. Gan, AFM tip-sample convolution effects for cylinder protrusions, Appl. Surf. Sci. 422 (2017) 482–491. doi:10.1016/j.apsusc.2017.06.053.