How much do you know about atomic force microscopy
The basic principle of atomic force microscopy (AFM) is that the atomic arrangement of the sample surface produces "concave and concave". When the probe scans in the horizontal direction, the distance between the needle tip and the sample surface will change in the vertical direction. It is known from the theory of solid state physics that when the probe tip is very close to the sample surface, an interatomic force will be generated between them. The change in the vertical distance between the needle tip and the sample surface leads to the change of the interatomic force between the needle tip and the sample surface. The changing interatomic force causes the cantilever to vibrate in the vertical direction. Therefore, the changing interatomic force between the needle tip and the sample surface can be detected by using the deflection of the laser beam. The deflection signal of the laser beam is input into the computer for processing, and the surface information of the sample surface can be obtained. A piezoelectric material is installed under the sample surface to receive the feedback signal output by the computer and adjust the height of the sample surface to achieve the purpose of protecting the probe tip.
Since the atomic force microscope is based on the theory of interatomic forces, the surface of the tested sample extends from conductors and semiconductors to the field of insulators, and its lateral resolution can reach 0.101nm. At present, according to the contact between the probe tip and the sample surface, the contact forms of the atomic force microscope are divided into contact type (C type), non-contact type (NC type), and intermittent contact type (IC type).
