| Atomic force microscopy(AFM)is an important part of the scanning probe microscope(SPM),which can realize nano or even atomic-scale quantum material characterization and atomic manipulation.It is one of the key technologies for the development of atomic sensors and quantum storage to realize atomic production in the future and plays an important role in the field of surface characterization.Atomic force microscopy is to measure the surface topography of the sample through the force between the probe and sample to realize the atomic recognition by accurately measuring the force,and realize the atomic manipulation.Therefore,the measurement and control of the atomic force in the atomic force microscopy technology is very important.However,because the AFM which can realize the atomic resolution imaging mostly works in the ultra-high vacuum environment and adopts the non-contact mode,its probe as a force detector can’t directly measure the force,so it has to convert the measured physical quantity into the interaction force.Therefore,based on the UHV-NC-FM-AFM,a sphere cone model of probe tip is established,and the composition of the probe sample atomic force is analyzed.Then,the window function algorithm is used to filter the frequency shift with Mathematica,and the longrange force and electrostatic force were composed to accurately extract short-range chemical force.Based on the secondary development of the AFM measurement and control platform of UHV room temperature,the software for calculating the interaction force between atoms is developed by using LabVIEW.On the basis of realizing the single point AFS solution method,two-dimensional and three-dimensional AFS measurement are realized by line and grid measurement methods,and two-dimensional and three-dimensional AFS measurement and solution are completed by ultra-high vacuum room temperature AFM based on Si(111)-7x7 structure surface,which verifies the accuracy of the measurement method.In the process of measuring the three-dimensional atomic force,the number of measuring points directly determines the resolution of the three-dimensional atomic force spectrum,but too many measuring points will greatly prolong the measurement time and lead to serious temperature offset.Therefore,the atom tracking offset suppression technology is used to realize the thermal drift compensation.The results show that the energy loss caused by the adhesion effect is not related to the thickness of the coating,but closely related to the uniformity of the coating.And this method can qualitatively compare the properties of anti-relaxation coating,which provides a new idea for the characterization of alkali metal vapor cell. |
