Research On The Simulation And Optimization Of Peakforce Tapping Mode Atomic Force Microscope

Peakforce tapping mode Atomic force microscopy(PF-AFM)is an instrument used to characterize physical and chemical properties such as topography,mechanical,electrical and electrochemical properties of the sample.When characterize the properties of the sample,it has the advantage of precisely controlling the interaction between the tip and the sample,not damaging the sample,can perform high-resolution imaging in a liquid environment,obtaining high resolution imaging in the liquid environment,simultaneously obtaining the morphology properties,quantitative nanomechanical properties,electrical properties and electrochemical properties of the sample.In addition,during the nano-etching process,the thickness of the nanowires is related to the interaction force between the tip-sample.The Peakforce tapping mode AFM has the advantage of precise force control.But the commercial Peakforce tapping mode AFM does not have an associated etch module.And there is no self-established Peakforce tapping mode AFM in China.In view of above reason,the paper mainly focuses on the basic working principle of the Peakforce tapping mode AFM.Then,work on the scientific problems and application techniques of the cantilever beam deflection model,the theory of Peakforce tapping mode AFM,the model of Peakforce tapping mode AFM,and the production of experimental platform for Peakforce tapping mode AFM.The main work of the paper as the followings:In the basic working principle of AFM,systematically studied the relationship between the interaction force and the distance,the deflection model of the cantilever beam,the amplification of the optical lever,and the normalization of the four-quadrant position detector model.The hardware background subtraction algorithm,software background subtraction algorithm,synchronization algorithm and average algorithm theory in the Peakforce tapping mode AFM were studied.Model and analyze the algorithm.Briefly introduced the basic principle of quantitative nanomechanical properties measurement by using Peakforce tapping mode AFM.It provides a theoretical basis for the establishment of the Peakforce tapping mode AFM simulation platform and experimental platform.Establishing Contact mode AFM and Peakforce tapping mode AFM simulation platform and explained different phenomena corresponding to different parameters in the simulation which provides the theoretical verification basis for establishing the Peakforce tapping mode AFM experimental platform.Moreover,it provides a powerful a priori analysis method for nano-characterization experiments,avoiding the damage of the tip and sample due to unreasonable parameter setting during the experiment,and the adverse effects of imaging,improving the controllability and practicability of the operation.Finally,the characterization experiment of the gold sample on the silica substrate by using Peakforce tapping mode AFM vertified the advantages of the Peakforce tapping mode AFM.The effect of electrostatic force on the ringing signal is also investigated to verify the possibility of characterizing the electrostatic force of the sample by using the ringing signal.It provided a scientific research method for the development and application of peak force tapping mode atomic force microscopy in the field of sample characterization.