Study On Trible-probe Atomic Force Microscope Imaging System

Since the invention of atomic force microscope,it has been used in many fields as an important tool in nanotechnology research.As a new member of the scanning probe microscope,AFM plays an irreplaceable role in the field of biological science research because of the looser requirements on the environment of the sample.With the development of nanotechnology,the requirements for AFM functionality are getting higher and higher.On the basis of imaging the sample,it is required to have more functions,such as manipulation,processing etching,and electrical property measurement.At present,the AFM system is dominated by a single probe structure,which can not meet more and more functional requirements.In order to expand the function and application range of the AFM system.In this paper,a trible-probe atomic force microscope system is designed to expand the application of nanometer manipulation and force characteristic measurement based on the imaging of samples.The main research contents of this paper are as follows:1.The development background and history of AFM are summarized.The development status of AFM at home and abroad is introduced.The shortcomings of single probe AFM system are summarized,and the research content of this paper is proposed.2.The basic working principle of AFM is introduced.The working mode of AFM system and the detection method of probe cantilever micro-displacement are summarized.The beam deflection method is used as the detection method of the probe cantilever micro-displacement in this design.The mathematical model of two detection optical paths in the liquid environment is established,and the solution to reduce the spot tracking error is analyzed.3.Based on the beam deflection method,the optical system of the trible-probe atomic force microscope system is designed,which mainly involves the calculation and selection of components such as laser,photodetector and mirror.Based on the optical system,the scanning positioning and data processing unit of the system is designed.Finally,the overall structure of the system is determined and the experimental optical system is built.The scanning range of the system is 200 ?m×200 ?m and the imaging resolution is 1 nm.4.In order to verify the performance of the system,the error of the optical system is analyzed.The imaging performance of the self-made AFM system is evaluated and verified by imaging the standard one-dimensional grating.The imaging of the two-dimensional grating was carried out under different parameters,and the effects of setpoint,proportional gain and integral gain on the scan results are analyzed.The imaging and force characteristics of the cells were studied.The target of the imaging was liver cancer cells.Finally,the force characteristic curves of the hippocampus neurons in rats were measured.The difference of the force curve when the probes were exposed to different samples was discussed.It laid the foundation for experiments such as measurement of cell electrical properties.5.The research work of this subject is summarized,the shortcomings in the system are analyzed,and the future work is prospected.