Research of Modified Mechanical Sensor of Atomic Force Microscope
Atomic force microscope (AFM) is a remarkable device for nanoscale surface scanning. Among several positive features, speed of a scanning limits implementation of AFM. This paper proposes method that enables to increase a speed of scanning by modifying so
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ract Atomic force microscope (AFM) is a remarkable device for nanoscale surface scanning. Among several positive features, speed of a scanning limits implementation of AFM. This paper proposes method that enables to increase a speed of scanning by modifying some features of mechanical sensor by adding a nonlinear force to lever of a mechanical sensor of AFM. Proposed method is modeled theoretically, using Simulink features by realizing original algorithm, and researched experimentally, using original modification of AFM sensor. Original results are obtained after a research is performed. Finally, comparison of results of original and modified AFM scans is made and corresponding conclusions are drawn.
1 Introduction Atomic Force Microscopy (AFM) is a form of scanning probe microscopy (SPM) where a small probe is scanned across the sample to obtain information about the sample’s surface. The information gathered from the probe’s interaction
V. Bučinskas (✉) ⋅ A. Dzedzickis ⋅ N. Šešok ⋅ E. Šutinys ⋅ I. Iljin Vilnius Gediminas Technical University, Basanaviciaus 28, LT03224 Vilnius, Lithuania e-mail: [email protected] A. Dzedzickis e-mail: [email protected] N. Šešok e-mail: [email protected] E. Šutinys e-mail: [email protected] I. Iljin e-mail: [email protected] © Springer International Publishing Switzerland 2016 J. Awrejcewicz (ed.), Dynamical Systems: Theoretical and Experimental Analysis, Springer Proceedings in Mathematics & Statistics 182, DOI 10.1007/978-3-319-42408-8_4
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with the surface can be as simple as physical topography or as diverse as measurements of the material’s physical, magnetic or chemical properties [6]. Data about these properties are collected when the probe is scanned in a raster pattern across the sample to form a map of the measured property relative to the X–Y position. Thus, the image from AFM shows the variation in the measured property, for example change of surface height over the scanned area. AFM working principle is based on dynamical characteristics of sensitive mechanical system. This system consists of about 200 µm long and 0.5 µm thick cantilever with sharp probe attached at the end. During measurement process, a probe is clamped with initial force to the sample surface. Then scanning starts deflection of cantilevers repeats topography of sample surface. Amplitude of cantilever movements is measured using an optical measurement system. Usually laser is used for this purpose, laser beam is projected on the upper surface of the cantilever close to the tip. Reflected beam by mirror is directed to optical sensor usually four-segment photodiode or camera. Typical system of AFM is schematically shown in Fig. 1. The main limitation of AFM is its quite low scanning speed, which directly depends on mechanical characteristics of sensor cantilever. If we increase scanning speed, frequency of a cantilever oscillation also increases. Problem is when oscillation frequency approaches the resonant frequency of cantilever, contact between
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