Abstract

The invention of the nanotechnology adds a new branch to investigate and control the physical properties of matters at atomic level. The aim of this technology is to image the characteristics of metals, biological organs, and polymers. Scanning probe microscopy (SPM) opens a new branch to analysis the atomic properties of the matters. Atomic force microscopy (AFM), a branch of SPM, is a versatile tool of nanotechnology to image both conductive and non-conductive matters with high resolution. Commercial AFM uses raster scanning technique to produce image of the matters that is responsible for low scanning speed and image quality. The performances of AFM are hampered due to low bandwidth of the scanning unit and vertical Proportional-Integral (PI) controller and may damage the surface of the samples. Different non-raster scanning techniques such as sinusoidal, rotational, spiral, cycloid, and lissajous scanning have been proposed to overcome the limitations of raster scanning method by providing high scanning speed, image quality, and resolution. This paper presents a survey of raster and non-raster scanning methods for high speed AFM and provides a compression between them in term of scanning speed, bandwidth and highest achievable scanning frequency. The control techniques applied to the AFM for improving raster, sinusoidal, spiral, cycloid, and lissajous scanning methods are studied in this paper to find most optimum scanning technique for AFM.

Highlights

  • Nanotechnology is the important invention of the modern science to control the properties of biological organs, metals, and polymers

  • We first derive the mathematical expression of the working principle for the raster, sinusoidal, rotational, spiral, cycloid, and lissajous scanning techniques, we summarize the performances of the scanning methods for a given scanning time and pixels-per-line and the summarization shows that lissajous scanning method performs faster as compared to the other scanning methods

  • This paper presents the summary of the non-raster scanning methods applied to the atomic force microscope (AFM) for fast image scanning at high scanning speeds

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Summary

INTRODUCTION

Nanotechnology is the important invention of the modern science to control the properties of biological organs, metals, and polymers. Unwanted vibration may be produced in the operation of high speed scanning that reduces the accuracy and reliability of the system and damages the surface This unwanted vibration is reduced by using three method such as, (i) minimize the impulsive force produced by high speed actuator, (ii) increase the resonant frequency of the cantilever, and (iii) reduce the quality factor [11], [15], [20]. Different kinds of forces such as van der waals force, electronic force are experienced by the cantilever when the tip touches the surface of the sample It can operate in the liquid medium where the interaction force on the tip is reduced. A number of nonlinearities are produced in triangular waveform such as creep, hysteresis etc. that distort the scanning image of the surface of the sample [24], [25]

SINUSOIDAL SCANNING METHOD
SPIRAL SCANNING METHOD
LISSAJOUS SCANNING METHOD
CONTROLLER DESIGN
Findings
CONCLUSION
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