Modeling and Simulation of Non-Contact Atomic Force Microscope

Author(s):  
Mohammadreza Bahrami ◽  
Asghar Ramezani ◽  
Kambiz Ghaemi Osquie

The Atomic force microscope in non-contact mode of operation is modeled as a lumped parameter system. The interaction of the cantilever tip with the sample surface through the van der Waals force introduces the nonlinearity to the model. The model is analyzed by the method of multiple scales and the frequency response equation is obtained. The effects of the nonlinearity, amplitude of excitation, and damping coefficient on the frequency response are studied.

2021 ◽  
Vol 285 ◽  
pp. 07035
Author(s):  
Mohammad Reza Bahrami

AFM has some unique properties such as higher spatial resolution, mapping even a single molecule, simple sample preparation, scanning in different types of medium, and can obtain a 3D scan of the sample surface. Therefore, with the help of AFM, one can obtain a unique understanding of the structure and functional behavior of materials. In this article, to construct the mathematical model of the base excited AFM cantilever mass spring system (lumped parameter model) is used and the solution obtained by the method of Multiple scales. Here, in this work, we consider the AFM operates in the non-contact mode. To study the effect of the non linearity, amplitude of excitation, and damping coefficient, frequency response equation obtained.


Author(s):  
Janik Schaude ◽  
Maxim Fimushkin ◽  
Tino Hausotte

AbstractThe article presents a redesigned sensor holder for an atomic force microscope (AFM) with an adjustable probe direction, which is integrated into a nano measuring machine (NMM-1). The AFM, consisting of a commercial piezoresistive cantilever operated in closed-loop intermitted contact-mode, is based on two rotational axes, which enable the adjustment of the probe direction to cover a complete hemisphere. The axes greatly enlarge the metrology frame of the measuring system by materials with a comparatively high coefficient of thermal expansion. The AFM is therefore operated within a thermostating housing with a long-term temperature stability of 17 mK. The sensor holder, connecting the rotational axes and the cantilever, inserted one adhesive bond, a soldered connection and a geometrically undefined clamping into the metrology circle, which might also be a source of measurement error. It has therefore been redesigned to a clamped senor holder, which is presented, evaluated and compared to the previous glued sensor holder within this paper. As will be shown, there are no significant differences between the two sensor holders. This leads to the conclusion, that the three aforementioned connections do not deteriorate the measurement precision, significantly. As only a minor portion of the positioning range of the piezoelectric actuator is needed to stimulate the cantilever near its resonance frequency, a high-speed closed-loop control that keeps the cantilever within its operating range using this piezoelectric actuator further on as actuator was implemented and is presented within this article.


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 362
Author(s):  
Luke Oduor Otieno ◽  
Bernard Ouma Alunda ◽  
Jaehyun Kim ◽  
Yong Joong Lee

A high-speed atomic force microscope (HS-AFM) requires a specialized set of hardware and software and therefore improving video-rate HS-AFMs for general applications is an ongoing process. To improve the imaging rate of an AFM, all components have to be carefully redesigned since the slowest component determines the overall bandwidth of the instrument. In this work, we present a design of a compact HS-AFM scan-head featuring minimal loading on the Z-scanner. Using a custom-programmed controller and a high-speed lateral scanner, we demonstrate its working by obtaining topographic images of Blu-ray disk data tracks in contact- and tapping-modes. Images acquired using a contact-mode cantilever with a natural frequency of 60 kHz in constant deflection mode show good tracking of topography at 400 Hz. In constant height mode, tracking of topography is demonstrated at rates up to 1.9 kHz for the scan size of 1μm×1μm with 100×100 pixels.


1999 ◽  
Vol 5 (S2) ◽  
pp. 962-963
Author(s):  
M. VanLandingham ◽  
X. Gu ◽  
D. Raghavan ◽  
T. Nguyen

Recent advances have been made on two fronts regarding the capability of the atomic force microscope (AFM) to characterize the mechanical response of polymers. Phase imaging with the AFM has emerged as a powerful technique, providing contrast enhancement of topographic features in some cases and, in other cases, revealing heterogeneities in the polymer microstructure that are not apparent from the topographic image. The enhanced contrast provided by phase images often allows for identification of different material constituents. However, while the phase changes of the oscillating probe are associated with energy dissipation between the probe tip and the sample surface, the relationship between this energy dissipation and the sample properties is not well understood.As the popularity of phase imaging has grown, the capability of the AFM to measure nanoscale indentation response of polymers has also been explored. Both techniques are ideal for the evaluation of multi-phase and multi-component polymer systems.


2004 ◽  
Vol 853 ◽  
Author(s):  
Massood Z. Atashbar ◽  
Valery N. Bliznyuk ◽  
Srikanth Singamaneni

ABSTRACTNickel nanowires were fabricated by electrodepositing Ni from an aqueous plating solution onto the step edges of Highly Oriented Pyrolytic Graphite (HOPG). Freshly cleaved HOPG was exposed to a plating solution of nickel and electro chemically deposited by cyclic voltametry. The morphology of the deposited nanoparticles was studied using an Atomic Force Microscope (AFM) in non-contact mode. The magnetic force of interaction between the nanoparticles was studied by magnetizing the particles. The critical force to displace the nanoparticles was estimated using contact mode of AFM.


Author(s):  
H. N. Pishkenari ◽  
Nader Jalili ◽  
A. Meghdari

Atomic force microscopes (AFM) can image and manipulate sample properties at the atomic scale. The non-contact mode of AFM offers unique advantages over other contemporary scanning probe techniques, especially when utilized for reliable measurements of soft samples (e.g., biological species). The distance between cantilever tip and sample surface is a time varying parameter even for a fixed sample height, and hence, difficult to identify. A remedy to this problem is to directly identify the sample height in order to generate high precision, atomic-resolution images. For this, the microcantilever is modeled by a single mode approximation and the interaction between the sample and cantilever is derived from a van der Waals potential. Since in most practical applications only the microcantilever deflection is accessible, this measurement is utilized to identify the sample height in each point. Using the proposed approach for identification of the sample height, the scanning speed can be increased significantly. Furthermore, for taking atomic-scale images of atomically flat samples, there is no need to use the feedback loop to achieve setpoint amplitude. Simulation results are provided to demonstrate the effectiveness of the approach and suggest the most suitable technique for the sample height identification.


2013 ◽  
Vol 378 ◽  
pp. 466-471
Author(s):  
Po Jen Shih ◽  
Shang Hao Cai

The dynamic behaviors of carbon nanotube probes applied in Atomic Force Microscope measurement are of interest in advanced nanoscalar topography. In this paper, we developed the characteristic equations and applied the model analysis to solve the eigenvalues of the microcantilever and the carbon nanotube. The eigenvalues were then used in the tapping mode system to predict the frequency responses against the tip-sample separations. It was found that the frequency drop steeply if the separation was less than certain distances. This instability of frequency is deduced from the jump of microcantilever or the jump of the carbon nanotube. Various lengths and binding angles of the carbon nanotube were considered, and the results indicated that the binding angle dominated the frequency responses and jumps.


1998 ◽  
Vol 05 (05) ◽  
pp. 989-996
Author(s):  
E. V. Blagov ◽  
G. L. Klimchitskaya ◽  
V. M. Mostepanenko

The paths are calculated for the surface and tip apex atoms when scanning the AFM tip above the close-packed lattice in contact mode. The interaction of the sample and the tip atoms is considered in elastic approximation. The dependence of the atomic paths on the type of the tip and its orientation is investigated. It is shown that the vertical characteristic sizes of the atomic paths are several times larger than the vertical resolution of the atomic force microscope.


1997 ◽  
Vol 82 (3) ◽  
pp. 966-979 ◽  
Author(s):  
Joseph A. Turner ◽  
Sigrun Hirsekorn ◽  
Ute Rabe ◽  
Walter Arnold

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