scholarly journals Modification of the AFM Sensor by the Precisely Regulated Air Stream to Increase the Imaging Speed and Accuracy

2018 ◽  
Author(s):  
Andrius Dzedzickis ◽  
Vytautas Bucinskas ◽  
Darius Viržonis ◽  
Nikolaj Sesok ◽  
Arturas Ulcinas ◽  
...  
Keyword(s):  
Aerodynamic Force ◽  
Scanning Speed ◽  
Interaction Force ◽  
Spring Constant ◽  
Force Microscopy ◽  
Atomic Force ◽  
Air Stream ◽  
Nonlinear Force ◽  
High Scanning Speed ◽  
Speed And Accuracy

Increasing of the imaging rate of conventional atomic force microscopy (AFM) is almost impossible without impairing of the imaging quality, since the probe tip tends to lose contact with the sample. We propose to apply the additional nonlinear force on the upper surface of a cantilever, which will help to keep the tip and surface in contact. In practice this force can be produced by the precisely regulated airflow. Such an improvement affects the AFM system dynamics, which were evaluated using a mathematical model presented in this paper. The model defines the relationships between the additional nonlinear force, the pressure of the applied air stream and the initial air gap between the upper surface of the cantilever and the end of the air duct. It was found that the nonlinear force created by the stream of compressed air (aerodynamic force) prevents the contact loss caused by the high scanning speed or higher surface roughness, and at the same time has minimal influence on the interaction force, thus maintaining stable contact between the probe and the surface. This improvement allows to effectively increase the scanning speed by at least 10 times using a soft (spring constant of 0.2 N/m) cantilever by applying the air pressure of 40 Pa. If a stiff cantilever (spring constant of 40 N/m) is used, the potential of accuracy improvement reaches 92 times. This method is suitable for use with different types of AFM sensors and can be implemented practically without essential changes in AFM sensor design.

scholarly journals Modification of the AFM Sensor by a Precisely Regulated Air Stream to Increase Imaging Speed and Accuracy in the Contact Mode

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2694 ◽  
Author(s):  
Andrius Dzedzickis ◽  
Vytautas Bucinskas ◽  
Darius Viržonis ◽  
Nikolaj Sesok ◽  
Arturas Ulcinas ◽  
...  
Keyword(s):  
Aerodynamic Force ◽  
Scanning Speed ◽  
Spring Constant ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Air Stream ◽  
Nonlinear Force ◽  
Loss Of Contact ◽  
High Scanning Speed

Increasing the imaging rate of atomic force microscopy (AFM) without impairing of the imaging quality is a challenging task, since the increase in the scanning speed leads to a number of artifacts related to the limited mechanical bandwidth of the AFM components. One of these artifacts is the loss of contact between the probe tip and the sample. We propose to apply an additional nonlinear force on the upper surface of a cantilever, which will help to keep the tip and surface in contact. In practice, this force can be produced by the precisely regulated airflow. Such an improvement affects the AFM system dynamics, which were evaluated using a mathematical model that is presented in this paper. The model defines the relationships between the additional nonlinear force, the pressure of the applied air stream, and the initial air gap between the upper surface of the cantilever and the end of the air duct. It was found that the nonlinear force created by the stream of compressed air (aerodynamic force) prevents the contact loss caused by the high scanning speed or the higher surface roughness, thus maintaining stable contact between the probe and the surface. This improvement allows us to effectively increase the scanning speed by at least 10 times using a soft (spring constant of 0.2 N/m) cantilever by applying the air pressure of 40 Pa. If a stiff cantilever (spring constant of 40 N/m) is used, the potential of vertical deviation improvement is twice is large. This method is suitable for use with different types of AFM sensors and it can be implemented practically without essential changes in AFM sensor design.

Spring constant calibration of atomic force microscopy cantilevers with a piezosensor transfer standard

2007 ◽  
Vol 78 (9) ◽  
pp. 093705 ◽  
Author(s):  
E. D. Langlois ◽  
G. A. Shaw ◽  
J. A. Kramar ◽  
J. R. Pratt ◽  
D. C. Hurley
Keyword(s):  
Atomic Force Microscopy ◽  
Spring Constant ◽  
Transfer Standard ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals High-speed dynamic-mode atomic force microscopy imaging of polymers: an adaptive multiloop-mode approach

2017 ◽  
Vol 8 ◽  
pp. 1563-1570 ◽  
Author(s):  
Juan Ren ◽  
Qingze Zou
Keyword(s):  
Atomic Force Microscopy ◽  
High Speed ◽  
Interaction Force ◽  
Dynamic Mode ◽  
Microscopy Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
Atomic Force Microscopy Imaging ◽  
Mode Tm ◽  
Mode Atomic Force Microscopy

Adaptive multiloop-mode (AMLM) imaging to substantially increase (over an order of magnitude) the speed of tapping-mode (TM) imaging is tested and evaluated through imaging three largely different heterogeneous polymer samples in experiments. It has been demonstrated that AMLM imaging, through the combination of a suite of advanced control techniques, is promising to achieve high-speed dynamic-mode atomic force microscopy imaging. The performance, usability, and robustness of the AMLM in various imaging applications, however, is yet to be assessed. In this work, three benchmark polymer samples, including a PS–LDPE sample, an SBS sample, and a Celgard sample, differing in feature size and stiffness of two orders of magnitude, are imaged using the AMLM technique at high-speeds of 25 Hz and 20 Hz, respectively. The comparison of the images obtained to those obtained by using TM imaging at scan rates of 1 Hz and 2 Hz showed that the quality of the 25 Hz and 20 Hz AMLM imaging is at the same level of that of the 1 Hz TM imaging, while the tip–sample interaction force is substantially smaller than that of the 2 Hz TM imaging.

scholarly journals Influence of spurious resonances on the interaction force in dynamic AFM

2015 ◽  
Vol 6 ◽  
pp. 420-427 ◽  
Author(s):  
Luca Costa ◽  
Mario S Rodrigues
Keyword(s):  
Calibration Method ◽  
Interaction Force ◽  
Measured Signal ◽  
Acoustic Excitation ◽  
Cantilever Deflection ◽  
Force Microscopy ◽  
Atomic Force ◽  
Excitation Force ◽  
Tip Position ◽  
Effective Excitation

The quantification of the tip–sample interaction in amplitude modulation atomic force microscopy is challenging, especially when measuring in liquid media. Here, we derive formulas for the tip–sample interactions and investigate the effect of spurious resonances on the measured interaction. Highlighting the differences between measuring directly the tip position or the cantilever deflection, and considering both direct and acoustic excitation, we show that the cantilever behavior is insensitive to spurious resonances as long as the measured signal corresponds to the tip position, or if the excitation force is correctly considered. Since the effective excitation force may depend on the presence of such spurious resonances, only the case in which the frequency is kept constant during the measurement is considered. Finally, we show the advantages that result from the use of a calibration method based on the acquisition of approach–retract curves.

scholarly journals Theoretical study of the frequency shift in bimodal FM-AFM by fractional calculus

2012 ◽  
Vol 3 ◽  
pp. 198-206 ◽  
Author(s):  
Elena T Herruzo ◽  
Ricardo Garcia
Keyword(s):  
Fractional Calculus ◽  
Frequency Shift ◽  
Interaction Force ◽  
Simultaneous Recording ◽  
Force Microscopy ◽  
Simultaneous Excitation ◽  
Lennard Jones ◽  
Atomic Force ◽  
Different Types ◽  
Microscopy Method

Bimodal atomic force microscopy is a force-microscopy method that requires the simultaneous excitation of two eigenmodes of the cantilever. This method enables the simultaneous recording of several material properties and, at the same time, it also increases the sensitivity of the microscope. Here we apply fractional calculus to express the frequency shift of the second eigenmode in terms of the fractional derivative of the interaction force. We show that this approximation is valid for situations in which the amplitude of the first mode is larger than the length of scale of the force, corresponding to the most common experimental case. We also show that this approximation is valid for very different types of tip–surface forces such as the Lennard-Jones and Derjaguin–Muller–Toporov forces.

Force Measurement by AFM Cantilever with Different Coating Layers

2006 ◽  
Vol 326-328 ◽  
pp. 377-380 ◽  
Author(s):  
Meng Kao Yeh ◽  
Bo Yi Chen ◽  
Nyan Hwa Tai ◽  
Chien Chao Chiu
Keyword(s):  
Force Measurement ◽  
Force Measurements ◽  
The Finite Element Method ◽  
Force Microscopy ◽  
Atomic Force ◽  
Nonlinear Force ◽  
Coating Layers ◽  
Afm Cantilever ◽  
Force Displacement ◽  
Spring Constants

Atomic force microscopy (AFM) is widely used in many fields, because of its outstanding force measurement ability in nano scale. Some coating layers are used to enhance the signal intensity, but these coating layers affect the spring constant of AFM cantilever and the accuracy of force measurement. In this paper, the spring constants of rectangular cantilever with different coating thickness were quantitatively measured and discussed. The finite element method was used to analyze the nonlinear force-displacement behavior from which the cantilever’s normal and torsional spring constants could be determined. The experimental data and the numerical results were also compared with the results from other methods. By considering the influence of coating layers and real cantilever geometries, the more accurate force measurements by AFM cantilever can be obtained.

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