Response Measurement Accuracy for Off-Resonance Excitation in Atomic Force Microscopy

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
R. Parker Eason ◽  
Andrew J. Dick
Keyword(s):  
Atomic Force Microscopy ◽  
Measurement Accuracy ◽  
Excitation Frequency ◽  
Operating Conditions ◽  
Laser Spot ◽  
Resonance Excitation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mode Behavior ◽  
Tip Mass

Displacement measurement in atomic force microscopy (AFM) is most commonly obtained indirectly by measuring the slope of the AFM probe and applying a calibration factor. Static calibration techniques operate on the assumption that the probe response approximates single mode behavior. For off-resonance excitation or different operating conditions the contribution of higher modes may become significant. In this paper, changes to the calibrated slope-displacement relationship and the corresponding implications on measurement accuracy are investigated. A model is developed and numerical simulations are performed to examine the effect of laser spot position, tip mass, quality factor and excitation frequency on measurement accuracy. Free response conditions and operation under nonlinear tip-sample forces are considered. Results are verified experimentally using a representative macroscale system. A laser spot positioned at a nominal position between x = 0.5 and 0.6 is determined to minimize optical lever measurement error under conditions where the response is dominated by contributions from the first two modes, due to excitation as well as other factors.

Response Measurement Accuracy for Off-Resonance Excitation in Atomic Force Microscopy

2010 ◽  
Author(s):  
Andrew J. Dick ◽  
R. Parker Eason
Keyword(s):  
Atomic Force Microscopy ◽  
Fundamental Frequency ◽  
Measurement Accuracy ◽  
Excitation Frequency ◽  
Resonance Excitation ◽  
Response Measurement ◽  
Force Microscopy ◽  
Atomic Force ◽  
Calibration Methods ◽  
Invaluable Tool

Dynamic atomic force microscopy (AFM) is an invaluable tool for characterizing and interacting with micro- and nano-scale systems. Standard measurement methods use a laser beam and a segmented photodiode to monitor the probe’s response. The diode reading is proportional to the slope of the probe and the displacement is obtained indirectly. As most operation methods use excitation around the fundamental frequency, calibration methods for determining the conversion factor to calculate the probe’s displacement are strongly inspired by the first vibrational mode shape. Within this paper, the results of an analytical study to predict measurement accuracy under non-standard excitation conditions with this calibration are presented. The influence of the excitation frequency, damping level, and laser spot location on this accuracy is investigated. The measurement accuracy for excitation at 2.5 times the fundamental frequency is of particular interest to the authors. Based upon the results, the use of a correction factor or a frequency-specific calibration is recommended.

Fundamental frequencies of a nano beam used for atomic force microscopy (AFM) in tapping mode

MRS Advances ◽  
2018 ◽  
Vol 3 (42-43) ◽  
pp. 2617-2626 ◽  
Author(s):  
MALESELA K. MOUTLANA ◽  
SARP ADALI
Keyword(s):  
Atomic Force Microscopy ◽  
Degree Of Freedom ◽  
Small Scale ◽  
Single Degree Of Freedom ◽  
Tapping Mode ◽  
Force Microscopy ◽  
Single Degree ◽  
Nano Scale ◽  
Atomic Force ◽  
Tip Mass

ABSTRACTIn this study we investigate the motion of a torsionally restrained beam used in tapping mode atomic force microscopy (TM-AFM), with the aim of manufacturing at nano-scale. TM-AFM oscillates at high frequency in order to remove material or shape nano structures. Euler-Bernoulli theory and Eringen’s theory of non-local continuum are used to model the nano machining structure composed of two single degree of freedom systems. Eringen’s theory is effective at nano-scale and takes into account small-scale effects. This theory has been shown to yield reliable results when compared to modelling using molecular dynamics.The system is modelled as a beam with a torsional boundary condition at one end; and at the free end is a transverse linear spring attached to the tip. The other end of the spring is attached to a mass, resulting in a single degree of freedom spring-mass system. The motion of the tip of the beam and tip mass can be investigated to observe the tip frequency response, displacement and contact force. The beam and spring–mass frequencies contain information about the maximum displacement amplitude and therefore the sample penetration depth and this allows

Nonlinear Tapping-Tip Dynamics in Atomic Force Microscopy

2002 ◽  
Author(s):  
Soo Il Lee ◽  
Arvind Raman ◽  
Shuiqing Hu ◽  
Stephen W. Howell ◽  
Ron Reifenberger
Keyword(s):  
Nonlinear Dynamics ◽  
Atomic Force Microscopy ◽  
Nonlinear Response ◽  
Excitation Frequency ◽  
Computational Tools ◽  
Force Microscopy ◽  
Atomic Force ◽  
Highly Nonlinear ◽  
Intermittent Contact ◽  
Resolution Imaging

Tapping or intermittent contact atomic force microscopy (AFM) is widely used scanning probe techniques for high resolution imaging, manipulation and nanolithography. The presence of van der Waals forces and nanoscale impacts render highly nonlinear the dynamics of the AFM microcantilever while it operates in the tapping mode. A comprehensive nonlinear analysis of the nonlinear dynamics of AFM microcantilevers tapping on a nanostructure using the theoretical and computational tools of modern nonlinear dynamics has not yet been presented. Also, a rational connection between certain features of the tip-sample interaction potential and the nonlinear response has not been established satisfactorily. To address this problem, we have combined both experimental and nonlinear computational analysis of the tapping response of a microcantilever as a function of the excitation frequency. We show that this approach enables a comprehensive understanding of the nonlinear dynamic behavior observed in AFM experiments.

scholarly journals Manipulation of gold colloidal nanoparticles with atomic force microscopy in dynamic mode: influence of particle–substrate chemistry and morphology, and of operating conditions

2011 ◽  
Vol 2 ◽  
pp. 85-98 ◽  
Author(s):  
Samer Darwich ◽  
Karine Mougin ◽  
Akshata Rao ◽  
Enrico Gnecco ◽  
Shrisudersan Jayaraman ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Operating Conditions ◽  
Critical Parameters ◽  
Dynamic Mode ◽  
Ambient Conditions ◽  
Force Microscopy ◽  
Substrate Structure ◽  
Atomic Force ◽  
Nanoscale Interactions ◽  
Lower Mobility

One key component in the assembly of nanoparticles is their precise positioning to enable the creation of new complex nano-objects. Controlling the nanoscale interactions is crucial for the prediction and understanding of the behaviour of nanoparticles (NPs) during their assembly. In the present work, we have manipulated bare and functionalized gold nanoparticles on flat and patterned silicon and silicon coated substrates with dynamic atomic force microscopy (AFM). Under ambient conditions, the particles adhere to silicon until a critical drive amplitude is reached by oscillations of the probing tip. Beyond that threshold, the particles start to follow different directions, depending on their geometry, size and adhesion to the substrate. Higher and respectively, lower mobility was observed when the gold particles were coated with methyl (–CH3) and hydroxyl (–OH) terminated thiol groups. This major result suggests that the adhesion of the particles to the substrate is strongly reduced by the presence of hydrophobic interfaces. The influence of critical parameters on the manipulation was investigated and discussed viz. the shape, size and grafting of the NPs, as well as the surface chemistry and the patterning of the substrate, and finally the operating conditions (temperature, humidity and scan velocity). Whereas the operating conditions and substrate structure are shown to have a strong effect on the mobility of the particles, we did not find any differences when manipulating ordered vs random distributed particles.

scholarly journals Material discrimination and mixture ratio estimation in nanocomposites via harmonic atomic force microscopy

2017 ◽  
Vol 8 ◽  
pp. 2771-2780 ◽  
Author(s):  
Weijie Zhang ◽  
Yuhang Chen ◽  
Xicheng Xia ◽  
Jiaru Chu
Keyword(s):  
Atomic Force Microscopy ◽  
Harmonic Signal ◽  
Laser Spot ◽  
Harmonic Amplitude ◽  
Mixture Ratio ◽  
Force Microscopy ◽  
Drive Frequency ◽  
Atomic Force ◽  
Potential Applications ◽  
Feedback Set

Harmonic atomic force microscopy (AFM) was employed to discriminate between different materials and to estimate the mixture ratio of the constituent components in nanocomposites. The major influencing factors, namely amplitude feedback set-point, drive frequency and laser spot position along the cantilever beam, were systematically investigated. Employing different set-points induces alternation of tip–sample interaction forces and thus different harmonic responses. The numerical simulations of the cantilever dynamics were well-correlated with the experimental observations. Owing to the deviation of the drive frequency from the fundamental resonance, harmonic amplitude contrast reversal may occur. It was also found that the laser spot position affects the harmonic signal strengths as expected. Based on these investigations, harmonic AFM was employed to identify material components and estimate the mixture ratio in multicomponent materials. The composite samples are composed of different kinds of nanoparticles with almost the same shape and size. Higher harmonic imaging offers better information on the distribution and mixture of different nanoparticles as compared to other techniques, including topography and conventional tapping phase. Therefore, harmonic AFM has potential applications in various fields of nanoscience and nanotechnology.

scholarly journals Effect of Eigenmode Frequency on Loss Tangent Atomic Force Microscopy Measurements

2021 ◽  
Vol 11 (15) ◽  
pp. 6813
Author(s):  
Babak Eslami ◽  
Dylan Caputo
Keyword(s):  
Atomic Force Microscopy ◽  
Loss Tangent ◽  
Oscillation Amplitude ◽  
Excitation Frequency ◽  
Chemical Properties ◽  
Sample Surface ◽  
Force Microscopy ◽  
Atomic Force ◽  
Afm Cantilever ◽  
Tip Radius

Atomic Force Microscopy (AFM) is no longer used as a nanotechnology tool responsible for topography imaging. However, it is widely used in different fields to measure various types of material properties, such as mechanical, electrical, magnetic, or chemical properties. One of the recently developed characterization techniques is known as loss tangent. In loss tangent AFM, the AFM cantilever is excited, similar to amplitude modulation AFM (also known as tapping mode); however, the observable aspects are used to extract dissipative and conservative energies per cycle of oscillation. The ratio of dissipation to stored energy is defined as tanδ. This value can provide useful information about the sample under study, such as how viscoelastic or elastic the material is. One of the main advantages of the technique is the fact that it can be carried out by any AFM equipped with basic dynamic AFM characterization. However, this technique lacks some important experimental guidelines. Although there have been many studies in the past years on the effect of oscillation amplitude, tip radius, or environmental factors during the loss tangent measurements, there is still a need to investigate the effect of excitation frequency during measurements. In this paper, we studied four different sets of samples, performing loss tangent measurements with both first and second eigenmode frequencies. It is found that performing these measurements with higher eigenmode is advantageous, minimizing the tip penetration through the surface and therefore minimizing the error in loss tangent measurements due to humidity or artificial dissipations that are not dependent on the actual sample surface.

Dual resonance excitation system for the contact mode of atomic force microscopy

2012 ◽  
Vol 83 (4) ◽  
pp. 043703 ◽  
Author(s):  
M. Kopycinska-Müller ◽  
A. Striegler ◽  
R. Schlegel ◽  
N. Kuzeyeva ◽  
B. Köhler ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Resonance Excitation ◽  
Excitation System ◽  
Contact Mode ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dual Resonance

scholarly journals High-resolution dynamic atomic force microscopy in liquids with different feedback architectures

2013 ◽  
Vol 4 ◽  
pp. 153-163 ◽  
Author(s):  
John Melcher ◽  
David Martínez-Martín ◽  
Miriam Jaafar ◽  
Julio Gómez-Herrero ◽  
Arvind Raman
Keyword(s):  
Atomic Force Microscopy ◽  
High Resolution ◽  
Amplitude Modulation ◽  
Performance Metrics ◽  
Operating Conditions ◽  
Atomic Resolution ◽  
Quality Factors ◽  
Liquid Media ◽  
Force Microscopy ◽  
Atomic Force

The recent achievement of atomic resolution with dynamic atomic force microscopy (dAFM) [Fukuma et al., Appl. Phys. Lett. 2005, 87, 034101], where quality factors of the oscillating probe are inherently low, challenges some accepted beliefs concerning sensitivity and resolution in dAFM imaging modes. Through analysis and experiment we study the performance metrics for high-resolution imaging with dAFM in liquid media with amplitude modulation (AM), frequency modulation (FM) and drive-amplitude modulation (DAM) imaging modes. We find that while the quality factors of dAFM probes may deviate by several orders of magnitude between vacuum and liquid media, their sensitivity to tip–sample forces can be remarkable similar. Furthermore, the reduction in noncontact forces and quality factors in liquids diminishes the role of feedback control in achieving high-resolution images. The theoretical findings are supported by atomic-resolution images of mica in water acquired with AM, FM and DAM under similar operating conditions.

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