High-bandwidth multimode self-sensing in bimodal atomic force microscopy

• Michael G. Ruppert and
• S. O. Reza Moheimani

Beilstein J. Nanotechnol. 2016, 7, 284–295, doi:10.3762/bjnano.7.26

• standard microelectromechanical system (MEMS) processes to coat a microcantilever with a piezoelectric layer results in a versatile transducer with inherent self-sensing capabilities. For applications in multifrequency atomic force microscopy (MF-AFM), we illustrate that a single piezoelectric layer can be

• fundamental mode, and phase imaging on the higher eigenmode. Keywords: atomic force microscopy; charge sensing; feedthrough cancellation; multimode sensor; piezoelectric cantilever; self-sensing; Introduction Emerging methods in multifrequency atomic force microscopy (MF-AFM) rely on the detection and

A simple and efficient quasi 3-dimensional viscoelastic model and software for simulation of tapping-mode atomic force microscopy

• Santiago D. Solares

Beilstein J. Nanotechnol. 2015, 6, 2233–2241, doi:10.3762/bjnano.6.229

• extremely useful in practice. Examples of typical force curves are provided for single- and multifrequency tapping-mode imaging, for both of which the force curves exhibit the expected features. Finally, a software tool to simulate amplitude and phase spectroscopy curves is provided, which can be easily

• modified to implement other controls schemes in order to aid in the interpretation of AFM experiments. Keywords: atomic force microscopy (AFM); modeling; multifrequency; multimodal; polymers; simulation; spectroscopy; standard linear solid; tapping-mode AFM; viscoelasticity; Introduction The

• simulations are provided in [10]. Figure 1b and Figure 1c give examples of tip–sample force curves for intermittent-contact AFM in single- and multifrequency operation, respectively, when using the SLS model to represent the surface. As can be seen, the force curve shows separate force minima for the position

Kelvin probe force microscopy for local characterisation of active nanoelectronic devices

• Tino Wagner,
• Hannes Beyer,
• Patrick Reissner,
• Philipp Mensch,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2015, 6, 2193–2206, doi:10.3762/bjnano.6.225

• remains in multifrequency AM-KFM and FM-KFM. Hence, for lift-mode the case A → 0 should be considered, whereas in single-scan modes the oscillation applied for tracking topography remains. For best sensitivity and minimal spatial averaging, AM and FM modes need to be operated very close to the surface

Optimization of phase contrast in bimodal amplitude modulation AFM

• Mehrnoosh Damircheli,
• Amir F. Payam and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 1072–1081, doi:10.3762/bjnano.6.108

• multifrequency force microscopy methods [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Bimodal force microscopy is a multifrequency AFM method that uses two eigenmode frequencies for excitation and detection (Figure 1) [9]. It has several configurations depending

• general those regimes appear when the modes are highly coupled. This happens when the energy of the first and second mode are comparable [35]. This context has also stimulated other multifrequency AFM variations such as trimodal AFM [39][40][41]. In trimodal AFM the first three flexural modes are excited

• these multifrequency AFM configurations. Conclusion We have studied the phase contrast in bimodal amplitude modulation AFM for the attractive and the repulsive interaction regimes as a function of the amplitude and amplitude ratio of the excited modes. We have found that the contrast increases by

Dynamic force microscopy simulator (dForce): A tool for planning and understanding tapping and bimodal AFM experiments

• Horacio V. Guzman,
• Pablo D. Garcia and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2015, 6, 369–379, doi:10.3762/bjnano.6.36

• spatial resolution and contrast of different dynamic AFM methods has also been studied by simulations [28][30][31]. Finally, the emergence of multifrequency AFM [32] in particular bimodal [33][34], trimodal [35], intermodulation [36] or torsional harmonics [37] has been supported by simulations [38]. In

• of multifrequency AFM. The future applications and understanding of dynamic AFM operation will be enhanced if accurate simulators are easily accessible to the experimentalist. These factors promote the development of AFM simulation platforms such as VEDA [41][42]. Here we present a dynamic AFM

Kelvin probe force microscopy in liquid using electrochemical force microscopy

• Liam Collins,
• Stephen Jesse,
• Jason I. Kilpatrick,
• Alexander Tselev,
• M. Baris Okatan,
• Sergei V. Kalinin and
• Brian J. Rodriguez

Beilstein J. Nanotechnol. 2015, 6, 201–214, doi:10.3762/bjnano.6.19

• long range and that any changes in separation due to drift were small compared to the tip–sample distance. Measurements in Figures 1–3 were performed using a multifrequency lock in amplifier (Zurich Instruments, HF2LI) having a built in electronic adder and Figures 4–7 were performed using two lock-in

High-frequency multimodal atomic force microscopy

• Adrian P. Nievergelt,
• Jonathan D. Adams,
• Pascal D. Odermatt and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2014, 5, 2459–2467, doi:10.3762/bjnano.5.255

• Adrian P. Nievergelt Jonathan D. Adams Pascal D. Odermatt Georg E. Fantner Laboratory for Bio- and Nano-Instrumentation, École Polytechnique Fédérale de Lausanne, Batiment BM 3109 Station 17, 1015 Lausanne, Switzerland 10.3762/bjnano.5.255 Abstract Multifrequency atomic force microscopy imaging

• topography as well as mechanical properties. Nevertheless, instrument bandwidth limitations on cantilever excitation and readout have restricted the ability of multifrequency techniques to fully benefit from small cantilevers. We present an approach for cantilever excitation and deflection readout with a

• bandwidth of 20 MHz, enabling multifrequency techniques extended beyond 2 MHz for obtaining materials contrast in liquid and air, as well as soft imaging of delicate biological samples. Keywords: atomic force microscopy; multifrequency imaging; nanomechanical characterization; photothermal excitation

Modeling viscoelasticity through spring–dashpot models in intermittent-contact atomic force microscopy

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 2149–2163, doi:10.3762/bjnano.5.224

• –distance curves, dissipated energy and any inherent unphysical artifacts. We focus in this paper on single-eigenmode tip–sample impacts, but the models and results can also be useful in the context of multifrequency AFM, in which the tip trajectories are very complex and there is a wider range of sample

• deformation frequencies (descriptions of tip–sample model behaviors in the context of multifrequency AFM require detailed studies and are beyond the scope of this work). Keywords: atomic force microscopy; creep; dissipated energy; multifrequency; stress relaxation; tapping mode; viscoelasticity

• progress has been recently achieved with regards to fast and simultaneous topographical and spectroscopic characterization of viscoelastic materials through the use of multifrequency AFM [21]. This work represents an important milestone in rapid and quantitative multi-property characterization, although it

Dynamic calibration of higher eigenmode parameters of a cantilever in atomic force microscopy by using tip–surface interactions

• Stanislav S. Borysov,
• Daniel Forchheimer and
• David B. Haviland

Beilstein J. Nanotechnol. 2014, 5, 1899–1904, doi:10.3762/bjnano.5.200

• physical amplitude of a higher eigenmode. Keywords: atomic force microscopy; calibration; multimodal AFM; multifrequency AFM; Introduction Atomic force microscopy [1] (AFM) is one of the primary methods of surface analysis with resolution at the nanometer scale. In a conventional AFM an object is scanned

• sets of cantilever parameters from Table 1. The cantilever is excited by using multifrequency drive (specified below) with frequencies being integer multiples of the base frequency δω = 2π·0.1 kHz. The tip–surface force F is represented by the vdW-DMT model [35] with the nonlinear damping term being

Trade-offs in sensitivity and sampling depth in bimodal atomic force microscopy and comparison to the trimodal case

• Babak Eslami,
• Daniel Ebeling and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1144–1151, doi:10.3762/bjnano.5.125

• ; multifrequency atomic force microscopy; indentation depth modulation; Nafion; open loop; proton exchange membranes; trimodal; Introduction Since its invention in the early 1980s [1], atomic force microscopy (AFM) has become one of the most widely used characterization tools in nanotechnology and a wide range of

• imaging modes is now available, each with its own capabilities and applications. Among them, a family of techniques known as multifrequency AFM [2][3][4][5][6][7][8][9][10][11] has expanded considerably since the introduction of the first bimodal method by Rodriguez and Garcia in 2004 [12]. In

• multifrequency AFM the cantilever probe is driven simultaneously at more than one frequency, with the objective of creating additional channels of information in order to provide a more complete picture of the sample morphology and properties [2]. In the original method of Garcia and coworkers [12][13] the first

Correction to "Energy dissipation in multifrequency atomic force microscopy"

• Valentina Pukhova,
• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2014, 5, 667–667, doi:10.3762/bjnano.5.78

• /bjnano.5.78 Keywords: band excitation; multifrequency atomic force microscopy (AFM); phase reference; wavelet transforms; In the section "Energy dissipation" of the above manuscript, there is a typesetting error in the mathematical expressions after Equation 5. The correct form must be: The energy

Energy dissipation in multifrequency atomic force microscopy

• Valentina Pukhova,
• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2014, 5, 494–500, doi:10.3762/bjnano.5.57

• evolution is studied by wavelet analysis techniques that have general relevance for multi-mode atomic force microscopy, in a regime where few cantilever oscillation cycles characterize the tip–sample interaction. Keywords: band excitation; multifrequency atomic force microscopy (AFM); phase reference

• ; wavelet transforms; Introduction Multifrequency dynamic atomic force microscopy [1] is a powerful technique to retrieve quantitative information on materials properties such as the elastic constants and the sample chemical environment with a lateral resolution in the nanometer range. In this context the

Challenges and complexities of multifrequency atomic force microscopy in liquid environments

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 298–307, doi:10.3762/bjnano.5.33

• context of multifrequency atomic force microscopy (AFM). The focus is primarily on (i) the amplitude and phase relaxation of driven higher eigenmodes between successive tip–sample impacts, (ii) the momentary excitation of non-driven higher eigenmodes and (iii) base excitation artifacts. The results and

• discussion are mostly applicable to the cases where higher eigenmodes are driven in open loop and frequency modulation within bimodal schemes, but some concepts are also applicable to other types of multifrequency operations and to single-eigenmode amplitude and frequency modulation methods. Keywords

• : amplitude-modulation; bimodal; frequency-modulation; liquids; multifrequency atomic force microscopy; Introduction Multifrequency atomic force microscopy (AFM) refers to a family of techniques that involve simultaneous excitation of the microcantilever probe at more than one frequency [1]. The first of

Frequency, amplitude, and phase measurements in contact resonance atomic force microscopies

• Gheorghe Stan and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 278–288, doi:10.3762/bjnano.5.30

• ), respectively [15][16][17][18][19][20]. In the last ten years, intermittent-contact measurements have been enhanced through multifrequency excitation methods [21][22][23][24][25][26][27]. In multifrequency AFM, the fundamental cantilever eigenmode is typically controlled in conventional AM- or FM-AFM mode for

Unlocking higher harmonics in atomic force microscopy with gentle interactions

• Sergio Santos,
• Victor Barcons,
• Josep Font and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2014, 5, 268–277, doi:10.3762/bjnano.5.29

• mapping of compositional variations [25] or as a closed loop, in which case the tip–sample stiffness kts can be computed [17][26]. More recently, the multifrequency AFM approach has been extended to employ three flexural modes [27] and/or simultaneous torsional modes [28], for which, typically, the

• and throughput [31]. The dynamics in the multifrequency approach, however, might lead to extra complexities in the analysis, acquisition and interpretation of data [31][32]. For example, recent studies [31] show that multiple regimes of operation might follow depending on the relative kinetic energy

• incommensurability between external drives in the standard multifrequency approach implies that the cantilever motion is not exactly periodic relative to the fundamental drive and that a sub-harmonic excitation typically follows [32]. Furthermore, simplifications in eigenmode frequency shift theory [36] might lead

Multiple regimes of operation in bimodal AFM: understanding the energy of cantilever eigenmodes

• Daniel Kiracofe,
• Arvind Raman and
• Dalia Yablon

Beilstein J. Nanotechnol. 2013, 4, 385–393, doi:10.3762/bjnano.4.45

• methods to calibrate stiffness and optical lever sensitivity of higher order eigenmodes. The current state of the art works well for the first few eigenmodes but becomes less reliable for third and higher modes. As multifrequency AFM evolves toward quantitative measurements using higher order eigenmodes

Polynomial force approximations and multifrequency atomic force microscopy

• Daniel Platz,
• Daniel Forchheimer,
• Erik A. Tholén and
• David B. Haviland

Beilstein J. Nanotechnol. 2013, 4, 352–360, doi:10.3762/bjnano.4.41

• to spectral data, and we demonstrate how it can be adapted to a force quadrature picture. Keywords: AFM; atomic force microscopy; force spectroscopy; multifrequency; intermodulation; polynomial; Introduction The combination of high-resolution imaging [1][2][3][4] and high-accuracy force

• measurements [5][6][7][8][9][10] is a strong driving force for the development of atomic force microscopy (AFM). The advent of multifrequency AFM resulted in a variety of new measurement techniques enabling enhanced contrast and spatial mapping of surface properties on a wide range of samples [11]. However

• , multifrequency AFM creates more data than conventional AFM, which both complicates the interpretation of measurement results and offers the possibility of much more detailed surface analysis. One of the goals when interpreting AFM data is the reconstruction of the force between a surface and the sharp tip at the

Bimodal atomic force microscopy driving the higher eigenmode in frequency-modulation mode: Implementation, advantages, disadvantages and comparison to the open-loop case

• Daniel Ebeling and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 198–207, doi:10.3762/bjnano.4.20

• of the second phase contrast to material properties in the small-amplitude regime. This method, which was later implemented experimentally [3] and studied further theoretically and computationally [4][5], gave birth to a new host of multifrequency AFM techniques, which nowadays include a wide variety

• -modulation (FM, [8][9]) method, as had been previously done for vacuum operations [10][11]. Our multifrequency technique was originally introduced for ambient air operation within a trimodal scheme [12][13], in which a third active eigenmode was added to the AM-OL method. Since the dynamics of this trimodal

• some cases, as well as facilitating mathematical reconstruction of the force curves and ensuring continuous acquisition of data without any jumps in the signals or cantilever response [29][30]. This is highly relevant in multifrequency operation, where one seeks to integrate imaging and spectroscopy

Towards 4-dimensional atomic force spectroscopy using the spectral inversion method

• Jeffrey C. Williams and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2013, 4, 87–93, doi:10.3762/bjnano.4.10

• phenomena take place when imaging samples in high-damping (liquid) environments [18] or in multifrequency AFM characterization [19]. Illustration of the surface depression by the tip–sample impact, and successive recovery within the standard linear solid model. Z1 is the undisturbed surface position, before

Interpreting motion and force for narrow-band intermodulation atomic force microscopy

• Daniel Platz,
• Daniel Forchheimer,
• Erik A. Tholén and
• David B. Haviland

Beilstein J. Nanotechnol. 2013, 4, 45–56, doi:10.3762/bjnano.4.5

• , providing deeper insight into the tip–surface interaction. We demonstrate the capabilities of ImAFM approach measurements on a polystyrene polymer surface. Keywords: atomic force microscopy; AFM; frequency combs; force spectroscopy; high-quality-factor resonators; intermodulation; multifrequency

• ][19]. In order to increase the accessible information while imaging with AFM, a variety methods have been put forward in which amplitude and phase at more than one frequency are analyzed. These multifrequency methods can be divided in to two general groups: those using only Fourier components with

Repulsive bimodal atomic force microscopy on polymers

• Alexander M. Gigler,
• Christian Dietz,
• Maximilian Baumann,
• Nicolás F. Martinez,
• Ricardo García and
• Robert W. Stark

Beilstein J. Nanotechnol. 2012, 3, 456–463, doi:10.3762/bjnano.3.52

• sample distortions [1][2][3][4][5]. In recent years, various multifrequency approaches for image-contrast enhancement in air and liquid environments have been established [6][7][8][9][10][11]. For example, in bimodal force microscopy [6][7][8][12], two modulation signals resonantly drive the cantilever