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

• understanding and, in the process, to improve the performance of amplitude modulation atomic force microscopy (AM-AFM), usually known as tapping mode AFM. The following discussion provides some examples. Simulations provided the first estimation of the forces and deformations involved in tapping mode AFM [1][2

• the case of bimodal AFM, numerical simulations [39] preceded and paved the way to its experimental development [33][40]. The complexity of amplitude modulation AFM makes it difficult to develop reliable code accessible for both the large community of tapping mode AFM users and the emerging community

• features. It can be run on Windows, Mac and Linux operating systems. It can be freely downloaded from our website [43]. The user interface has been designed to mimick some of the main steps of an amplitude modulation AFM experiment (Figure 1). The dForce user must be aware that the accuracy of the

Boosting the local anodic oxidation of silicon through carbon nanofiber atomic force microscopy probes

• Gemma Rius,
• Matteo Lorenzoni,
• Soichiro Matsui,
• Masaki Tanemura and
• Francesc Perez-Murano

Beilstein J. Nanotechnol. 2015, 6, 215–222, doi:10.3762/bjnano.6.20

• tip apex of AFM probes for the application of LAO on silicon substrates in the AFM amplitude modulation dynamic mode of operation. We show the good performance of CNF-AFM probes in terms of resolution and reproducibility, as well as demonstration that the CNF apex provides enhanced conditions in terms

• substrates in amplitude modulation dynamic mode of operation. In spite of the morphological and chemical resemblance, CNFs and CNTs exhibit fundamental structural differences. Both CNF and CNT are high aspect ratio morphologies (one-dimensional) made primarily of atomic carbon. However, a CNF consists of

• stages of the LAO-AFM tests (Zeiss, LEO 1530 operated at 3 keV). For comparison purposes, commercially available non-coated doped Si AFM probes from Nanosensors, OTESPA (force constant, k = 40 N·m−1), are employed. LAO-AFM and AFM imaging are performed in the amplitude modulation dynamic mode while using

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

• to higher frequencies. For simultaneous high-frequency imaging and mechanical property mapping, we use a bimodal resonant technique which tracks topography in amplitude modulation on the first eigenmode [5][38]. This mode is one of the possibilities of achieving materials contrast while

• and inversely with the quality factor. The increased ratio of resonance frequency to spring constant makes it clear that the use of small cantilevers is ideally suited for low-dissipation imaging on multiple dynamic modes. Drive amplitude modulation imaging For biophysical imaging with atomic force

• microscopy, the ability to scan delicate samples in high resolution is required when investigating soft nanostructures. A related technique to the dissipation imaging described above, drive amplitude modulation (DAM) is an imaging mode that allows for the control of the dissipation in the AC-mode tip–sample

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

• ; Introduction Atomic force microscopy (AFM) has evolved rapidly since its invention in the mid-1980s [1] and has been used since then for measuring topography and probe–sample forces on micro- and nanoscale surfaces in different environments. Tapping mode AFM (amplitude modulation, AM-AFM) is the most common

Mechanical properties of sol–gel derived SiO₂ nanotubes

• Boris Polyakov,
• Mikk Antsov,
• Sergei Vlassov,
• Leonid M Dorogin,
• Mikk Vahtrus,
• Roberts Zabels,
• Sven Lange and
• Rünno Lõhmus

Beilstein J. Nanotechnol. 2014, 5, 1808–1814, doi:10.3762/bjnano.5.191

• at its resonance frequency in amplitude modulation regime. The signal was enhanced by a lock-in amplifier (SR830, Stanford Research Systems) and recorded together with the data of the displacement sensors of the nanomanipulator. The measurements of the Young’s modulus consisted of a one-directional

Probing viscoelastic surfaces with bimodal tapping-mode atomic force microscopy: Underlying physics and observables for a standard linear solid model

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1649–1663, doi:10.3762/bjnano.5.176

• properties and the AFM observables. The physics of the tip–sample interactions and its effect on the observables are illustrated and discussed, and a brief research outlook on viscoelasticity measurement with intermittent-contact AFM is provided. Keywords: amplitude-modulation; bimodal; dissipation

• by using the conventional amplitude-modulation scheme (AM-AFM, tapping-mode [2]) to obtain the topography, while the second eigenmode is excited with constant drive amplitude and frequency. Compositional contrast is extracted from the response amplitude and phase of the second eigenmode (in this

• paper this mode of operation is referred to as AM-OL since the first mode is driven by using amplitude-modulation and the second mode is driven in ‘open loop’). Since the settings of the higher eigenmode are not controlled by the AM-AFM loop, its excitation amplitude (and in principle also the drive

Multi-frequency tapping-mode atomic force microscopy beyond three eigenmodes in ambient air

• Santiago D. Solares,
• Sangmin An and
• Christian J. Long

Beilstein J. Nanotechnol. 2014, 5, 1637–1648, doi:10.3762/bjnano.5.175

• future research opportunities. Keywords: amplitude-modulation; bimodal; frequency-modulation; multi-frequency atomic force microscopy; multimodal; open loop; trimodal; Introduction Multi-frequency atomic force microscopy (AFM) refers to a family of techniques in which the microcantilever probe is

• results of Figure 3 also highlight subtleties in the amplitude curve that could be important depending on the sample and the type of information sought. Specifically, the results show that the amplitude curve for the first eigenmode, which is the basis of the amplitude modulation method [24], is not a

• , and that the work reported here represents by no means an exhaustive study. High-damping environments may offer even greater complexities [31] and our amplitude-modulation/open-loop results are not directly applicable to vacuum environments [24][32]. Methods Experimental The tetramodal experiments

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

• demonstrate that the two eigenmodes can be highly coupled in practice, especially when highly repulsive imaging conditions are used. Finally, we also offer a comparison with a previously reported trimodal AFM method, where the above competing effects are minimized. Keywords: amplitude modulation; bimodal

• eigenmode of the cantilever is driven using the amplitude modulation scheme (AM-AFM [14]) while a higher eigenmode is simultaneously driven at or near its resonance frequency with constant amplitude and frequency (i.e., in “open loop”) in order to track its phase with respect to the excitation signal. Since

• the higher eigenmode is not directly subject to the amplitude modulation control loop that governs the acquisition of the topography, the user has freedom in selecting its operating parameters, thus allowing it to explore a wider range of tip–sample interactions. Additionally, since its amplitude is

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

• : 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

• these methods was proposed by García and coworkers in 2004 to carry out simultaneous non-contact amplitude-modulation imaging and open-loop (phase contrast) compositional mapping of surfaces in air by exciting and controlling the first two eigenmodes of the cantilever [2]. This approach has since been

• most directly applicable to bimodal techniques where the higher eigenmode is driven in open loop [5][8] or frequency modulation [4], but the principles are general enough that they are also relevant to other multifrequency methods and in some cases also to single-mode frequency and amplitude modulation

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

• using the tapping-mode (amplitude modulation) technique [13], within which variations in the phase contrast can be directly related to changes in energy dissipation [14][15]. Conservative and dissipative interactions are generally expressed in terms of the virial (Vts) and the dissipated power (Pts

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

• between the higher mode of choice and the fundamental eigenmode [31][33]. Here, exact multiple harmonics of the fundamental drive frequency are externally excited above the noise level to open multiple contrast channels that are sensitive to compositional variations. The focus is on amplitude modulation

Manipulation of nanoparticles of different shapes inside a scanning electron microscope

• Boris Polyakov,
• Sergei Vlassov,
• Leonid M. Dorogin,
• Jelena Butikova,
• Mikk Antsov,
• Sven Oras,
• Rünno Lõhmus and
• Ilmar Kink

Beilstein J. Nanotechnol. 2014, 5, 133–140, doi:10.3762/bjnano.5.13

• cantilevers is tilted about 15 degrees relative to the cantilever, providing visibility of the tip from the top (Figure 1). In the experiments the QTF was driven electrically on its resonance frequency in the self-excitation regime in amplitude-modulation mode. The oscillation parameters of such a system

Exploring the retention properties of CaF₂ nanoparticles as possible additives for dental care application with tapping-mode atomic force microscope in liquid

• Matthias Wasem,
• Joachim Köser,
• Sylvia Hess,
• Enrico Gnecco and
• Ernst Meyer

Beilstein J. Nanotechnol. 2014, 5, 36–43, doi:10.3762/bjnano.5.4

• International AG, Grabetsmattweg, 4106 Therwil, Switzerland Instituto Madrileño de Estudios Avanzados, IMDEA Nanociencia, 28049 Madrid, Spain 10.3762/bjnano.5.4 Abstract Amplitude-modulation atomic force microscopy (AM-AFM) is used to determine the retention properties of CaF2 nanoparticles adsorbed on mica

• substrate roughness, morphology and size of the particles. Keywords: AM-AFM in liquid; nanodentistry; nanoparticles; Introduction Amplitude-modulation atomic force microscopy (AM-AFM), also known as tapping mode AFM, is a variant of scanning probe microscopy. In this dynamic technique imaging is achieved

Noise performance of frequency modulation Kelvin force microscopy

• Heinrich Diesinger,
• Dominique Deresmes and
• Thierry Mélin

Beilstein J. Nanotechnol. 2014, 5, 1–18, doi:10.3762/bjnano.5.1

• electrostatic forces in amplitude modulation Kelvin force microscopy (AM-KFM) [1] or the measurement of the electrostatic force gradient in FM-KFM [2], in analogy with the FM mode used in noncontact atomic force microscopy (nc-AFM) [3]. The FM-KFM mode is often favored either because when a higher derivative of

Peak forces and lateral resolution in amplitude modulation force microscopy in liquid

• Horacio V. Guzman and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2013, 4, 852–859, doi:10.3762/bjnano.4.96

• microscopy; lateral resolution; nanomechanics; peak force; Introduction The high-resolution imaging of heterogeneous materials, in particular soft materials in liquid, by amplitude modulation atomic force microscopy (AM-AFM) is an active area of research in nanotechnology [1][2][3][4][5][6][7][8][9][10][11

• nm. We have separated the plots into regions, for soft materials (Figure 5a) a small sub-100 pN force value is used; while for rigid materials (Figure 5b) a sub-1 nN reference value is considered. Conclusion The numerical simulation of the tip motion in amplitude modulation AFM provides a

Kelvin probe force microscopy of nanocrystalline TiO₂ photoelectrodes

• Alex Henning,
• Gino Günzburger,
• Res Jöhr,
• Yossi Rosenwaks,
• Biljana Bozic-Weber,
• Catherine E. Housecroft,
• Edwin C. Constable,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2013, 4, 418–428, doi:10.3762/bjnano.4.49

• H2O and <10 ppm O2) on a commercial microscope (Solver PH-47, NT-MDT). Amplitude modulation (AM) KPFM was conducted with a two-scan method (lift mode) meaning that the topography and CPD were measured separately (Figure 10). During the first line scan the topography was determined in tapping mode AFM

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

• -/nanoscale [1]. Although there are many different operating modes in AFM, one of the most popular is amplitude modulation (AM-AFM), commonly known as tapping mode, in which the cantilever is oscillated at its first natural frequency. AM-AFM provides two basic images of the surface, a height (topography

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

• fundamental eigenmode is driven by using the amplitude-modulation technique (AM-AFM) while a higher eigenmode is driven by using either the constant-excitation or the constant-amplitude variant of the frequency-modulation (FM-AFM) technique. We also offer a comparison to the original bimodal AFM method, in

• provides information and guidelines that can be useful in selecting the most appropriate operation mode to characterize different samples in the most efficient and reliable way. Keywords: amplitude-modulation; atomic force microscopy; frequency-modulation; phase-locked loop; spectroscopy; Introduction

• the amplitude-modulation (AM) scheme while the second eigenmode was driven with a much smaller amplitude in open loop (OL, that is, only the first mode amplitude signal was used to control the tip–sample distance feedback loop. The second eigenmode drive signal had a constant amplitude and frequency

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

• John Melcher,
• David Martínez-Martín,
• Miriam Jaafar,
• Julio Gómez-Herrero and
• Arvind Raman

Beilstein J. Nanotechnol. 2013, 4, 153–163, doi:10.3762/bjnano.4.15

• 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

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

• consists of (i) defining the system parameters (cantilever eigenfrequencies, force constants and quality factors, free flexural amplitude and amplitude setpoint, tip–sample force model, etc.); (ii) numerical implementation of the amplitude-modulation imaging scheme; (iii) recording of the flexural and

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

• slow-time-scale dynamics is given by the down-shifted intermodulation spectrum, which describes a slow amplitude modulation and a slow phase or frequency modulation of the signal in the time domain. Physical interpretation of the tip motion and force envelope functions in ImAFM In ImAFM the measured

• -modulation AFM (FM-AFM) and amplitude-modulation AFM (AM-AFM) FI and FQ are usually probed by a slow variation of the probe height h with fixed oscillation amplitude at each height. To measure FI and FQ in FM-AFM the oscillation frequency shift and the drive force are recorded as the static probe height is

• slowly extending the z-piezo toward the surface. However, in contrast to FM-AFM and AM-AFM measurements, the oscillation amplitude is rapidly modulated as the probe slowly approaches the surface. Because the height variation is much slower (order of seconds) than the amplitude modulation (order of

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

• at two eigenmodes simultaneously. In the amplitude modulation mode, two lock-in amplifiers demodulate the signal with respect to both driving frequencies. Thus, one obtains the amplitude and phase signal for both oscillations. The fundamental eigenmode provides the amplitude signal for topography

• can enhance material contrast with respect to conventional amplitude-modulation modes [7][8][14][15][16], with piconewton force sensitivity. Local variations of the Hamaker constant cause material contrast in the attractive imaging regime [8][15]. Repulsive bimodal force microscopy imaging has been

• conventional single-mode amplitude-modulation imaging (e.g., [22]; data not shown). We recorded amplitude and phase images for the second eigenmode. The amplitude signal of the second eigenmode (Figure 5c) reveals local mechanical and dissipative properties of the thin film. For PS, the oscillation amplitude

Drive-amplitude-modulation atomic force microscopy: From vacuum to liquids

• Miriam Jaafar,
• David Martínez-Martín,
• Mariano Cuenca,
• John Melcher,
• Arvind Raman and
• Julio Gómez-Herrero

Beilstein J. Nanotechnol. 2012, 3, 336–344, doi:10.3762/bjnano.3.38

• , Spain Department of Engineering Mathematics, University of Bristol, Bristol BS8 1TR, United Kingdom Birck Nanotechnology Center and School of Mechanical Engineering, Purdue University, West Lafayette, IN 47904-2088, USA 10.3762/bjnano.3.38 Abstract We introduce drive-amplitude-modulation atomic force

• nanoscale resolution. Amplitude-modulation AFM (AM-AFM) [7] and in particular its large-amplitude version, commonly known as tapping mode [8], is the most extended dAFM mode, but it has limitations: Its application to the vacuum environment is very difficult because of the long scanning times imposed by the

• involved in the experiment [19]. In this work we present a new AFM scanning mode, which we have called “drive amplitude modulation” (DAM-AFM) [20] and which takes advantage of the aformentioned monotonicity of the dissipation to obtain stable images in all environments from vacuum to liquids. Moreover, DAM

Nano-FTIR chemical mapping of minerals in biological materials

• Sergiu Amarie,
• Paul Zaslansky,
• Yusuke Kajihara,
• Erika Griesshaber,
• Wolfgang W. Schmahl and
• Fritz Keilmann

Beilstein J. Nanotechnol. 2012, 3, 312–323, doi:10.3762/bjnano.3.35

• notice on close inspection of all biocarbonate surfaces, e.g., in Figure 1, a shallow amplitude modulation on a 50–200 nm lateral scale, which we tentatively explain to be due to a mesocrystalline substructure that has been recently observed by SEM [35]. In Figure 3 and Figure 5 the infrared resonance is

Wavelet cross-correlation and phase analysis of a free cantilever subjected to band excitation

• Francesco Banfi and
• Gabriele Ferrini

Beilstein J. Nanotechnol. 2012, 3, 294–300, doi:10.3762/bjnano.3.33

• of the superposition of spectral contributions generated at different times. In amplitude-modulation AFM (tapping mode) wavelet analysis is useful to track the time evolution of the nonlinearities in tip–surface dynamics. The wavelet analysis allows one to follow more than a single flexural mode