Quantitative comparison of wideband low-latency phase-locked loop circuit designs for high-speed frequency modulation atomic force microscopy

• Kazuki Miyata and
• Takeshi Fukuma

Beilstein J. Nanotechnol. 2018, 9, 1844–1855, doi:10.3762/bjnano.9.176

• the FPGA to enable measurement of the frequency response of the PLL itself. In the measurements, we modulated the phase to induce Δω. This method perfectly reproduces what happens in actual FM-AFM experiments, in which the tip–sample interaction force first induces a phase shift of the cantilever

Know your full potential: Quantitative Kelvin probe force microscopy on nanoscale electrical devices

• Amelie Axt,
• Ilka M. Hermes,
• Victor W. Bergmann,
• Niklas Tausendpfund and
• Stefan A. L. Weber

Beilstein J. Nanotechnol. 2018, 9, 1809–1819, doi:10.3762/bjnano.9.172

• tip–sample interaction is minimized (Feed-forward compensation [40]). The lift height was set to 10 nm. As we show in the wiring scheme (Figure S14 and Figure S15, Supporting Information File 1) UDC is applied to the tip. We connected the cantilever chip with an external wire to minimizie electrical

Direct AFM-based nanoscale mapping and tomography of open-circuit voltages for photovoltaics

• Katherine Atamanuk,
• Justin Luria and
• Bryan D. Huey

Beilstein J. Nanotechnol. 2018, 9, 1802–1808, doi:10.3762/bjnano.9.171

• underpins nearly all AFM topography imaging. Normally, this feedback loop continually updates the AFM probe height in order to maintain a constant AFM tip–sample interaction, which is sensed via the integrated cantilever deflection or amplitude that, of course, changes at surface protrusions or depressions

Correlative electrochemical strain and scanning electron microscopy for local characterization of the solid state electrolyte Li_1.3Al_0.3Ti_1.7(PO₄)₃

• Nino Schön,
• Deniz Cihan Gunduz,
• Shicheng Yu,
• Hermann Tempel,
• Roland Schierholz and
• Florian Hausen

Beilstein J. Nanotechnol. 2018, 9, 1564–1572, doi:10.3762/bjnano.9.148

• ]. Further information on how to connect this instrument to a Bruker Dimension Icon AFM is described in [35]. The applied AC frequency must match the contact resonance frequency of the cantilever used, and is exactly given in the respective figure caption. To ensure a stable tip–sample interaction, a slow

Optical near-field mapping of plasmonic nanostructures prepared by nanosphere lithography

• Gitanjali Kolhatkar,
• Alexandre Merlen,
• Jiawei Zhang,
• Chahinez Dab,
• Gregory Q. Wallace,
• François Lagugné-Labarthet and
• Andreas Ruediger

Beilstein J. Nanotechnol. 2018, 9, 1536–1543, doi:10.3762/bjnano.9.144

• can be attributed to an interference phenomenon between the light scattered by the tip, the tip–sample interaction and the sample itself, as illustrated in Figure 1d. All these contributions combine to form a complex interferometric pattern recorded by the PMT. But this pattern does not contain any

Electrostatically actuated encased cantilevers

• Benoit X. E. Desbiolles,
• Gabriela Furlan,
• Adam M. Schwartzberg,
• Paul D. Ashby and
• Dominik Ziegler

Beilstein J. Nanotechnol. 2018, 9, 1381–1389, doi:10.3762/bjnano.9.130

• Background: Encased cantilevers are novel force sensors that overcome major limitations of liquid scanning probe microscopy. By trapping air inside an encasement around the cantilever, they provide low damping and maintain high resonance frequencies for exquisitely low tip–sample interaction forces even when

• resonances of the chip, chip holder, or dither piezo [1] along with modes of fluid vibration when working in liquids [2]. The problem is accentuated at high frequencies when operating in high-viscosity liquids. A user can easily select the wrong peak resulting in increased tip–sample interaction forces or

• implementation remains difficult because alignment of an electrode is generally cumbersome and electrostatic forces frequently convoluted with the tip–sample interaction where changes in capacitance gradient due to topographical features influence cantilever excitation. An optically transparent electrode [20] or

Imaging of viscoelastic soft matter with small indentation using higher eigenmodes in single-eigenmode amplitude-modulation atomic force microscopy

• Miead Nikfarjam,
• Enrique A. López-Guerra,
• Santiago D. Solares and
• Babak Eslami

Beilstein J. Nanotechnol. 2018, 9, 1116–1122, doi:10.3762/bjnano.9.103

• model with the parameters of Table 1. The results show: (a) the peak tip–sample interaction force, and (b) the maximum indentation depth, with respect to amplitude setpoint ratio for AM-AFM using the first eigenmode (red line), AM-AFM using the second eigenmode (blue line), and bimodal AFM using the

Scanning speed phenomenon in contact-resonance atomic force microscopy

• Christopher C. Glover,
• Jason P. Killgore and
• Ryan C. Tung

Beilstein J. Nanotechnol. 2018, 9, 945–952, doi:10.3762/bjnano.9.87

• –sample interaction, in permanent contact with the surface, alleviating the complicated effects introduced by liquid environments and nonlinear tip–sample interaction forces. CR methods can measure surface elastic [2], viscoelastic [3], electromechanical [4], and chemical properties [5]. For mechanical

• properties, the methods are well understood, producing highly accurate quantitative measurements at the nanoscale [6]. The effect of scan velocity, with regards to the dynamic behavior of the tip–sample interaction in AFM, has been largely ignored [7][8][9]. Enhancement of scan speeds in AFM is a rich and

• phenomenon was not observed in the regime suggests that the additional water layers have changed the dynamics of the tip–sample interaction. Furthermore, higher adhesion forces found on mica at 70% RH might change the threshold speed needed to achieve hydrodynamic lift. Conclusion This work has shown the

A robust AFM-based method for locally measuring the elasticity of samples

• Alexandre Bubendorf,
• Stefan Walheim,
• Thomas Schimmel and
• Ernst Meyer

Beilstein J. Nanotechnol. 2018, 9, 1–10, doi:10.3762/bjnano.9.1

• . On the right, a schematic of the tip–sample interaction is depicted. Loosely bound FDTS molecules are able to migrate to the AFM tip and can therefore functionalize by forming a thin layer on the tip apex. Value of the inverse of the fitting curve slope of Z(FN,meas) for the measured samples in

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

• Weijie Zhang,
• Yuhang Chen,
• Xicheng Xia and
• Jiaru Chu

Beilstein J. Nanotechnol. 2017, 8, 2771–2780, doi:10.3762/bjnano.8.276

• 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

• of the sixth harmonic amplitude on the set-point, a theoretical simulation of the harmonic imaging was carried out. The cantilever dynamics in the presence of the tip–sample interaction forces can be described by [31], In Equation 2, the integer number n refers to the nth eigenmode and yn denotes the

• estimate their mixture ratio in nanocomposites. Several important factors including the amplitude set-point, drive frequency and laser spot location were investigated systematically. Changing the set-point will induce alternation of the tip–sample interaction forces and thus different harmonic amplitudes

Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

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

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• . This satisfactory agreement has been observed for all cases studied, which illustrates the robustness of the analytical solution. It is important to note that the analytical solution derived does not consider the attractive portion of the vdW tip–sample interaction (for simplicity), but instead only

• dissipation in the tip–sample interaction [34][40][41]. However, it is well known that varying the dynamic AFM parameters (e.g., excitation frequency, tapping amplitude) can significantly alter the calculated values of dissipated energy when imaging viscoelastic polymers [35]. This clearly represents a

• parameters) and Zeq. Fortunately, San Paulo and García [18] have shown that, besides energy dissipation, it is possible to obtain another meaningful energy quantity defined as the convolution of the tip–sample interaction force with the tip deflection [44], as described in Equation 9. This is the virial that

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

• Juan Ren and
• Qingze Zou

Beilstein J. Nanotechnol. 2017, 8, 1563–1570, doi:10.3762/bjnano.8.158

• 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. Keywords: adaptive multiloop mode; atomic force microscopy (AFM); heterogeneous polymer sample; tapping-mode

• imaging because an increase of the speed can cause a loss of the tip–sample interaction and/or the annihilation of the cantilever tapping vibration, particularly when the imaging size is large. Existing efforts on high-speed TM imaging [6][7][8][9] only led to a speed increase up to three times at the

• cost of a substantially (over five times) increased imaging force. By using the AMLM imaging mode, it is aimed to achieve high-speed dynamic-mode AFM imaging while maintaining the tip–sample interaction force similar as that in low-speed TM imaging. The speed increase of TM imaging is limited by the

A review of demodulation techniques for amplitude-modulation atomic force microscopy

• Michael G. Ruppert,
• David M. Harcombe,
• Michael R. P. Ragazzon,
• S. O. Reza Moheimani and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2017, 8, 1407–1426, doi:10.3762/bjnano.8.142

• the late 1980s had little to do with modulation to begin with, a fundamental prerequisite was given by the nonlinear tip–sample interaction force. With the advent of dynamic imaging modes [9], in which the microcantilever is excited at one of its resonance frequencies, the foundation for transmitting

Scaling law to determine peak forces in tapping-mode AFM experiments on finite elastic soft matter systems

• Horacio V. Guzman

Beilstein J. Nanotechnol. 2017, 8, 968–974, doi:10.3762/bjnano.8.98

• oscillates at its fundamental flexural resonant frequency while the amplitude is used as the feedback parameter to record the topography while imaging. When the tip is in close proximity to the sample the amplitude and the phase shift of the oscillation change with the strength of the tip–sample interaction

• with a certain salt concentration that reduces the electrostatic interactions to a minimum are assumed as medium conditions in this article [33]. The use of Hertzian mechanics has been generalized to model the tip–sample interaction forces for relatively rigid materials [34]. However, for finite soft

• mass of the fluid [39], and ω0, Q, k and Fts are the angular resonant frequency, quality factor, spring constant and tip–sample interaction forces, respectively. The latter has been modelled according to the Tatara contact mechanics [35][36][37] which is given by with the constitutive material

Functional dependence of resonant harmonics on nanomechanical parameters in dynamic mode atomic force microscopy

• Federico Gramazio,
• Matteo Lorenzoni,
• Francesc Pérez-Murano,
• Enrique Rull Trinidad,
• Urs Staufer and
• Jordi Fraxedas

Beilstein J. Nanotechnol. 2017, 8, 883–891, doi:10.3762/bjnano.8.90

• frequencies fn = nf [2][3]: where a is a constant amplitude value. The An coefficients can be analytically calculated, in the limit of weak tip–sample interaction (A1 >> An for n > 1), by integrating the force field Fts that is modulated by weighted Chebyshev polynomials of the first kind, Tn(u) [4][5]. The

• tip radius, free oscillation amplitude, cantilever stiffness and sample Young’s modulus. Because of the low amplitudes of the involved harmonics (well below 1 nm), we concentrate on the repulsive regime of the tip–sample interaction and on those harmonics close to flexural eigenmodes of rectangular

Noise in NC-AFM measurements with significant tip–sample interaction

• Jannis Lübbe,
• Matthias Temmen,
• Philipp Rahe and
• Michael Reichling

Beilstein J. Nanotechnol. 2016, 7, 1885–1904, doi:10.3762/bjnano.7.181

• amplitude noise if there are significant tip–sample interactions. The total noise power spectral density DΔf(fm) is, however, not just the sum of these noise contributions. Instead its magnitude and spectral characteristics are determined by the strongly non-linear tip–sample interaction, by the coupling

• compare experimental data to simulations based on a model of the NC-AFM system that includes the tip–sample interaction. The good agreement between predicted and measured noise spectra confirms that the model covers the relevant noise contributions and interactions. Results yield a general understanding

• : amplitude noise; cantilever stiffness; closed loop; detection system noise; frequency shift noise; non-contact atomic force microscopy (NC-AFM); Q-factor; spectral analysis; thermal noise; tip–sample interaction; Introduction Non-contact atomic force microscopy (NC-AFM) [1][2] is an unmatched surface

Customized MFM probes with high lateral resolution

• Óscar Iglesias-Freire,
• Miriam Jaafar,
• Eider Berganza and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2016, 7, 1068–1074, doi:10.3762/bjnano.7.100

• magnetostatic tip–sample interaction as a function of the magnetic field. By assuming that the sample magnetization remains unchanged during the experiment (Hc >> Happlied), as is commonly assumed to be the case for magnetic hard disks, one can gain insight into the evolution of the spins at the tip apex with

Generalized Hertz model for bimodal nanomechanical mapping

• Aleksander Labuda,
• Marta Kocuń,
• Waiman Meinhold,
• Deron Walters and
• Roger Proksch

Beilstein J. Nanotechnol. 2016, 7, 970–982, doi:10.3762/bjnano.7.89

• interaction stiffness for both resonant modes, each yielding a simple analytical expression. These two independent pieces of information are refactored to provide information about modulus and indentation depth. While the theory is generally applicable to a wide range of tip–sample interaction models, the

• the Appendix (b). Importantly, it is the true contact radius rc that defines the tip–sample interaction stiffness, as derived by Oliver and Pharr [27]: Substituting in the expression for rc leads to the general form The interaction stiffness in Equation 5 is plotted for three special cases in Figure 3

• parameter L in the degenerate case m = 2 (cone), a half-angle parameter θ may be introduced by multiplying kint by (tan θ)−1 to fully define the geometry of the conical indenter, if necessary.) Bimodal interaction theory This section first describes how the tip–sample interaction stiffness of a paraboloidal

Modelling of ‘sub-atomic’ contrast resulting from back-bonding on Si(111)-7×7

• Adam Sweetman,
• Samuel P. Jarvis and
• Mohammad A. Rashid

Beilstein J. Nanotechnol. 2016, 7, 937–945, doi:10.3762/bjnano.7.85

• deflection of the probe particle as it explores the tip–sample interaction. Interestingly, when only the adatoms and rest atoms are included in the surface slab (right hand column) the rest atoms appear clearly triangular, and the adatoms also have a triangular symmetry, despite the lack of atoms in the

Understanding interferometry for micro-cantilever displacement detection

• Alexander von Schmidsfeld,
• Tobias Nörenberg,
• Matthias Temmen and
• Michael Reichling

Beilstein J. Nanotechnol. 2016, 7, 841–851, doi:10.3762/bjnano.7.76

• any tip–sample interaction. The optical fiber, IV, is glued in a ferrule, V, which is bent by 15° with respect to the vertical axis to match the cantilever angle. The fiber end is coarse-approached from the top with a piezoelectric actuator moving the triangular sapphire prism, VI, along the z-axis

Correlative infrared nanospectroscopic and nanomechanical imaging of block copolymer microdomains

• Benjamin Pollard and
• Markus B. Raschke

Beilstein J. Nanotechnol. 2016, 7, 605–612, doi:10.3762/bjnano.7.53

• dissipation of the tip–sample interaction, simultaneously [12][13]. Corresponding quantitative values can be extracted from calibrated force–distance curves at every pixel to build up a multidimensional force–distance image. In this work we acquire force–distance curves, as shown in Figure 1a, using a

• surface, as shown schematically in Figure 1b. The localized tip–sample interaction depends on the optical properties of the sample directly below the apex. By scanning the sample, keeping the tip stationary with respect to the laser focus, we can create maps of optical properties of the sample

• match the range measured on PS-b-PMMA from similar techniques [14][26][27]. The height (Figure 3d), tapping phase (Figure 3e), adhesion (Figure 3f), dissipation (Figure 3g), and deformation (Figure 3h) images represent aspects of the physical tip–sample interaction. For example, we observe a topographic

Nanoscale effects in the characterization of viscoelastic materials with atomic force microscopy: coupling of a quasi-three-dimensional standard linear solid model with in-plane surface interactions

• Santiago D. Solares

Beilstein J. Nanotechnol. 2016, 7, 554–571, doi:10.3762/bjnano.7.49

• microscopy (AFM) methods designed to measure surface material properties. However, current methods are based on one-dimensional (1D) descriptions of the tip–sample interaction forces, thus neglecting the intricacies involved in the material behavior of complex samples (such as soft viscoelastic materials) as

• indentation profiles and tip–sample interaction force curves, as well as their implications with regards to experimental interpretation. A variety of phenomena are examined in detail, which highlight the need for further development of more physically accurate sample models that are specifically designed for

• the AFM tip is very small, so the tip–sample interaction force curve at the desired force setpoint can be considered to be a straight line for the range of tip positions explored. Similar approaches have been used in force modulation techniques (FMOD-AFM), where the sample is dynamically probed at

Length-extension resonator as a force sensor for high-resolution frequency-modulation atomic force microscopy in air

• Hannes Beyer,
• Tino Wagner and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2016, 7, 432–438, doi:10.3762/bjnano.7.38

• stiffness k of the LER leads to a frequency shift signal about 20 times smaller compared to quartz tuning fork sensors. For accurate measurements with the LER it is important to minimise disturbances of the resonance frequency by sources unrelated to the tip–sample interaction. Figure 2a shows the variation

• . Conclusion We have demonstrated high-resolution FM-AFM imaging under ambient conditions with the length-extension resonator. The resonator can be operated stably at small as well as large tip–sample interaction forces. Adsorbates of nitrogen were imaged on HOPG, which paves the road for high-resolution

Rigid multipodal platforms for metal surfaces

• Michal Valášek,
• Marcin Lindner and
• Marcel Mayor

Beilstein J. Nanotechnol. 2016, 7, 374–405, doi:10.3762/bjnano.7.34

• these strongly bounded azobenzenes 13 with tripodal anchor mounted on the gold surfaces results in an in situ change of the tip apexes and in a radically different tip–sample interaction. These features not only allow for novel kinds of chemical analysis on submolecular scale but also enable high

Large area scanning probe microscope in ultra-high vacuum demonstrated for electrostatic force measurements on high-voltage devices

• Urs Gysin,
• Thilo Glatzel,
• Thomas Schmölzer,
• Adolf Schöner,
• Sergey Reshanov,
• Holger Bartolf and
• Ernst Meyer

Beilstein J. Nanotechnol. 2015, 6, 2485–2497, doi:10.3762/bjnano.6.258

• certain surface area. The tip height is controlled by a feedback loop correlating the tip–sample interaction with the deflection of the cantilever. However, the interaction force contains many different components which can only be partly suppressed (e.g., magnetic forces when inspecting non-magnetic