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

• generated as a result of sample deformation increase as the tip velocity increases. Since the eigenfrequencies in a cantilever increase with eigenmode order, and since higher oscillation frequencies lead to higher tip velocities for a given amplitude (in viscoelastic materials), the sample indentation can

• in some cases be reduced by using higher eigenmodes of the cantilever. This effect competes with the lower sensitivity of higher eigenmodes, due to their larger force constant, which for elastic materials leads to greater indentation for similar amplitudes, compared with lower eigenmodes. We offer a

• versatility of the instrument, it has been proposed to use higher cantilever eigenmodes, either by themselves in single-eigenmode imaging [6][7][8][9] or within multifrequency techniques [10]. For example, in the original multifrequency AFM method, introduced by Garcia and coworkers and known as bimodal AFM

A simple extension of the commonly used fitting equation for oscillatory structural forces in case of silica nanoparticle suspensions

• Sebastian Schön and
• Regine von Klitzing

Beilstein J. Nanotechnol. 2018, 9, 1095–1107, doi:10.3762/bjnano.9.101

• before use. Methods Experiments have been conducted using the colloidal probe atomic force microscopy technique (CP-AFM) as introduced by Ducker and Butt [60][61]. For this method, a large silica sphere, 6.7 μm in diameter, is glued (UHU endfest 300) onto the tip of a cantilever (CSC38 tipless micromash

• ) serving as colloidal probe. The spring constant of the cantilever was determined via the thermal noise method [62]. The surface of the colloidal probe and the silicon wafer form the two confining walls for the experiment. As the colloidal probe is orders of magnitude larger than their distance, the forces

• an increased variation for the amplitude (24.4%) and the decay length (14.5%) for experiments conducted with different cantilevers/colloidal probes (nine measurements) compared to experiments conducted with the same cantilever/colloidal probe (five measurements), where the amplitude varied by 7.2

Automated image segmentation-assisted flattening of atomic force microscopy images

• Yuliang Wang,
• Tongda Lu,
• Xiaolai Li and
• Huimin Wang

Beilstein J. Nanotechnol. 2018, 9, 975–985, doi:10.3762/bjnano.9.91

• while the z-scanner adjusts the vertical position of the AFM cantilever substrate to maintain constant interaction between the cantilever tip and sample surface. Together, the two stages provide a three-dimensional (3D) topographical reconstruction of the sample surface. However, the obtained images are

• AFM (Resolve, Bruker) in tapping mode with 96% setpoint value. A silicon cantilever (NSC36/ALBS, MikroMasch) with quoted stiffness of 0.6 N/m and tip radius of 8 nm was used for scanning. The scanning frequency and scanning angle were 2 Hz and 0°, respectively. Methods The step-by-step procedure of

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• data acquired under (no) illumination. A plot enabling a direct comparison of all data for −3 V < VTip < 3 V and their variation according region and illumination condition is shown in Figure S3 in Supporting Information File 1. In conventional EFM, cantilever oscillation frequency shift (∆ω) can be

• resulting from permanent polarization or free charges on the surface [34]. In a simpler form, Equation 1 can be rewritten as According to Equation 1 and Equation 2, and since all EFM experiments were performed using the same cantilever and at a fixed lift height (fixed capacitance geometry), ∆ω in each

• smaller than the symbol size in the graphs). The SKPM imaging was performed in the amplitude mode (AM-SKPM) with an AC bias VAC = 2 V applied to the probe at the resonant frequency of the cantilever and a lift height z = 20 nm. Steady-state photoluminescence (PL) measurements of RA monolayer/graphene

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

• dependence has also been observed in contact-resonance spectroscopy experiments. Killgore et al. [3] reported a scan-speed dependence of the measured CR frequencies of an AFM cantilever. Above a critical speed, CR frequency and quality factor decreased with increasing scan speed. However, in that work, the

• Equation 2 can be neglected. Integrating across the length of the channel, we obtain the vertical lift force F: The fluid film stiffness is then given by: In order to measure the sample stiffness using CR, we use a combination of measured in-contact resonance frequencies. The cantilever beam is modeled as

• , in the absence of a fluid layer, is defined as α = ks/kc, where ks is the sample stiffness and kc is the static cantilever stiffness (). The characteristic equation has the form . Using the measured in-contact frequencies, we can calculate the non-dimensional wavenumbers using the relation where

Combined pulsed laser deposition and non-contact atomic force microscopy system for studies of insulator metal oxide thin films

• Daiki Katsube,
• Hayato Yamashita,
• Satoshi Abo and
• Masayuki Abe

Beilstein J. Nanotechnol. 2018, 9, 686–692, doi:10.3762/bjnano.9.63

• ][35][36][37][38][39][40][41][42][43][44][45][46][47] have played important roles. NC-AFM in particular can be used to elucidate the structures of surfaces at the atomic scale. An NC-AFM measures the shift in cantilever resonance due to the interaction force between the tip and the sample, hence it is

• observations. To image the insulator metal oxide thin films with atomic resolution, NC-AFM with the frequency modulation mode is used [51]. A commercial cantilever (Budget Sensors, TAP190) is used to obtain NC-AFM topographic images. An Ar+ sputtering gun is installed in the preparation chamber to clean the

• water before performing PLD. AFM images are processed using the WSxM software [57]. NC-AFM topographic images and line profiles of insulator thin films of (a, b) anatase TiO2(001) and (c, d) LaAlO3(100). Values of the cantilever resonance frequency, spring constant, oscillation amplitude and frequency

Lyapunov estimation for high-speed demodulation in multifrequency atomic force microscopy

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

Beilstein J. Nanotechnol. 2018, 9, 490–498, doi:10.3762/bjnano.9.47

• 10.3762/bjnano.9.47 Abstract An important issue in the emerging field of multifrequency atomic force microscopy (MF-AFM) is the accurate and fast demodulation of the cantilever-tip deflection signal. As this signal consists of multiple frequency components and noise processes, a lock-in amplifier is

• the lateral scan trajectories of the nanopositioner. In static-mode AFM (contact mode), the control loop attempts to maintain a constant contact force [3]. Where as in dynamic modes, for example intermittent-contact constant-amplitude AFM [4], the control loop acts to maintain a constant cantilever

• axis (x, y and z), cantilever, vertical feedback controller and demodulator. In this article, the demodulator component is improved with respect to its key performance metrics: tracking bandwidth, sensitivity to other frequency components, and implementation complexity. Tracking bandwidth is defined as

Kinetics of solvent supported tubule formation of Lotus (Nelumbo nucifera) wax on highly oriented pyrolytic graphite (HOPG) investigated by atomic force microscopy

• Sujit Kumar Dora,
• Kerstin Koch,
• Wilhelm Barthlott and
• Klaus Wandelt

Beilstein J. Nanotechnol. 2018, 9, 468–481, doi:10.3762/bjnano.9.45

• be plotted as there is always a certain delay in measurement due to cantilever approach time in AFM. This initial growth rate turned out to be independent of the concentration of the applied solution of wax in pure chloroform, so that no further plots need to be shown here. Another series of AFM

• between 10 min and 160 min and then slowed to <5% of this value as mentioned above. The initial growth prior to measurement could again not be followed due to the cantilever approach time in AFM. Although the slopes in Figure 3a and Figure 3b are almost the same, the initial tubule height in Figure 3b of

Wafer-scale bioactive substrate patterning by chemical lift-off lithography

• Chong-You Chen,
• Chang-Ming Wang,
• Hsiang-Hua Li,
• Hong-Hseng Chan and
• Wei-Ssu Liao

Beilstein J. Nanotechnol. 2018, 9, 311–320, doi:10.3762/bjnano.9.31

• tapping mode atomic force microscopy (AFM, Dimension Fastscan, Bruker Nano Surfaces, Hsinchu, Taiwan). Topographic AFM images were collected using a silicon cantilever with a spring constant of 48 N/m and a resonance frequency of 190 kHz (Nanosensors, Neuchatel, Switzerland). The substrates were gently

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

• ] top-down NEM switch fabrication approaches. Similarly to copper, the fabrication of a platinum cantilever NEM switching element involved an additional thermal annealing step at 300 °C to reduce the stress gradient in the beam. The usability of platinum for electron-beam lithography-based fabrication

Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy

• Sara Freund,
• Antoine Hinaut,
• Nathalie Marinakis,
• Edwin C. Constable,
• Ernst Meyer,
• Catherine E. Housecroft and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2018, 9, 242–249, doi:10.3762/bjnano.9.26

•  2 shows topography images of the bare NiO(001) surface measured by bimodal nc-AFM using both the first normal and torsional resonance frequency of the cantilever. In this mode high stability and resolution can be combined in order to get detailed information at the atomic scale even under room

• ), using silicon cantilever (Nanosensors PPP-NCR, stiffness k = 20–30 N/m, resonance frequency f1 around 165 kHz, Qf1 factor around 30000, torsional frequency fTR around 1.5 MHz, and QTR factors around 100000) with compensated contact potential difference (CPD). Kelvin probe force microscopy was performed

Combined scanning probe electronic and thermal characterization of an indium arsenide nanowire

• Tino Wagner,
• Fabian Menges,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2018, 9, 129–136, doi:10.3762/bjnano.9.15

• -range electrostatic forces between the cantilever and sample structures, force-gradient sensitive detection is required [7][19]. In our setup, this is assured by direct demodulation of the sidebands that appear upon electrical modulation of the tip–sample electrostatic force [20]. Figure 2b shows the

• contact region as visible in Figure S1 and Figure S2 (Supporting Information File 1). Scanning thermal microscopy Our SThM setup relies on a cantilever with an integrated resistive heater, whose resistance is measured in a Wheatstone bridge configuration (Figure 1a). To be sensitive to changes of the

• interactions in amplitude-modulation mode (Afree = 8.5 nm, Aset = 7.7 nm) using an Olympus AC160TS-R3 cantilever (f0 = 323.2 kHz, k = 40 N·m−1, Q = 500). To obtain the surface potential simultaneously with topography, we modulate the voltage applied to the tip (Uac = 2 V at fm = 4 kHz) on top of a dc bias, and

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

• of samples (Nat. Commun. 2014, 5, 3126). This method gives evidence for the linearity of the relation between the frequency shift of the cantilever first flexural mode Δf1 and the square of the frequency shift of the second flexural mode Δf22. In the present work, we showed that a similar linear

• , pressure or humidity. Since its invention, the atomic force microscope (AFM) [4] has confirmed its value for locally determining nanomechanical properties, such as the Young’s modulus, of the sample surface. Initially, the measures were done qualitatively, with the cantilever operated in intermittent

• on the equations established by Rabe [9] and Rabe et al. [10] for atomic force acoustic microscopy (AFAM) [11][12][13][14]. They describe the dynamics of a clamped cantilever elastically coupled with the sample surface at its tip end. These equations have the disadvantage of strongly depending on the

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

• 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

• interpretation of tapping phase results is rather complex because many factors may influence the results [14][15]. For force modulation and contact resonance operations, the tip is maintained in contact with the sample during the scan while the cantilever oscillations are monitored. The amplitude in force

Dry adhesives from carbon nanofibers grown in an open ethanol flame

• Christian Lutz,
• Julia Syurik,
• C. N. Shyam Kumar,
• Christian Kübel,
• Michael Bruns and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2017, 8, 2719–2728, doi:10.3762/bjnano.8.271

• from force–distance curves measured with an AFM (Dimension Icon, Bruker). In order to have a defined contact, a 20 μm SiO2 sphere was glued to the end of a tipless silicon cantilever (All In One-TL from BudgetSensors) using the approach of Mak and co-workers [33]. We confirmed by SEM that no glue was

• left on the top of the SiO2 sphere (see the insert in Figure 7 below). For the adhesion measurements a constant ramp rate of 1.5 μm/s was applied (adhesion measurement with ramp rates between 0.2 and 8 μm/s showed similar results). The spring constant of the cantilever was determined to 7.74 N/m with

• the thermal tune method [34] integrated in the AFM software. All the measurements presented here were conducted with the same cantilever. Results and Discussion Growth of carbon nanofibers Inspired by the study of Zhang and Pan [9], we aligned the sample, the magnet and the shield parallel to the

Exploring wear at the nanoscale with circular mode atomic force microscopy

• Olivier Noel,
• Aleksandar Vencl and
• Pierre-Emmanuel Mazeran

Beilstein J. Nanotechnol. 2017, 8, 2662–2668, doi:10.3762/bjnano.8.266

• lateral force microscopy (LFM) signal proportional to the friction force) of the cantilever stemming from the circular displacement of the contact features a sinusoidal signal with the same frequency as the relative circular displacement of the contact. Then a lock-in amplifier is used to register the

• real-time amplitude of the LFM signal of the cantilever (or friction force) during the wear experiment in order to determine prospective variations of the friction properties during the experiment. For example, this option may be advantageously implemented for investigating the correlation between

• range of cantilever stiffness. Experimental images as shown in Figure 3C and in Figure 4 also show that the material is not uniformly worn along the circular wear track. Wear is more intensive at some random locations of the material, evidencing heterogeneous wear (as in Figure 3C) or production of wear

Patterning of supported gold monolayers via chemical lift-off lithography

• Liane S. Slaughter,
• Kevin M. Cheung,
• Sami Kaappa,
• Huan H. Cao,
• Qing Yang,
• Thomas D. Young,
• Andrew C. Serino,
• Sami Malola,
• Jana M. Olson,
• Stephan Link,
• Hannu Häkkinen,
• Anne M. Andrews and
• Paul S. Weiss

Beilstein J. Nanotechnol. 2017, 8, 2648–2661, doi:10.3762/bjnano.8.265

• -force set-point between 200 and 400 pN was maintained, except where otherwise indicated. These conditions enabled sufficient contact between tips and samples for imaging, while minimizing the load from the cantilever applied to the PDMS. Scanning electron microscopy of Au-on-Si masters Scanning electron

Robust nanobubble and nanodroplet segmentation in atomic force microscope images using the spherical Hough transform

• Yuliang Wang,
• Tongda Lu,
• Xiaolai Li,
• Shuai Ren and
• Shusheng Bi

Beilstein J. Nanotechnol. 2017, 8, 2572–2582, doi:10.3762/bjnano.8.257

• both air and DI water using a commercial AFM (Resolve, Bruker) in tapping mode with 96% setpoint value. Silicon cantilevers (NSC36/ALBS, MikroMasch) with a quoted stiffness of 0.6 N/m and tip radius of 8 nm were used for scanning. The measured resonance frequencies of the cantilever were 55 kHz and 16

• studied, as shown in Figure 12c and Figure 12d. One can see that the cantilever tip radius causes an overestimation of the NB/ND width and contact angle. The width error introduced by the applied tip radius is about 3%, while the contact angle error is near 0.4%. Conclusion Current automated NB/ND

Interface conditions of roughness-induced superoleophilic and superoleophobic surfaces immersed in hexadecane and ethylene glycol

• Yifan Li,
• Yunlu Pan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2017, 8, 2504–2514, doi:10.3762/bjnano.8.250

• AFM technique was used for the measurement of boundary slip, as shown in Figure 3. A borosilicate sphere (GL018B/45-33, MO-Sci Corporation) with a measured diameter of about 56.5 μm was glued to the end of a rectangular cantilever of an AFM tip (ORC8, Bruker) by using epoxy resin to prepare the

• characterizes the degree of boundary slip at the solid–liquid interface, and can be obtained by the hydrodynamic force on the cantilever detected with CCD. Schematic illustrating possible definitions of the boundary-slip condition at a rough surface. (a) The boundary-slip condition with the reference surface

Fabrication of gold-coated PDMS surfaces with arrayed triangular micro/nanopyramids for use as SERS substrates

• Jingran Zhang,
• Yongda Yan,
• Peng Miao and
• Jianxiong Cai

Beilstein J. Nanotechnol. 2017, 8, 2271–2282, doi:10.3762/bjnano.8.227

• machined micro/nanostructures. The scan size was 50 × 50 μm2. The elastic constant of the silicon cantilever was 0.2 N/m and contact mode was employed. A Merlin Compact SEM system (Zeiss, Germany) was employed to detect the machined structures on a large scale. Schematic of the SERS substrate basic

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

• penetrating a viscoelastic solid in an intermittent-contact manner, which is a problem relevant to nanoscale spectroscopy techniques, such as tapping-mode AFM [34][35]. In standard tapping-mode AFM, a cantilever is harmonically excited either by imposing an oscillatory motion at the base (acoustic excitation

• tip trajectory for an AFM cantilever interacting with a viscoelastic surface in tapping-mode AFM (simulation details are provided in the figure caption). The instantaneous tip–sample distance, taking as reference the undeformed sample surface, is approximately given by: where Zeq refers to the average

• tip–sample position, A is the tapping amplitude, ω is the excitation frequency, and Asin(ωt) = z(t) is the instantaneous tip deflection. We have omitted the phase term, usually expressed as a phase lag between cantilever excitation and response, due to the sample-oriented analytical approach that we

Velocity dependence of sliding friction on a crystalline surface

• Christian Apostoli,
• Giovanni Giusti,
• Jacopo Ciccoianni,
• Gabriele Riva,
• Rosario Capozza,
• Rosalie Laure Woulaché,
• Andrea Vanossi,
• Emanuele Panizon and
• Nicola Manini

Beilstein J. Nanotechnol. 2017, 8, 2186–2199, doi:10.3762/bjnano.8.218

• infinitely rigid AFM cantilever, wait until a steady-sliding regime is established, and discard the initial part affected by transients. For the remaining part of the simulation, we record the total force experienced by the slider as a function of time. This force has fluctuations as a result of collisions

• cantilever. In that scheme a stick-slip to smooth-sliding transition can also be investigated, especially at low speed (see Appendix “The static friction force”), allowing one to study in detail the nonlinear phenomena and mechanisms of phonon excitations that arise at slip times. The stick-slip regime and

Magnetic properties of optimized cobalt nanospheres grown by focused electron beam induced deposition (FEBID) on cantilever tips

• Soraya Sangiao,
• César Magén,
• Darius Mofakhami,
• Grégoire de Loubens and
• José María De Teresa

Beilstein J. Nanotechnol. 2017, 8, 2106–2115, doi:10.3762/bjnano.8.210

• work, we present a detailed investigation of the magnetic properties of cobalt nanospheres grown on cantilever tips by focused electron beam induced deposition (FEBID). The cantilevers are extremely soft and the cobalt nanospheres are optimized for magnetic resonance force microscopy (MRFM) experiments

• strong field gradients from the magnetic probe [46] and ultra-soft cantilevers [47] are required. Therefore, the magnetic probe should be precisely located at the apex of the cantilever and be as small as possible to gain spatial resolution, and it should have as high magnetization as possible to

• is, the apex of the cantilever (Olympus BioLever, around 30 nm in size). We have scanned the beam over a circular area centered on the apex of the cantilevers and varied the radius of the circular area being scanned and the beam scanning time to obtain the different targeted diameters. The diameter

High-stress study of bioinspired multifunctional PEDOT:PSS/nanoclay nanocomposites using AFM, SEM and numerical simulation

• Alfredo J. Diaz,
• Hanaul Noh,
• Tobias Meier and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2069–2082, doi:10.3762/bjnano.8.207

• free cantilever resonance frequency, is directly related to stiffness (larger stiffness leads to larger frequency and vice-versa) [49], while the quality factor maps the sample damping of the cantilever tip oscillation (greater dissipation leads to lower quality factor and vice-versa) [50]. The contact

• complexity in the interpretation of the measurements as quantitative mechanical properties, the mechanical parameters (contact-resonance frequency and quality factor) of the fabricated samples are used in this study, whereby the same cantilever and imaging conditions are used for all samples, which enables

• discussion of their relative properties and changes. Figure 2 shows a summary of the mechanical parameters for thick and thin samples using the same cantilever and characterizing the samples in a random sequence. It is known, from macroscopic tensile testing, that the addition of nanoclays increases the

Evaluation of preparation methods for suspended nano-objects on substrates for dimensional measurements by atomic force microscopy

• Petra Fiala,
• Daniel Göhler,
• Benno Wessely,
• Michael Stintz,
• Giovanni Mattia Lazzerini and
• Andrew Yacoot

Beilstein J. Nanotechnol. 2017, 8, 1774–1785, doi:10.3762/bjnano.8.179

• Inc., Orem, Utah, USA) were used for instrument calibration. AFM AFM measurements were performed with a traceable atomic force microscope that uses two integrated optical interferometry systems for detecting the deflection of the cantilever and for measuring the vertical motion of the piezoelectric

• laser (λ = 632.8 nm). Two parallel mirrors are required for the interferometer; one for each optical path. One mirror is rigidly connected to the PZT tube that moves the cantilever, and the other forms the sample holder. The interferometer is a double pass interferometer with each optical path having

• a temperature-controlled environment (20 ± 0.01 °C). Nanosensors PPP-NCLR tips (i.e., point probe plus non-contact long cantilever reflex coating) with nominal tip radius <10 nm were used. The AFM images were numerically corrected for tilt using the “mean plane subtraction” and “correction of