Development of a novel nanoindentation technique by utilizing a dual-probe AFM system

• Eyup Cinar,
• Ferat Sahin and
• Dalia Yablon

Beilstein J. Nanotechnol. 2015, 6, 2015–2027, doi:10.3762/bjnano.6.205

• be tackled [5][6][7][8]. Nanoindentation experiments requiring very low force values and high resolution usually use a standard AFM system. With this setup, an AFM cantilever probe is used for indenting the material and the probe displacement is monitored by laser beam bounce technology also known as

• optical lever method. With this methodology, a laser beam is reflected off the back end of the cantilever and directed towards a quadrant photodiode detector that monitors both vertical and lateral motion [9]. Force–distance (FD) curves can be generated based on displacement data and the spring constant

• value of the cantilever. Depending on the type of the material, various models can be applied in order to interpret and extract the elastic modulus of materials. One of the problems with this AFM-based approach is cantilever bending. Most of the conventional AFM nanoindentation probes have spring

A simple method for the determination of qPlus sensor spring constants

• John Melcher,
• Julian Stirling and
• Gordon A. Shaw

Beilstein J. Nanotechnol. 2015, 6, 1733–1742, doi:10.3762/bjnano.6.177

• for tip heights exceeding 400 μm or one sixth of the cantilever length. Experimental results with a calibrated nanoindenter reveal excellent agreement with an Euler–Bernoulli beam model for the sensor. Prior to the attachment of a tip, measured spring constants of 1902 ± 29 N/m are found to be in

• approach has been to estimate the spring constant from plane view geometry and the Young’s modulus of the appropriate crystallographic orientation. In this case, the qPlus sensor is treated as a uniform, rectangular cantilever and the spring constant is predicted from Euler–Bernoulli beam theory [1][7

• violated by the chamfered edge at the base of the tine, and the assumption of base rigidity has been questioned [25]. The attachment of a tip can alter the length of the cantilever, introduce parasitic tip motion [31], and, in extreme cases, introduce additional vibratory modes [32][33]. In what follows

Lower nanometer-scale size limit for the deformation of a metallic glass by shear transformations revealed by quantitative AFM indentation

• Arnaud Caron and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2015, 6, 1721–1732, doi:10.3762/bjnano.6.176

• nanometer-scale plastic deformation of Pt(111) and the Pt57.5Cu14.7Ni5.3P22.5 metallic glass was investigated in ultra-high vacuum by AFM indentation and subsequent nc-AFM imaging using a VT-AFM manufactured by Omicron Nanotechnology GmbH, Germany. In non-contact AFM an AFM cantilever is driven to oscillate

• close to a sample surface at its resonance frequency. The tip–sample distance is of the order of a few nanometers. Changes in tip–sample distance during scanning over a sample surface due to sample topography yield changes in the oscillation amplitude and in a frequency shift of the cantilever resonance

• . In order to measure topography both amplitude and frequency shift are tracked by a feedback loop so as to keep the cantilever oscillation in resonance [15]. For indentation and imaging we used a diamond-coated silicon single crystalline cantilever (Type: CDT-NCLR, manufactured by NanoSensors). The

Continuum models of focused electron beam induced processing

• Milos Toth,
• Charlene Lobo,
• Vinzenz Friedli,
• Aleksandra Szkudlarek and
• Ivo Utke

Beilstein J. Nanotechnol. 2015, 6, 1518–1540, doi:10.3762/bjnano.6.157

• effects which can cause disruptions in surface flatness [23]. A specific simulation of a gas-flow distribution on a cantilever-based mass sensor enabled the estimation of the residence time of Me3PtCpMe on SiO2 [47]. With the released code the reader can include new nozzle geometries or substrate

Atomic force microscopy as analytical tool to study physico-mechanical properties of intestinal cells

• Christa Schimpel,
• Oliver Werzer,
• Eleonore Fröhlich,
• Gerd Leitinger,
• Markus Absenger-Novak,
• Birgit Teubl,
• Andreas Zimmer and
• Eva Roblegg

Beilstein J. Nanotechnol. 2015, 6, 1457–1466, doi:10.3762/bjnano.6.151

• getting an image of the cell surface to observe its morphological and structural features. The latter is used to study elastic properties of a cell. Briefly, the central part of an AFM is a sharp tip, situated at the end of a flexible cantilever. The reflection of a laser beam focused at the back side of

• the cantilever is used to measure the movement of the tip. When the probe at the end of the cantilever interacts with the sample surface, the laser light pathway changes and is finally detected by a photodiode detector. The measured cantilever deflections vary (depending on the sample nature, i.e

• ., high features on the sample cause the cantilever to deflect more) hence, a map of surface topography can be generated [21][22][24]. Moreover, quantitative analysis of the cell elasticity is possible by analyzing force-distance curves via monitoring the response of a cantilever once the tip is pushed

Improved atomic force microscopy cantilever performance by partial reflective coating

• Zeno Schumacher,
• Yoichi Miyahara,
• Laure Aeschimann and
• Peter Grütter

Beilstein J. Nanotechnol. 2015, 6, 1450–1456, doi:10.3762/bjnano.6.150

• Zeno Schumacher Yoichi Miyahara Laure Aeschimann Peter Grutter Department of Physics, McGill University, Montreal, Quebec, H3A 2T8, Canada NanoWorld AG, Neuchâtel, 2002, Switzerland 10.3762/bjnano.6.150 Abstract Optical beam deflection systems are widely used in cantilever based atomic force

• microscopy (AFM). Most commercial cantilevers have a reflective metal coating on the detector side to increase the reflectivity in order to achieve a high signal on the photodiode. Although the reflective coating is usually much thinner than the cantilever, it can still significantly contribute to the

• damping of the cantilever, leading to a lower mechanical quality factor (Q-factor). In dynamic mode operation in high vacuum, a cantilever with a high Q-factor is desired in order to achieve a lower minimal detectable force. The reflective coating can also increase the low-frequency force noise. In

Nanomechanical humidity detection through porous alumina cantilevers

• Olga Boytsova,
• Alexey Klimenko,
• Vasiliy Lebedev,
• Alexey Lukashin and
• Andrey Eliseev

Beilstein J. Nanotechnol. 2015, 6, 1332–1337, doi:10.3762/bjnano.6.137

• behavior of the resonance frequency of porous anodic alumina cantilever arrays during water vapor adsorption and emphasize their possible use in the micromechanical sensing of humidity levels at least in the range of 10–22%. The sensitivity of porous anodic aluminium oxide cantilevers (Δf/Δm) and the

• humidity sensitivity equal about 56 Hz/pg and about 100 Hz/%, respectively. The approach presented here for the design of anodic alumina cantilever arrays by the combination of anodic oxidation and photolithography enables easy control over porosity, surface area, geometric and mechanical characteristics

• of the cantilever arrays for micromechanical sensing. Keywords: anodic aluminium oxide; atomic force microscopy (AFM); cantilever arrays; humidity; mechanical sensor; porous alumina; Introduction The last two decades have seen a surge in resonant micro- and nanomechanical engineering raised by the

Tattoo ink nanoparticles in skin tissue and fibroblasts

• Colin A. Grant,
• Peter C. Twigg,
• Richard Baker and
• Desmond J. Tobin

Beilstein J. Nanotechnol. 2015, 6, 1183–1191, doi:10.3762/bjnano.6.120

• ]. With highly specialised instrumentation and techniques, it is even possible to resolve molecular bonds [16][17]. Details of AFM operation and capabilities can be found elsewhere [18][19]. However, in brief, the AFM instrument involves a sharp probe at the end of a cantilever interacting with a surface

• . Microscopy of tattoo particles in skin tissue Using the AFM top down optical microscope it was straightforward to manipulate the skin tissue section so that the cantilever was at the periphery of a clump of ink particles in the dermis (Figure 2a). A number of images were taken at various locations; Figure 2b

• fibril networks without particle matter, but were of lower quality (Figure 5). AFM fluid imaging has to use a cantilever spring constant that is about two orders of magnitude lower, which makes scanning trickier. Also, the tissue surface becomes softer. Tattoos inevitably fade over time with a

Probing fibronectin–antibody interactions using AFM force spectroscopy and lateral force microscopy

• Andrzej J. Kulik,
• Małgorzata Lekka,
• Kyumin Lee,
• Grazyna Pyka-Fościak and
• Wieslaw Nowak

Beilstein J. Nanotechnol. 2015, 6, 1164–1175, doi:10.3762/bjnano.6.118

• , resolution, and/or force sensitivity are essential in nanotechnology development. In the majority of AFMs, the cantilever deflection is recorded by an optical detection system composed of a laser and a position-sensitive photodiode having an active area divided into four quadrants. The deflection (referred

• to here as the normal deflection) and torsion (referred to here as the lateral deflection) signals are determined as follows: the signal difference between the two upper and lower quadrants is a measure of the normal deflection, while torsion of the cantilever is represented as the signal difference

• between the two left and two right quadrants. For an AFM working in force spectroscopy mode (referred to here as AFM-FS), the interactions forces are determined from the analysis of force curves. A force curve represents the dependence between the deflection of the AFM cantilever in the direction

Electrical characterization of single molecule and Langmuir–Blodgett monomolecular films of a pyridine-terminated oligo(phenylene-ethynylene) derivative

• Henrry M. Osorio,
• Santiago Martín,
• María Carmen López,
• Santiago Marqués-González,
• Simon J. Higgins,
• Richard J. Nichols,
• Paul J. Low and
• Pilar Cea

Beilstein J. Nanotechnol. 2015, 6, 1145–1157, doi:10.3762/bjnano.6.116

• experiments employed to study the topography of the monolayers were performed by means of a Multimode 8 AFM system from Veeco, using tapping mode. The data were collected with a scan rate of 1 Hz and in ambient air conditions by using a silicon cantilever provided by Bruker, with a force constant of 40 N·m−1

Tunable magnetism on the lateral mesoscale by post-processing of Co/Pt heterostructures

• Oleksandr V. Dobrovolskiy,
• Maksym Kompaniiets,
• Roland Sachser,
• Fabrizio Porrati,
• Christian Gspan,
• Harald Plank and
• Michael Huth

Beilstein J. Nanotechnol. 2015, 6, 1082–1090, doi:10.3762/bjnano.6.109

• [3] and memory [4], fabrication of Hall sensors [5] and cantilever tips [6] for magnetic force microscopy (MFM). In particular, the ability to tune the magnetization is the basic property needed for the realization of stacked nanomagnets [7], pinning of magnetic domain walls [8] and Abrikosov

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

• microscopy (AM-AFM) was designed to excite the cantilever near or at its fundamental free resonant frequency [2]. However, the need to improve and/or provide quantitative compositional contrast without compromising the data acquisition speed has led to the development of several AFM modes, specifically

• different parameters we have used numerical simulations. For this we consider that bimodal AFM is characterized by the simultaneous excitation of two cantilever resonant frequencies, usually the lowest flexural eigenmodes [42]. The total driving force is expressed as Then, the cantilever–tip ensemble will

• be described by the system of two differential modal equations, with i = 1,2; ωi, ki, Qi, , Ai and A0i are, respectively, the angular frequency, the force constant, quality factor, phase shift, amplitude and free amplitude of mode i; m = 0.25mc is an effective mass while mc is the real cantilever–tip

Automatic morphological characterization of nanobubbles with a novel image segmentation method and its application in the study of nanobubble coalescence

• Yuliang Wang,
• Huimin Wang,
• Shusheng Bi and
• Bin Guo

Beilstein J. Nanotechnol. 2015, 6, 952–963, doi:10.3762/bjnano.6.98

• (MultiMode III, Digital Instruments) operating in tapping mode was used for imaging the sample. A silicon rotated force-modulated etched silicon probe (RFESP, Bruker Corporation) cantilever with a tip radius of 8 nm and a stiffness of 3 N/m was used. A modified tip holder was used for tapping mode atomic

• determine the resonance frequency of a cantilever. In this study, a tapping mode tip holder for non-fluid use in air was modified, as shown in Figure 1. A horizontal slot was carved out above the piezo element in the opening of the tip holder to insert a glass slide. When the liquid is added between the

• frequency. The measured resonance frequency in water was about 25 Hz. The free oscillation amplitude of the cantilever at the working frequency was 7.3 nm. To minimize the force applied to the samples, the setpoint was set at 95% of the free amplitude, which was 6.9 nm. The sample surface was scanned at a

Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

• Jana Vlachová,
• Rebekka König and
• Diethelm Johannsmann

Beilstein J. Nanotechnol. 2015, 6, 845–856, doi:10.3762/bjnano.6.87

• experiments. A contact is established between a resonator (which is a quartz crystal microbalance here and is the cantilever in AFM experiments) and an external object. The geometry is configured such that the contact does not overdamp the resonance, but rather shifts the resonance frequency and the resonance

Stick–slip behaviour on Au(111) with adsorption of copper and sulfate

• Nikolay Podgaynyy,
• Sabine Wezisla,
• Christoph Molls,
• Shahid Iqbal and
• Helmut Baltruschat

Beilstein J. Nanotechnol. 2015, 6, 820–830, doi:10.3762/bjnano.6.85

• ; Introduction Atomic-scale friction processes constitute a fascinating field of research which has been opened by the invention of the atomic force microscope (AFM) [1]. The AFM allows us to determine the force necessary to move a cantilever tip laterally across the surface with atomic resolution. A theoretical

• quality factor of the cantilever. All AFM measurements were performed at room temperature. Friction force maps shown here are the difference images between both scan directions. Due to the relatively high load used in our experiments, the tip radius quickly approached a value of around 100 nm, but then

• below the figure) characterizes the effective lateral stiffness of the surface–tip contact. In our case it is 10 N/m and therefore much smaller than the lateral stiffness of the cantilever (190 N/m). The somewhat rounded shape might be due to a not completely commensurable tip–substrate contact [32

Capillary and van der Waals interactions on CaF₂ crystals from amplitude modulation AFM force reconstruction profiles under ambient conditions

• Annalisa Calò,
• Oriol Vidal Robles,
• Sergio Santos and
• Albert Verdaguer

Beilstein J. Nanotechnol. 2015, 6, 809–819, doi:10.3762/bjnano.6.84

• large tip–sample distances [12][13] and can exhibit unexpected distance dependencies [14]. Contact AFM measurements, in which the force is determined from the static deflection of the cantilever during approach [15], can readily record the tip–sample interaction force and have been used extensively to

• in air and when soft cantilevers were employed to increase the sensitivity [6][7][15][24]. Dynamic modes proved to overcome the limitations of contact measurements in detecting attractive forces [11][25][26][27]. In these modes the cantilever is mechanically driven at a fixed oscillation frequency

• measurements, as for example amplitude modulation AM-AFM measurements, is that experimental observables, i.e., the phase lag of the cantilever relative to the driving force, can be directly related to the energy dissipated in the tip–sample interaction [31][32][33]. Identifying and separating individual

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

• M. Kalyan Phani,
• Anish Kumar,
• T. Jayakumar,
• Walter Arnold and
• Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

• cantilever with damped flexural modes. The cantilever dynamics model considering damping, which was proposed recently, has been used for mapping of indentation modulus and damping of different phases in a metallic structural material. The study indicated that in a Ti-6Al-4V alloy the metastable β phase has

• cantilever. In UAFM the cantilever is excited by attaching a transducer to the cantilever base. In AFAM, the transducer is placed under the sample and periodic displacements of the sample are sensed by the cantilever when in contact. Rabe et al. [4], Hurley et al. [5] have discussed in detail the development

• successfully mapped the indentation modulus of α- and β-phases in a Ti-6Al-4V alloy by using AFAM while using a cantilever dynamic model in which damping, however, was neglected. In this paper, we report mapping of elastic modulus and damping using a modified cantilever dynamic model in various phases, such as

A scanning probe microscope for magnetoresistive cantilevers utilizing a nested scanner design for large-area scans

• Tobias Meier,
• Alexander Förste,
• Ali Tavassolizadeh,
• Karsten Rott,
• Dirk Meyners,
• Roland Gröger,
• Günter Reiss,
• Eckhard Quandt,
• Thomas Schimmel and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2015, 6, 451–461, doi:10.3762/bjnano.6.46

• read-out of a micro-fabricated cantilever [10][11]. However, the optical read-out contains bulky mechanical parts to focus a laser on the backside of the cantilever and to move the position sensitive photodetector (PSD) or a mirror which puts severe limits on a compact instrument design. Additionally

• , optical read-outs have to be readjusted not only after every cantilever exchange but also after temperature drifts which can offset the focal position of the laser and photo-detector due to thermal expansion. Additionally, the optical read-out can influence the cantilevers deflection by photothermal

• and set their sensitivity at maximum for imaging atomic step edges. Setup of a nonmagnetic large scan range AFM In order to characterize magnetoresistive strain sensors integrated into AFM cantilevers, the deflection of the cantilever has to be measured in parallel by independent means. Therefore, our

Influence of spurious resonances on the interaction force in dynamic AFM

• Luca Costa and
• Mario S. Rodrigues

Beilstein J. Nanotechnol. 2015, 6, 420–427, doi:10.3762/bjnano.6.42

• force microscopy is challenging, especially when measuring in liquid media. Here, we derive formulas for the tip–sample interactions and investigate the effect of spurious resonances on the measured interaction. Highlighting the differences between measuring directly the tip position or the cantilever

• deflection, and considering both direct and acoustic excitation, we show that the cantilever behavior is insensitive to spurious resonances as long as the measured signal corresponds to the tip position, or if the excitation force is correctly considered. Since the effective excitation force may depend on

• morphology during the scan. Obviously, the cantilever excitation plays a central role in AM-AFM. Conventionally, mechanical vibration of the cantilever holder is provided through the excitation of a small piezoelectric element (dither). The setup is widely employed in many commercial and custom-made AFMs and

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

• experiments. The simulator presents the cantilever–tip dynamics for two dynamic AFM methods, tapping mode AFM and bimodal AFM. It can be applied for a wide variety of experimental situations in air or liquid. The code provides all the variables and parameters relevant in those modes, for example, the

• the presence of higher harmonic components in the tip motion with the presence of nonlinear interactions [15]. In the process, the cross talk between modes and harmonics has been clarified [16][17][18][19][20]. The complicated cantilever motion in liquid and the differences observed between the

• excitation methods have been analyzed by simulations [21][22][23]. The tip–surface force controls the cantilever motion, however, the force itself is not an observable. Numerical simulations have been used to derive parametric approximations [24], scaling laws [25] and insights about the role of different

Mechanical properties of MDCK II cells exposed to gold nanorods

• Anna Pietuch,
• Bastian Rouven Brückner,
• David Schneider,
• Marco Tarantola,
• Christina Rosman,
• Carsten Sönnichsen and
• Andreas Janshoff

Beilstein J. Nanotechnol. 2015, 6, 223–231, doi:10.3762/bjnano.6.21

• ) mounted on an inverted optical microscope (Axiovert 200, Zeiss, Oberkochen, Germany) to localize cell position. Silicon nitride cantilever (MLCT-AUHW, Bruker, Germany) were used with a nominal force constant of ≈0.05 N/m. Imaging of cells has been carried out using a fluid-heating chamber (Biocell, JPK

• Instrument AG, Berlin, Germany) with HEPES buffered culture medium kept at 37 °C. AFM images were performed in contact mode. Before force spectroscopy measurements the exact spring constant of the used cantilever was determined by thermal noise analysis using software provided by the manufacturer. Local

• mechanical measurements were carried out on confluent MDCK II monolayers directly after imaging using the same cantilever. Force curves were collected with a z-scan velocity of 1 μm/s. Analysis of the elasticity modulus was done with a tool developed in our laboratory using IGOR Pro (WaveMetrics, Lake Oswego

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

• relatively stiff cantilevers as specified above. The routines and conditions to perform LAO-AFM in the dynamic mode have been described in [1][19]. In brief, a target location onto the Si substrate is inspected for surface cleanliness. Then, the cantilever free oscillation is set to a low amplitude value

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

• second harmonic cantilever amplitude (Aω and A2ω) and phase (θω and θ2ω) using lock-in techniques. Equation 2 predicts a linear dependence of Fω with respect to the probe–sample DC bias, which is minimized when Vdc = Vcpd. KPFM employs this principle via a feedback loop to minimize Aω. Depending on the

• . Raiteri et al. reported similar hysteretic behavior in the static electrochemical stress experienced for biased Au electrodes in a variety of electrolytes [54]. Umeda et al. also observed similar hysteresis in this bias range for a cantilever above a platinum surface in water [55]. For all bias sweeps

• electrode. In OLBS measurements, when using bias sweeps larger than 2 V, large changes in the AFM cantilever deflection signal occurred (not shown), often followed by visible bubble nucleation in the probe–sample gap (e.g., Figure 1f). Attempts at implementing KPFM in ionically-active liquids will often

Increasing throughput of AFM-based single cell adhesion measurements through multisubstrate surfaces

• Miao Yu,
• Nico Strohmeyer,
• Jinghe Wang,
• Daniel J. Müller and
• Jonne Helenius

Beilstein J. Nanotechnol. 2015, 6, 157–166, doi:10.3762/bjnano.6.15

• SCFS, a single cell is attached to a cantilever (Figure 1A,B), commonly facilitated by an adhesive coating (e.g., concanavalin A, poly-L-lysine or CellTak) [17][18][19][20][21][22]. The attached cell is lowered (approach) onto a substrate (Figure 1A(i)), which is a protein-coated surface, another cell

• or a biomaterial [23], until a set force is reached and the cell is kept stationary for a set time to allow the formation of adhesive interactions (Figure 1A(ii)). During the subsequent raising (retraction) of the cantilever (Figure 1A(iii)), the force acting on the cell and the distance between cell

• and substrate is recorded in a force–distance curve (Figure 1C). The force range that can be detected with AFM-based SCFS is from ≈10 pN up to ≈100 nN [14], thereby, SCFS allows both the overall cell adhesion and the contribution of single adhesion receptors to be quantified. During initial cantilever

Accurate, explicit formulae for higher harmonic force spectroscopy by frequency modulation-AFM

• Kfir Kuchuk and
• Uri Sivan

Beilstein J. Nanotechnol. 2015, 6, 149–156, doi:10.3762/bjnano.6.14

• Kfir Kuchuk Uri Sivan Department of Physics and The Russell Berrie Nanotechnology Institute, Technion – Israel Institute of Technology, Haifa 32000, Israel 10.3762/bjnano.6.14 Abstract The nonlinear interaction between an AFM tip and a sample gives rise to oscillations of the cantilever at

• generated by the nonlinear tip–surface interaction (to be distinguished from higher flexural modes of the cantilever) are related to higher derivatives of the force, and thus carry additional information on the interaction [5][6][7][8][9][10][11]. Broad implementation of force spectroscopy by analysing

• formulae for both conservative and dissipative forces. In FM-AFM, a cantilever is oscillated at its resonance frequency using an external driving force and a feedback loop. The motion of the cantilever is often modelled as a driven damped harmonic oscillator with an additional force, Fts, stemming from tip