An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

• Santiago H. Andany,
• Gregor Hlawacek,
• Stefan Hummel,
• Charlène Brillard,
• Mustafa Kangül and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2020, 11, 1272–1279, doi:10.3762/bjnano.11.111

• correlative imaging on electrically insulating samples. In this first attempt, the readout of cantilever deflection was achieved using the electron beam itself. Shortly after, better performing combined setups were described utilizing more conventional self-sensing [5] and optical [6] techniques for the

• readout of cantilever deflection. Since then, more advanced and versatile combined instruments have been proposed for a broad spectrum of applications in nanoscale characterization and nanoscale fabrication inside SEM and focused ion beam (FIB) setups [7][8][9][10][11]. Given the extent of the interest

• depicted in Figure 1. The prototype tip-scanning AFM scan head is designed explicitly for correlative analysis inside electron and ion-beam microscopes. Unlike sample scanning solutions [9][16], where the sample is raster-scanned relative to a stationary cantilever, a tip-scanning configuration [10][17

Ultrasensitive detection of cadmium ions using a microcantilever-based piezoresistive sensor for groundwater

• Dinesh Rotake,
• Anand Darji and
• Nitin Kale

Beilstein J. Nanotechnol. 2020, 11, 1242–1253, doi:10.3762/bjnano.11.108

• . [28], but it is not suitable for other high-temperature sputtering processes. Microcantilevers based on SiO2 have been manufactured by Tang et al. [29] to enhance the sensitivity of cantilever sensors. Many authors use optical setups for microcantilevers. However, an optical output has several

• cantilever sensors. Moreover, the proposed piezoresistive device has capabilities to directly capture the surface stress make this a better option for HMI applications. Microfluidic Platform with Piezosensor In the proposed method, the benefits of three different technologies are combined, namely thin film

• the fabricated MEMS-based sensor is capable of selective Cd(II) detection using SAMs of cysteamine with cross-linked ᴅʟ-glyceraldehyde (Cys-DL-GC). To characterize the SAM on the microcantilever device only a few analytical techniques are available because of the fragile nature of the cantilever

Extracting viscoelastic material parameters using an atomic force microscope and static force spectroscopy

• Cameron H. Parvini,
• M. A. S. R. Saadi and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 922–937, doi:10.3762/bjnano.11.77

• materials. AFM static force spectroscopy (SFS) is one approach commonly used in pursuit of this goal. It is capable of acquiring rich temporal insight into the behavior of a sample. During AFM-SFS experiments the cantilever base approaches samples with a nearly constant velocity, which is manipulated to

• cantilever, and the time-derivative of the Z-Sensor data should be equal to the experimental approach velocity. To perform the fit procedure, only the deflection and Z-Sensor datasets are necessary. Figure 2a illustrates the shape of a common result as read from a force–distance curve output file. Because

• using the cantilever stiffness (kc), the minimum deflection offsets (z0, d0), the deflection (d(t)), and the following relations: where kc in Equation 14 is the AFM cantilever stiffness. This data is not used directly in the fit, but can be useful for showing the indentation and force during the

Measurement of electrostatic tip–sample interactions by time-domain Kelvin probe force microscopy

• Christian Ritz,
• Tino Wagner and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2020, 11, 911–921, doi:10.3762/bjnano.11.76

• conventional frequency-modulated (FM-) KFM, the contributions at ωm and 2ωm are detected via lock-in techniques, either at the Δf output of a phase-locked loop (PLL) [12] or by detecting the sidebands of the cantilever oscillation [13]. In closed-loop FM-KFM, a feedback loop is employed to nullify the

• response of the cantilever at the modulation frequency ωm (not visible in Figure 1 since Udc ≈ Ulcpd) and at 2ωm [13][26][27]. A feedback loop is used to adjust Udc in order to nullify the component at ωm. If this is achieved, the resulting Δfmean, which is used for the topography control, is independent

• PLL is used, its transfer function, which is known for a given cantilever and given PI gains, can be approximated by the transfer function of a low-pass filter. Using the relationship shown in Equation 10 and the transfer function of the detection system, the sample properties, the expected error

Three-dimensional solvation structure of ethanol on carbonate minerals

• Hagen Söngen,
• Ygor Morais Jaques,
• Peter Spijker,
• Christoph Marutschke,
• Stefanie Klassen,
• Ilka Hermes,
• Ralf Bechstein,
• Lidija Zivanovic,
• John Tracey,
• Adam S. Foster and
• Angelika Kühnle

Beilstein J. Nanotechnol. 2020, 11, 891–898, doi:10.3762/bjnano.11.74

• nature. Experimental and Theoretical Methods Atomic force microscopy For the AFM experiments we used a modified commercial atomic force microscope [22] with custom photothermal cantilever excitation [23] and a custom three-dimensional scanning and data acquisition mode [24] in the frequency-modulation

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

Quantitative determination of the interaction potential between two surfaces using frequency-modulated atomic force microscopy

• Nicholas Chan,
• Carrie Lin,
• Tevis Jacobs,
• Robert W. Carpick and
• Philip Egberts

Beilstein J. Nanotechnol. 2020, 11, 729–739, doi:10.3762/bjnano.11.60

• laterally relative to the sample. A piezoactuator acting in the z-direction brings the probe closer or further from the sample. Due to non-linear tip–sample interaction forces, the resonance frequency of the oscillating cantilever will shift. This shift can be used as a feedback signal to measure the sample

• topography, among other parameters. In order to determine the interaction force behavior as a function of the separation distance, we measured the frequency shift of the oscillating cantilever as a function of the separation distance (Δf–d curves) between a silicon AFM probe and a diamond sample. An

• analytical relationship between the resonance frequency shift and the tip–sample interaction force in FM-AFM was first derived by Giessibl [42] and is seen in the following equation: In Equation 1, Δf represents the change in the primary flexural resonance frequency of the cantilever near the surface, fres

Stochastic excitation for high-resolution atomic force acoustic microscopy imaging: a system theory approach

• Edgar Cruz Valeriano,
• José Juan Gervacio Arciniega,
• Christian Iván Enriquez Flores,
• Susana Meraz Dávila,
• Joel Moreno Palmerin,
• Martín Adelaido Hernández Landaverde,
• Yuri Lizbeth Chipatecua Godoy,
• Aime Margarita Gutiérrez Peralta,
• Rafael Ramírez Bon and
• José Martín Yañez Limón

Beilstein J. Nanotechnol. 2020, 11, 703–716, doi:10.3762/bjnano.11.58

• frequency resolution, with less computational cost and at a faster speed than other similar techniques. This technique is referred to as stochastic atomic force acoustic microscopy (S-AFAM), and the frequency shifts of the free resonance frequencies of an AFM cantilever are used to determine the mechanical

• nanotechnology [3] because it offers a non-destructive alternative for measuring mechanical properties at the nanoscale using the small size of the cantilever tip with a radius of 5–50 nm. There are two kinds of conventional AFM methods for the measurement of mechanical properties [4][5], i.e., the measurement

• of force–displacement curves or of contact resonance frequencies. The techniques based on force–displacement curves are ideal when the stiffness of the cantilever and the sample are similar. The techniques based on contact resonance frequencies are appropriate when the stiffness of the sample

Examination of the relationship between viscoelastic properties and the invasion of ovarian cancer cells by atomic force microscopy

• Mengdan Chen,
• Jinshu Zeng,
• Weiwei Ruan,
• Zhenghong Zhang,
• Yuhua Wang,
• Shusen Xie,
• Zhengchao Wang and
• Hongqin Yang

Beilstein J. Nanotechnol. 2020, 11, 568–582, doi:10.3762/bjnano.11.45

• . Force–distance curve-based AFM measurements were carried out to calculate the optical photodiode deflection sensitivity and the cantilever spring constant was verified by the thermal noise method before experiments. MLCT cantilevers (Bruker, USA) made of silicon nitride with approximate spring constant

Current measurements in the intermittent-contact mode of atomic force microscopy using the Fourier method: a feasibility analysis

• Berkin Uluutku and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 453–465, doi:10.3762/bjnano.11.37

• approaches. Conductivity, in particular, is mapped using the contact-mode method. However, this modality can be destructive to delicate samples, since it involves continuously dragging the cantilever tip on the surface during the raster scan, while a constant tip–sample force is applied. In this paper we

• discuss a possible approach to develop an intermittent-contact conductive AFM mode based on Fourier analysis, whereby the measured current response consists of higher harmonics of the cantilever oscillation frequency. Such an approach may enable the characterization of soft samples with less damage than

• cantilever oscillation, can be a less destructive technique [16][19][20], and this could be advantageous also for performing current measurements on such samples. Additionally, scanning tunnelling microscopy (STM) applications may also benefit from current measurements during which the tip oscillates above

Atomic-resolution imaging of rutile TiO₂(110)-(1 × 2) reconstructed surface by non-contact atomic force microscopy

• Daiki Katsube,
• Shoki Ojima,
• Eiichi Inami and
• Masayuki Abe

Beilstein J. Nanotechnol. 2020, 11, 443–449, doi:10.3762/bjnano.11.35

• performed using Pt-coated Si cantilevers (Budget Sensors, ElectriTAP190G). All cantilevers were cleaned by Ar+ sputtering (0.6 keV, Ar partial pressure of 1.0 × 10−5 Pa, ion current of 0.05 µA, 5 min) before scanning. STM imaging was performed in constant-current mode without cantilever oscillation. NC-AFM

• feedback control was applied in frequency-modulation mode [30] with constant amplitude oscillation. The cantilever deflection was detected using an optical interferometer [31]. Since the electrostatic force due to the contact potential difference (CPD) between the tip and sample prevents high-resolution NC

• 10 pA, respectively. (a) STM and (b) NC-AFM images of a rutile TiO2(110)-(1 × 2) reconstructed surface. (c, d) Height profiles along black (STM) and blue (NC-AFM) lines in the images. The STM and NC-AFM images were obtained using a Pt-coated Si cantilever with a resonance frequency of f0 = 154.1 kHz

Implementation of data-cube pump–probe KPFM on organic solar cells

• Benjamin Grévin,
• Olivier Bardagot and
• Renaud Demadrille

Beilstein J. Nanotechnol. 2020, 11, 323–337, doi:10.3762/bjnano.11.24

• –acceptor blends with sub-ms time resolution [1]. Subsequent works have shown that sub-μs time resolution can be achieved by acquiring the full information on the cantilever oscillation, leading to the development of fast trEFM [2] and general-mode KPFM [3]. Contrary to feedback-free electrostatic methods

• ][14] and nanocrystal-based [15] solar cells. However, there are some disadvantages to using this technique. First, at specific frequencies, the excitation signal used to generate charge carriers can interfere [16] with the cantilever oscillation or the ac voltage applied for the detection of the CPD

• be taken into account, which renders the interpretation of IM-KPFM data even more difficult. Upon illumination, the capacitive junction formed by the cantilever tip and the conducting substrate onto which the organic layer is deposited is indeed reduced due to photogenerated carriers [19]. As a first

Nonclassical dynamic modeling of nano/microparticles during nanomanipulation processes

• Moharam Habibnejad Korayem,
• Ali Asghar Farid and
• Rouzbeh Nouhi Hefzabad

Beilstein J. Nanotechnol. 2020, 11, 147–166, doi:10.3762/bjnano.11.13

• cantilever frequencies to contact stiffness and investigated the variation of sensitivity with cantilever slope [3][4]. Shi and Zhao examined the contact models at the nanoscale and compared Derjaguin–Muller–Toporov (DMT), Johnson–Kendall–Roberts–Sperling (JKRS) and Maugis–Dugdale (MD) models with the Hertz

• model. They studied the effect of dimensionless load and the transition parameter on the contact area. They emphasized the importance of the MD model that covers a large area of AFM surveys [5]. Owing to the importance of the AFM cantilever spring constant and its use in calculation of the rupture force

• of protein bonds and Young’s modulus of nanoparticles, Clifford and Seah determined the AFM cantilever normal spring constant [6]. Korayem and Zakeri studied the effects of different parameters on the times and forces in a 2D manipulation. Using their proposed algorithm, the location of the

A review of demodulation techniques for multifrequency atomic force microscopy

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

Beilstein J. Nanotechnol. 2020, 11, 76–91, doi:10.3762/bjnano.11.8

• sensing the interaction between a sharp microcantilever probe and the sample [2]. Initial operation was in constant-force contact-mode, where a static deflection is maintained through a constant contact force [3]. In dynamic imaging modes [4], the cantilever is driven at, or near, a resonance frequency

• , which establishes the requirement for demodulation in AFM. In intermittent-contact constant-amplitude AFM [5], a constant cantilever oscillation amplitude is maintained by feeding back the demodulated fundamental amplitude of the deflection signal. The imaging of delicate biological samples [6][7][8] is

• particularly suited to intermittent-contact AFM [9] when tip–sample contact is gentle. Environmental damping has a large effect on the quality factor (Q) of the cantilever. Values can range from as low as Q ≈ 1 in liquid [10], up to Q ≈ 10,000 in ultra-high vacuum [11]. This affects the mechanical bandwidth of

The effect of heat treatment on the morphology and mobility of Au nanoparticles

• Sven Oras,
• Sergei Vlassov,
• Simon Vigonski,
• Boris Polyakov,
• Mikk Antsov,
• Vahur Zadin,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2020, 11, 61–67, doi:10.3762/bjnano.11.6

• manipulation of the NPs was performed with a Bruker Multimode 8 AFM in the PeakForce quantitative nanoscale mechanical characteriztion (PeakForce QNM) mode using a rectangular AFM cantilever (Bruker, RTESPA-300, k = 40 N/m) with a resonance frequency of around 300 kHz. Prior to each manipulation, the samples

• calculated with the following equation [20]: where k is the cantilever spring constant, f0 is the resonance frequency of the cantilever, Aset is the setpoint amplitude, Apiezo is the drive amplitude, θ is the phase signal and Q is the quality factor of the AFM cantilever. The dissipated power was used as a

• measure of the mobility of the NPs. The calibration of the cantilevers was performed by the thermal tuning method. The oscillation amplitudes ranged from 0.05 to 0.6 V with a sensitivity of 25 to 31 nm/V. The sensitivity was measured individually for each cantilever by means of damping the AFM tip against

The different ways to chitosan/hyaluronic acid nanoparticles: templated vs direct complexation. Influence of particle preparation on morphology, cell uptake and silencing efficiency

• Arianna Gennari,
• Julio M. Rios de la Rosa,
• Erwin Hohn,
• Maria Pelliccia,
• Enrique Lallana,
• Roberto Donno,
• Annalisa Tirella and
• Nicola Tirelli

Beilstein J. Nanotechnol. 2019, 10, 2594–2608, doi:10.3762/bjnano.10.250

• , Abingdon, UK) equipped with an OTESPA-R3 cantilever (Bruker, Camarillo, CA, USA) was used to acquire AFM images in air at room temperature in tapping mode. Igor-Pro AFM software (Oxford Instrument, UK) was used to analyse the images. Nuclease protection assay. The protection effect against nuclease

Evaluation of click chemistry microarrays for immunosensing of alpha-fetoprotein (AFP)

• Seyed Mohammad Mahdi Dadfar,
• Sylwia Sekula-Neuner,
• Vanessa Trouillet,
• Hui-Yu Liu,
• Ravi Kumar,
• Annie K. Powell and
• Michael Hirtz

Beilstein J. Nanotechnol. 2019, 10, 2505–2515, doi:10.3762/bjnano.10.241

• was spotted onto them via microchannel cantilever spotting (µCS). Based on the fluorescence measurements, the optimal microarray design was found and its sensitivity was determined. Keywords: alpha-fetoprotein (AFP); cancer biomarker; click chemistry; fluorescent immunosensor; hepatocellular

• fabricated by microchannel cantilever spotting (μCS). Here, patterns are written with fluorescently labeled AFP (as antigen) on the surfaces modified with anti-AFP (as antibody). In different studies, many selective biosensors have been developed based on antigen–antibody interactions [22][30][31][33][34][35

Abrupt elastic-to-plastic transition in pentagonal nanowires under bending

• Sergei Vlassov,
• Magnus Mets,
• Boris Polyakov,
• Jianjun Bian,
• Leonid Dorogin and
• Vahur Zadin

Beilstein J. Nanotechnol. 2019, 10, 2468–2476, doi:10.3762/bjnano.10.237

• in cantilever beam configuration inside a scanning electron microscope. We demonstrated an unusual, abrupt elastic-to-plastic transition, observed as a sudden change of the NW profile from smooth arc-shaped to angled knee-like during the bending in the narrow range of bending angles. In contrast to

• NWs were studied both theoretically and experimentally in different configurations, including uniaxial loading (tensile and compression tests) [24][25], three-point bending [26][27], cantilever beam bending [28][29] and nanoindentation [30]. Several interesting phenomena were reported that can be

• curved pathways for electromagnetic radiation. Any crack or other discontinuities that are introduced by bending can prevent plasmon propagation in the NW [19]. Pure bending conditions are realized in the cantilever beam bending configuration where the NW is fixed at one end and the free end is pushed by

Mobility of charge carriers in self-assembled monolayers

• Zhihua Fu,
• Tatjana Ladnorg,
• Hartmut Gliemann,
• Alexander Welle,
• Asif Bashir,
• Michael Rohwerder,
• Qiang Zhang,
• Björn Schüpbach,
• Andreas Terfort and
• Christof Wöll

Beilstein J. Nanotechnol. 2019, 10, 2449–2458, doi:10.3762/bjnano.10.235

• . Then, the process of nanografting was performed in the contact mode (cantilever type: NSC-18/Cr-Au, spring const. 2.8 N/m, µmasch, NanoAndMore GmbH) with an increased force (setpoint: −0.66 V) of the tip on the surface. During the scanning process (scan rate: 5 Hz, number of lines: 512), the targeted

Integration of sharp silicon nitride tips into high-speed SU8 cantilevers in a batch fabrication process

• Nahid Hosseini,
• Matthias Neuenschwander,
• Oliver Peric,
• Santiago H. Andany,
• Jonathan D. Adams and
• Georg E. Fantner

Beilstein J. Nanotechnol. 2019, 10, 2357–2363, doi:10.3762/bjnano.10.226

• cantilever made out of a polymer material do not meet the requirements for tip sharpness and durability. Combining the high imaging bandwidth of polymer cantilevers with making sharp and wear-resistant tips is essential for a future adoption of polymer cantilevers in routine AFM use. In this work, we have

• any photo-processable polymer cantilever. Keywords: Atomic force microscopy (AFM); durability; imaging speed; polymer cantilever; silicon nitride tip; Introduction Atomic force microscopy (AFM) cantilevers have been developed for numerous applications since the invention of scanning probe microscopy

• (SPM) [1]. Quality and accuracy of an AFM image strongly depend on the tip geometry since the image topography is the convolution of the surface topography and the cantilever tip geometry [2]. More precisely, the resulting images suffer from the effect of dilation [3]. AFM images with tip artefacts are

Atomic force acoustic microscopy reveals the influence of substrate stiffness and topography on cell behavior

• Yan Liu,
• Li Li,
• Xing Chen,
• Ying Wang,
• Meng-Nan Liu,
• Jin Yan,
• Liang Cao,
• Lu Wang and
• Zuo-Bin Wang

Beilstein J. Nanotechnol. 2019, 10, 2329–2337, doi:10.3762/bjnano.10.223

• biomechanical studies [21]. Atomic force acoustic microscopy (AFAM) is a technique based on AFM for nondestructive imaging. This technique operates on a dynamic mode in which the AFM cantilever vibrates upon ultrasound excitation. Accordingly, AFAM shows the ability to measure nanomechanical properties and is

• the sample holder was used to generate ultrasound waves propagating into the sample. An AFM tapping probe (Tap300Al-G, BudgetSensors) was used in all imaging experiments. A lock-in amplifier (SR830DSP, Stanford Research Systems, USA) was employed to analyze the cantilever oscillation signals. When the

• probe tip scanned across the specimen surface, acoustic and morphological images were acquired simultaneously. The deflections of the cantilever represent the morphological information, and the vibrations of the cantilever correspond to the acoustic signals. By employing a suitable mechanical model to

Nontoxic pyrite iron sulfide nanocrystals as second electron acceptor in PTB7:PC₇₁BM-based organic photovoltaic cells

• Olivia Amargós-Reyes,
• José-Luis Maldonado,
• Omar Martínez-Alvarez,
• María-Elena Nicho,
• José Santos-Cruz,
• Juan Nicasio-Collazo,
• Irving Caballero-Quintana and
• Concepción Arenas-Arrocena

Beilstein J. Nanotechnol. 2019, 10, 2238–2250, doi:10.3762/bjnano.10.216

• active layer thickness was measured by AFM (Easyscan2 from Nanosurf) in contact mode employing cantilever tips with the aluminum reflective coating (ContAl-G) from BudgetSensors. The AFM roughness images were acquired in dynamic force mode (using PPP-NCLAu from NanoSensors), because it shows better

Synthesis and potent cytotoxic activity of a novel diosgenin derivative and its phytosomes against lung cancer cells

• Liang Xu,
• Dekang Xu,
• Ziying Li,
• Yu Gao and
• Haijun Chen

Beilstein J. Nanotechnol. 2019, 10, 1933–1942, doi:10.3762/bjnano.10.189

• under ambient conditions with a silicon cantilever with L = 115 μm, W = 25 μm, and T = 605 nm. For TEM measurements, the DiP and P2P were diluted with ddH2O to a concentration of 10 μg/mL. 8.5 μL of the dispersion was dripped on the copper grid and dried in air overnight before imaging. Cell cultures

Subsurface imaging of flexible circuits via contact resonance atomic force microscopy

• Wenting Wang,
• Chengfu Ma,
• Yuhang Chen,
• Lei Zheng,
• Huarong Liu and
• Jiaru Chu

Beilstein J. Nanotechnol. 2019, 10, 1636–1647, doi:10.3762/bjnano.10.159

• sample properties was systematically investigated by combining experimental results with theoretical analysis from finite element simulations. The results show that imaging with a softer cantilever and a lower eigenmode will improve the subsurface contrast. The experimental results and theoretical

• microscopy where the sample is ultrasonically excited at a specified frequency and the amplitude and phase of the cantilever are recorded [13][14]. After that, the theoretical analysis of the cantilever vibration with the tip contacting the sample surface was intensively investigated, including the influence

• of tip position on the cantilever, lateral forces and cantilever tilt [14][15][16]. Since the contact resonance is sensitive to the sample’s local mechanical properties, CR-AFM has been employed for characterization of elastic and viscoelastic properties [17][18][19][20]. In addition, mechanically

Kelvin probe force microscopy work function characterization of transition metal oxide crystals under ongoing reduction and oxidation

• Dominik Wrana,
• Karol Cieślik,
• Wojciech Belza,
• Christian Rodenbücher,
• Krzysztof Szot and
• Franciszek Krok

Beilstein J. Nanotechnol. 2019, 10, 1596–1607, doi:10.3762/bjnano.10.155

• behavior, with the correct CPD values measured when TiO nanowires are separated by more than 40 nm. This stands in perfect agreement with the real tip radius of 15 nm, which was measured for the same cantilever in high-resolution SEM (see Figure 4d insets). Here, the use of uniformly PtIr-coated tips

• noncontact mode measurements (with a Kelvin loop) using the very same tip, maintaining oscillations at the higher harmonics of the fundamental frequency (≈75 kHz). Hence, in order to record current and CPD maps from the very same sample area, KPFM measurements were first performed with the soft cantilever

• actual PtSi cantilever used in the experiments with a tip radius of 15 nm. Characterization of the SrTiO3(100) surface by KPFM. a) Topography of a TiO/SrTiO3 structure (Δf = −20 Hz), b) corresponding work function map from KPFM, c) work function histogram from the selected area in b), d) and e