ReactorAFM/STM – dynamic reactions on surfaces at elevated temperature and atmospheric pressure

• Tycho Roorda,
• Hamed Achour,
• Matthijs A. van Spronsen,
• Marta E. Cañas-Ventura,
• Sander B. Roobol,
• Willem Onderwaater,
• Mirthe Bergman,
• Peter van der Tuijn,
• Gertjan van Baarle,
• Johan W. Bakker,
• Joost W. M. Frenken and
• Irene M. N. Groot

Beilstein J. Nanotechnol. 2025, 16, 397–406, doi:10.3762/bjnano.16.30

• AFM; model catalysts; nc-AFM; operando catalysis; qPlus tuning fork sensor; Introduction Operando catalysis is the field of research that monitors the structure, composition, and morphology of a catalyst while simultaneously investigating its activity, reactivity, and selectivity under industrially

• conductive substrate limits STM techniques in relevant industrial applications involving such more complex catalysts. For this reason, an atomic force microscopy (AFM) version of the high-pressure STM employing a quartz tuning fork (QTF) was introduced to overcome this limitation [16]. Unlike STM, which uses

• AFM/STM integrated in a high-pressure gas flow reactor. The combined technique is based on the state-of-the-art tuning fork sensor in a qPlus configuration with three contacts, two for AFM and one for STM [17]. In order to illustrate the applicability of the technique, operando oxidation of Pd(100

Stiffness calibration of qPlus sensors at low temperature through thermal noise measurements

• Laurent Nony,
• Sylvain Clair,
• Daniel Uehli,
• Aitziber Herrero,
• Jean-Marc Themlin,
• Andrea Campos,
• Franck Para,
• Alessandro Pioda and
• Christian Loppacher

Beilstein J. Nanotechnol. 2024, 15, 580–602, doi:10.3762/bjnano.15.50

• little precision. An accurate stiffness calibration is therefore mandatory if accurate force measurements are targeted. In nc-AFM, the probe may either be a silicon cantilever, a quartz tuning fork (QTF), or a length extensional resonator (LER). When used in ultrahigh vacuum (UHV) and at low temperature

• the framework focuses on a particular kind of sensor, it may be adapted to any high-k, high-Q nc-AFM probe used under similar conditions, such as silicon cantilevers and LERs. Keywords: low temperature; non-contact atomic force microscopy; qPlus sensors; quartz tuning fork; stiffness calibration

• optical detection setup. Nc-AFM experiments are then mostly performed with quartz sensors, essentially implemented according to two geometries: quartz tuning fork (QTF) [19] or length-extensional resonator (LER) [20][21][22]. The commercial versions of these probes are the qPlus sensor (Scienta-Omicron

Unveiling the nature of atomic defects in graphene on a metal surface

• Karl Rothe,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2024, 15, 416–425, doi:10.3762/bjnano.15.37

• are indeed lacking the graphene atomic lattice structure in their interior. Spatially resolved spectroscopy of the differential conductance (dI/dV, I: tunneling current, V: bias voltage) and of the tuning fork resonance frequency change (Δf) further unravel marked differences between these two kinds

• of an oscillating piezoelectric tuning fork sensor [37][38] (resonance frequency: 30.5 kHz, quality factor: 45000, amplitude: 50 pm) were mapped at constant height for topographic images. The vertical force between tip and sample was extracted from distance-dependent measurements of the resonance

A cantilever-based, ultrahigh-vacuum, low-temperature scanning probe instrument for multidimensional scanning force microscopy

• Hao Liu,
• Zuned Ahmed,
• Sasa Vranjkovic,
• Manfred Parschau,
• Andrada-Oana Mandru and
• Hans J. Hug

Beilstein J. Nanotechnol. 2022, 13, 1120–1140, doi:10.3762/bjnano.13.95

• tuning fork force sensor became increasingly popular. In comparison to microfabricated cantilevers, the more macroscopic tuning forks, however, lack sensitivity, which limits the measurement bandwidth. Moreover, multimodal and multifrequency techniques, such as those available in cantilever-based AFM

• attractive or repulsive inter-atomic forces occur between tip apex atom and atoms at the surface. In recent years, functionalizing the tip apex with a lowly coordinated atom/molecule resulted in exceptional submolecular resolution at low temperature [8][9][10][11]. Tuning fork AFM has become increasingly

• popular for atomic resolution work performed under UHV conditions [12]. In tuning fork AFM, one of the prongs of the tuning fork is fixed to the tip holder, while the other one acts like a macroscopic cantilever. The comparatively large dimensions of the prongs facilitate the attachment of a small but

Quantitative dynamic force microscopy with inclined tip oscillation

• Philipp Rahe,
• Daniel Heile,
• Reinhard Olbrich and
• Michael Reichling

Beilstein J. Nanotechnol. 2022, 13, 610–619, doi:10.3762/bjnano.13.53

• sensor often used in low-temperature environments (tuning fork sensor [21] with f0 = 30 kHz, k0 = 1800 N/m, and A = 0.45 nm). However, similar effects can be present when using parameters for other sensors as well. Frequency shift Δf data are calculated with the piezo axis located at xts = yts = 0 and

Topographic signatures and manipulations of Fe atoms, CO molecules and NaCl islands on superconducting Pb(111)

• Carl Drechsel,
• Philipp D’Astolfo,
• Jung-Ching Liu,
• Thilo Glatzel,
• Rémy Pawlak and
• Ernst Meyer

Beilstein J. Nanotechnol. 2022, 13, 1–9, doi:10.3762/bjnano.13.1

• temperature in the preparation chamber. Low-temperature scanning tunneling microscope The experiments were performed using a low-temperature STM/AFM microscope (T = 4.8 K) from Omicron GmbH in UHV (p ≈ 1 × 10−10 mbar) operated with Nanonis RC5 electronics. The sensor is a tuning fork sensor in a qPlus design

Numerical analysis of vibration modes of a qPlus sensor with a long tip

• Kebei Chen,
• Zhenghui Liu,
• Yuchen Xie,
• Chunyu Zhang,
• Gengzhao Xu,
• Wentao Song and
• Ke Xu

Beilstein J. Nanotechnol. 2021, 12, 82–92, doi:10.3762/bjnano.12.7

• . The vibration modes of a qPlus sensor with a long tip are quite different from those of a cantilever with a short tip. Flexural vibration of the tungsten tip will occur. The tip can no longer be considered as a rigid body that moves with the prong of the tuning fork. Instead, it oscillates both

• the optimal diameter was found to be 0.1 mm. Keywords: finite element method; long tilted tip; noncontact atomic force microscopy; qPlus sensor; quartz tuning fork; simulations; Introduction Quartz tuning forks are widely used in the watch industry because of their low frequency offset over a wide

• temperature range [1]. In addition, quartz tuning forks have a high elastic constant, a high quality factor (Q factor), and are self-sensing due to the piezoelectric effect [1]. Therefore, a quartz tuning fork can be used as a force sensor. The central part of the “qPlus sensor” is a quartz tuning fork of

Protruding hydrogen atoms as markers for the molecular orientation of a metallocene

• Linda Laflör,
• Michael Reichling and
• Philipp Rahe

Beilstein J. Nanotechnol. 2020, 11, 1432–1438, doi:10.3762/bjnano.11.127

• instrument (ScientaOmicron GmbH, Taunusstein, Germany), while experiments on thin films used a ScientaOmicron LT qPlus gen.II machine, both operated with a MATRIX controller. W tips attached to tuning fork sensors in qPlus configuration [29] were used in both systems. For the measurements on thin film

Revealing the local crystallinity of single silicon core–shell nanowires using tip-enhanced Raman spectroscopy

• Marius van den Berg,
• Ardeshir Moeinian,
• Arne Kobald,
• Yu-Ting Chen,
• Anke Horneber,
• Steffen Strehle,
• Alfred J. Meixner and
• Dai Zhang

Beilstein J. Nanotechnol. 2020, 11, 1147–1156, doi:10.3762/bjnano.11.99

• ) along the perimeter of a SiNW. The tip–sample distance is controlled by a shear-force feedback. For this purpose, the tip is mounted on an oscillating tuning fork, which experiences a phase shift of the oscillation upon approach. This phase shift is recorded with a lock-in amplifier and fed to a

• further increase the resolution a chemically etched gold tip, attached to a tuning fork, is brought into the focus [37][38][39][40][41]. A plasmonic oscillation is generated at the tip apex by the excitation with a radially polarized laser beam along the tip axis. Here, the local field intensity is

Experimental study of an evanescent-field biosensor based on 1D photonic bandgap structures

• Jad Sabek,
• Francisco Javier Díaz-Fernández,
• Luis Torrijos-Morán,
• Zeneida Díaz-Betancor,
• Ángel Maquieira,
• María-José Bañuls,
• Elena Pinilla-Cienfuegos and
• Jaime García-Rupérez

Beilstein J. Nanotechnol. 2019, 10, 967–974, doi:10.3762/bjnano.10.97

• the photonic chip using a cleaved single-mode optical fiber and the near-field signal from the PBG structure was collected using a bent fiber tip pre-mounted on a tuning fork working in tapping mode. Figure 3 shows the SNOM signal measured for one of the PBG sensing structures having transversal

• coated, pre-mounted on a tuning fork working in tapping mode at 36.19 kHz and placed perpendicular to the sample was used to scan the photonic structures and measure the near-field signal using a FWPR-S femtowatt photoreceiver. A step size of 40 nm in the xy-plane was used when acquiring the SNOM image

Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy

• Majid Fazeli Jadidi,
• Umut Kamber,
• Oğuzhan Gürlü and
• H. Özgür Özer

Beilstein J. Nanotechnol. 2018, 9, 2953–2959, doi:10.3762/bjnano.9.274

• apex. However, the uncertainty whether there is sufficient coating at the very apex of the tip or not and whether that coating remains during the experiments casts doubt on the metallic nature of the tip. Only in a limited number of experiments where a tuning fork is used as the sensing element, W tips

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• advantage of AFM manipulation methods, CB[n] is ideally suited to mediate sub-nanometer gap formation. For this, a sharply pointed glass tip is glued to a piezoelectric quartz tuning fork (Figure 1C), which enables to control the tip position with respect to AuNPs deposited on a glass surface with sub

• formed of spherical AuNPs attached to a sharply pointed glass tip. Inset: Magnification to the gap region showing the aligned CB[n]s on the NP surfaces, which results in a sub-nanometer gap distance. (C) Macroscale picture of a glass tip attached to a piezoelectric quartz tuning fork acting as a force

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

• then glued onto an Abracon Corporation, AB38T-32.768 kHz tuning fork operated in shear force configuration. Image treatment To perform the FFT analysis of the optical images we used the open source software Gwyddion [38]. Any AFM software offering these processing options could be used to achieve the

Optimizing qPlus sensor assemblies for simultaneous scanning tunneling and noncontact atomic force microscopy operation based on finite element method analysis

• Omur E. Dagdeviren and
• Udo D. Schwarz

Beilstein J. Nanotechnol. 2017, 8, 657–666, doi:10.3762/bjnano.8.70

• lateral resolution of the setup. As a consequence, establishing a highly symmetric tunneling connection with the smallest possible stiffness should receive highest priority during the assembly of tuning fork-based sensors. Methods The results presented in the paper expand on a previously introduced

• approach for the FEM modeling of a tip-less, but otherwise complete qPlus-style sensor setup [26]. This previous model included a tuning fork of length L = 2426.3 µm, width w = 130.7 µm, and thickness τ = 234.1 µm mounted with epoxy glue on a holder made of Macor, with material choices and sensor geometry

• closely reflecting the design that we actually use in our lab. While in [26] the thickness of the epoxy layer and its overlap with the tuning fork (referred therein as parameters ‘ethick’ and ‘eover’, respectively) were varied to uncover their influence on the sensor properties, we keep them constant

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

• the sample surface [2], typically a cantilever, a tuning fork, or a needle sensor [8]. The resolution of force measurements is limited by the noise in the frequency shift signal [9][10], which strongly depends on the noise floor of the detection system, the frequency response of the frequency

Nanoanalytics for materials science

• Thilo Glatzel and
• Tom Wirtz

Beilstein J. Nanotechnol. 2016, 7, 1674–1675, doi:10.3762/bjnano.7.159

• “Nanoanalytics for materials science” groups six exciting articles around the aforementioned aspects of nanoanalytics, describing the development of both new instrumentation as well as new methodologies. On the side of instrumental development, a ultra-high resolution multi-probe device based on tuning fork

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

Virtual reality visual feedback for hand-controlled scanning probe microscopy manipulation of single molecules

• Philipp Leinen,
• Matthew F. B. Green,
• Taner Esat,
• Christian Wagner,
• F. Stefan Tautz and
• Ruslan Temirov

Beilstein J. Nanotechnol. 2015, 6, 2148–2153, doi:10.3762/bjnano.6.220

• position of the SPM tip during manipulation in real time, while simultaneously plotting the experimentally measured frequency shift (Δf) of the non-contact atomic force microscope (NC-AFM) tuning fork sensor as well as the magnitude of the electric current (I) flowing between the tip and the surface. The

• commercial, combined qPlus tuning fork [4] non-contact atomic force/scanning tunnelling microscope (NC-AFM/STM) operated at 5 K under ultra-high vacuum conditions. Each extraction attempt started with positioning the tip over one of the four carboxylic oxygen atoms (marked by red circles in Figure 1) of the

• improved further. Note, however, that the oscillation amplitude of the NC-AFM tuning fork sensor (approx. 0.4 Å) directly adds to the error of the trajectory tracking and thus limits the achievable accuracy. Further, we applied the extended HCM set-up to our model manipulation problem of [1], i.e

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

• nanoindentation is described that exhibits improved resolution and depth sensing. The approach is based on a multi-probe scanning probe microscopy (SPM) tool that utilizes tuning-fork based probes for both indentation and depth sensing. Unlike nanoindentation experiments performed with conventional AFM systems

• using beam-bounce technology, this technique incorporates a second probe system with an ultra-high resolution for depth sensing. The additional second probe measures only the vertical movement of the straight indenter attached to a tuning-fork probe with a high spring constant and it can also be used

• point of contact detection measurement of tuning forks. Oiko et al. recently demonstrated the development of nanoindentation probes that can be manipulated inside a scanning electron microscope (SEM) [13]. This system also utilizes tuning-fork technology, which can be used as an ultra-sensitive force

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

• ]. However, a direct comparison between theory and experiment requires that an absolute, quantitative framework for the measurement is established, as illustrated by a recent work in single dimer manipulation [5]. In recent years, quartz tuning fork sensors have emerged as an attractive alternative to

• traditional silicon microcantilevers for ncAFM. The stiff spring constant of the tuning fork enables precise control over the tip–sample separation at short stand-off distances despite relatively large van der Waals interactions. Moreover, the mass production of tuning forks for timing applications has

• provided highly-stable frequencies with self-sensing and self-actuating electromechanical properties all at low cost [6]. Tuning fork sensors were originally used as a traditional, dual-tine oscillator. This evolved into the more widely used qPlus configuration where the sensing tine oscillates and the

Nano-contact microscopy of supracrystals

• Adam Sweetman,
• Nicolas Goubet,
• Ioannis Lekkas,
• Marie Paule Pileni and
• Philip Moriarty

Beilstein J. Nanotechnol. 2015, 6, 1229–1236, doi:10.3762/bjnano.6.126

• based on a combination of STM and dynamic force microscopy (DFM) imaging and spectroscopy. DFM experiments, also known as non-contact AFM (NC-AFM), are carried out using a quartz tuning fork sensor in the qPlus geometry [16][17] to which a tip has been glued. Shifts in the resonant frequency of a tine

• of the tuning fork due to variations in the tip–sample interaction are tracked and, via the formula introduced by Sader and Jarvis [18], can be converted to force or potential energy measurements. The qPlus sensor facilitates, in principle, a straight-forward method of acquiring tunnelling current

• etched tungsten wire glued to one tine of the tuning fork were first prepared on clean Si(111)-(7 × 7) samples by standard STM techniques before imaging of the nanocrystal samples. During imaging of the supracrystal surface, spontaneous and regular tip changes were observed, thus it is possible that the

Graphene on SiC(0001) inspected by dynamic atomic force microscopy at room temperature

• Mykola Telychko,
• Jan Berger,
• Zsolt Majzik,
• Pavel Jelínek and
• Martin Švec

Beilstein J. Nanotechnol. 2015, 6, 901–906, doi:10.3762/bjnano.6.93

• custom-built quartz-tuning fork sensor was used for the measurements. It had a main resonance frequency of 51294 Hz, a quality factor above 1000 and an estimated stiffness of ≈3800 N·m−1 [22]. The contact to the tungsten tip was made of a thin golden wire in order to avoid crosstalk with the deflection

• signal from the tuning fork piezo [22][23]. The tip has been treated by annealing to 1200 °C in contact with a hot tungsten filament. The simultaneous current and frequency shift measurements were done in constant height mode. A very slow tunneling current feedback was applied for compensation of the

• graphene overgrows a step (see Figure 1c), there is no visible rippling. The set of curves in Figure 2a shows local spectroscopy taken just before the imaging above the single-layer graphene with the tuning-fork-based dAFM sensor, oscillating at amplitudes of 150 pm. The Δf, time-averaged current (

Dissipation signals due to lateral tip oscillations in FM-AFM

• Michael Klocke and
• Dietrich E. Wolf

Beilstein J. Nanotechnol. 2014, 5, 2048–2057, doi:10.3762/bjnano.5.213

• distinguishing further degrees of freedom, these equations of motion describe the combined elastic response of cantilever and tip. A recent innovation in FM-AFM is the use of tuning fork cantilevers. Their spring constants are several orders of magnitude larger than those of ordinary cantilevers. In this case

Patterning a hydrogen-bonded molecular monolayer with a hand-controlled scanning probe microscope

• Matthew F. B. Green,
• Taner Esat,
• Christian Wagner,
• Philipp Leinen,
• Alexander Grötsch,
• F. Stefan Tautz and
• Ruslan Temirov

Beilstein J. Nanotechnol. 2014, 5, 1926–1932, doi:10.3762/bjnano.5.203

• used a qPlus sensor [17] manufactured by CREATEC. The AFM/STM tip was made from a 0.3 mm long and 15 μm thick PtIr wire glued to the tuning fork of the qPlus sensor, and sharpened with a gallium focused ion beam (FIB). The resulting resonance frequency of the qPlus sensor was f0 = 30,300 Hz with a

• quality factor of Q ≈ 70,000. Contacting and manipulation were performed with the qPlus sensor oscillating with an amplitude of A0 ≈ 0.2–0.3 Å. Interactions in the junction were monitored by measuring the frequency shift Δf(z) ≈ −(f0/2k0)dFz/dz, where k0 = 1800 N/m is the stiffness of the quartz tuning

• fork used. The essence of our approach lies in the coupling of the sub-angstrom precise positioning of the tip of our instrument to the motion of the operator's hand [18]. This is achieved with the help of a commercial motion tracking system from VICON (see Figure 2). The VICON software was used to

Mechanical properties of sol–gel derived SiO₂ nanotubes

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

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

• cantilevers, Nanosensors, C = 0.2 N/m) to one prong of a commercially available quartz tuning fork (QTF, ELFA). The tip of the ATEC-CONT cantilevers is tilted about 15 degrees relative to the cantilever, which makes the tip visible from the top. In experiments the QTF was driven electrically by an AC voltage