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

• bond formation (Supporting Information File 1, Figure S3). The propensity to form a chemical bond between the Au tip apex atom and C atoms close to the center of type-1 defects is likewise reflected by the occurrence of hysteresis loops in Δf and I approach and retraction traces. Figure 5 compares Δf

• form a sufficiently strong bond with the tip apex atom. In addition, a voltage polarity effect was not observed, which renders the involvement of current-induced forces unlikely [64]. Another difference to the previous report concerns the actual behavior of I↓ and I↑. Within the hysteresis loop, the

Quantitative wear evaluation of tips based on sharp structures

• Ke Xu and
• Houwen Leng

Beilstein J. Nanotechnol. 2024, 15, 230–241, doi:10.3762/bjnano.15.22

• perpendicularly above the sample matrix. When the tip apex touched the sample, the difference between the tip and sample matrices was calculated to determine the position of the tip apex. The position of the tip apex was then recorded, and the tip apex was moved horizontally to contact the next pixel of the

• sample matrix. This process was repeated until all points on the sample matrix had been scanned. The resulting image comprised the recorded height information of the tip apex. Figure 4 illustrates the two tip shapes used in the simulation, a blunt tip with a tip diameter of 20 nm at a distance of 5 nm

• from the tip apex (Figure 4a), and a sharper tip with a tip diameter of 10 nm also at a distance of 5 nm from the tip apex (Figure 4b). The sample exhibits a prominent sharp structure standing at a height of 15 nm (Figure 4c and Figure 4d). Figure 4a presents the form of the first tip. The top of the

Determination of the radii of coated and uncoated silicon AFM sharp tips using a height calibration standard grating and a nonlinear regression function

• Perawat Boonpuek and
• Jonathan R. Felts

Beilstein J. Nanotechnol. 2023, 14, 1200–1207, doi:10.3762/bjnano.14.99

• corner segment of the scanline profile of the tip apex was used to determine the tip radius with a nonlinear regression method. This method fits the arc curve through the measured point-to-point data of tip position in an (x, y) coordinate system, allowing us to obtain the exact value of the tip radius

• bright area means that the tip apex physically touched the grate’s curved surface of the corner edge. In contrast, the dark area represents inability of the tip to reach the bottom corner of the grating structure (a 20 nm SiO2 column [15]), because the tip cone angle is not parallel to the tip cone

A multi-resistance wide-range calibration sample for conductive probe atomic force microscopy measurements

• François Piquemal,
• Khaled Kaja,
• Pascal Chrétien,
• José Morán-Meza,
• Frédéric Houzé,
• Christian Ulysse and
• Abdelmounaim Harouri

Beilstein J. Nanotechnol. 2023, 14, 1141–1148, doi:10.3762/bjnano.14.94

• commonly observed in C-AFM because of highly localized electric fields at the tip apex leading to structural damage considerably affecting the measurement reliability. These effects are further amplified during scanning in contact mode due to shear forces and strong mechanical stress imposed on the tip

• still observed of the order of 8%. Resistance values from C-AFM I–V curves To comprehend the origin of this remaining error, we proceeded into removing any possible contamination of the tip apex by repeatedly scanning over a fixed line (typically a few tens of nanometers) on the sample surface (i.e., by

• core. Thus, the photovoltage effect observed in our paper is solely related to the tip apex and does not depend on the measured sample. We were able to confirm this aspect by running I–V curves using new probes with intact apexes, which showed no shift around zero even with the AFM laser on. This

Cross-sectional Kelvin probe force microscopy on III–V epitaxial multilayer stacks: challenges and perspectives

• Mattia da Lisca,
• José Alvarez,
• James P. Connolly,
• Nicolas Vaissiere,
• Karim Mekhazni,
• Jean Decobert and
• Jean-Paul Kleider

Beilstein J. Nanotechnol. 2023, 14, 725–737, doi:10.3762/bjnano.14.59

• resolution. In particular, in AM-KPFM the electrical force between the tip and the sample is directly evaluated, whereas in FM-KPFM the gradient of the force is analysed. As a result, FM-KPFM is more sensitive to local tip apex–sample surface interactions; therefore, long-range electrostatic interactions of

From a free electron gas to confined states: A mixed island of PTCDA and copper phthalocyanine on Ag(111)

• Alfred J. Weymouth,
• Emily Roche and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2022, 13, 1572–1577, doi:10.3762/bjnano.13.131

• to images taken with a CO-terminated tip [23]. However, it could be due to another molecule at the tip apex leading to similar contrast as has been previously discussed in the literature [24]. As there was a slight drift in the vertical direction, the AFM data was plane-subtracted to enhance the

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

• 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

• must be stored in the cantilever oscillation such that stochastic energy loss events caused by stochastic position changes of the tip apex [63] or sample atoms in interaction with the tip will not unlock (crash) the phase-locked loop. To obtain an oscillation energy of a few tens of electronvolts at

• stochastic changes of atomic positions at the tip apex or sample atoms interacting with the tip [64]. Such stiffnesses are typically obtained in the second flexural oscillation mode of cantilevers with a first flexural mode stiffness of a few tens of newtons per meter (Equation 5). While the second modal

Comparing the performance of single and multifrequency Kelvin probe force microscopy techniques in air and water

• Jason I. Kilpatrick,
• Emrullah Kargin and
• Brian J. Rodriguez

Beilstein J. Nanotechnol. 2022, 13, 922–943, doi:10.3762/bjnano.13.82

• , respectively. This approach is strictly only valid for z ≪ R. This simplistic expression only considers the capacitance contribution at the tip apex and ignores the overall geometry of the rest of the cantilever. The contribution at the tip apex is also commonly modelled as a spherical capped cone with [83][97

• ] and where ϕ is the half cone angle. Figure 1 shows the z dependence of the capacitance gradients using the sphere and cone models. Again, this simplistic expression only considers the capacitance contribution at the tip apex and ignores the overall geometry of the rest of the cantilever. For

Temperature and chemical effects on the interfacial energy between a Ga–In–Sn eutectic liquid alloy and nanoscopic asperities

• Yujin Han,
• Pierre-Marie Thebault,
• Corentin Audes,
• Xuelin Wang,
• Haiwoong Park,
• Jian-Zhong Jiang and
• Arnaud Caron

Beilstein J. Nanotechnol. 2022, 13, 817–827, doi:10.3762/bjnano.13.72

• smaller than 5 nm for spherical particles. In our experiments, the Au tip apex can be considered a sphere with a radius R = 25 nm. According to [23], the surface energy of the gold tip can be assumed to be in the range of = 1.15–1.30 J/m2. The surface energy of stochiometric PtSi(010) was calculated as a

• that a factor of two to eight reduces the interfacial energy compared to the surface energy. Figure 7 shows SEM images of the tips after measurements on the Ga–In–Sn eutectic liquid. Unlike the PtSi and Au tips, the SiOx tip in Figure 7 exhibits residues of the liquid alloy up to a height from the tip

• apex of h ≈ 200 nm, which corresponds to the penetration depth of the tip into the liquid alloy. Coincidently, we determined the largest interfacial tension value at the melting point of the liquid alloy for the same tip, = 230 mN/m. The adhesion of melt residues at the SiOx tip can be attributed to

Relationship between corrosion and nanoscale friction on a metallic glass

• Haoran Ma and
• Roland Bennewitz

Beilstein J. Nanotechnol. 2022, 13, 236–244, doi:10.3762/bjnano.13.18

• area of the inner layer and tip apex at a higher normal load [34][35]. The friction force of the outer layer reveals the lateral plowing resistance of the outer layer to the sliding tip, which must depend on the shear strength of the layer and its structure. The friction data for each respective load

Reducing molecular simulation time for AFM images based on super-resolution methods

• Zhipeng Dou,
• Jianqiang Qian,
• Yingzi Li,
• Rui Lin,
• Jianhai Wang,
• Peng Cheng and
• Zeyu Xu

Beilstein J. Nanotechnol. 2021, 12, 775–785, doi:10.3762/bjnano.12.61

• schematic of the AM mode simulation model with conical tip apex is illustrated in Figure 1. The bottom layer atoms of the substrate are fixed to keep the sample stable. For the graphite substrate, the carbon–carbon interactions within each graphene layer are described by the AIREBO potential [55]. The

• virtual atom is added above the tip apex and they are connected with a spring in the z-direction. The virtual atom is excited by a sinusoidal signal, mimicking the acoustic excitation of AM-AFM. The excited frequency is adjusted by the spring stiffness. A damping force is applied on the tip to ensure the

• atoms intermittently interact with the sample in oscillation periods. The size effect of the tip apex is not obvious and the energy map is mainly affected by the height of the sample atoms. In the AM mode, we need 5000 time steps to keep the tip in a stable vibration to, then, calculate the average

A review of defect engineering, ion implantation, and nanofabrication using the helium ion microscope

• Frances I. Allen

Beilstein J. Nanotechnol. 2021, 12, 633–664, doi:10.3762/bjnano.12.52

• region of the tip apex forms the positively charged ions that are extracted and delivered to the sample via the ion optical column (Figure 1a). Generally, the source is configured to run in the stable configuration of just three atoms at the tip apex (named the trimer), generating three beamlets. Via

Local stiffness and work function variations of hexagonal boron nitride on Cu(111)

• Abhishek Grewal,
• Yuqi Wang,
• Matthias Münks,
• Klaus Kern and
• Markus Ternes

Beilstein J. Nanotechnol. 2021, 12, 559–565, doi:10.3762/bjnano.12.46

• to some mechanical relaxations of the rim areas under the influence of the force exerted by the tip. To analyse this effect we separate the short-range forces, which act between the tip apex and the sample and which vary over the corrugation of the monolayer, from electrostatic and van der Waals long

Determining amplitude and tilt of a lateral force microscopy sensor

• Oliver Gretz,
• Alfred J. Weymouth,
• Thomas Holzmann,
• Korbinian Pürckhauer and
• Franz J. Giessibl

Beilstein J. Nanotechnol. 2021, 12, 517–524, doi:10.3762/bjnano.12.42

• , Germany) operating in ultra-high vacuum at 5.6 K equipped with a qPlus sensor [25]. The sensor was equipped with an etched tungsten tip, which was repeatedly poked into a Cu(111) surface to generate well-defined tip apex configurations. Cu(111) was cleaned by standard sputtering and annealing cycles

Extended iron phthalocyanine islands self-assembled on a Ge(001):H surface

• Rafal Zuzak,
• Marek Szymonski and
• Szymon Godlewski

Beilstein J. Nanotechnol. 2021, 12, 232–241, doi:10.3762/bjnano.12.19

• surrounding the island shows no signs of any discontinuity of the STM appearance. This makes the modification of the STM tip apex unlikely and points to the fact that the observed shift may originate from a real shift of the island on the Ge(001):H surface. This observation indicates a weak interaction

Mapping the local dielectric constant of a biological nanostructured system

• Wescley Walison Valeriano,
• Rodrigo Ribeiro Andrade,
• Juan Pablo Vasco,
• Angelo Malachias,
• Bernardo Ruegger Almeida Neves,
• Paulo Sergio Soares Guimarães and
• Wagner Nunes Rodrigues

Beilstein J. Nanotechnol. 2021, 12, 139–150, doi:10.3762/bjnano.12.11

• expression from which the relative permittivity εr can be extracted: where R is the tip apex radius, θ is the tip conical angle, z is the tip–sample distance, and h is the sample thickness. Figure 3 shows a scheme of the model, which is commonly applied for such a configuration [12][13][14][15][16]. This

• FIB. Capacitance model with tip, sample, conductive plate, and the parameters used in our calculations. R is the tip apex radius, θ is the tip conical angle, z is the tip–sample distance, h is the sample thickness and εr is the relative permittivity of the sample. The sample is shown on top of the

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

• can be detected due to the multi-directional vibration of the tip [17]. Furthermore, by using a qPlus sensor with a long tilted tip, vertical incident light can be coupled to the tip apex. This setup has the added benefit of locating the exact target location with high resolution when it is combined

• tuning fork (Atfz) and its output current In this paper, the amplitude in the Z direction of point A on the tuning fork prong in Figure 3a is denoted as Atfz. The amplitude of point B at the tip in Figure 3a is denoted as Atip. Az and Ax represent the two components of the amplitude of the tip apex in

• output current and of Atfz with respect to the tip length are not necessarily synchronous. Tip oscillation and SEM observation Since the tip swings around the end of the tuning fork prong, Atip is different from Atfz. We should focus on the vibration of the tip apex itself. Figure 6 gives Atip and the

Direct observation of the Si(110)-(16×2) surface reconstruction by atomic force microscopy

• Tatsuya Yamamoto,
• Ryo Izumi,
• Kazushi Miki,
• Takahiro Yamasaki,
• Yasuhiro Sugawara and
• Yan Jun Li

Beilstein J. Nanotechnol. 2020, 11, 1750–1756, doi:10.3762/bjnano.11.157

• and no evaporation occurred. Figure 3b shows an AFM image scanned just after Figure 3a, where the scan direction was the same as in Figure 3a. The state of the tip apex changed in the position indicated by a black arrow. The image appearance changed from Figure 3a and the sudden protrusions on L-P3

• protrusions did not appear after the state of the tip apex changed, it can be concluded that the LP-3 atom state (that is, whether it is pulled up by the tip or not) depends on the state of the tip apex. Figure 3c shows the same phenomenon as Figure 3a when using a different tip and a different Si(110) sample

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

• evolution of a sharp line (one example marked by an arrow in Figure 2d), which suggests a relaxation of the front tip apex in agreement with earlier observations in organic [33][34] or inorganic [35][36] systems. For the smallest tip–sample separation, two short elongated dark segments (see markers in

• molecule. (3) The tip end is atomically sharp. The third condition implies the stabilisation of the tip-terminating atom by one or very few bonds directed towards the tip apex. Such a bond will always exhibit sufficient lateral elasticity to yield a sharp contrast feature when the tip terminating atom

Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

• Jeremiah Croshaw,
• Thomas Dienel,
• Taleana Huff and
• Robert Wolkow

Beilstein J. Nanotechnol. 2020, 11, 1346–1360, doi:10.3762/bjnano.11.119

• File 1, Figure S2) while avoiding unwanted tip–sample contact. Figure 1f shows a variation of constant height STM where the tip apex is functionalized with a flexible hydrogen atom. The use of a flexible species at the apex of a metallic tip to provide enhanced contrast was first reported using CO

• resolution by directly functionalizing the tip apex with a single hydrogen atom, picked up from the H–Si surface through the application of a voltage pulse, as reported in prior works [25][26][36]. Our ability to achieve STHM resolution using an H-functionalized tip aligns with recent STHM theory suggesting

• asymmetry in either the shape of the tip apex, or the attachment location of the functionalizing H atom. To highlight how differing asymmetries can affect STHM image appearance, Supporting Information File 1, Figure S3 shows a variety of images of the H–Si(100)-2 × 1 surface acquired with different H

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

• beam. The near field localized at the tip apex enhances the optical field in the tip–sample gap by several orders of magnitude and simultaneously directs the emitted photons from the gap into the far field for detection. With recent demonstrations of a spatial resolution even at the angstrom level [25

• across the laser focus gives an Airy disc-like pattern (Figure 4b), which is due to the photoluminescence emitted from the sharp tip apex. Irregularities can arise from the slight asymmetry of the tip apex. Figure 4c shows the polarization angle-resolved optical pattern of the photoluminescence of the

• dominant field component lays out-of-plane (parallel to the tip shaft). Figure 4b,c demonstrates that the tip apex can be easily excited, which is a precondition for producing a localized near field at the tip apex. Next, we approached the sample to the tip and recorded the topography (size: 250 × 250 nm2

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• . In our previous work [14], the adsorption process of SnPc on the (011) face of rutile TiO2 was studied by microscopic methods. Up to a monolayer, SnPc molecules exhibit comparable behavior on both rutile surfaces including the observation of a very short residence time under the tip apex at room

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

• frequency-modulated atomic force microscopy (AFM). Furthermore, this technique can be extended to the experimental verification of potential forms for any given material pair. Specifically, interaction forces are determined between an AFM tip apex and a nominally flat substrate using dynamic force

• separation distances. This methodology represents the first experimental technique in which material interaction potential parameters were verified over a range of tip–sample separation distances for a tip apex of arbitrary geometry. Keywords: adhesion; atomic force microscopy; diamond; frequency-modulated

• control of environment and probe/sample materials [36][37]. Therefore, we seek to leverage these advances to create a methodology for better validation of empirical pair potentials. In particular, we will do this by combining measurements of tip–sample interaction forces and experimental tip apex

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

• perturb the controller for a period of time, during which the tip apex structure could be damaged further due to additional tip–sample impacts. However, if a noncontact oscillatory current measurement mode is used, where the control variable is not the instantaneous value of the current, these unexpected

• intermittent-contact experiment, because in the former case electrical tip–sample contact may also be established on the sides of the tip apex, particularly if indentation is significant during the experiment. However, indentation during an ICM-AFM experiment may be smaller and thus the tip contact region may

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

• structure and the state of the tip apex [7][9][33][34]. Also, deformation of the surface structure sometimes occurs due to interactions between the tip apex and the sample surface [35]. To address the possibility that the asymmetric contrast in the NC-AFM image in Figure 4a is caused by these artifacts, we

• . There is a case in which the tip apex asymmetry causes an unexpected local image pattern, i.e., dimers of the same height would be imaged at different heights due to the tip apex asymmetry. We obtained NC-AFM images with two types of asymmetric contrast for during repeated NC-AFM imaging. Two types of

• Ti2O3 rows, with either the left side or the right side in a higher position, are shown in the NC-AFM image and height profile in Figure 5, indicating that the asymmetric image is not caused by an asymmetric tip apex structure. The other possibility to be considered is interactions between the tip and