Numerical analysis of single-point spectroscopy curves used in photo-carrier dynamics measurements by Kelvin probe force microscopy under frequency-modulated excitation

• Pablo A. Fernández Garrillo,
• Benjamin Grévin and
• Łukasz Borowik

Beilstein J. Nanotechnol. 2018, 9, 1834–1843, doi:10.3762/bjnano.9.175

• given to the mathematical model used in the data-fitting process as it constitutes a determining aspect in the calculation of time constants. Here, we propose and demonstrate an automatic numerical simulation routine that enables to predict the behavior of spectroscopy curves of the average surface

• work, where the minority-carrier lifetime in a silicon nanocrystal solar cell was obtained by KPFM spectroscopy under frequency-modulated light illumination [3]. This can be done by fixing the SPV decay time in the numerical simulation to the value predicted by the mathematical fit used on that

• occasion and comparing the correspondence between the spectroscopy curve resulting from the mathematical fit and the data points obtained from the numerical simulation. In [3], minority-carrier lifetime values were calculated through a mathematical fit procedure derived from previous publications [5] using

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• parameters of plasmonic metal nanostructures such as particle size, work function, surface facet and plasmonic band is a challenging task that demands numerical simulation. It is known that the photocatalysis performance is affected by the noble metal particle size and thus finite difference time domain

Revealing the interference effect of Majorana fermions in a topological Josephson junction

• Jie Liu,
• Tiantian Yu and
• Juntao Song

Beilstein J. Nanotechnol. 2018, 9, 520–529, doi:10.3762/bjnano.9.50

• trivial fermion states interfere with each other, the situation is very different. Though an analytic result cannot be obtained, our numerical simulation suggest that the general formula for the DOS for the electron (hole) part should be , with a and b being real constants. This can be understood as

Numerical investigation of the tribological performance of micro-dimple textured surfaces under hydrodynamic lubrication

• Kangmei Li,
• Dalei Jing,
• Jun Hu,
• Xiaohong Ding and
• Zhenqiang Yao

Beilstein J. Nanotechnol. 2017, 8, 2324–2338, doi:10.3762/bjnano.8.232

• hydrodynamic lubrication. Due to the complexity of the governing equations, however, it is difficult to obtain an analytical solution. Therefore, a numerical simulation is adopted in this study to solve the problem. Characterization of tribological properties The effect of the micro-dimple array on the

• . Numerical simulation Meshing The three-dimensional model of the computational domain was meshed by using GAMBIT software. In order to obtain a high-quality mesh, the model was divided into three domains (see Figure 3). The micro-dimple was located in domain two and domain three. In order to guarantee the

• are required to fill the horizontal extent of the dimple. Since the mesh size has a great effect on the accuracy and efficiency of the numerical simulation, the grid independence analysis was carried out to develop the proper meshing strategy. The variation of the mesh size may affect the film

Molecular dynamics simulations of nanoindentation and scratch in Cu grain boundaries

• Shih-Wei Liang,
• Ren-Zheng Qiu and
• Te-Hua Fang

Beilstein J. Nanotechnol. 2017, 8, 2283–2295, doi:10.3762/bjnano.8.228

• of the material along with the complex dislocation phenomenon of the grain boundary is unclear at the macroscopic scale. In the past few years, many researchers have used numerical simulation analysis to discuss the mechanical properties of metals [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17

Material property analytical relations for the case of an AFM probe tapping a viscoelastic surface containing multiple characteristic times

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2017, 8, 2230–2244, doi:10.3762/bjnano.8.223

• three previously described components, and it is evident that none of the components is negligible. Additionally, the results for the numerical simulation are depicted in Figure 3 with a gray thick-solid line, and it is also clear that a close agreement with the analytical solution (Equation 29) exists

• visualized in Figure 5 for the case of a flat-punch probe tapping on a polyisobutylene sample (this corresponds to the same numerical simulation used to construct Figure 4). Here it is also evident that the intermittent-contact nature of the interaction forbids the derivation of a simple equation as in the

• obtain its viscoelastic counterpart, as previously done by Cheng et al. [28]. For the case of a time-independent Poisson’s ratio, the cell constant reduces to b = 4R/(1 − ν). Scheme of intermittent-contact tip–sample interaction in AFM. The figure shows the results of a numerical simulation of a

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

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

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

• nanocomposite. As discussed previously, the force applied by the tip to the surface increases with the use of higher eigenmodes and by increasing their free amplitude. Supporting Information File 1, Figure S5 shows the results of a virtual AFM numerical simulation, where the increase in peak forces as the free

• properties and flexibility. With regards to methodology, the comprehensive experimental approach followed, supplemented with numerical simulation, illustrates the systematic combination of intrinsic and complementary advantages of different AFM methods (C-AFM, CRFM and bimodal AFM) to modify, characterize

Stick–slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

• Iakov A. Lyashenko,
• Vadym N. Borysiuk and
• Valentin L. Popov

Beilstein J. Nanotechnol. 2017, 8, 1889–1896, doi:10.3762/bjnano.8.189

• the stick–slip mode of boundary friction. An analytical description and numerical simulation with radial distributions of the order parameter, stress and strain were performed to investigate the spatial inhomogeneity. It is shown that in the case when the driving device is connected to the upper part

• of the friction block through an elastic spring, the frequency of the melting/solidification phase transitions increases with time. Keywords: boundary friction; dimensionality reduction; numerical simulation; shear stress and strain; stick–slip motion; tribology; Introduction The boundary friction

• computed at the points ri = ia0 / N (xi = ia0 / N), where . In our simulation we set the time step to be Δt = 10−8 s and number of segments N = 2000. Figure 2 shows the results of a numerical simulation of the shifting of the free end of the spring with constant velocity V0 at constant system parameters

Modeling of the growth of GaAs–AlGaAs core–shell nanowires

• Qian Zhang,
• Peter W. Voorhees and
• Stephen H. Davis

Beilstein J. Nanotechnol. 2017, 8, 506–513, doi:10.3762/bjnano.8.54

• the shell with the same conditions as the last numerical simulation, i.e., F{112} = 1.1F{110} with F{110} being large enough. These deposition rates can be different on facets of different orientations due to different sticking coefficients or exchange rates between the surface and bulk. Instead of

• balance between the surface diffusion and deposition giving a slowly varying facet size at early times. The numerical simulation is compared with the experiment result in [3] (Figure 5b) giving almost quantitative agreement. When a certain thickness of the shell is reached, the size of the {112} facets

• transient growth (Figure 7b). The configuration obtained in the numerical simulation is very close to that seen experimentally (Figure 7a). Besides the dot configuration shown in Figure 7b, Heiss et al. [2] also observed the segregation of Al in the shell of the nanowire (see the Al concentration shown in

Dynamic of cold-atom tips in anharmonic potentials

• Tobias Menold,
• Peter Federsel,
• Carola Rogulj,
• Hendrik Hölscher,
• József Fortágh and
• Andreas Günther

Beilstein J. Nanotechnol. 2016, 7, 1543–1555, doi:10.3762/bjnano.7.148

• microscope. To illustrate the dynamics of the cold-atom tip, Figure 1a shows in the two-dimensional phase space at four different times after the initial displacement. The data are derived from a numerical simulation of the cold atom tip with 5 × 105 atoms at 500 nK, moving in an harmonic potential with ω0

• illustrates the resulting tip dynamics in the two-dimensional phase space. The tip parameters have been chosen as before (T = 500 nK, N = 5 × 105, ω0 = 2π × 50 Hz) with an anharmonicity ε = 2 × 108 m−1 s−2. Figure 2a shows the distribution function as derived from a full numerical simulation at four

• anharmonic component of the trap potential, we performed a full numerical simulation of the ultracold cloud dynamics and the microwave outcoupling process. Thereby, we tried to model the physical reality as accurately as possible. This includes particle interactions, as well as a realistic model of the total

Fracture behaviors of pre-cracked monolayer molybdenum disulfide: A molecular dynamics study

• Qi-lin Xiong,
• Zhen-huan Li and
• Xiao-geng Tian

Beilstein J. Nanotechnol. 2016, 7, 1411–1420, doi:10.3762/bjnano.7.132

• from the results obtained using experimental measurement by Bertolazzi et al. [10], the present numerical simulation results are far greater than the experimental results. The significant discrepancy can be attributed to the inevitable defect in the experimental specimen and the difference of load

The self-similarity theory of high pressure torsion

• Yan Beygelzimer,
• Roman Kulagin,
• Laszlo S. Toth and
• Yulia Ivanisenko

Beilstein J. Nanotechnol. 2016, 7, 1267–1277, doi:10.3762/bjnano.7.117

• = 0.25 and m = 0. The first case simulates a high-friction case while the second corresponds to low friction on the side surface. A description of our numerical simulation conditions are given in Table 1. The results of the simulations are displayed in Figures 3–5. Analysis of the simulation results

Kelvin probe force microscopy for local characterisation of active nanoelectronic devices

• Tino Wagner,
• Hannes Beyer,
• Patrick Reissner,
• Philipp Mensch,
• Heike Riel,
• Bernd Gotsmann and
• Andreas Stemmer

Beilstein J. Nanotechnol. 2015, 6, 2193–2206, doi:10.3762/bjnano.6.225

• negligible compared to the modulation frequency. For low modulation frequencies approaches instead (Equation 9). To further demonstrate the validity of the sideband transfer function, we show in Figure 3 the response to a step in from both the approximation in Equation 8 and from a numerical simulation of

• from Equation 8 (dashed), show oscillations at fm, exponentially decaying with 1/ωc, which are removed by the low-pass filter of the lock-in amplifier (solid, fcut = 250 Hz, 24 dB/oct). The solid black lines show the demodulated sideband amplitudes from a direct numerical simulation of the perturbed

Magnetic reversal dynamics of a quantum system on a picosecond timescale

• Nikolay V. Klenov,
• Alexey V. Kuznetsov,
• Igor I. Soloviev,
• Sergey V. Bakurskiy and
• Olga V. Tikhonova

Beilstein J. Nanotechnol. 2015, 6, 1946–1956, doi:10.3762/bjnano.6.199

• selective magnetization reversal of a superconducting flux qubit using an SFQ pulse is confirmed by the results of the numerical simulation of the three-level system dynamics (see Figure 7). An alternative, promising procedure is based on the so-called Λ-scheme, involving not only the two lowest energy

Modeling viscoelasticity through spring–dashpot models in intermittent-contact atomic force microscopy

• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 2149–2163, doi:10.3762/bjnano.5.224

• may be such that they favor only a particular relaxation time of the sample or none at all. Despite the above disadvantages of the Linear Kelvin–Voigt model, it has been previously used in tapping mode AFM, both in experimental and numerical simulation approaches [16][17]. This model is also

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

• frequency ratio ωx/ωz for different systems. Dashed line indicates the lower bound of experimentally observed values. Dissipation rate is averaged over 300 cycles. Dissipation rate with respect to the variation of the Q-factor for nominal distances of d = 0.8 nm and d = 1.1 nm. Numerical simulation for 300

Probing viscoelastic surfaces with bimodal tapping-mode atomic force microscopy: Underlying physics and observables for a standard linear solid model

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 1649–1663, doi:10.3762/bjnano.5.176

• , a detailed treatment of viscoelasticity within the ever-growing of number of intermittent-contact AFM techniques is in the opinion of the author an extremely important area of opportunity necessitating a combination of strong experimental, analytical and computational efforts. Conclusion A numerical

• simulation study of the interactions observed in single-mode and bimodal AFM characterization of viscoelastic surfaces modeled as standard linear solids (SLSs) is presented. Examples of the extremely complex behavior of the tip–sample forces and observables are provided, along with an illustration of their

Fibrillar adhesion with no clusterisation: Functional significance of material gradient along adhesive setae of insects

• Stanislav N. Gorb and
• Alexander E. Filippov

Beilstein J. Nanotechnol. 2014, 5, 837–845, doi:10.3762/bjnano.5.95

• system in general. However, this hypothesis is difficult to prove experimentally using native biological specimens. That is why we decided to test it by the numerical simulation, which is the main aim of the present study. In this paper we ask following questions: Does the presence of the material

Challenges and complexities of multifrequency atomic force microscopy in liquid environments

• Santiago D. Solares

Beilstein J. Nanotechnol. 2014, 5, 298–307, doi:10.3762/bjnano.5.33

• Santiago D. Solares Department of Mechanical Engineering, University of Maryland, College Park, MD 20742, USA 10.3762/bjnano.5.33 Abstract This paper illustrates through numerical simulation the complexities encountered in high-damping AFM imaging, as in liquid enviroments, within the specific

Peak forces and lateral resolution in amplitude modulation force microscopy in liquid

• Horacio V. Guzman and
• Ricardo Garcia

Beilstein J. Nanotechnol. 2013, 4, 852–859, doi:10.3762/bjnano.4.96

• nm. We have separated the plots into regions, for soft materials (Figure 5a) a small sub-100 pN force value is used; while for rigid materials (Figure 5b) a sub-1 nN reference value is considered. Conclusion The numerical simulation of the tip motion in amplitude modulation AFM provides a

Mapping of plasmonic resonances in nanotriangles

• Simon Dickreuter,
• Julia Gleixner,
• Andreas Kolloch,
• Johannes Boneberg,
• Elke Scheer and
• Paul Leiderer

Beilstein J. Nanotechnol. 2013, 4, 588–602, doi:10.3762/bjnano.4.66

• object. Two main factors are complicating this task: Firstly, solving Maxwell´s equations for a system more complex than a simple geometric object requires a certain amount of simplification or a careful numerical treatment. Commonly used numerical simulation methods are, for example, discrete dipole

Multiple regimes of operation in bimodal AFM: understanding the energy of cantilever eigenmodes

• Daniel Kiracofe,
• Arvind Raman and
• Dalia Yablon

Beilstein J. Nanotechnol. 2013, 4, 385–393, doi:10.3762/bjnano.4.45

• appears that there are two distinct operating regimes in bimodal AFM, which have distinctly different responses to material property contrast and distinctly different energy dissipations in the first eigenmode. In the next section, numerical simulation is used to provide further insight into this second

• regime. Simulation Modeling In order to provide insight into the physical processes at work, we use numerical simulations. The VEDA simulator (a freely available, open-source, web-based [20] AFM simulator developed by the authors) is used for numerical simulation. A full description of the simulator is

• coupling between the eigenmodes. We have shown that the experimentally observed contrast reversals can be qualitatively predicted by the use of numerical simulation. Further, the numerical simulation has shown that there are actually three distinct imaging regimes in bimodal AFM, and that the discontinuous

Near-field effects and energy transfer in hybrid metal-oxide nanostructures

• Ulrich Herr,
• Barat Achinuq,
• Cahit Benel,
• Giorgos Papageorgiou,
• Manuel Goncalves,
• Johannes Boneberg,
• Paul Leiderer,
• Paul Ziemann,
• Peter Marek and
• Horst Hahn

Beilstein J. Nanotechnol. 2013, 4, 306–317, doi:10.3762/bjnano.4.34

• light. These effects have been further explored by numerical simulations of the electromagnetic field in model structures, which will be presented in the next section. C. Numerical simulation of the electrical field distribution Numerical simulations have been performed using the COMSOL Multiphysics RF

Influence of diffusion on space-charge-limited current measurements in organic semiconductors

• Thomas Kirchartz

Beilstein J. Nanotechnol. 2013, 4, 180–188, doi:10.3762/bjnano.4.18

• erroneously attributed to an increased Vbi. Figure 3 shows the mobility resulting from the fit of Equation 8 to the numerical simulation normalized to the value that was used as input for the simulation (μ = μn = μp = 10−4 cm2/Vs). Note that the results hardly change when changing the mobility in the range

Spring constant of a tuning-fork sensor for dynamic force microscopy

• Dennis van Vörden,
• Manfred Lange,
• Merlin Schmuck,
• Nico Schmidt and
• Rolf Möller

Beilstein J. Nanotechnol. 2012, 3, 809–816, doi:10.3762/bjnano.3.90

• negligible either. In summary, the combination of experimental techniques and numerical simulation provides insight into the contributions of various parameters to the spring constant of tuning fork sensors used for dynamical force microscopy. This is of major importance whenever quantitative values for the

• we compare the results for the determination of the spring constant of tuning fork sensors in the qPlus configuration [1][2] based on the following methods: a simple calculation for a cantilever beam; the measured deflection as a function of the applied force; the thermal noise; and a numerical

• simulation by the finite-element method. Result and Discussion Calculation for a rectangular beam The formula for the spring constant of a beam that is clamped on one side is where E is the Young’s modulus (for quartz), τ is the thickness, w the width, and L the length of a prong. For the cantilevers used in