Dual-heterodyne Kelvin probe force microscopy

• Benjamin Grévin,
• Fatima Husainy,
• Dmitry Aldakov and
• Cyril Aumaître

Beilstein J. Nanotechnol. 2023, 14, 1068–1084, doi:10.3762/bjnano.14.88

• measurements [16], which consists in analysing the intermodulation products between the mechanical oscillation of the cantilever and the photogenerated surface potential. In short, intermodulation spectroscopy allows working in the frequency domain (instead of the time domain) by extracting, during a single

• yields a measurement of the Fourier spectrum of the time-periodic surface potential, which may be in principle used to reconstruct the signal in the time domain. However, in the current version of our implementation, this retro-conversion process from the frequency domain will only provide data that are

Spatial mapping of photovoltage and light-induced displacement of on-chip coupled piezo/photodiodes by Kelvin probe force microscopy under modulated illumination

• Zeinab Eftekhari,
• Nasim Rezaei,
• Hidde Stokkel,
• Jian-Yao Zheng,
• Andrea Cerreta,
• Ilka Hermes,
• Minh Nguyen,
• Guus Rijnders and
• Rebecca Saive

Beilstein J. Nanotechnol. 2023, 14, 1059–1067, doi:10.3762/bjnano.14.87

• position within a defined surface region. Herein, the acquired topography and CPD images shown in Figure 1b and Figure 1c were represented in the time domain. Therefore, the horizontal scale of the images indicates the time at which a given pixel has been acquired in one line, while the vertical scale

A wearable nanoscale heart sound sensor based on P(VDF-TrFE)/ZnO/GR and its application in cardiac disease detection

• Yi Luo,
• Jian Liu,
• Jiachang Zhang,
• Yu Xiao,
• Ying Wu and
• Zhidong Zhao

Beilstein J. Nanotechnol. 2023, 14, 819–833, doi:10.3762/bjnano.14.67

• MATLAB was employed to standardize the data signals separately. This yielded signal indicators of the same magnitude, increasing the comparability between data. Figure 16 shows a time domain diagram of a raw heart sound signal (normal heart sound) in the heart sound database, while Figure 17 illustrates

• the time domain diagram of the preprocessed heart sound signal. Comparing the waveforms of the two figures, it can be observed that the characteristics of the first heart sound and the second heart sound of the preprocessed heart sound signal are more apparent, the noise removal is better, and the

• amplitude of the heart sound signal is improved. In this experiment, 34 heart sound features were selected, including 14 time domain features, 13 mel frequency cepstral coefficient (MFCC) features, and seven wavelet features. Table 2 displays the selected time and frequency domain features. MFCC is a speech

A mid-infrared focusing grating coupler with a single circular arc element based on germanium on silicon

• Xiaojun Zhu,
• Shuai Li,
• Ang Sun,
• Yongquan Pan,
• Wen Liu,
• Yue Wu,
• Guoan Zhang and
• Yuechun Shi

Beilstein J. Nanotechnol. 2023, 14, 478–484, doi:10.3762/bjnano.14.38

• depth. The incident angle is θ. In our work, the numerical simulations have been performed by using a commercial software of Lumerical FDTD solutions, which is based on the finite-difference time-domain method, and the light source we used for exciting the grating coupler is a Gaussian laser beam. The

Plasmonic nanotechnology for photothermal applications – an evaluation

• A. R. Indhu,
• L. Keerthana and
• Gnanaprakash Dharmalingam

Beilstein J. Nanotechnol. 2023, 14, 380–419, doi:10.3762/bjnano.14.33

Coherent amplification of radiation from two phase-locked Josephson junction arrays

• Mikhail A. Galin,
• Vladimir M. Krasnov,
• Ilya A. Shereshevsky,
• Nadezhda K. Vdovicheva and
• Vladislav V. Kurin

Beilstein J. Nanotechnol. 2022, 13, 1445–1457, doi:10.3762/bjnano.13.119

• are calculated by the finite-difference time-domain (FDTD) method [21], as described in [8][12][22]. We used the following junction parameters: Ic = 2.5 mA, normal resistance Rn = 0.1 Ω, and McCumber parameter β = 2. These parameters are consistent with experimental data for Nb/NbSi/Nb junctions

Analytical and numerical design of a hybrid Fabry–Perot plano-concave microcavity for hexagonal boron nitride

• Felipe Ortiz-Huerta and
• Karina Garay-Palmett

Beilstein J. Nanotechnol. 2022, 13, 1030–1037, doi:10.3762/bjnano.13.90

• . Opt. Express 2018, 26, 33245), we managed to find analytical and finite-difference time-domain (FDTD) values for the, experimentally achievable, geometrical parameters of a hybrid plano-concave microcavity that enhances the spontaneous emission (i.e., Purcell enhancement) of color centers in two

A broadband detector based on series YBCO grain boundary Josephson junctions

• Egor I. Glushkov,
• Alexander V. Chiginev,
• Leonid S. Kuzmin and
• Leonid S. Revin

Beilstein J. Nanotechnol. 2022, 13, 325–333, doi:10.3762/bjnano.13.27

• , additional expressions were used [23]. The tool used for the simulation was time domain solver of CST Microwave Studio. Two methods for calculating the receiving characteristics of the antenna were used. In the first method, microwave (MW) currents and voltages excited in each receiving element (port) were

Cantilever signature of tip detachment during contact resonance AFM

• Devin Kalafut,
• Ryan Wagner,
• Maria Jose Cadena,
• Anil Bajaj and
• Arvind Raman

Beilstein J. Nanotechnol. 2021, 12, 1286–1296, doi:10.3762/bjnano.12.96

• -state time-domain slope response of the AFM cantilever at the location of the probe tip is used to extract the first harmonic amplitude for comparison with measurements. Using the full cantilever response, stroboscopic sampling throughout a period provides explanation of the shapes experienced during

Assessment of the optical and electrical properties of light-emitting diodes containing carbon-based nanostructures and plasmonic nanoparticles: a review

• Keshav Nagpal,
• Erwan Rauwel,
• Frédérique Ducroquet and
• Protima Rauwel

Beilstein J. Nanotechnol. 2021, 12, 1078–1092, doi:10.3762/bjnano.12.80

• on ITO glass. The inset shows the TEM image of AuNP with a particle size of 20 nm. (c) The electromagnetic field distribution around AuNP with 20 nm diameter simulated by finite-difference time-domain modelling. Figure 6a–c was adapted from [51] (© 2018 J. Feng et al., distributed under the terms of

A new method for obtaining model-free viscoelastic material properties from atomic force microscopy experiments using discrete integral transform techniques

• Berkin Uluutku,
• Enrique A. López-Guerra and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2021, 12, 1063–1077, doi:10.3762/bjnano.12.79

• convolutions in the time domain, such as the right-hand side of Equation 1 and Equation 2, transform into simple multiplications in the Laplace domain (s-domain) [32][33]. Thus, Equations 1 and 2 transform as follows: From Equation 3 and Equation 4, we can write the relaxance (Q(s)) and retardance (U(s)) as

• responses to these standard excitations are known as “standard viscoelastic responses” and are used widely to characterize viscoelastic materials. A very common standard excitation is the harmonic excitation. For example, a harmonic stress input in the time domain that is governed by the angular frequency ω

• . Invoking the correspondence principle for the case of a parabolic tip indenting a viscoelastic half-space yields the following force–distance relationship for the time domain [14][15]: where h is the sample indentation, F is the probe–sample force, and R is the radius of the indenter. Transforming this

The patterning toolbox FIB-o-mat: Exploiting the full potential of focused helium ions for nanofabrication

• Victor Deinhart,
• Lisa-Marie Kern,
• Jan N. Kirchhof,
• Sabrina Juergensen,
• Joris Sturm,
• Enno Krauss,
• Thorsten Feichtner,
• Sviatoslav Kovalchuk,
• Michael Schneider,
• Dieter Engel,
• Bastian Pfau,
• Bert Hecht,
• Kirill I. Bolotin,
• Stephanie Reich and
• Katja Höflich

Beilstein J. Nanotechnol. 2021, 12, 304–318, doi:10.3762/bjnano.12.25

• round. Each monomer acts as a small dipole in our measurement configuration and its response is not very sensitive to its actual shape as long as surface roughness does not increase the scattering losses. Finite-difference time-domain modeling taking into account the slightly varying geometries led to

Correction: 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. 2021, 12, 137–138, doi:10.3762/bjnano.12.10

• ). Similarly, it is stated that the loss modulus (E″) and loss compliance (J″) are inverses of one another (Equation 11). However, it is the relaxance (Q) and retardance (U) that are inverses of one another in the Laplace domain (not in the time domain), leading to a more complex relationship between the

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

• integral replaces the multiplication of and in the Laplace domain during translation back to the time domain. As mentioned previously, the approach outlined here is preferred for AFM as it both removes the requirement of a step function in stress and of a measurement of the force application rate. Since

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

• Kalman filter; Kelvin probe force microscopy (KFM); time domain; Introduction Electrostatic forces are important interactions in non-contact atomic force microscopy (NC-AFM). They arise from differences in the work function of the tip and the sample, from trapped charges, or from potentials applied to

• . Another possibility for compensating the remaining frequency shift is the use of two-pass methods with feed-forward compensation techniques [20][21]. In this paper, we present a time-domain (TD) controller for KFM as a single-pass solution to the problem outlined above. Our method uses a Kalman filter as

• , and the coefficient a. Since our technique is based on the time domain, it is not limited by the bandwidth of additional filters in the loop, for example lock-in amplifiers. Therefore, we expect to achieve higher bandwidths compared to standard KFM implementations. An asymmetrical bias dependence, as

Integrated photonics multi-waveguide devices for optical trapping and Raman spectroscopy: design, fabrication and performance demonstration

• Gyllion B. Loozen,
• Arnica Karuna,
• Mohammad M. R. Fanood,
• Erik Schreuder and
• Jacob Caro

Beilstein J. Nanotechnol. 2020, 11, 829–842, doi:10.3762/bjnano.11.68

• (the typical medium in our experiments) for various waveguide thicknesses using the 3D finite-difference time-domain (FDTD) method with Lumerical’s FDTD solutions [10]. We choose a waveguide width wexc of 1 μm, which is the minimum width for the contact lithography we use. We aim for single-mode

Effect of Ag loading position on the photocatalytic performance of TiO₂ nanocolumn arrays

• Jinghan Xu,
• Yanqi Liu and
• Yan Zhao

Beilstein J. Nanotechnol. 2020, 11, 717–728, doi:10.3762/bjnano.11.59

• the influence of Ag loading position and deposition thickness on the photocatalytic reaction, we used a finite-difference time-domain (FDTD) simulation to study the electromagnetic field distribution of Ag-loaded TiO2 arrays with different structures. Figure 8 shows the simulation of the electric

Comparison of fresh and aged lithium iron phosphate cathodes using a tailored electrochemical strain microscopy technique

• Matthias Simolka,
• Hanno Kaess and
• Kaspar Andreas Friedrich

Beilstein J. Nanotechnol. 2020, 11, 583–596, doi:10.3762/bjnano.11.46

• -voltage with the resulting oscillating surface displacement amplitude (ESM signal) is then employed to track the induced concentration change due to the dc-voltage pulse – this technique is called time-domain ESM. In the simple approximation, given in Equation 1, the resulting surface displacement uS is

• , which is induced by the ionic vibration in the material. Due to the modified experimental set-up, the presented ESM technique does not correspond to the classical ESM technique introduced by Balke et al. [24], but is similar to the time-domain measurements reported by Jesse et al. [33], therefore we

Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• the nanostructures are calculated by finite-difference time-domain (FDTD) simulations. For calculations a novel approach based on modelling the whole sample with a realistic shape of the nanoparticles, instead of full spheres, was used. This led to a very good agreement with the experiment. Keywords

• : dewetting; finite-difference time-domain (FDTD) method; plasmon resonance; silver (Ag) nanostructures; thin films; UV–vis absorption; Introduction In the last decade there has been significant development in sensor-related research regarding the application in optical, medical or biological areas [1][2][3

• pulse duration was set to 2.5 fs, thus it contained all frequencies within the visible light range. This allowed for the use of discrete Fourier transformation for switching from the time domain to the frequency domain and calculating the spectral response of the sample. Also, the Mie theory [18] was

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

• treat this expression in a similar manner as for the previously analysed ideal case and obtain the following current expression in the time domain: We can again easily apply the Fourier transform to find the frequency-domain representation of the tunnelling current. In this case, however, although it is

• trivial to obtain the Fourier transform of the Fourier series, we have an infinite number of different Fourier series multiplied with one another. These multiplications in the time domain correspond to convolutions in the frequency domain: This infinite number of convolutions between infinite series may

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

• less data points to probe the parts of the time-domain where the SP evolves more slowly. Organic BHJ Solar Cells In this work, PTB7:PC71BM BHJ photovoltaic thin films have been used as test samples (Figure 3) for pp-KPFM experiments. In the following, a few concepts of organic photovoltaics are

Nanosecond resistive switching in Ag/AgI/PtIr nanojunctions

• Botond Sánta,
• Dániel Molnár,
• Patrick Haiber,
• Agnes Gubicza,
• Edit Szilágyi,
• Zsolt Zolnai,
• András Halbritter and
• Miklós Csontos

Beilstein J. Nanotechnol. 2020, 11, 92–100, doi:10.3762/bjnano.11.9

• paper we explore the dynamical properties of room-temperature resistive switching established in metallic Ag/AgI/PtIr nanojunctions. Hysteretic I(V) traces were studied as a function of the frequency and the amplitude of triangular voltage signals covering five orders of magnitude in the time domain

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

• and direct-design methods benefit from cross-coupling zeros across all bandwidths allowing them to maintain a strong OMR. The ability to precisely resolve the zeros is limited by the DAC resolution. However, the performance distinction between open-loop and closed-loop methods is clear. Time-domain

• amplitude estimation error () in the time-domain and amplitude estimate power spectral density (PSD) for both low (1%fi) and high (50%fi) tracking bandwidth settings. When the three-tone sinewave is applied, the performance of each demodulator at low bandwidths is shown to be similar. Each channel is able

• significantly less estimation error as seen in Figure 9. In Figure Figure 9a, the lock-in amplifier 50 kHz estimate contains mixing products at 2fi = 100 kHz in the time-domain, shown as distinct peaks in the PSD. In contrast, the coherent demodulator in Figure 9b strongly attenuates the mixing products. The

Nitrogen-vacancy centers in diamond for nanoscale magnetic resonance imaging applications

• Alberto Boretti,
• Lorenzo Rosa,
• Jonathan Blackledge and
• Stefania Castelletto

Beilstein J. Nanotechnol. 2019, 10, 2128–2151, doi:10.3762/bjnano.10.207

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents

• Natalia E. Gervits,
• Andrey A. Gippius,
• Alexey V. Tkachev,
• Evgeniy I. Demikhov,
• Sergey S. Starchikov,
• Igor S. Lyubutin,
• Alexander L. Vasiliev,
• Vladimir P. Chekhonin,
• Maxim A. Abakumov,
• Alevtina S. Semkina and
• Alexander G. Mazhuga

Beilstein J. Nanotechnol. 2019, 10, 1964–1972, doi:10.3762/bjnano.10.193

• ZF-NMR spectra were obtained by integration over the spin echo magnitude envelope in the time domain at a given frequency and averaging over the scan accumulation number. Due to the low natural abundance of the 57Fe isotope (2.19%), a relatively large amount (about 1.5 g) of powder Fe nanoparticles