Superconductor–insulator transition in capacitively coupled superconducting nanowires

• Alex Latyshev,
• Andrew G. Semenov and
• Andrei D. Zaikin

Beilstein J. Nanotechnol. 2020, 11, 1402–1408, doi:10.3762/bjnano.11.124

• experiments [7][8][9][10]. Likewise, quantum phase slips in superconducting nanowires yield shot noise of the voltage [11] which originates from the process of quantum tunneling of magnetic flux quanta across the wire. One can also proceed beyond the voltage–voltage correlator and evaluate all cumulants of

Cryogenic low-noise amplifiers for measurements with superconducting detectors

• Ilya L. Novikov,
• Boris I. Ivanov,
• Dmitri V. Ponomarev and
• Aleksey G. Vostretsov

Beilstein J. Nanotechnol. 2020, 11, 1316–1320, doi:10.3762/bjnano.11.115

• bipolar junction transistor technology. The amplifiers show high gain values of more than 60 dB at 300, 77, and 48 K. The minimum voltage noise spectral density was achieved at 77 K and corresponded to 0.33 nV/Hz0.5 with a flicker noise of 20 Hz. The maximum voltage gain was 70 dB at 77 K for a frequency

• range from DC to 17 kHz. We experimentally show that the parallel differential circuit design allows for a reduction of the voltage noise from 0.55 to 0.33 nV/Hz0.5 at 77 K. Keywords: cryogenic amplifier; cryogenic low-noise amplifier; differential cryogenic amplifier; superconducting circuit readout

• Josephson junctions and superconducting thin films. Experimental studies of such sensors require the design of low-noise cryogenic readout electronics with a direct coupling to the sample. For example, investigations of noise sources in low-temperature tunnel Josephson junctions are still ongoing for high

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

• [19]. Although optical beam deflection (OBD) techniques are traditionally preferred for their lower noise, they require bulky components and precise optical alignment. Prohibitively large instruments with optical readout are difficult to integrate into electron or ion microscopes and re-alignment of

• to a spring-loaded kinematic mount. Operating the AFM inside the HIM chamber has drawbacks regarding resolution and noise performance. Ideally, the mechanical loop between the cantilever probe and the sample needs to be compact and stiff for optimal AFM performance. The mechanical loop for the

Role of redox-active axial ligands of metal porphyrins adsorbed at solid–liquid interfaces in a liquid-STM setup

• Thomas Habets,
• Sylvia Speller and
• Johannes A. A. W. Elemans

Beilstein J. Nanotechnol. 2020, 11, 1264–1271, doi:10.3762/bjnano.11.110

• solution or solutes therein. In most cases the additional current is of the order of the noise level of the STM (approx. 1 pA), or at least significantly smaller than the applied tunneling current. However, after the addition of a 1-phenyloctane solution of MnTUPCl (c = 1 × 10−4 M), significant currents

• not directly imply that the redox reactions in Equation 1 and Equation 2 do not occur under these conditions; the redox reaction rates may be very low, i.e., below 2.5 × 107 e−/s (comparable with a current of approx. 4 pA), and not exceed the noise level of the STM setup. Possible aspects that could

Magnetic-field-assisted synthesis of anisotropic iron oxide particles: Effect of pH

• Andrey V. Shibaev,
• Petr V. Shvets,
• Darya E. Kessel,
• Roman A. Kamyshinsky,
• Anton S. Orekhov,
• Sergey S. Abramchuk,
• Alexei R. Khokhlov and
• Olga E. Philippova

Beilstein J. Nanotechnol. 2020, 11, 1230–1241, doi:10.3762/bjnano.11.107

• sufficient to avoid any structural changes or phase degradation in the samples. Under these conditions, the typical total acquisition time to obtain a spectrum with good signal-to-noise ratio was several hours. Temporal variation of pH when 2 mL of the ion mixture (1 M FeCl3 + 0.5 M FeSO4 in 0.1 M HCl) is

Influence of the magnetic nanoparticle coating on the magnetic relaxation time

• Mihaela Osaci and
• Matteo Cacciola

Beilstein J. Nanotechnol. 2020, 11, 1207–1216, doi:10.3762/bjnano.11.105

• vacuum magnetic permeability. The random Brownian force and torque are usually modelled using the Gaussian noise [21][22]. Besides the random Brownian torque, the conservative torque acting on the nanoparticle is the magnetic torque: where is the local magnetic field on each nanoparticle, given by

Hybridization vs decoupling: influence of an h-BN interlayer on the physical properties of a lander-type molecule on Ni(111)

• Maximilian Schaal,
• Takumi Aihara,
• Marco Gruenewald,
• Felix Otto,
• Jari Domke,
• Roman Forker,
• Hiroyuki Yoshida and
• Torsten Fritz

Beilstein J. Nanotechnol. 2020, 11, 1168–1177, doi:10.3762/bjnano.11.101

• , respectively, and d being the film thickness. Each reflectance spectrum was accumulated over 30 s to increase the signal-to-noise ratio. Furthermore, we used the difference of consecutive reflectance spectra to calculate the ΔDRS intensity using the following formula: The lateral structure of the DBP films was

Thermophoretic tweezers for single nanoparticle manipulation

• Jošt Stergar and
• Natan Osterman

Beilstein J. Nanotechnol. 2020, 11, 1126–1133, doi:10.3762/bjnano.11.97

• heating. While it is also possible to trap atoms and molecules in vacuum using electromagnetic traps, thermal noise is a governing factor when particles are under biological conditions, namely at room temperature in an aqueous medium. Laser tweezers [1][2][3], invented long ago and recognized with the

• quadrants to isolate fluorescent particles in the frame while eliminating possible background light. Areas of appropriate size are selected on the image, discarding too big or too small objects, corresponding to salt-and-pepper noise and aggregated blobs of particles, respectively. Centroids of remaining

Uniform Fe₃O₄/Gd₂O₃-DHCA nanocubes for dual-mode magnetic resonance imaging

• Miao Qin,
• Yueyou Peng,
• Mengjie Xu,
• Hui Yan,
• Yizhu Cheng,
• Xiumei Zhang,
• Di Huang,
• Weiyi Chen and
• Yanfeng Meng

Beilstein J. Nanotechnol. 2020, 11, 1000–1009, doi:10.3762/bjnano.11.84

• imaging (T1WI) and T2-weighted imaging (T2WI) were performed in Sprague Dawley (SD) rats. After intravenous injection of a 0.8 mg Fe/kg dose, FGDA nanocubes spread systemically through the bloodstream. The lumbar muscle was chosen as the MRI region of interest and the signal-to-noise ratio (ΔSNR) was

Electrochemical nanostructuring of (111) oriented GaAs crystals: from porous structures to nanowires

• Elena I. Monaico,
• Eduard V. Monaico,
• Veaceslav V. Ursaki,
• Shashank Honnali,
• Vitalie Postolache,
• Karin Leistner,
• Kornelius Nielsch and
• Ion M. Tiginyanu

Beilstein J. Nanotechnol. 2020, 11, 966–975, doi:10.3762/bjnano.11.81

• biased at 5 V. The estimation of the detectivity D*, which is defined as where A is the active area of the photodetector, and e is the elementary charge, gives a value of ca. 1.2 × 109 cm·Hz1/2·W−1, under the assumption that shot noise is the primary source of noise in the detector [32]. Taking into

Microwave photon detection by an Al Josephson junction

• Leonid S. Revin,
• Andrey L. Pankratov,
• Anna V. Gordeeva,
• Anton A. Yablokov,
• Igor V. Rakut,
• Victor O. Zbrozhek and
• Leonid S. Kuzmin

Beilstein J. Nanotechnol. 2020, 11, 960–965, doi:10.3762/bjnano.11.80

• significant improvement of the noise immunity of a device, radically decreasing the dark count rate, but it will also decrease the single-photon sensitivity of the considered threshold detector. Quantization of the switching probability tilt as a function of the signal attenuation for various bias currents

• the JJ constantly inspires new applications, such as thermometry [8][9], noise statistics [10][11][12] and single-photon detection [13]. There are, at least, two different approaches for the practical realization of single-photon detectors based on Josephson junctions, both having their advantages and

• than the switching time after the photon absorption (typically less than nanoseconds). In [4] it was shown theoretically that both the required sensitivity and the noise immunity can be reached at the same time in JJ with a suppressed critical current. Besides that, the mesoscopic junctions with low

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

• occurs (tmax(z), marked as t2 in Figure 2a) are removed from the dataset. The resulting curve is illustrated in Figure 2b. Due to a number of possible factors, e.g., calibration and noise, the deflection in the region t0 to t1 can be non-zero despite the probe not being in contact with the surface. To

• , smoothing the deflection data with a simple first-order Butterworth filter can remove some of the measurement noise and make finding the deflection minimum easier. While searching for the smallest value without filtering, noise can cause neighboring points to appear lower than the actual minimum and

• velocities were selected in a logarithmic distribution: 10, 100, and 1000 nm/s. The probe utilized was an OLYMPUS AC 240TS-R3, featuring a tip radius of roughly 10 nm. Before measurement, the tip was calibrated using the thermal noise method [29] in which a hard silicon sample was used after sonicating using

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

• effect is amplified when a significant change in the capacitance gradient is present. To reduce the impact of this component onto the height measurement, the modulation amplitude Uac must be minimized. Since the signal-to-noise ratio (SNR) scales with Uac, this is only possible to a certain extent

• , are introduced by the vector This vector, the so-called transition noise vector, is anticipated to be Gaussian white noise (0,QK) with the covariance matrix The output of the Kelvin system is the scalar value of the intrinsic frequency shift . It is defined by using the definition in Equation 10. The

• measurement noise is assumed to be Gaussian white noise and is defined by . This is the case for measurements where thermal noise is the dominating noise source, i.e., when the modulation frequency is below the crossover of thermal white noise and (with increasing frequency) detection noise [29]. The power

A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer

• Pavel M. Marychev and
• Denis Yu. Vodolazov

Beilstein J. Nanotechnol. 2020, 11, 858–865, doi:10.3762/bjnano.11.71

• achieve high noise immunity. Also many of these applications require to have a nonhysteretic current–voltage characteristic (IVC) and a large characteristic voltage Vc = IcRn, where Rn is the normal-state resistance of the junction. Tunnel superconductor–insulator–superconductor (SIS) Josephson junctions

• obtain high noise immunity. But due to large critical current and bad heat dissipation their IVCs are hysteretic due to Joule heating () and the subsequent formation of a stable region with suppressed superconductivity (a so-called “hot spot”) at I > Ic [6][7][8][9]. At temperatures near the critical

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• a function of P at T = 298 K. In order to minimize the laser-induced effects on the crystallinity and structural changes in the WSe2, a laser P ≤ 3.35 mW was used. It was also found that the minimum P required to get a good signal-to-noise ratio for the Raman and PL data was when P ≥ 0.31 mW

• cell allowed the temperature to reach 523 K. During the cooling process, it was found that the signal to noise ratio was very poor when both the T and P became very low, particularly in case of PL measurements. The best signal to noise ratio in both the Raman and PL measurements was found for P = 3.35

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

• are plotted as a function of time with the time-interval histograms building up in real-time. These coincidences are collected over enough time duration to extract a decent coincidence curve for the incident light with acceptable noise limits. The total collection time is dependent on the intensity of

• the incoming light, being very large for dim or low-intensity light and very small for high-intensity light. This raw coincidence curve for the detection events on the two detectors also contains events from the background emission. The background noise comes from the dark counts on the two detectors

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

• into an F(z) curve using the procedure of Sader and Jarvis [45]. It should be noted that there is a smoothing algorithm applied to the Δf–d curve to prevent spurious force jumps caused by noise in the Δf–d curves when converted to F(z) curves. Furthermore, we assumed that the interaction force relation

• measurement due to noise or step-like interaction force changes can significantly change an experimentally extracted F(z) curve converted from a measured Δf–d curve. This factor should be considered minimal due to relatively large oscillation amplitudes used in the present study. Sader showed that this ill

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

• . It can be seen from the figure that tiny Ag nanoparticles are supported on the TiO2 columns. Figure 4d shows the high-resolution TEM image of the Ag nanocolumns shown in Figure 4c. After removing the noise by performing Fourier transform on the selected area using software, we can clearly see lattice

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

• that gives a qualitative relationship between a set of contact resonance frequencies and the indentation modulus. It is based on white-noise excitation of the tip–sample interaction and uses system theory for the extraction of the resonance modes. During conventional scanning, for each pixel, the tip

• –sample interaction is excited with a white-noise signal. Then, a fast Fourier transform is applied to the deflection signal that comes from the photodiodes of the atomic force microscopy (AFM) equipment. This approach allows for the measurement of several vibrational modes in a single step with high

• compared to conventional techniques. Keywords: atomic force microscopy; fast Fourier transform; mechanical properties; system theory; white noise; Introduction There are several methods to measure mechanical properties at the nanoscale level, based on, e.g., nanoindentation or on other physical phenomena

Electromigration-induced directional steps towards the formation of single atomic Ag contacts

• Atasi Chatterjee,
• Christoph Tegenkamp and
• Herbert Pfnür

Beilstein J. Nanotechnol. 2020, 11, 680–687, doi:10.3762/bjnano.11.55

• peak at 0.6. Strong peaks below 0.5 again correspond to instabilities between other metastable configurations. On the other hand, a noticeable difference between Figure 3 and Figure 5 is that the contribution from the [111] orientation is absent in Figure 5. There is no peak above noise level at 1.3

Soybean-derived blue photoluminescent carbon dots

• Shanshan Wang,
• Wei Sun,
• Dong-sheng Yang and
• Fuqian Yang

Beilstein J. Nanotechnol. 2020, 11, 606–619, doi:10.3762/bjnano.11.48

• number of the photons emitted at time t, A represents the baseline/noise level, Bi (i = 1, 2, 3) are proportionality constants for the corresponding decay functions, and τi is the corresponding lifetime. Using Equation 1 to fit the PL decay curves in Figure 4a,b, we obtain the lifetimes of τi and the

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

• trend. Reconstruction of the tip–sample current should be possible if one can record its power spectrum. It is of course desirable to be able to record as many harmonics as possible, although this may not always be possible, in part due to signal-to-noise ratio limitations for very high frequencies or

• challenges in the experimental implementation of the proposed method, which can be significant. We expect these challenges to arise from probe-related phenomena, data acquisition limitations, noise, the electrical nature of the sample, or some combination of all these factors. With regards to probe

• -conductive tip. Electrical noise is anticipated to also introduce challenges. Although classical C-AFM can be affected by noise as well, the expected current magnitude in this mode of imaging should be larger than for ICM-AFM for the reasons described above, such that the current signal-to-noise ratio for

High dynamic resistance elements based on a Josephson junction array

• Konstantin Yu. Arutyunov and
• Janne S. Lehtinen

Beilstein J. Nanotechnol. 2020, 11, 417–420, doi:10.3762/bjnano.11.32

• current-biasing elements [7][8][9][10]. However, it was later understood that resistive dissipative elements inevitably act as a source of Johnson noise, leading to degradation of system performance [11]. Here we present an experimental study of a quasi-1D chain of JJs. A sufficient high-frequency

• impedance was demonstrated to study the QPS phenomena without the undesired impact of Johnson noise typically associated with dissipative elements [12]. The I–V dependence studied in [12] demonstrated clear and expected characteristics at low current, I → 0: the so-called “Bloch nose” (back-bending of I–V

• current values have been detected so far [10]. Later it was understood that the straightforward approach of using a high-Ohmic dissipative environment, Renv > RQ, is far from optimal, as it introduces Johnson noise, washing out the desired current singularities [11]. Various JJ-based systems were

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

• , it is crucial to set a suitable time constant for the KPFM feedback loop and an adequate integration time per pixel. The signal-to-noise (S/N) ratio dramatically decreases when switching from KPFM to pp-KPFM due to a reduction of the bandwidth [22]. This effect demands a reduction of the loop gain

• illumination source. In other words, in this test, pp-KPFM is not used to perform a time-resolved measurement as a function of Δt. It is rather used to monitor a SP at two different levels of illumination, namely in a dark state and under cw illumination. Neglecting noise, both configurations yielded identical

• SP levels in the dark and upon cw illumination. However, as expected, the noise level increases for pp-KPFM, and a much longer time delay is needed to stabilize the compensation potential upon turning on and off the illumination. As noted above, this urged us to use pre-integration delays when