Biomimetic surface structures in steel fabricated with femtosecond laser pulses: influence of laser rescanning on morphology and wettability

• Camilo Florian Baron,
• Alexandros Mimidis,
• Daniel Puerto,
• Evangelos Skoulas,
• Emmanuel Stratakis,
• Javier Solis and
• Jan Siegel

Beilstein J. Nanotechnol. 2018, 9, 2802–2812, doi:10.3762/bjnano.9.262

• below the single pulse ablation threshold, which we have determined experimentally as Fabl = 164 mJ/cm2 (following the method proposed by Liu in [38]). This indicates that the ablation is mediated by incubation and/or heat accumulation at the high repetition rate used [39][40] (a more detailed

Variation of the photoluminescence spectrum of InAs/GaAs heterostructures grown by ion-beam deposition

• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Eleonora M. Danilina and
• Sergei N. Chebotarev

Beilstein J. Nanotechnol. 2018, 9, 2794–2801, doi:10.3762/bjnano.9.261

• ][25]. But the IBD method differs from MBE. Therefore, it remains relevant to research the vertical stacking of QDs grown by using IBD. In the beginning, ST#1 samples were studied. The statistical analysis by the threshold tool in the Image Analysis 2.1.2 program showed that the density of QDs in the

Comparative biological effects of spherical noble metal nanoparticles (Rh, Pd, Ag, Pt, Au) with 4–8 nm diameter

• Alexander Rostek,
• Marina Breisch,
• Kevin Pappert,
• Kateryna Loza,
• Marc Heggen,
• Manfred Köller,
• Christina Sengstock and
• Matthias Epple

Beilstein J. Nanotechnol. 2018, 9, 2763–2774, doi:10.3762/bjnano.9.258

• (Olympus MVX10, Olympus, Hamburg, Germany). The quantification of cell viability was performed by phase analysis (CellSens Dimensions, Olympus, Hamburg, Germany) of calcein-positive fluorescence signals calculating the fluorescent area. For calculating the phase analysis data, a threshold was set which

Oriented zinc oxide nanorods: A novel saturable absorber for lasers in the near-infrared

• Pavel Loiko,
• Tanujjal Bora,
• Josep Maria Serres,
• Haohai Yu,
• Magdalena Aguiló,
• Francesc Díaz,
• Uwe Griebner,
• Valentin Petrov,
• Xavier Mateos and
• Joydeep Dutta

Beilstein J. Nanotechnol. 2018, 9, 2730–2740, doi:10.3762/bjnano.9.255

• output power of 221 mW at 1.942 µm with a slope efficiency η of 10% (with respect to the absorbed pump power Pabs), see Figure 5a,b. The laser threshold was at Pabs = 1.05 W. In the CW regime, the laser operated with higher efficiency, η of 56% and lower laser threshold of 0.70 W, so that the conversion

• average output power of 139 mW at 1.034 µm with η = 9%, as shown in Figure 6a,b. The laser threshold was at Pabs = 1.90 W. In the CW regime, the laser operated with higher η of 66% and ηconv was 14%. In the CW regime, a multi-peak emission at 1.035–1.040 µm was observed. These results correspond to the

Size-selected Fe₃O₄–Au hybrid nanoparticles for improved magnetism-based theranostics

• Maria V. Efremova,
• Yulia A. Nalench,
• Eirini Myrovali,
• Anastasiia S. Garanina,
• Ivan S. Grebennikov,
• Polina K. Gifer,
• Maxim A. Abakumov,
• Marina Spasova,
• Makis Angelakeris,
• Alexander G. Savchenko,
• Michael Farle,
• Natalia L. Klyachko,
• Alexander G. Majouga and
• Ulf Wiedwald

Beilstein J. Nanotechnol. 2018, 9, 2684–2699, doi:10.3762/bjnano.9.251

• the late stage of apoptosis. The two sets of experiments, direct AMF treatments and precultivation for 6 h, both show clear apoptosis/necrosis of 4T1 cells induced by the hyperthermia treatment. The more efficient precultivation might help to decrease the concentration threshold for MPH in future

Characterization of the microscopic tribological properties of sandfish (Scincus scincus) scales by atomic force microscopy

• Weibin Wu,
• Christian Lutz,
• Simon Mersch,
• Richard Thelen,
• Christian Greiner,
• Guillaume Gomard and
• Hendrik Hölscher

Beilstein J. Nanotechnol. 2018, 9, 2618–2627, doi:10.3762/bjnano.9.243

• topography images obtained after the scratching experiments. Figure 7b summarizes the scratching depth as a function of normal load. All samples get finally scratched when normal load reaches a certain threshold but this value is different for every material. After reaching this threshold, the scratching

• depth increases nearly linearly with normal load. Figure 7c condenses the scratching depth versus scratching distance. The scratching depth increases constantly for the sandfish scale, Teflon, and PMMA. For aluminium the chosen threshold (19.6 µN) was too small to obtain any wear, so the scratching

Enhancement of X-ray emission from nanocolloidal gold suspensions under double-pulse excitation

• Wei-Hung Hsu,
• Frances Camille P. Masim,
• Armandas Balčytis,
• Hsin-Hui Huang,
• Tetsu Yonezawa,
• Aleksandr A. Kuchmizhak,
• Saulius Juodkazis and
• Koji Hatanaka

Beilstein J. Nanotechnol. 2018, 9, 2609–2617, doi:10.3762/bjnano.9.242

• threshold of X-ray generation, which is obtained only under double-pulse irradiation. The delay of the main pulse relative to the pre-pulse, Δt, was controlled within three time zones: 0–5 ns (I), 5–10 ns (II) and 10–15 ns (III), which were set into the optical path of the pre-pulse. The optical delay for

• permittivity of material, ν is the electron–ion collision rate, ω is the optical cyclic frequency at the wavelength of excitation, ne,a,cr are the electron, atom and critical densities, respectively. The imaginary part of the permittivity is given by: The threshold fluence for water to reach the ENZ state can

• be calculated from the consideration that all absorbed energy density is converted to thermal energy of electrons. It can be calculated from the ablation threshold expression of a dielectric [37]: where ls = c/(κω) is the skin depth related to the imaginary part of the refractive index , c is the

Exploring the photoleakage current and photoinduced negative bias instability in amorphous InGaZnO thin-film transistors with various active layer thicknesses

• Dapeng Wang and
• Mamoru Furuta

Beilstein J. Nanotechnol. 2018, 9, 2573–2580, doi:10.3762/bjnano.9.239

• works have highlighted that the electrical properties of the device (for both the initial and after stress conditions) such as threshold voltage, on/off ratio, and field effect mobility, can be effectively adjusted by controlling the active layer thickness [19][20][21][22][23]. Up to now, the impact of

• thicknesses were prepared by magnetron sputtering. The initial electrical properties and the photoleakage current of a-IGZO TFTs with various active layer thicknesses were investigated. The subthreshold value slightly increased while the threshold voltage (Vth) and mobility (μ) decreased with increasing TIGZO

• active layer thicknesses (TIGZO) measured at VDS = 20.1 V are shown in Figure 1b. Table 1 summarizes the electrical properties, such as field effect mobility in the saturation region (μsat), threshold voltage Vth (VGS at IDS of 1 nA), hysteresis of the transfer curves (the difference of VGS at IDS of 1

Cytotoxicity of doxorubicin-conjugated poly[N-(2-hydroxypropyl)methacrylamide]-modified γ-Fe₂O₃ nanoparticles towards human tumor cells

• Zdeněk Plichta,
• Yulia Kozak,
• Rostyslav Panchuk,
• Viktoria Sokolova,
• Matthias Epple,
• Lesya Kobylinska,
• Pavla Jendelová and
• Daniel Horák

Beilstein J. Nanotechnol. 2018, 9, 2533–2545, doi:10.3762/bjnano.9.236

• molecular weight of PHPMA can be kept below the renal threshold (Mw < 50 kDa), which allows for rapid renal clearance and avoids accumulation in the body. Indeed, the molecular weight of P(HPMA-MMAA) according to HPLC SEC chromatography was moderate (Mn = 33 kDa) with polydispersity index = 1.36. Formation

Evidence of friction reduction in laterally graded materials

• Roberto Guarino,
• Gianluca Costagliola,
• Federico Bosia and
• Nicola Maria Pugno

Beilstein J. Nanotechnol. 2018, 9, 2443–2456, doi:10.3762/bjnano.9.229

• (i) opposes the total driving force, so that Ffr(i) = −Fmot(i) , up to the threshold value Ffr(i) = µs(i) Fn(i). When this threshold is exceeded, a constant dynamic friction force with modulus Ffr(i) = µk(i) Fn(i) opposes the motion. Thus, Newton’s equation of motion for the block i can be written as

• velocity, and νc is the critical velocity for the transition [38]. This expression ensures that the value of the dynamic coefficient of friction is reached only when the sliding velocity is sufficiently high (i.e., ν >> νc). The static friction threshold is retrieved for ν = 0, so that the friction force

• shear stress is reached (i.e., the static friction threshold). The first detachment of the sliding surface produces a detachment avalanche propagating towards the region with higher static friction threshold, as shown in Figure 5 (see also Supporting Information File 1). Analogous effects on the

ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

• Marina Krasovska,
• Vjaceslavs Gerbreders,
• Irena Mihailova,
• Andrejs Ogurcovs,
• Eriks Sledevskis,
• Andrejs Gerbreders and
• Pavels Sarajevs

Beilstein J. Nanotechnol. 2018, 9, 2421–2431, doi:10.3762/bjnano.9.227

• was repeated with cadmium, where the same concentration of aqueous Cd(NO3)2 solution was used as a source of Cd2+ ions. The aqueous solutions of analytes were freshly prepared prior to measurement. In order to determine the sensor sensitivity threshold and quantify the change in ion concentration, a

• to 2 mM). The reduction peak current for the highest concentration can be explained by mass crystallization in the solution, in parallel with the sorption process. It is the threshold above which crystallites of lead oxides become visible on the ZnO nanostructured surface by SEM. In order to visually

• maximum concentration was chosen 10 and 100 times lower than CV sensitivity threshold of 1.5–3 mM. As shown in Figure 8, the DPV method is actually more sensitive than the CV method: using the same electrodes, it is possible to detect concentrations that are 100 times smaller than the CV sensitivity

Performance analysis of rigorous coupled-wave analysis and its integration in a coupled modeling approach for optical simulation of complete heterojunction silicon solar cells

• Ziga Lokar,
• Benjamin Lipovsek,
• Marko Topic and
• Janez Krc

Beilstein J. Nanotechnol. 2018, 9, 2315–2329, doi:10.3762/bjnano.9.216

• (most accurate) simulation. For 30 or more sublayers, the simulated |ΔJSC| drops below the chosen threshold line of 0.1 mA/cm2 for 0° light incidence, while 50 sublayers are required for 45° incidence. This threshold corresponds to 0.27% of the total JSC reflectance loss (36.87 mA/cm2) of the structure

• light drops below the threshold of 0.1 mA/cm2 with three modes (ten modes were used as the reference), while in case of non-normal incident light, at least six modes are required to meet this threshold. When comparing the |ΔJSC| plots corresponding to the variation in the number of sublayers (Figure 5e

• ) and number of modes (Figure 5f), we generally observe a smaller effect for the changing number of modes (note the different scales). 50 sublayers and six modes were found to be sufficient for both normal incident light as well as at 45° incidence, considering the chosen 0.1 mA/cm2 threshold. These

Intrinsic ultrasmall nanoscale silicon turns n-/p-type with SiO₂/Si₃N₄-coating

• Dirk König,
• Daniel Hiller,
• Noël Wilck,
• Birger Berghoff,
• Merlin Müller,
• Sangeeta Thakur,
• Giovanni Di Santo,
• Luca Petaccia,
• Joachim Mayer,
• Sean Smith and
• Joachim Knoch

Beilstein J. Nanotechnol. 2018, 9, 2255–2264, doi:10.3762/bjnano.9.210

• region. The “doping” due to the presence of the SiO2 coating is taken into consideration as a volume, active dopant concentration (see Supporting Information File 1); the presence of the Si3N4 layer underneath the gate is accounted for by an appropriate shift of the threshold voltage of the transistor

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

• Mattia Scardamaglia and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

• : for energies close to the threshold for carbon substitution, functionalization takes place, while at higher energies the main electronic signatures of graphene are compromised indicating the destruction of the hexagonal lattice due to the metallic atoms backscattering from the substrate [55][88]. In

• contrast, for suspended graphene, using similar ion kinetic energies, the type of defects was mainly affected while maintaining a clean and non-destructive functionalization [37][55][89]. Theoretical reports showed also that if the ion energy is set slightly below the threshold needed to create single

• atom %. Above this threshold cross-linking between the layers starts to occur and an sp3-coordination of carbon begins to occur [95]. At intermediate concentrations, the system is stabilized by nitrogen saturation of edges and vacancies, implicating an increasing content of pyridinic N compared to

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• substrates (Figure 4) play a crucial role in tribology. Experiments [164] agree with theory and numerical simulations [165][166][167][168] in showing the radical change of the static-friction threshold from the highly pinned regime of the lattice-matched colloidal layer to a practically superlubric

• locally disturbing the charge density waves [188] (Figure 7). At a certain threshold, the CDW shows a phase slip, which then leads to dissipation. Another example where non-contact friction can be influenced by external parameters are the measurements of superconductors across the critical temperature

Self-assembled quasi-hexagonal arrays of gold nanoparticles with small gaps for surface-enhanced Raman spectroscopy

• Emre Gürdal,
• Simon Dickreuter,
• Fatima Noureddine,
• Pascal Bieschke,
• Dieter P. Kern and
• Monika Fleischer

Beilstein J. Nanotechnol. 2018, 9, 1977–1985, doi:10.3762/bjnano.9.188

• . The SEM images for each sample were evaluated using a python script that applies a threshold in order to generate binary images. Blob detection is used to find the particles in the binary images and to evaluate the pixel count for each individual particle. From this pixel count, the area coverage and

• Raman laser. To approximately correct for the different amounts of molecules on the different samples one can use the filling factor (area coverage) of the samples: A threshold was applied to the SEM images, and the white pixels representing the presence of gold were counted. The filling factor was then

Defect formation in multiwalled carbon nanotubes under low-energy He and Ne ion irradiation

• Santhana Eswara,
• Jean-Nicolas Audinot,
• Brahime El Adib,
• Maël Guennou,
• Tom Wirtz and
• Patrick Philipp

Beilstein J. Nanotechnol. 2018, 9, 1951–1963, doi:10.3762/bjnano.9.186

• noble gas ion species, but Olejniczak et al. used only much lower fluences in their work for MeV irradiation and stayed most likely below the threshold for severe damage formation [53]. Niwase et al. carried out 25 keV He+ irradiation of graphite up to fluences of 1018 ions/cm2 and observed also a

A differential Hall effect measurement method with sub-nanometre resolution for active dopant concentration profiling in ultrathin doped Si_1−xGe_x and Si layers

• Richard Daubriac,
• Emmanuel Scheid,
• Hiba Rizk,
• Richard Monflier,
• Sylvain Joblot,
• Rémi Beneyton,
• Pablo Acosta Alba,
• Sébastien Kerdilès and
• Filadelfo Cristiano

Beilstein J. Nanotechnol. 2018, 9, 1926–1939, doi:10.3762/bjnano.9.184

• /cm2, the observed structure is identical to that found in the as-implanted sample with the SiGe layer being almost fully crystalline (and having a surface roughness of about 1 nm). This suggests that the laser energy density used in these cases is always lower than the threshold value necessary to

• melt the surface. In contrast, following a LTA at 0.79 J·cm−2 the SiGe top layer is completely amorphous, clearly indicating that in this case the whole SiGe layer was molten, leaving no seed for a perfect recrystallization. The threshold energy for surface melt is therefore located between 0.76 and

• sheet resistance values observed for high laser energies was due to the formation of a poly-Si layer as a consequence of the full melt of the entire top-Si layer during LTA. For LTA energies below the melting threshold of 0.74 J·cm−2, some dopant activation occurs. However, the Hall effect measurements

Electrical characterization of single nanometer-wide Si fins in dense arrays

• Steven Folkersma,
• Janusz Bogdanowicz,
• Andreas Schulze,
• Paola Favia,
• Dirch H. Petersen,
• Ole Hansen,
• Henrik H. Henrichsen,
• Peter F. Nielsen,
• Lior Shiv and
• Wilfried Vandervorst

Beilstein J. Nanotechnol. 2018, 9, 1863–1867, doi:10.3762/bjnano.9.178

• is observed that the magnitude of Ipulse must be chosen larger than a certain threshold current (Ithreshold, typically >100 µA for blanket materials) in order to reduce the contact resistance RC between the electrodes and the sample and hence activate the required electrical contact. The given

The role of the Ge mole fraction in improving the performance of a nanoscale junctionless tunneling FET: concept and scaling capability

• Hichem Ferhati,
• Fayçal Djeffal and
• Toufik Bentrcia

Beilstein J. Nanotechnol. 2018, 9, 1856–1862, doi:10.3762/bjnano.9.177

• current. This is due to the smaller band gap energy of Ge, yielding a higher tunneling efficiency. Moreover, the higher electron mobility of Ge (3900 cm2·V−1·s−1) contributes to the increased drain current at the threshold voltage as compared to the conventional design with silicon (1400 cm2·V−1·s−1

• current capability as shown in Figure 3a. It can be also concluded that the Ge mole fraction modulates the threshold voltage for the tunnel-current generation, which can in turn influence greatly the subthreshold behavior of the device. Moreover, the proposed Si1−xGex/Si/Ge heterochannel enables a

Magnetic properties of Fe₃O₄ antidot arrays synthesized by AFIR: atomic layer deposition, focused ion beam and thermal reduction

• Juan L. Palma,
• Alejandro Pereira,
• Raquel Álvaro,
• José Miguel García-Martín and
• Juan Escrig

Beilstein J. Nanotechnol. 2018, 9, 1728–1734, doi:10.3762/bjnano.9.164

• does not continue indefinitely, since the limiting case in which the holes are infinitely separated can be considered as a thin film, the coercivity of which is lower than that of an antidot pattern. More studies would be needed to obtain the threshold value of the lattice parameter at which the

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• particle and hole levels closest to the Fermi level, closes if |B| = Eφ. If one defines the two threshold fields Bmin = |ε| and , one can verify that the spectrum is gapped for both small |B| < Bmin and large |B| > Bmax Zeeman fields. For intermediate fields Bmin < |B| < Bmax, the energy gap closes at

• difference φ. At intermediate fields Bmin < |B| < Bmax, the particle–hole gap closes at the gapless points ±φ* that satisfy Equation 21. One can verify that the effect of a small Coulomb interaction U/2 < |ε|, |Γ| is a shift of the threshold fields Bmin and Bmax and of the value of the phases ±φ* where the

Toward the use of CVD-grown MoS₂ nanosheets as field-emission source

• Geetanjali Deokar,
• Nitul S. Rajput,
• Junjie Li,
• Francis Leonard Deepak,
• Wei Ou-Yang,
• Nicolas Reckinger,
• Carla Bittencourt,
• Jean-Francois Colomer and
• Mustapha Jouiad

Beilstein J. Nanotechnol. 2018, 9, 1686–1694, doi:10.3762/bjnano.9.160

• increasing of the applied electric field (Figure 6a). The turn-on field, defined at a current density of 10 µA/cm2, and the threshold field at 1 mA/cm2, are 3.1 and 5.3 V/µm, respectively. These data are found to be better than the previously reported values for MoS2 nanoflowers [13] or multilayered MoS2 [8

• promising for FE applications [30]. The low turn-on field and threshold field of the MoS2 NSs could be due to their vertically aligned extremely thin edges, forming a nano-tip-like structure (Figure S1, Supporting Information File 1). A considerable enhancement in FE can be achieved by tuning the

• transfer process. These NSs show very interesting FE properties at room temperature and in high vacuum (10−6 mbar) as proven by the low turn-on field of 3.1 V/μm and low threshold field of 5.3 V/µm. In future, the as-grown NSs could be potentially used for FE and display device applications. (a–c) Typical

Interaction-tailored organization of large-area colloidal assemblies

• Silvia Rizzato,
• Elisabetta Primiceri,
• Anna Grazia Monteduro,
• Adriano Colombelli,
• Angelo Leo,
• Maria Grazia Manera,
• Roberto Rella and
• Giuseppe Maruccio

Beilstein J. Nanotechnol. 2018, 9, 1582–1593, doi:10.3762/bjnano.9.150

• top-view configuration. In order to analyze the particle distribution, ImageJ 1.42R (National Institutes of Health, USA) software was used and the images were processed to allow easier recognition. From each image, the background was eliminated and a threshold level was defined to identify the

Photoluminescence of CdSe/ZnS quantum dots in nematic liquid crystals in electric fields

• Margarita A. Kurochkina,
• Elena A. Konshina and
• Daria Khmelevskaia

Beilstein J. Nanotechnol. 2018, 9, 1544–1549, doi:10.3762/bjnano.9.145

• simultaneously in the passive LC matrix in contrast to the active nematic matrix. Thus, in weak electric fields up to the Fréedericksz threshold, it is possible to control the buildup of the CdSe/ZnS QDs luminescence. By changing, the strength of electric field is possible to control the quenching of QDs