Electrostatic force microscopy for the accurate characterization of interphases in nanocomposites

• Diana El Khoury,
• Richard Arinero,
• Jean-Charles Laurentie,
• Mikhaël Bechelany,
• Michel Ramonda and
• Jérôme Castellon

Beilstein J. Nanotechnol. 2018, 9, 2999–3012, doi:10.3762/bjnano.9.279

• “calibrating” the EFM technique for future interphase studies. EFM was demonstrated to be able to discriminate between alumina and silicon dioxide interphase layers of 50 and 100 nm thickness deposited over polystyrene spheres and different types of matrix materials. Consistent permittivity values were also

• deduced by comparison of experimental data and numerical simulations, as well as the interface state of silicone dioxide layers. Keywords: atomic force microscopy; building-block materials; dielectric permittivity; electrostatic force microscopy; finite element simulation; interphases; nanocomposites

• filler. For instance, although the inorganic filler usually displays higher permittivity values than the polymer, the resulting nanofiller mixture in the matrix presents, at low nanofiller concentrations, a surprisingly lower dielectric constant than that of the two mixture components [10][11][12][13

In situ characterization of nanoscale contaminations adsorbed in air using atomic force microscopy

• Jesús S. Lacasa,
• Lisa Almonte and
• Jaime Colchero

Beilstein J. Nanotechnol. 2018, 9, 2925–2935, doi:10.3762/bjnano.9.271

• , h is the total thickness of the dielectric films on tip and sample, ε0 is the dielectric permittivity of vacuum and ε is the relative dielectric constant [43][44][45][46]. For a purely metallic system in air or vacuum were no dielectric layer is present (h = 0), the expression simplifies to C″(d

Time-resolved universal temperature measurements using NaYF₄:Er³⁺,Yb³⁺ upconverting nanoparticles in an electrospray jet

• Kristina Shrestha,
• Arwa A. Alaulamie,
• Ali Rafiei Miandashti and
• Hugh H. Richardson

Beilstein J. Nanotechnol. 2018, 9, 2916–2924, doi:10.3762/bjnano.9.270

• permittivity and permeability of water, l is an integer, and a is the radius of the WGM cavity [39][40]. The plot of wavenumbers of WGM peaks vs as a function of l + 1/2 is shown in Figure 6B. The slope from a linear fit is used to calculate the cavity radius of 2.87 ± 0.02 μm. The Q-factor of the WGM cavity

Site-controlled formation of single Si nanocrystals in a buried SiO₂ matrix using ion beam mixing

• Xiaomo Xu,
• Thomas Prüfer,
• Daniel Wolf,
• Hans-Jürgen Engelmann,
• Lothar Bischoff,
• René Hübner,
• Karl-Heinz Heinig,
• Wolfhard Möller,
• Stefan Facsko,
• Johannes von Borany and
• Gregor Hlawacek

Beilstein J. Nanotechnol. 2018, 9, 2883–2892, doi:10.3762/bjnano.9.267

• temperature, the diameter of an individual Si NC, 2rNC, has to be smaller than 5.7 nm. The other factors are the unit charge e and ε0 and εr = 3.9 are the vacuum permittivity and the relative permittivity of silicon dioxide, respectively. Recently, advanced lithographic methods [21] and directed self-assembly

Contactless photomagnetoelectric investigations of 2D semiconductors

• Marian Nowak,
• Marcin Jesionek,
• Barbara Solecka,
• Piotr Szperlich,
• Piotr Duka and
• Anna Starczewska

Beilstein J. Nanotechnol. 2018, 9, 2741–2749, doi:10.3762/bjnano.9.256

• ] (ε0ε/we)Vg, where ε0 and ε are the permittivity of free space and the used dielectric, respectively; e is the electron charge; and w is the thickness of the dielectric. The authors of [35] provided the theoretical description of the current compact model of graphene field-effect transistors. In our

• case, the energy position of the Fermi level of graphene was modulated by the field effect through the 170 μm thick PET foil. The relative permittivity of PET is ε = 3.5 at 71 kHz [42]. Figure 6b shows the PME voltage induced in the measuring coil as a function of the back-gate bias. The inserts depict

Polarization-dependent strong coupling between silver nanorods and photochromic molecules

• Gwénaëlle Lamri,
• Alessandro Veltri,
• Jean Aubard,
• Pierre-Michel Adam,
• Nordin Felidj and
• Anne-Laure Baudrion

Beilstein J. Nanotechnol. 2018, 9, 2657–2664, doi:10.3762/bjnano.9.247

• approximation: where and refer to the polarization of the incoming light, Vp is the volume of the particle, ε1 is silver permittivity, ε2 is the permittivity of the host medium, deduced by the ellipsometric measurements; while and are geometrical factors given by: Here e is the eccentricity calculated as

Impact of the anodization time on the photocatalytic activity of TiO₂ nanotubes

• Jesús A. Díaz-Real,
• Geyla C. Dubed-Bandomo,
• Juan Galindo-de-la-Rosa,
• Luis G. Arriaga,
• Janet Ledesma-García and
• Nicolas Alonso-Vante

Beilstein J. Nanotechnol. 2018, 9, 2628–2643, doi:10.3762/bjnano.9.244

• the Mott–Schottky equation (Equation 2): where Csc is the capacitance of the space-charge region, ND is the density of dopant atoms (cm−3), Efb is the flat-band potential, q is the elementary charge (1.602 × 10−19 C), ε0 is the vacuum permittivity (8.85 × 10−14 F·cm−1), and ε (42, [70]) is the

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

• was revealed that the volume around gold nanoparticles where the permittivity is near zero, ε ≈ 0, accounts for the strongest absorption, which leads to the effective enhancements of X-ray emission. Keywords: double pulse; gold nanoparticles; intense femtosecond laser; plasma; water; X-ray

• [26], respectively. Theory: Epsilon-Near-Zero (ENZ)-Material A strong generation of X-rays is related to a large amount of absorbed energy and a high temperature [3][4]. In terms of relative permittivity (dielectric constant), εr, a transparent medium (water) with colloidal gold nanoparticles

• represents an effective medium with an overall positive real part of the permittivity. Upon excitation, the material is approaching dielectric breakdown and a state of εr ≈ 0 (epsilon-near-zero (ENZ) state; ). Under the ENZ condition, the strongest absorption takes place [36][37]: Here, εi is the intrinsic

Au–Si plasmonic platforms: synthesis, structure and FDTD simulations

• Anna Gapska,
• Marcin Łapiński,
• Paweł Syty,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2018, 9, 2599–2608, doi:10.3762/bjnano.9.241

• , characterized by a large number of free electrons, which leads to a high plasma frequency and a negative real permittivity over a wide range of frequencies. Taking into account the existence of a eutectic from Au and Si, which gives the possibility of producing metal nanostructures on Si, and the aforementioned

Interaction-induced zero-energy pinning and quantum dot formation in Majorana nanowires

• Samuel D. Escribano,
• Alfredo Levy Yeyati and
• Elsa Prada

Beilstein J. Nanotechnol. 2018, 9, 2171–2180, doi:10.3762/bjnano.9.203

• charges that emerge in the electrostatic environment. We compute the electrostatic potential using Poisson’s equation where is the non-homogeneous dielectrical permittivity of the entire system and is the quantum and thermal average of the charge density of the nanowire obtained with Equation 1. The

• and the unavoidable presence of disorder [38]. If this is the case, it is then characterized by a finite effective dielectric permittivity which depends on the SC shell width as well as its composition, as we show in Section 1 of Supporting Information File 1. Some experiments [39] have reported that

• for ultrathin metallic layers (ca. 5–10 nm) it is of the order of εSC ≈ 100. For these values, as we show in the next section, we find a repulsive environment, i.e., an environment the effective permittivity of which is smaller than that of the wire so that the bound charges that arise at the

Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• dopant ionization energies increase, which decreases exponentially the free carrier density [1]. If a doped Si-nanovolume is embedded in a matrix of lower permittivity (e.g., a dielectric), the dopant charge is not fully screened in the silicon and a Coulomb interaction with its image charge in the

Tailoring polarization and magnetization of absorbing terahertz metamaterials using a cut-wire sandwich structure

• Hadi Teguh Yudistira,
• Shuo Liu,
• Tie Jun Cui and
• Han Zhang

Beilstein J. Nanotechnol. 2018, 9, 1437–1447, doi:10.3762/bjnano.9.136

• (SZU), Shenzhen 518060, China Mechanical Engineering Program, Institut Teknologi Sumatera (ITERA), Lampung 35365, Indonesia, State Key Laboratory of Milimeter Waves, Southeast University, Nanjing 210096, China 10.3762/bjnano.9.136 Abstract The permittivity and permeability of a cut-wire sandwich

• structure can be controlled by laterally shifting the upper and lower layers. The use of this process for designing specific application-oriented devices may lack clear-cut guidelines because the lateral misalignment will significantly change the permittivity and permeability simultaneously. Therefore, in

• smaller than the wavelength of the terahertz electromagnetic (EM) wave. Thus, such structures can be considered a homogeneous medium from the perspective of the EM wave. The existence of multiple metallic structures in a device may affect the EM properties, such as permittivity and permeability. Several

Formation and development of nanometer-sized cybotactic clusters in bent-core nematic liquid crystalline compounds

• Yuri P. Panarin,
• Sithara P. Sreenilayam,
• Jagdish K. Vij,
• Anne Lehmann and
• Carsten Tschierske

Beilstein J. Nanotechnol. 2018, 9, 1288–1296, doi:10.3762/bjnano.9.121

• clusters (NcybC) of the SmC type as explained above. The second compound, BCN84, has two asymmetrical alkyl chains of different lengths and is of the same molar mass as BCN66. The dielectric permittivity measurements were carried out using a broadband alpha high-resolution dielectric analyzer (Novocontrol

• correlations among the neighboring molecules were revealed and the cybotactic clusters were established [35][36][48]. This was the first successful attempt for determining the cluster size by using the Maier–Meier equations using dielectric parameters such as anisotropic permittivity and the anisotropic

• individual molecular modes [30][31]. Temperature dependence of the dielectric properties The dielectric spectra of BCN66 were analyzed by using the WINFIT software of Novocontrol GmbH. The dielectric data on the complex permittivity were fitted to the Havriliak–Negami (H–N) equation (Equation 1). where ε∞ is

Surface characterization of nanoparticles using near-field light scattering

• Eunsoo Yoo,
• Yizhong Liu,
• Chukwuazam A. Nwasike,
• Sebastian R. Freeman,
• Brian C. DiPaolo,
• Bernardo Cordovez and
• Amber L. Doiron

Beilstein J. Nanotechnol. 2018, 9, 1228–1238, doi:10.3762/bjnano.9.114

• . On the basis of the Stogryn model, the solution dielectric constant (permittivity), εs, is inversely proportional to the solute concentration, C [43][44]. As the solute concentration C increases, the solution dielectric constant εs decreases, thus the particle polarizability α also decreases [45

A novel copper precursor for electron beam induced deposition

• Caspar Haverkamp,
• George Sarau,
• Mikhail N. Polyakov,
• Ivo Utke,
• Marcos V. Puydinger dos Santos,
• Silke Christiansen and
• Katja Höflich

Beilstein J. Nanotechnol. 2018, 9, 1220–1227, doi:10.3762/bjnano.9.113

• . Optical transmission/reflection measurements of deposited pads showed a dielectric behavior of the material in the optical spectral range. The general behavior of the permittivity could be described by applying the Maxwell–Garnett mixing model to amorphous carbon and copper. The dielectric function

• investigated concerning their morphology, composition and electrical properties. Transmission and reflection spectra of planar deposits of various heights served as input for the retrieval of the complex permittivity of the copper-containing material. The obtained values were used to numerically model the

• function of the resulting material since the permittivity of a metal depends on the oxidation state. To survey the oxidation state in detail, cross-sections of FEBID deposits were investigated by transmission electron microscopy (TEM). Figure 2c and Figure 2d show the inner FEBID structure of the copper

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

• Tarek A. Ameen,
• Hesameddin Ilatikhameneh,
• Archana Tankasala,
• Yuling Hsueh,
• James Charles,
• Jim Fonseca,
• Michael Povolotskyi,
• Jun Oh Kim,
• Sanjay Krishna,
• Monica S. Allen,
• Jeffery W. Allen,
• Rajib Rahman and
• Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

• initial and final states, ń is the refractive index of the material, c is the speed of light in free space, ε0 is the free space permittivity, is the polarization of the incident light, and is the first-order dipole moment that is given by , where q is the electron charge. For transitions between bound

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

• Ying Wang,
• Yue Shen,
• Xingya Wang,
• Zhiwei Shen,
• Bin Li,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 900–906, doi:10.3762/bjnano.9.84

• liquid interfacial tension, θ0 is the contact angle at zero external voltage, and d, εr and ε0 are the thickness, relative permittivity of the dielectric layer, and the absolute dielectric permittivity of vacuum, respectively. Hence, the adhesion force between the AFM tip and the sample is affected by

Effect of annealing treatments on CeO₂ grown on TiN and Si substrates by atomic layer deposition

• Silvia Vangelista,
• Rossella Piagge,
• Satu Ek and
• Alessio Lamperti

Beilstein J. Nanotechnol. 2018, 9, 890–899, doi:10.3762/bjnano.9.83

• permittivity (κ) of 23–24 [5]. In all the cases, the valence of the Ce ions is fundamental, since it determines some of the material specific ability, such as the oxygen storage. More generally, the structure of cerium oxide is essential in defining its specific capabilities [6]. At the thermodynamic

Effect of ferroelectric BaTiO₃ particles on the threshold voltage of a smectic A liquid crystal

• Abbas R. Imamaliyev,
• Mahammadali A. Ramazanov and
• Shirkhan A. Humbatov

Beilstein J. Nanotechnol. 2018, 9, 824–828, doi:10.3762/bjnano.9.76

• features observed in the C–V characteristics are given. Keywords: colloidal systems; dielectric permittivity; ferroelectric BaTiO3 particles; smectic A liquid crystals; threshold voltage; Introduction Interest in liquid crystals (LC) as a unique state of matter arises not only from a scientific point of

• electro-optical cell. The electro-optical effect changes the effective dielectric permittivity of LC, which is reflected a change of capacitance of the electro-optical cell. The electro-optical effect in the investigated LC is the planar–homeotropic transition due to the positive dielectric anisotropy of

• effective dielectric permittivity starts to increase. Note that the latter is determined as the ratio ε = C/C0, where C and C0 are the capacitances of the filled cell and an empty cell, respectively. Figure 3 presents the effective dielectric permittivity as a function of the voltage for pure smectic A LC

Valley-selective directional emission from a transition-metal dichalcogenide monolayer mediated by a plasmonic nanoantenna

• Haitao Chen,
• Mingkai Liu,
• Lei Xu and
• Dragomir N. Neshev

Beilstein J. Nanotechnol. 2018, 9, 780–788, doi:10.3762/bjnano.9.71

• edges, we model the gold bars having rounded corners with a radius of curvature of 5 nm. The permittivity of the gold in the visible and near-infrared spectral region is modeled based on experimental data from [48]. The intensity of the electric field along X direction (I) and phase information (φ) at

Tuning adhesion forces between functionalized gold colloidal nanoparticles and silicon AFM tips: role of ligands and capillary forces

• Sven Oras,
• Sergei Vlassov,
• Marta Berholts,
• Rünno Lõhmus and
• Karine Mougin

Beilstein J. Nanotechnol. 2018, 9, 660–670, doi:10.3762/bjnano.9.61

• moments, α1 = 6.8 × 10−40 C2·m2/J and α2 = 5.8 × 10−40 C2·m2/J are the polarizabilities, ν1 = 2.8 × 1015 Hz and ν2 = 2.1 × 1015 Hz are the ionisation frequencies of silicon and thiol respectivly, kB is Boltzmann’s constant, T = 293 K is the temperature of the medium, ε0 is the vacuum permittivity, ε = 1

• is the relative permittivity and r = 0.165 nm [33] is the typical cut-off distance. According to calculations, the average values of vdW force between the molecules are around 13 nN. This value allows validating AFM measurements (Figure 3b). Therefore, vdW forces remain one of the main interactions

Dynamic behavior of nematic liquid crystal mixtures with quantum dots in electric fields

• Emil Petrescu,
• Cristina Cirtoaje and
• Octavian Danila

Beilstein J. Nanotechnol. 2018, 9, 399–406, doi:10.3762/bjnano.9.39

• threshold, the deviation angle is very small and the free energy caused by the elastic forces is: where K1 and K3 are the splay and bent elastic constants and θz = ∂θ/∂z. Due to the presence of the QDs, the electric properties of the mixture change. Hence, instead of perpendicular dielectric permittivity

• , , and electric anisotropy, εa, we use the effective perpendicular permittivity, , and effective anisotropy, εaeff. If a small spherical cavity is considered inside the liquid crystal, a polarisation field on the hole surface appears. According to classical theory developed by Landau and Lifshitz [20

• permittivity, is the perpendicular permittivity. In this case H becomes: where d(z) the depolarization coefficient, which for an ellipsoid with almost spherical shape (horizontal axis equal b = R and vertical axis a = R + 0.0005R) is If a quantum dot is placed inside this cavity, another polarization field

Design of polar self-assembling lactic acid derivatives possessing submicrometre helical pitch

• Alexej Bubnov,
• Cyril Vacek,
• Michał Czerwiński,
• Terezia Vojtylová,
• Wiktor Piecek and
• Věra Hamplová

Beilstein J. Nanotechnol. 2018, 9, 333–341, doi:10.3762/bjnano.9.33

• results of the imaginary part, ε”, of complex permittivity versus temperature and versus frequency are presented in Figure 4a,b. The dielectric absorption ε” spectra obtained within the whole temperature range of the ferroelectric SmC* phase at zero bias electric field reveal a strong contribution of the

• permittivity was measured during cooling using a Schlumberger 1260 impedance analyser in the frequency range of 10 Hz–1 MHz, keeping the temperature of the sample stable during frequency sweeps within ±0.1 K. Differential scanning calorimetry (DSC) plot of heating/cooling runs (indicated by horizontal arrows

• (blue triangle) and KL 4/6 (cyan diamond) as indicated. Temperature dependencies of the helix pitch length p for KL 3/4 (black rectangle), KL 3/5 (red cicle), KL 4/4 (green triangle), KL 4/5 (blue triangle) and KL 4/6 (cyan diamond) as indicated. 3D plots of the imaginary part of complex permittivity

The nanofluidic confinement apparatus: studying confinement-dependent nanoparticle behavior and diffusion

• Stefan Fringes,
• Felix Holzner and
• Armin W. Knoll

Beilstein J. Nanotechnol. 2018, 9, 301–310, doi:10.3762/bjnano.9.30

• interaction energy U(h) of a charged spherical particle at a distance h to a charged plane is given by [23][36]: where κ−1 is the Debye length, ε is the dielectric constant of the medium, ε0 is the vacuum permittivity, a is the radius, and ψP,eff and ψS,eff are the effective surface potentials of plane and

Dynamic behavior of a nematic liquid crystal with added carbon nanotubes in an electric field

• Emil Petrescu and
• Cristina Cirtoaje

Beilstein J. Nanotechnol. 2018, 9, 233–241, doi:10.3762/bjnano.9.25

• crystal with the electric field (Figure 2) is: where Here is the transverse component of the dielectric permittivity and is the dielectric anisotropy of the liquid crystal. Since D, the electric displacement, is constant, the voltage between the electrodes can be written as: and Equation 7 becomes: If