Micro- and nano-surface structures based on vapor-deposited polymers

• Hsien-Yeh Chen

Beilstein J. Nanotechnol. 2017, 8, 1366–1374, doi:10.3762/bjnano.8.138

• , dielectric constant, temperature, and morphology and various chemical compositions [58][59][60][61][62][63][64][65]. Because of the challenges in fabrication processes, gradients are often generated with solution-based technology. Limitations remain for the ongoing technologies, for example, the lack long

A top-down approach for fabricating three-dimensional closed hollow nanostructures with permeable thin metal walls

• Carlos Angulo Barrios and
• Víctor Canalejas-Tejero

Beilstein J. Nanotechnol. 2017, 8, 1231–1237, doi:10.3762/bjnano.8.124

• (thickness tAl) and varying on the sidewalls from a value of 0.5 × (tAl − tAlO) at the upper vertical surfaces to tAl at the bottom (on the Al substrate). The top cladding (superstrate) is considered to be air. The dielectric constant of Al was modelled by the well-known Drude–Lorentz equation. The

Optical response of heterogeneous polymer layers containing silver nanostructures

• Miriam Carlberg,
• Florent Pourcin,
• Olivier Margeat,
• Judikaël Le Rouzo,
• Gérard Berginc,
• Rose-Marie Sauvage,
• Jörg Ackermann and
• Ludovic Escoubas

Beilstein J. Nanotechnol. 2017, 8, 1065–1072, doi:10.3762/bjnano.8.108

• oscillator and ε∞ is the high energy dielectric constant. We focused on the plasmonic properties of the silver NPs in the visible wavelength range. Therefore, the Lorentz model was sufficient to account for the optical properties of the NPs, and the electronic intraband transitions occurring in the UV [27

• the Lorentz laws, we noticed that the two constants (n∞ from the Cauchy model and ε∞ from the Lorentz model) are only contained in the real part of the dielectric constant and correspond to an offset. Nanospheres of 10 nm diameter were included in a 55,000 g·mol−1 PVP layer on a silicon substrate

• distributed in the layer, the effective dielectric constant accounts for the averaged optical response of the nanoprisms. A single Lorentz oscillator is required to fit the nanospheres and nanoprisms in PVP. This easy method allows us to obtain the optical indices of thin films with complex inclusions. The

Near-field surface plasmon field enhancement induced by rippled surfaces

• Mario D’Acunto,
• Francesco Fuso,
• Ruggero Micheletto,
• Makoto Naruse,
• Francesco Tantussi and
• Maria Allegrini

Beilstein J. Nanotechnol. 2017, 8, 956–967, doi:10.3762/bjnano.8.97

• two-dimensional system corresponds to the condition Re(εm(ωr)) = −εd, where εm(ωr) is the dielectric function of the metal at the resonant frequency and εd is the effective dielectric constant. In a randomly organized nanostructure, collective plasmon oscillations are deeply influenced by the locally

Vapor-phase-synthesized fluoroacrylate polymer thin films: thermal stability and structural properties

• Paul Christian and
• Anna Maria Coclite

Beilstein J. Nanotechnol. 2017, 8, 933–942, doi:10.3762/bjnano.8.95

• surfaces are used as biocompatible surfaces [1], antifouling coatings [2], and as low dielectric constant materials [3] for microelectronics. Perfluoroacrylates are particularly appealing for such applications, as they combine the hydrophobic properties of the fluorinated pendant groups with easy

Relationships between chemical structure, mechanical properties and materials processing in nanopatterned organosilicate fins

• Gheorghe Stan,
• Richard S. Gates,
• Qichi Hu,
• Kevin Kjoller,
• Craig Prater,
• Kanwal Jit Singh,
• Ebony Mays and
• Sean W. King

Beilstein J. Nanotechnol. 2017, 8, 863–871, doi:10.3762/bjnano.8.88

• organosilicate clearly results in a slight stiffening of the fins, it also results in the incorporation of significant amounts of hydroxyl groups (Si–OH) that can increase both the dielectric constant/capacitance and electrical leakage of nanoporous oganosilicate dielectrics [51]. This is typically counteracted

Advances in the fabrication of graphene transistors on flexible substrates

• Gabriele Fisichella,
• Stella Lo Verso,
• Silvestra Di Marco,
• Vincenzo Vinciguerra,
• Emanuela Schilirò,
• Salvatore Di Franco,
• Raffaella Lo Nigro,
• Fabrizio Roccaforte,
• Amaia Zurutuza,
• Alba Centeno,
• Sebastiano Ravesi and
• Filippo Giannazzo

Beilstein J. Nanotechnol. 2017, 8, 467–474, doi:10.3762/bjnano.8.50

• applications. In this case the thickness and the dielectric constant of the insulating film have crucial importance in order to maintain a reasonably high gate capacitance of the final device. In particular, considering high κ-dielectrics such as HfO2 or Al2O3 with film thickness in the order of 10 nm, the

• substrate. The resulting dielectric constant is 6.9, which is reasonably high considering the low temperature (100 °C) adopted for the dielectric growth and the high roughness of the substrate. As a way of comparison with silicon dioxide, the resulting equivalent oxide thickness (EOT) is 16.8 nm. Several

Fabrication of black-gold coatings by glancing angle deposition with sputtering

• Alan Vitrey,
• Rafael Alvarez,
• Alberto Palmero,
• María Ujué González and
• José Miguel García-Martín

Beilstein J. Nanotechnol. 2017, 8, 434–439, doi:10.3762/bjnano.8.46

• evolution is quite different. The continuous film shows the characteristic reflecting behavior of metallic films, related to the contribution of the free electrons (Drude) to the dielectric constant. The reflectance of this sample goes up to 80%. In the nanostructured sample, on the other hand, the same

• contribution of the free electrons to the dielectric constant is responsible for the appearance of LSPRs, which as discussed above induce enhanced multiple scattering and light-trapping effects for the particular size distribution and separation among nanostructures occurring in the nanostructured films

Impact of contact resistance on the electrical properties of MoS₂ transistors at practical operating temperatures

• Filippo Giannazzo,
• Gabriele Fisichella,
• Aurora Piazza,
• Salvatore Di Franco,
• Giuseppe Greco,
• Simonpietro Agnello and
• Fabrizio Roccaforte

Beilstein J. Nanotechnol. 2017, 8, 254–263, doi:10.3762/bjnano.8.28

• ≈ 9.1 × 10−5 F/m2 (ε0 is the vacuum dielectric constant, εox = 3.9, tox = 380 nm, the permittivity and the thickness of the SiO2 film, respectively), on the capacitance of the MoS2 depletion region, Cs, as well as on the capacitance associated with MoS2/SiO2 interface traps, Cit [5]. In the depletion

Optical and photocatalytic properties of TiO₂ nanoplumes

• Viviana Scuderi,
• Massimo Zimbone,
• Maria Miritello,
• Giuseppe Nicotra,
• Giuliana Impellizzeri and
• Vittorio Privitera

Beilstein J. Nanotechnol. 2017, 8, 190–195, doi:10.3762/bjnano.8.20

• reflectance spectrum of the titanium layer before the chemical etching. We assumed that the functional form for the dielectric constant of the metallic film is given by the “Drude free carrier” expression [26]: where ω, ωP, γ and ε∞ are, respectively, the light frequency, the plasma frequency, the damping

• constant, and the low-frequency dielectric constant tabulated for titanium. The refractive index of titanium is calculated by the square root of Equation 1 [26]: The refractive index of the TiO2 film was extracted by fitting both the reflectance and transmittance spectra of the Ti (430-190) sample, by

Graphene–polymer coating for the realization of strain sensors

• Carmela Bonavolontà,
• Carla Aramo,
• Massimo Valentino,
• Giampiero Pepe,
• Sergio De Nicola,
• Gianfranco Carotenuto,
• Angela Longo,
• Mariano Palomba,
• Simone Boccardi and
• Carosena Meola

Beilstein J. Nanotechnol. 2017, 8, 21–27, doi:10.3762/bjnano.8.3

• is the effective relative dielectric constant of the layer. The value of τ found by the fitting procedure implies that for Ec ≈ 100 meV, an intergrain distance d of few nanometers is found, consistently with the adopted model. From Equation 3, and taking into account the definition of gauge factor

Streptavidin-coated gold nanoparticles: critical role of oligonucleotides on stability and fractal aggregation

• Roberta D'Agata,
• Pasquale Palladino and
• Giuseppe Spoto

Beilstein J. Nanotechnol. 2017, 8, 1–11, doi:10.3762/bjnano.8.1

• surface plasmons (SPs) propagating along the interface between the flat metal surface and dielectric. The signal enhancement produced when AuNPs are used in assays is a consequence of the large variation of the local dielectric constant caused by AuNPs [8]. In fact, the interaction between propagating and

• , respectively. The shift is a consequence of changes in the local dielectric constant and effective thickness of the layer adsorbed on the AuNP surface [30]. No significant broadening of peaks is observed after the functionalization steps, indicating that particles did not appreciably aggregate. The 4 nm shift

• Equation 1: where εs and εm represent the dielectric constant of the shell (SA) and the surrounding medium (water), respectively, λp is the bulk metal plasmon wavelength (131 nm for gold [32]), λmax,bare is the wavelength of maximum absorption for AuNPs (520 nm, Figure 2), g is the fraction of nanoparticle

Effect of Anderson localization on light emission from gold nanoparticle aggregates

• Mohamed H. Abdellatif,
• Marco Salerno,
• Gaser N. Abdelrasoul,
• Ioannis Liakos,
• Alice Scarpellini,
• Sergio Marras and
• Alberto Diaspro

Beilstein J. Nanotechnol. 2016, 7, 2013–2022, doi:10.3762/bjnano.7.192

• electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The dielectric constant of the surrounding medium plays a crucial role in determining the aggregate geometry, which affects the Anderson localization of light in the aggregates and hence causes a red-shift in the plasmonic

• revealed a primary particle size of ≈14 nm. For spherical nanoparticles, the condition of plasmon resonance excitation is satisfied when εreal = −2εm, where εreal is the real part of the dielectric constant of the particle material and εm is the dielectric constant of the medium. For nonspherical

• into several modes. According to the Drude free-electron model [16], the electron resonance for small spherical metallic nanoparticles is described according to the following expression for the static polarizability α: where R is the particle radius, ε is the complex dielectric constant of the

A dioxaborine cyanine dye as a photoluminescence probe for sensing carbon nanotubes

• Mohammed Al Araimi,
• Petro Lutsyk,
• Anatoly Verbitsky,
• Yuri Piryatinski,
• Mykola Shandura and
• Aleksey Rozhin

Beilstein J. Nanotechnol. 2016, 7, 1991–1999, doi:10.3762/bjnano.7.190

• red-shifted in comparison to neat SWNTs (Table 2, Figure 3b). However, the E11 peaks of the mixtures practically do not change due to the aging (Figure 3b, curves 3 and 4). The Eii optical transition energies of the SWNTs strongly depend on the dielectric constant of both the nanotubes and the

Low temperature co-fired ceramic packaging of CMOS capacitive sensor chip towards cell viability monitoring

• Niina Halonen,
• Joni Kilpijärvi,
• Maciej Sobocinski,
• Timir Datta-Chaudhuri,
• Antti Hassinen,
• Someshekar B. Prakash,
• Peter Möller,
• Pamela Abshire,
• Sakari Kellokumpu and
• Anita Lloyd Spetz

Beilstein J. Nanotechnol. 2016, 7, 1871–1877, doi:10.3762/bjnano.7.179

• frames/min. The CMOS chip continued to function upon the addition of the fluid, confirming the robustness of the package. The important thing to note is that the signal increased upon the addition of DMEM (Figure 6). This was expected because the dielectric constant of water is higher than that of air

Fingerprints of a size-dependent crossover in the dimensionality of electronic conduction in Au-seeded Ge nanowires

• Maria Koleśnik-Gray,
• Gillian Collins,
• Justin D. Holmes and
• Vojislav Krstić

Beilstein J. Nanotechnol. 2016, 7, 1574–1578, doi:10.3762/bjnano.7.151

• (screening) length, , which is defined as [27]: where εNW = 16 is the dielectric constant of the NW material (assumed the same as for bulk Ge [28]), ε0 the vacuum permittivity, kB the Boltzmann constant, T the temperature and q the electron charge. In Figure 4, is plotted together with R as a function of Nd

• description of the charge carriers is not a reasonable approach, the 1D screening length λ(1D) is better suited [29]. For our NWs, we can write where εox ≈ 7.44 [27] is the dielectric constant of the native oxide, tox ≈ 3 nm (cf. Figure 1b) its thickness, and R(Nd) is the inverted Nd(R) ~ R−α (see above

Graphene-enhanced plasmonic nanohole arrays for environmental sensing in aqueous samples

• Christa Genslein,
• Peter Hausler,
• Eva-Maria Kirchner,
• Rudolf Bierl,
• Antje J. Baeumner and
• Thomas Hirsch

Beilstein J. Nanotechnol. 2016, 7, 1564–1573, doi:10.3762/bjnano.7.150

• enhanced to achieve low detection limits. To address this issue nanomaterials ranging from metallic nanoparticles, carbon-based structures to liposomes were used [10][11][12]. Plasmonic transducers are sensitive to changes of optical properties such as the dielectric constant and hence the refractive index

Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal

• Eduardo Aluicio-Sarduy,
• Simone Callegari,
• Diana Gisell Figueroa del Valle,
• Andrea Desii,
• Ilka Kriegel and
• Francesco Scotognella

Beilstein J. Nanotechnol. 2016, 7, 1404–1410, doi:10.3762/bjnano.7.131

• for silver as where N is the carrier density, e is the electron charge, m* is the effective mass and ε0 is the dielectric constant of the vacuum. Qualitatively, we can state that the polarization charges that accumulate at the silver/titanium dioxide interface, because of the electric field

• dielectric function of the silver nanoparticle film (a network of necked silver nanoparticles with air pores) can be described by the Maxwell–Garnett effective medium approximation [21][22][23], which is given by where εAir is the dielectric constant of air, and δAg accounts for the volume fraction occupied

• charges in an ITO film by applying a constant voltage demonstrated that besides an increase in carrier density, other Drude parameters such as the damping constant and the high frequency dielectric constant are altered through the introduction of additional carriers [30]. Thus, a deeper study of the

Diameter-driven crossover in resistive behaviour of heavily doped self-seeded germanium nanowires

• Stephen Connaughton,
• Maria Koleśnik-Gray,
• Richard Hobbs,
• Olan Lotty,
• Justin D. Holmes and
• Vojislav Krstić

Beilstein J. Nanotechnol. 2016, 7, 1284–1288, doi:10.3762/bjnano.7.119

• coordinates [20][21] and for simplicity assuming a constant free-hole concentration nh. One finds the expression [22] where Φ0 is the electrostatic potential at the core/shell interface, ε0 is the vacuum permittivity, εr the dielectric constant of germanium, and e the elementary charge. The confinement of

Manufacturing and investigation of physical properties of polyacrylonitrile nanofibre composites with SiO₂, TiO₂ and Bi₂O₃ nanoparticles

• Tomasz Tański,
• Wiktor Matysiak and
• Barbara Hajduk

Beilstein J. Nanotechnol. 2016, 7, 1141–1155, doi:10.3762/bjnano.7.106

• then examined. The morphology of the fibres and the dispersion of nanoparticles in their volume were examined using scanning electron microscopy (SEM). All of the physical properties, which included the band gap width, dielectric constant and refractive index, were tested and plotted against the

• determine the dielectric constant, refractive index and the thickness of the obtained fibrous mats. Keywords: ceramic nanoparticles; electrospinning methods; polyacrylonitrile; polymer composite nanofibres; spectroscopic ellipsometry; Introduction Over the last decade, there has been a noticeable

• . This significantly influenced the quality of the measurements of the refractive index n, the extinction coefficient k, and the real and the imaginary part of the dielectric constant ε. Ellipsometry measurements were carried out using a Sentech SE 850 E ellipsometer in the wavelength range of 240–2500

Role of solvents in the electronic transport properties of single-molecule junctions

• Katharina Luka-Guth,
• Sebastian Hambsch,
• Andreas Bloch,
• Philipp Ehrenreich,
• Bernd Michael Briechle,
• Filip Kilibarda,
• Torsten Sendler,
• Dmytro Sysoiev,
• Thomas Huhn,
• Artur Erbe and
• Elke Scheer

Beilstein J. Nanotechnol. 2016, 7, 1055–1067, doi:10.3762/bjnano.7.99

• parameters, i.e., the dielectric constant εr and the bulk conductivity σ of the solvent, have to be considered, see Table 2. Furthermore, capacitive effects cannot explain the finite offset (I(V = 0)) that is bigger than the opening of the loop (current difference between up- and down-sweep) observed in EtOH

• properties of the respective solvents are: µ the dipole moment, εr the low frequency dielectric constant, and σ the DC conductivity. Data taken form the Reaxys® data base and references therein. Acknowledgements We thank A. Fischer for technical assistance, and D. Schmid, J. Artois, L. Stoppel, S. Tibus, M

Dielectrophoresis of gold nanoparticles conjugated to DNA origami structures

• Anja Henning-Knechtel,
• Matthew Wiens,
• Mathias Lakatos,
• Andreas Heerwig,
• Frieder Ostermaier,
• Nora Haufe and
• Michael Mertig

Beilstein J. Nanotechnol. 2016, 7, 948–956, doi:10.3762/bjnano.7.87

• conductivity, σ, and the dielectric constant, ε, respectively [31]. It applies that for pDEP has to be larger than . Since the ε of water is approximately 8-fold larger than that of DNA, we expect pDEP only to occur in the σ-dominated range at σp >> σm. In order to ensure this condition, the as-prepared 6HB

• of a negatively charged DNA molecule is proposed to be due to a combination of its surrounding and mobile counter ions [32]. A physical measure of the polarizability is the dielectric constant, ε. Experimental data show that DNA molecules with ε = 8.5 are a less polarizable material than gold

• nanoparticles influence on the electrical field the software package FEMM4.2 (http://www.femm.info/wiki/HomePage) was used. For the simulation, a dielectric constant of 8.5 and 78 was used for DNA and the surrounding medium, respectively. Six-helix bundle. The (a) front and (b) side view of the six-helix bundle

Reorientation of single-wall carbon nanotubes in negative anisotropy liquid crystals by an electric field

• Amanda García-García,
• Ricardo Vergaz,
• José F. Algorri,
• Gianluigi Zito,
• Teresa Cacace,
• Antigone Marino,
• José M. Otón and
• Morten A. Geday

Beilstein J. Nanotechnol. 2016, 7, 825–833, doi:10.3762/bjnano.7.74

• along the long axis (which roughly matches the director orientation) or perpendicular to the long axis. They are customarily classified as positive and negative LCs according to their dielectric anisotropy [6]. In a positive LC material, the dielectric constant along the director is larger than the

• degenerate dielectric constant perpendicular to the director. Consequently, the molecules tend to align with an applied electrical field. In a negative LC material the opposite is the case. Thus, a homogenously aligned, positive LC sandwiched between two electrodes will reorient when a sufficiently large

• LC), it may be described in impedance terms as a capacitor, where capacitance depends on the dielectric constant of the LC. The presence of SWCNTs (being conductive nanoparticles) in the LC media may change the impedance of the system. Their reorientation from planar to the substrate (i.e., the

Antibacterial activity of silver nanoparticles obtained by pulsed laser ablation in pure water and in chloride solution

• Brunella Perito,
• Emilia Giorgetti,
• Paolo Marsili and
• Maurizio Muniz-Miranda

Beilstein J. Nanotechnol. 2016, 7, 465–473, doi:10.3762/bjnano.7.40

• (blue line). In the latter case, the plasmon resonance appears blue-shifted in both ps and ns samples. Such a shift could be attributed either to a change in the dielectric constant of the liquid environment or, more reasonably, to the different oxidation grade of the NP surfaces, where the NPs obtained

Mismatch detection in DNA monolayers by atomic force microscopy and electrochemical impedance spectroscopy

• Maryse D. Nkoua Ngavouka,
• Pietro Capaldo,
• Elena Ambrosetti,
• Giacinto Scoles,
• Loredana Casalis and
• Pietro Parisse

Beilstein J. Nanotechnol. 2016, 7, 220–227, doi:10.3762/bjnano.7.20

• ), where A is the area of the electrode, d the thickness of the ssDNA layer, and ε0 and ε are the dielectric constant of vacuum and ssDNA layer, respectively. When we insert a complementary strand in the electrochemical cell, the molecular recognition between the two strands will cause a change in the