Refractive index sensing and surface-enhanced Raman spectroscopy using silver–gold layered bimetallic plasmonic crystals

• Somi Kang,
• Sean E. Lehman,
• Matthew V. Schulmerich,
• An-Phong Le,
• Tae-woo Lee,
• Stephen K. Gray,
• Rohit Bhargava and
• Ralph G. Nuzzo

Beilstein J. Nanotechnol. 2017, 8, 2492–2503, doi:10.3762/bjnano.8.249

• effect which limits the degree of conformal coverage realized in the sputter coating metallization step. In the calculation, we used a Drude plus two-pole Lorentzian model to obtain the dielectric constant of the metal as a function of wavelength [48][61]. Figure 2 presents the experimentally measured

Synthesis of metal-fluoride nanoparticles supported on thermally reduced graphite oxide

• Alexa Schmitz,
• Kai Schütte,
• Vesko Ilievski,
• Juri Barthel,
• Laura Burk,
• Rolf Mülhaupt,
• Junpei Yue,
• Bernd Smarsly and
• Christoph Janiak

Beilstein J. Nanotechnol. 2017, 8, 2474–2483, doi:10.3762/bjnano.8.247

• important technical applications [15][16][17][18][19][20][21][22]. They can be used as composite materials [23][24], in chemical sensors [25], electrodes for fuel cells [26][27][28], for catalysis [29][30][31][32] or for hydrogen storage [33]. Because of their high ionic charge, polarity and dielectric

• constant, ILs are an ideal media for microwave reactions and for the stabilization of M-NPs [34][35][36][37]. Soft wet-chemical synthesis in organic solvents from metal-organic complexes is an essential method to obtain metal or metal alloy nanoparticles [38][39][40][41][42][43][44][45][46][47][48][49][50

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• capacitance (C) can be estimated considering a metallic cylinder-plane system from [19]: where L is the length of the FET channel, ε0 the vacuum permittivity, εr = 3.9 the relative dielectric constant of the SiO2 insulator layer, h = 300 nm the thickness of the SiO2 layer, and d the nanowire diameter. From

Self-assembly of chiral fluorescent nanoparticles based on water-soluble L-tryptophan derivatives of p-tert-butylthiacalix[4]arene

• Pavel L. Padnya,
• Irina A. Khripunova,
• Olga A. Mostovaya,
• Timur A. Mukhametzyanov,
• Vladimir G. Evtugyn,
• Vyacheslav V. Vorobev,
• Yuri N. Osin and
• Ivan I. Stoikov

Beilstein J. Nanotechnol. 2017, 8, 1825–1835, doi:10.3762/bjnano.8.184

• in methanol (Figure 4, Supporting Information File 1, Figure S29). It turned out that the emission maxima are close for all compounds in methanol, which indicates the absence of excimer formation. Perhaps this is due to the fact that in water, as a more polar solvent (dielectric constant 78.36

The effect of the electrical double layer on hydrodynamic lubrication: a non-monotonic trend with increasing zeta potential

• Dalei Jing,
• Yunlu Pan and
• Xiaoming Wang

Beilstein J. Nanotechnol. 2017, 8, 1515–1522, doi:10.3762/bjnano.8.152

• = [2n0c2e2/(εε0kBT)]1/2 (n0 is the original bulk ion concentration of the lubricant, c is the chemical valence of free ions in the lubricant, e is the elementary charge, ε is the lubricant’s relative permittivity, and ε0 is vacuum’s absolute dielectric constant) is the reciprocal of the Debye length, z is

Adsorption and electronic properties of pentacene on thin dielectric decoupling layers

• Sebastian Koslowski,
• Daniel Rosenblatt,
• Alexander Kabakchiev,
• Klaus Kuhnke,
• Klaus Kern and
• Uta Schlickum

Beilstein J. Nanotechnol. 2017, 8, 1388–1395, doi:10.3762/bjnano.8.140

• of εr = 4 is assumed for the dielectric constant of h-BN, as proposed by Kim et al. [19] for 2–5 nm thin h-BN films. Using the following formula, the resulting energy shift can be estimated: Approximating the ion as a point charge yields an estimate for the energy shift of about 0.64 eV, compared to

• of the molecular position d and the dielectric constant of a single sheet of h-BN. Similar STS measurements of pentacene were carried out on KCl/Au(111), KCl/Cu(111) and KCl/(Cu110). The resulting STS data are depicted in Figure 7. The HOMO–LUMO gap can be used as a measure of the efficiency of an

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