Kelvin probe force microscopy in liquid using electrochemical force microscopy

• Liam Collins,
• Stephen Jesse,
• Jason I. Kilpatrick,
• Alexander Tselev,
• M. Baris Okatan,
• Sergei V. Kalinin and
• Brian J. Rodriguez

Beilstein J. Nanotechnol. 2015, 6, 201–214, doi:10.3762/bjnano.6.19

• static and dynamic components of the electrostatic force resulting when a DC bias, Vdc, and AC voltage, Vac, at a frequency, ω, is applied between a conducting probe and a sample (Vprobe = Vdc + Vac cos(ωt)) are given by: where is the capacitance gradient, governed by the geometry and permittivity of

• be expressed as where D is the diffusivity of the ions in solution, L is the separation of the electrodes and λ is the Debye screening length, given by where k is Boltzmann’s constant, Cb is the molar concentration, ε is the dielectric permittivity of the solvent, T is the temperature, e is the

Tunable light filtering by a Bragg mirror/heavily doped semiconducting nanocrystal composite

• Ilka Kriegel and
• Francesco Scotognella

Beilstein J. Nanotechnol. 2015, 6, 193–200, doi:10.3762/bjnano.6.18

• * the effective mass and ε0 the vacuum dielectric permittivity. The absorption of the ITO NC film has been described by applying the effective medium theory or Maxwell–Garnett effective medium approximation (MG-EMA) [40][41][42]. This theory has been developed to describe the macroscopic properties of a

• properties [28]. The refractive index of the film is 1.5 (same as that of the glass). For the NCs we consider a free carrier damping Γ = 0.31 eV and a high frequency dielectric permittivity of ε∞ = 4 [28][29][30]. The volume fraction of ITO in the film is chosen to be 0.01 [35]. In Figure 2b the absorption

Effect of channel length on the electrical response of carbon nanotube field-effect transistors to deoxyribonucleic acid hybridization

• Hari Krishna Salila Vijayalal Mohan,
• Jianing An,
• Yani Zhang,
• Chee How Wong and
• Lianxi Zheng

Beilstein J. Nanotechnol. 2014, 5, 2081–2091, doi:10.3762/bjnano.5.217

• capacitance per unit length of the nanotube, (when modeled as a cylinder on a planar substrate) is given by where ε0 is the permittivity of free space (8.8542 × 10−12 Fm−1), εr is the dielectric constant of the SiO2 gate insulator (≈3.9), tox is the SiO2 thickness, r is the radius of the nanotube, and L is

Optical properties and electrical transport of thin films of terbium(III) bis(phthalocyanine) on cobalt

• Peter Robaschik,
• Pablo F. Siles,
• Daniel Bülz,
• Peter Richter,
• Manuel Monecke,
• Michael Fronk,
• Svetlana Klyatskaya,
• Daniel Grimm,
• Oliver G. Schmidt,
• Mario Ruben,
• Dietrich R. T. Zahn and
• Georgeta Salvan

Beilstein J. Nanotechnol. 2014, 5, 2070–2078, doi:10.3762/bjnano.5.215

• of the organic film, ε is the relative dielectric constant, ε0 is the permittivity of free space, µ is the charge carrier mobility and V is the applied voltage. From the ohmic-like regime (see Figure 7b) we obtained parameters of σ/L equal to 1.38 and 0.97 kA/cm2 V for the samples of 20 and 80 nm

Spin annihilations of and spin sifters for transverse electric and transverse magnetic waves in co- and counter-rotations

• Hyoung-In Lee and
• Jinsik Mok

Beilstein J. Nanotechnol. 2014, 5, 1887–1898, doi:10.3762/bjnano.5.199

• limits |q| → 0 and |q| → ∞ refer, respectively, to the pure TM and pure TE modes. Besides, |q|2 ≡ q*·q, and ε is the permittivity, which is positive for dielectric media so that ε ≡ n2 with n being the refractive index. In addition, μ = 1 is the permeability for non-magnetic materials. Note that both ε

• superscripts "−" and "+", respectively. For instance, the electric permittivity is denoted by ε±. For the sake of simplicity, we keep constant in this study n− = 2 and n+ = 1 (vacuum). Furthermore, we introduce normalized variables and operators: ρ ≡ kr and . Hence, the Maxwell's equations become and , thus

The influence of molecular mobility on the properties of networks of gold nanoparticles and organic ligands

• Edwin J. Devid,
• Paulo N. Martinho,
• M. Venkata Kamalakar,
• Úna Prendergast,
• Christian Kübel,
• Tibebe Lemma,
• Jean-François Dayen,
• Tia. E. Keyes,
• Bernard Doudin,
• Mario Ruben and
• Sense Jan van der Molen

Beilstein J. Nanotechnol. 2014, 5, 1664–1674, doi:10.3762/bjnano.5.177

• ]. According to the Mie theory in the dipolar quasi-static approximation (in which the diameter d of the nanoparticle is assumed to be much smaller than the wavelength, i.e., d << λ), the position of the SPR is directly related to the permittivity of the medium surrounding the nanoparticle [29][30]. In

• molecule–gold nanoparticle arrays, this permittivity will be largely influenced by the molecules separating the nanoparticles. Hence, Au-NP–S-BPP arrays are expected to have optical properties different from reference alkanethiol–gold nanoparticle arrays. A further influence on the SPR is exerted by the

Organic and inorganic–organic thin film structures by molecular layer deposition: A review

• Pia Sundberg and
• Maarit Karppinen

Beilstein J. Nanotechnol. 2014, 5, 1104–1136, doi:10.3762/bjnano.5.123

The study of surface wetting, nanobubbles and boundary slip with an applied voltage: A review

• Yunlu Pan,
• Bharat Bhushan and
• Xuezeng Zhao

Beilstein J. Nanotechnol. 2014, 5, 1042–1065, doi:10.3762/bjnano.5.117

• liquid ρe can be written as: Then the potential ψ can be expressed by the Poisson equation [88]: where ε is the relative dielectric constant of the liquid, ε0 is the permittivity of vacuum. The boundary conditions of Poisson equation are where ξ is the surface potential at the boundary, called zeta

Hole-mask colloidal nanolithography combined with tilted-angle-rotation evaporation: A versatile method for fabrication of low-cost and large-area complex plasmonic nanostructures and metamaterials

• Jun Zhao,
• Bettina Frank,
• Frank Neubrech,
• Chunjie Zhang,
• Paul V. Braun and
• Harald Giessen

Beilstein J. Nanotechnol. 2014, 5, 577–586, doi:10.3762/bjnano.5.68

• based on metallic split-ring resonators (SRRs) were able to simultaneously demonstrate negative dielectric permittivity as well as magnetic permeability, which leads to a negative refractive index [11]. In hybrid solar cells and organic light emitting diodes, plasmonic nanostructures enhanced the

Dye-doped spheres with plasmonic semi-shells: Lasing modes and scattering at realistic gain levels

• Nikita Arnold,
• Boyang Ding,
• Calin Hrelescu and
• Thomas A. Klar

Beilstein J. Nanotechnol. 2013, 4, 974–987, doi:10.3762/bjnano.4.110

• is somewhat similar to the scattering by weakly dissipating plasmonic spheres, in which very narrow higher order resonances can dominate [52]. These effects are even more pronounced for the anisotropic dielectric permittivity with transverse or longitudinal gain [53]. Computational details are

3D nano-structures for laser nano-manipulation

• Gediminas Seniutinas,
• Lorenzo Rosa,
• Gediminas Gervinskas,
• Etienne Brasselet and
• Saulius Juodkazis

Beilstein J. Nanotechnol. 2013, 4, 534–541, doi:10.3762/bjnano.4.62

• , hence · D = 0 with D = ε0εrE = ε0E + P where P is the material polarization due to the bound charges and εr is complex if the medium is not transparent. On the other hand, we have jf = 0, jb = ∂t P, which leads to: For materials whose dielectric permittivity accounts for conduction electrons, i.e

Kelvin probe force microscopy of nanocrystalline TiO₂ photoelectrodes

• Alex Henning,
• Gino Günzburger,
• Res Jöhr,
• Yossi Rosenwaks,
• Biljana Bozic-Weber,
• Catherine E. Housecroft,
• Edwin C. Constable,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2013, 4, 418–428, doi:10.3762/bjnano.4.49

• surface and bulk defect states. TiO2 is regarded as an insulator with a relative permittivity of εr = 36 and consequently acts as a charge storage capacitor between a metallic tip and a highly conductive SnO2:F contact. Upon photoelectric charge injection, the redistribution of charge carriers (by

• work function, ΔΦS, is related to the surface dipole through the Helmholtz equation: where (N/A) is the number of dipoles/molecules per surface area, ε = (P0/P) is the effective dielectric constant of a molecular monolayer and ε0 is the permittivity in vacuum. The dipole layer is oriented at an angle

Influence of diffusion on space-charge-limited current measurements in organic semiconductors

• Thomas Kirchartz

Beilstein J. Nanotechnol. 2013, 4, 180–188, doi:10.3762/bjnano.4.18

• density J would to a first approximation not depend on the equilibrium electron concentration anymore. Instead J would just depend on the mobility μ, which is typically the only unknown parameter, as well as the voltage V, the device thickness d and the permittivity ε = ε0εr and would ideally follow the

• Mott–Gurney law [18][19] Here ε0 is the vacuum permittivity and εr is the relative permittivity. The Mott–Gurney law is frequently used to determine the mobility of organic semiconductors used for light emitting diodes and solar cells. However, its derivation uses three assumptions that are often not

• simulations except for the one with Vbi = 1 V in Figure 2, where the contact barrier at the cathode (x = d) is 0.1 eV and the contact barrier at the anode (x = 0) is 1.1 eV. The relative permittivity used in all simulations is εr = 3.8 and the capture coefficient for the Gaussian defect is 10−10 cm3·s−1 for

Plasmonics-based detection of H₂ and CO: discrimination between reducing gases facilitated by material control

• Gnanaprakash Dharmalingam,
• Nicholas A. Joy,
• Benjamin Grisafe and
• Michael A. Carpenter

Beilstein J. Nanotechnol. 2012, 3, 712–721, doi:10.3762/bjnano.3.81

• inducing a blue shift or increase in LSPR frequency, ω, as characterized by the Drude model in Equation 1. In the above equation N0 is the free-electron density of the Au particle, e the electron charge, εm the dielectric constant of the matrix and ε0 the permittivity of vacuum [24]. These reactions will

Distinguishing magnetic and electrostatic interactions by a Kelvin probe force microscopy–magnetic force microscopy combination

• Miriam Jaafar,
• Oscar Iglesias-Freire,
• Luis Serrano-Ramón,
• Manuel Ricardo Ibarra,
• Jose Maria de Teresa and
• Agustina Asenjo

Beilstein J. Nanotechnol. 2011, 2, 552–560, doi:10.3762/bjnano.2.59

• distance. When both the tip and the sample are conductive and there is an electrostatic potential difference (U) between them, the electrostatic force [27][28] is where R is the radius of the metallic part of the spherical tip, ε0 is the permittivity of free space and z is the effective tip–sample distance

Simple theoretical analysis of the photoemission from quantum confined effective mass superlattices of optoelectronic materials

• Debashis De,
• Sitangshu Bhattacharya,
• S. M. Adhikari,
• A. Kumar,
• P. K. Bose and
• K. P. Ghatak

Beilstein J. Nanotechnol. 2011, 2, 339–362, doi:10.3762/bjnano.2.40

• magnitude of electronic charge, mr is the reduced mass and is given by mr−1 = (m*)−1 + mv−1, mv is the effective mass of the heavy hole at the top of the valance band in the absence of any field, I0 is the light intensity of wavelength λ, ε0 is the permittivity of vacuum, εsc is the permittivity of the

Schottky junction/ohmic contact behavior of a nanoporous TiO₂ thin film photoanode in contact with redox electrolyte solutions

• Masao Kaneko,
• Hirohito Ueno and
• Junichi Nemoto

Beilstein J. Nanotechnol. 2011, 2, 127–134, doi:10.3762/bjnano.2.15

• permittivity (ε of TiO2 = 85.8 and 170, anisotropic), ε0 the vacuum permittivity (8.854 × 10−12 F·m−1), q the elementary electric charge (1.602 × 10−19 C), N the carrier density [m−3], E the applied potential [V], Efb the flat band potential [V], kB the Boltzman constant (1.380 × 10−23 J·K−1), and T the

• Equation 2, the flat band potential Efb, carrier density N, and the thickness of space charge layer dsc were calculated and are shown in Table 1. For the calculation, since the relative permittivity ε of TiO2 is anisotropic (85.8 and 170), we used both the values in the calculation, and thereafter took

Single-pass Kelvin force microscopy and dC/dZ measurements in the intermittent contact: applications to polymer materials

• Sergei Magonov and
• John Alexander

Beilstein J. Nanotechnol. 2011, 2, 15–27, doi:10.3762/bjnano.2.2

• enable measurements of electrical properties (surface potential, dielectric permittivity, capacitance, etc.) at a tip–sample junction. Here we will demonstrate that single-pass Kelvin force microscopy (KFM) studies based on sensing of an electrostatic force gradient can be performed in the intermittent

• to dC/dZ. Both the dC/dZ and d2C/dZ2 signals are related to the local dielectric permittivity and we used these for compositional mapping. The interplay between the experimental measurements and theoretical studies is needed for a better understanding of the sensitivity of dC/dZ and d2C/dZ2 based

• dielectric studies, and for the extraction of quantitative permittivity data. In addition, we also recorded the phase response at 2ωelec that can be used for detection of complex dielectric response. In the following we will demonstrate that surface potential and dC/dZ data, which are measured simultaneously

Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

• Thomas König,
• Georg H. Simon,
• Lars Heinke,
• Leonid Lichtenstein and
• Markus Heyde

Beilstein J. Nanotechnol. 2011, 2, 1–14, doi:10.3762/bjnano.2.1

• friction forces. The forces relevant in this work are described below. Coulomb forces are a result of interacting charges and can be stronger than most chemical binding forces [9]. The Coulomb potential ECoulomb between two charges Q1 and Q2 is given by where ε0 is the permittivity constant, ζ is the

• relative permittivity or dielectric constant of the medium and z the distance between the charges. The Coulomb force FCoulomb is given by It is well known [12] that for very small amplitudes, the shift of the resonance frequency Δf corresponds to the derivative of the tip-sample forces with respect to z