Computational exploration of two-dimensional silicon diarsenide and germanium arsenide for photovoltaic applications

• Sri Kasi Matta,
• Chunmei Zhang,
• Yalong Jiao,
• Anthony O'Mullane and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1247–1253, doi:10.3762/bjnano.9.116

• frequency-dependent dielectric tensor matrix through hybrid DFT based on the Heyd–Scuseria–Ernzerhof (HSE) exchange–correlation functional [15][16], implemented in VASP [21][22][23]. The corrected average electrostatic potential in the unit cell with regard to the vacuum potential is obtained from HSE band

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

• altering the salt concentration of the suspension solution affected the velocity of particles due to the change of dielectric constant and viscosity of the solution. These findings suggest that this technique is suitable for studying particle surface changes and perhaps can be used to dynamically study

• microscope is efficient in characterization of polymer-coated nanoparticles. However, due to the fact that the nanoparticle scattering intensity depends on the dielectric constant of the material, multicomponent particle coatings, especially those on metallic or metal oxide materials such as those studied

• studies of reaction kinetics at the particle surface that result in changes in particle size, dielectric constant, or surface chemistry, which is of particular interest in protein adsorption to nanoparticles for biomedical applications. Results and Discussion Size, morphology, and elemental analysis of

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

• material before and after FEBID suggest a complete break of all bonds present in the crystalline structure. The three small peaks visible in the deposited FEBID pad at 150, 220 and 630 cm−1 suggest a partially oxidized copper state of the copper particles [17]. This is important in view of the dielectric

• copper is un-oxidized. Hence, the optical response of the composite is expected to be determined by pure copper particles dispersed in a dielectric carbonaceous matrix. The regions around 1300 cm−1 and 1500 cm−1 in the Raman spectrum displayed in Figure 2b provide information about the configuration of

Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

• Nor Fazila Khairudin,
• Mohd Farid Fahmi Sukri,
• Mehrnoush Khavarian and
• Abdul Rahman Mohamed

Beilstein J. Nanotechnol. 2018, 9, 1162–1183, doi:10.3762/bjnano.9.108

• long-term reaction and resistance to carbon formation. As highlighted, 15 wt % of Ni metal loading is required for substantial metal–support interaction and high catalytic activity in DRM [97]. Hua et al. [36] synthesized a Ni/MgO catalyst via a dielectric barrier discharge plasma and compared the

• catalyst with the ones prepared via the conventional impregnation method. The Ni/MgO catalyst prepared using a dielectric barrier discharge plasma presented a smaller particle size, higher dispersion, and higher specific surface area. Moreover, the recorded CO2 and CH4 conversions were 20% higher than that

Electrostatic force spectroscopy revealing the degree of reduction of individual graphene oxide sheets

• Yue Shen,
• Ying Wang,
• Yuan Zhou,
• Chunxi Hai,
• Jun Hu and
• Yi Zhang

Beilstein J. Nanotechnol. 2018, 9, 1146–1155, doi:10.3762/bjnano.9.106

• (EFM) phase with high resolution as a function of the electrical direct current bias applied either to the probe or sample. Based on the dielectric constant difference of graphene oxide (GO) sheets (reduced using various methods), EFS can be used to characterize the degree of reduction of uniformly

• or valley EFM phases) and the EFM phase contrast at a certain tip bias less than the peak value can all indicate the degree of reduction of rGO samples, which is positively correlated with the dielectric constant. In addition, we gave the ranking of degree for reduction on thermally or chemically

• applications. Furthermore, as a general and quantitative technique for evaluating the small differences in the dielectric properties of nanomaterials, the EFS technique will extend and facilitate its nanoscale electronic devices applications in the future. Keywords: degree of reduction; dielectric property

P3HT:PCBM blend films phase diagram on the base of variable-temperature spectroscopic ellipsometry

• Barbara Hajduk,
• Henryk Bednarski,
• Bożena Jarząbek,
• Henryk Janeczek and
• Paweł Nitschke

Beilstein J. Nanotechnol. 2018, 9, 1108–1115, doi:10.3762/bjnano.9.102

• polarization of reflected light. The change of light polarization is described by ellipsometric angles Ψ and Δ. Typically, ellipsometric investigations allow one to determine optical parameters, i.e., the refractive index n and the extinction coefficient k, or equivalently the complex dielectric function ε

Electro-optical interfacial effects on a graphene/π-conjugated organic semiconductor hybrid system

• Karolline A. S. Araujo,
• Luiz A. Cury,
• Matheus J. S. Matos,
• Thales F. D. Fernandes,
• Luiz G. Cançado and
• Bernardo R. A. Neves

Beilstein J. Nanotechnol. 2018, 9, 963–974, doi:10.3762/bjnano.9.90

• region of the image is proportional to the dielectric constant of the material underneath the EFM tip, surface potential differences and to any accumulated charges/permanent polarization at the surface [34]. Equation 2 was used to fit all experimental data in Figure 4c–e (blue or brown solid lines in

• these plots) and Table 1 shows the respective fitting parameters. Considering, initially, parameter α in Table 1, which is related to the geometric capacitance and dielectric constant, there is no significant variation, as expected, since the geometric capacitance should remain the same. The minor

• variation of α for both functionalized graphene (Gf) and RA upon illumination may reflect slight changes on the hybrid dielectric constant upon charge transfer (doping). Such charge transfer, including photo-generated charges, may also account for the observed variation of parameter γ in Table 1, which is

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

• Qinghai Province, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, Qinghai 810008, China University of Chinese Academy of Sciences, Beijing 100049, China 10.3762/bjnano.9.84 Abstract The detection of local dielectric properties is of great importance in a wide variety of scientific

• studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar

• thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion

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

• structure [8][16][17][18], which influences the dielectric behavior [18]. ALD guarantees high compatibility with many applications, thanks to the atomic level control of the film thickness with large-area uniformity and conformality also on 3D surfaces. In this study, we use Ce β-diketonate as metal source

• integration of CeO2 as dielectric material in capacitors. In this respect, the electrical characterization of our CeO2 films in a metal–insulator–metal (MIM) capacitor would be useful to study the electrical behavior of CeO2. However, this is beyond the scope of our study. On a more fundamental point, the

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

• reduce the threshold voltage. The obtained result is explained by two factors: an increase of dielectric anisotropy of the liquid crystals and the formation of a strong electric field near polarized particles of BaTiO3. It was shown that the role of the second factor is dominant. The explanations of some

• 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

• ferroelectric BaTiO3 nanoparticles were found to exhibit a nonvolatile electromechanical memory effect in the isotropic phase [9]. Ferroelectric nanoparticles reduce the threshold voltage by enhancing the dielectric anisotropy of the nematic LC and the system becomes sensitive to the sign of the applied

Surface-plasmon-enhanced ultraviolet emission of Au-decorated ZnO structures for gas sensing and photocatalytic devices

• T. Anh Thu Do,
• Truong Giang Ho,
• Thu Hoai Bui,
• Quang Ngan Pham,
• Hong Thai Giang,
• Thi Thu Do,
• Duc Van Nguyen and
• Dai Lam Tran

Beilstein J. Nanotechnol. 2018, 9, 771–779, doi:10.3762/bjnano.9.70

• [10][11]. SPR of Au NPs strongly depends upon the Au–ZnO matrix interface, as well as the dielectric properties of the surrounding ZnO matrix [12][13]. (ii) The AuNPs possibly deplete more carriers near the ZnO surface, which increases the charge density of ZnO and leads to enhanced interaction with

The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene

• Egor A. Kolesov,
• Mikhail S. Tivanov,
• Olga V. Korolik,
• Olesya O. Kapitanova,
• Xiao Fu,
• Hak Dong Cho,
• Tae Won Kang and
• Gennady N Panin

Beilstein J. Nanotechnol. 2018, 9, 704–710, doi:10.3762/bjnano.9.65

• graphene transferred to Cu and Al2O3 as typical conducting and dielectric materials, a stronger carrier density change was obtained for the latter. As the pressure decreases, removal of adsorbates from the surface of graphene on Al2O3 results in the Raman spectra parameters becoming close to those typical

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

• Kah Hon Leong,
• Azrina Abd Aziz,
• Lan Ching Sim,
• Pichiah Saravanan,
• Min Jang and
• Detlef Bahnemann

Beilstein J. Nanotechnol. 2018, 9, 628–648, doi:10.3762/bjnano.9.59

• allow the enhanced absorption of photon energy from the visible light spectrum. Larger metallic nanoparticles (>5 nm) produce a robust surface plasmon emission in the visible spectrum [10]. The intensity of the plasmon band is highly dependent on the morphology, surrounding medium dielectric constant

• the visible spectrum was promoted through LSPR and is very well ascribed to the electric polarization effect. Moreover, LSPR also speeds up the electron movement from the photoexcited noble metal to the semiconductor [5]. The morphology, interparticle interactions and the local dielectric environment

• produced; however, this phenomenon is mainly affected by morphology, size, and composition of the NPs as well as the dielectric properties of the surrounding medium [99][100]. Xu et al. reported that the content of metallic Ag and the extent of metallic Ag dispersion were factors which can be controlled to

High-contrast and reversible scattering switching via hybrid metal-dielectric metasurfaces

• Jonathan Ward,
• Khosro Zangeneh Kamali,
• Lei Xu,
• Guoquan Zhang,
• Andrey E. Miroshnichenko and
• Mohsen Rahmani

Beilstein J. Nanotechnol. 2018, 9, 460–467, doi:10.3762/bjnano.9.44

• , Nankai University, Tianjin 300457, China School of Engineering and Information Technology, University of New South Wales at the Australian Defence Force Academy, Canberra, ACT 2600, Australia 10.3762/bjnano.9.44 Abstract Novel types of optical hybrid metasurfaces consist of metallic and dielectric

• is shown that by adjusting the intermediate distance between metallic and dielectric elements, opposite scattering directionalities are achievable in an arbitrary wavelength. Interestingly, this effect is shown to have a direct influence on nonlinear properties, too, where 10-fold enhancement in the

• remarkable advantages in controlling optical responses [14][15][16][17][18]. All-dielectric, high refractive index metasurfaces are the second generation of metasurfaces [19]. Besides their CMOS compatibility and low optical losses compared with plasmonic metasurfaces, all-dielectric metasurfaces offer

Facile synthesis of ZnFe₂O₄ photocatalysts for decolourization of organic dyes under solar irradiation

• Arjun Behera,
• Debasmita Kandi,
• Sanjit Manohar Majhi,
• Satyabadi Martha and
• Kulamani Parida

Beilstein J. Nanotechnol. 2018, 9, 436–446, doi:10.3762/bjnano.9.42

• the band edge of the prepared materials. The Mott–Schottky graphs were plotted according to Equation 2: where C, Vfb, k, T, e, ND, ε, ε0 and A are capacitance of the sample, flat-band potential, Boltzmann constant, absolute temperature, electron charge, donor density, semiconductor dielectric constant

• , dielectric constant in vacuum and area, respectively. C−2 was plotted as a function of the applied potential, Vapp. The extrapolation of the graph leads to the intersection point at the Y-axis, which gives the flat-band potential of the sample [33]. Figure 8 shows the Mott–Schottky plot of ZFO-500. The

Engineering of oriented carbon nanotubes in composite materials

• Razieh Beigmoradi,
• Abdolreza Samimi and
• Davod Mohebbi-Kalhori

Beilstein J. Nanotechnol. 2018, 9, 415–435, doi:10.3762/bjnano.9.41

• polymer matrix by stretching. They reported that a high degree of alignment was achieved and the composite dielectric properties changed upon CNT alignment [36]. Although this method is relatively simple, and some polymers such as polyethylene can be stretched more than 30 times without failure, its

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

• quantum dot surface. Dynamic experiments performed in alternating electric fields proved that by adding a small amount of CdSe/ZnS quantum dots in thermotropic nematic liquid crystal with positive dielectric anisotropy, we obtain a decrease of the relaxation time. When an external electric field higher

• -based device parameters. Theoretical Background When a nematic liquid crystal with positive dielectric anisotropy is exposed to an electric field, and if the intensity of the field is higher than the Fréedericksz transition threshold, the molecular director changes its orientation, trying to align in

• 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

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

• electro-optic and dielectric spectroscopy. The materials possess a self-assembling behaviour on the nanoscale level as they form polar smectic liquid crystalline mesophases, namely the orthogonal paraelectric SmA* and the tilted ferroelectric SmC* phases, in a broad temperature range down to room

• promoting opposite handedness, as described in [49]. The values of the helical pitch length considerably decrease with the decrease of both alkyl chain lengths while comparing to the results obtained on similar compounds [20][37][40]. Dielectric spectroscopy For the two selected materials, illustrative

• 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

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

• incident angle into the dielectric layers by using Snell's law. Parallelization of the surfaces is achieved by measuring the interference signal in the four corners and at the center of the illuminated area (see Figure 2b): From the relative phase shift of the respective signals (see Figure 2c), the tilt

• 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

Review: Electrostatically actuated nanobeam-based nanoelectromechanical switches – materials solutions and operational conditions

• Liga Jasulaneca,
• Jelena Kosmaca,
• Raimonds Meija,
• Jana Andzane and
• Donats Erts

Beilstein J. Nanotechnol. 2018, 9, 271–300, doi:10.3762/bjnano.9.29

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

• -cyano-4’-pentylbiphenyl (5CB) liquid crystal (LC). Theoretical Background When a liquid crystal with positive dielectric anisotropy is exposed to an external electric field higher than the critical Fréedericksz transition threshold, its molecules have a tendency to orient their director parallel to the

• 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

• elastic molecular forces making the molecules move faster to their original position. Other dynamic measurements performed on similar systems [25][26] confirm this faster response. Other publications [27][28][29][30] show the influence of the addition of nanotubes on the dielectric properties of the

Al₂O₃/TiO₂ inverse opals from electrosprayed self-assembled templates

• Arnau Coll,
• Sandra Bermejo,
• David Hernández and
• Luís Castañer

Beilstein J. Nanotechnol. 2018, 9, 216–223, doi:10.3762/bjnano.9.23

• opals is challenging, requiring large size, three-dimensional ordered layers of high dielectric constant ratio. In this article, alumina/TiO2–air inverse opals with a 98.2% reflectivity peak at 798 nm having an area of 2 cm2 and a thickness of 17 µm are achieved using a sacrificial self-assembled

Dielectric properties of a bisimidazolium salt with dodecyl sulfate anion doped with carbon nanotubes

• Doina Manaila Maximean,
• Viorel Cîrcu and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 164–174, doi:10.3762/bjnano.9.19

• characterized by 1H NMR, 13C NMR and IR spectroscopy. Its liquid crystalline properties were analyzed by polarizing optical microscopy (POM), differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD) studies. The dielectric spectra of the ILC doped with different concentrations of carbon

• nanotubes (CNT) were recorded over a wide frequency and temperature range of 10−1 to 107 Hz and 293–338 K, respectively. The values of the activation energy were found in the range of 0.46–0.61 eV; the characteristic time was obtained by fitting the spectra of the dielectric loss with the Havriliak–Negami

• functions. As a result of doping the ILC with CNT, the electric conductivity increases significantly. Ionic conductivity is dominant and it was indirectly observed through the electrode polarization (EP) effect. The very high dielectric permittivity values and the decrease of the electric conductivity at

Electrical properties of a liquid crystal dispersed in an electrospun cellulose acetate network

• Doina Manaila Maximean,
• Octavian Danila,
• Pedro L. Almeida and
• Constantin Paul Ganea

Beilstein J. Nanotechnol. 2018, 9, 155–163, doi:10.3762/bjnano.9.18

• techniques, such as polarized optical microscopy, dielectric spectroscopy and impedance measurements. Dielectric constant and electric energy loss were studied as a function of frequency and temperature. The activation energy was evaluated and the relaxation time was obtained by fitting the spectra of the

• dielectric loss with the Havriliak–Negami functions. To determine the electrical characteristics of the studied samples, impedance measurements results were treated using the Cole–Cole diagram and the three-element equivalent model. Keywords: cellulose nanocomposite; dielectric spectroscopy; impedance

• investigations of the electrical properties of an electrospun CA network with dispersed liquid crystals. Dielectric spectroscopy (DS) was performed over wide ranges of frequency and temperature to determine physical properties such as activation energy and characteristic time. The experimental results of DS were

Atomic layer deposition and properties of ZrO₂/Fe₂O₃ thin films

• Kristjan Kalam,
• Helina Seemen,
• Peeter Ritslaid,
• Mihkel Rähn,
• Aile Tamm,
• Kaupo Kukli,
• Aarne Kasikov,
• Joosep Link,
• Raivo Stern,
• Salvador Dueñas,
• Helena Castán and
• Héctor García

Beilstein J. Nanotechnol. 2018, 9, 119–128, doi:10.3762/bjnano.9.14

• with a Zr/Fe atomic ratio of 2.0. Keywords: atomic layer deposition; metal oxides; thin films; Introduction Doped ZrO2 has been a subject of interest because of several potential applications, for example, in microelectronics as a memory material [1]. Also, doping a dielectric film with a magnetic