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Beilstein Journal of Nanotechnology

Vilgelmina Stepkova, Jiří Hlinka
The phase-field simulations of ferroelectric Bloch domain walls in BaTiO3 -SrTiO3 crystalline superlattices performed in this study suggest that a paraelectric layer with a thickness comparable to the thickness of the domain wall itself can act as an efficient pinning layer. At the same time, such a layer facilitates the possibility to switch domain wall helicity by an external electric field or even to completely change the characteristic structure of a ferroelectric Bloch wall passing through it. Thus, ferroelectric Bloch domain walls are shown to be ideal nanoscale objects with switchable properties...
2018: Beilstein Journal of Nanotechnology
Andreea Costas, Camelia Florica, Elena Matei, Maria Eugenia Toimil-Molares, Ionel Stavarache, Andrei Kuncser, Victor Kuncser, Ionut Enculescu
Arrays of magnetic Ni-Cu alloy nanowires with different compositions were prepared by a template-replication technique using electrochemical deposition into polycarbonate nanoporous membranes. Photolithography was employed for obtaining interdigitated metallic electrode systems of Ti/Au onto SiO2 /Si substrates and subsequent electron beam lithography was used for contacting single nanowires in order to investigate their galvano-magnetic properties. The results of the magnetoresistance measurements made on single Ni-Cu alloy nanowires of different compositions have been reported and discussed in detail...
2018: Beilstein Journal of Nanotechnology
Roberto Nisticò
Highly ordered porous coatings find applications in many fields, such as nanotechnology, microfluidics and nanofluidics, membrane separation, and sensing. In recent years, there has been great interest regarding the synthesis of isoporous and well-ordered (in)organic coatings for the production of highly selective functional membranes. Among the different strategies that have been proposed to date for preparing these porous thin coatings, one simple route involves the use of self-assembled amphiphilic block copolymers either as the porogen (acting as sacrificial templating agents for the production of inorganic architectures) or as a source of the porogen (by self-assembly for the production of polymeric substrates)...
2018: Beilstein Journal of Nanotechnology
Enrico Gnecco, Susan Perkin, Andrea Vanossi, Ernst Meyer
No abstract text is available yet for this article.
2018: Beilstein Journal of Nanotechnology
Ziga Lokar, Benjamin Lipovsek, Marko Topic, Janez Krc
A variety of light management structures have been introduced in solar cells to improve light harvesting and further boost their conversion efficiency. Reliable and accurate simulation tools are required to design and optimize the individual structures and complete devices. In the first part of this paper, we analyze the performance of rigorous coupled-wave analysis (RCWA) for accurate three-dimensional optical simulation of solar cells, in particular heterojunction silicon (HJ Si) solar cells. The structure of HJ Si solar cells consists of thin and thick layers, and additionally, micro- and nano-textures are also introduced to further exploit the potential of light trapping...
2018: Beilstein Journal of Nanotechnology
Valerio F Gili, Lavinia Ghirardini, Davide Rocco, Giuseppe Marino, Ivan Favero, Iännis Roland, Giovanni Pellegrini, Lamberto Duò, Marco Finazzi, Luca Carletti, Andrea Locatelli, Aristide Lemaître, Dragomir Neshev, Costantino De Angelis, Giuseppe Leo, Michele Celebrano
Background: Dielectric nanoantennas have recently emerged as an alternative solution to plasmonics for nonlinear light manipulation at the nanoscale, thanks to the magnetic and electric resonances, the strong nonlinearities, and the low ohmic losses characterizing high refractive-index materials in the visible/near-infrared (NIR) region of the spectrum. In this frame, AlGaAs nanoantennas demonstrated to be extremely efficient sources of second harmonic radiation. In particular, the nonlinear polarization of an optical system pumped at the anapole mode can be potentially boosted, due to both the strong dip in the scattering spectrum and the near-field enhancement, which are characteristic of this mode...
2018: Beilstein Journal of Nanotechnology
Shijie Li, Wei Jiang, Shiwei Hu, Yu Liu, Yanping Liu, Kaibing Xu, Jianshe Liu
Developing highly active and durable visible-light-driven photocatalysts for the degradation of toxic pollutants is of vital significance. Herein, Ag2 CO3 nanoparticles were in situ formed on Bi2 MoO6 microflowers to produce Ag2 CO3 /Bi2 MoO6 heterostructures via a facile procedure. The morphologies, phases, chemical compositions, and optical properties of Ag2 CO3 /Bi2 MoO6 were examined by multiple characterization techniques. The Ag2 CO3 /Bi2 MoO6 heterostructures exhibited substantially improved performance in the removal of industrial dyes (rhodamine B (RhB), methyl orange (MO), and methyl blue (MB)), and the antibiotic tetracycline hydrochloride (TC), compared with bare Bi2 MoO6 and Ag2 CO3 under visible-light irradiation...
2018: Beilstein Journal of Nanotechnology
Lukáš Ondič, Marian Varga, Ivan Pelant, Alexander Kromka, Karel Hruška, Robert G Elliman
We have fabricated two-dimensional photonic crystals (PhCs) on the surface of Si nanocrystal-rich SiO2 layers with the goal to maximize the photoluminescence extraction efficiency in the normal direction. The fabricated periodic structures consist of columns ordered into square and hexagonal pattern with lattice constants computed such that the red photoluminescence of Si nanocrystals (SiNCs) could couple to leaky modes of the PhCs and could be efficiently extracted to surrounding air. Samples having different lattice constants and heights of columns were investigated in order to find the configuration with the best performance...
2018: Beilstein Journal of Nanotechnology
Ana S Viana, Romana Santos
Background: Unlike the thin homogeneous films that are typical for adhesives produced by humans, biological adhesives present complex hierarchical micro- and nanostructures. Most studies on marine adhesives have focused on permanent adhesives, whereas the nanostructures of nonpermanent, temporary or reversible adhesives have only been examined in some organisms such as marine flatworms, barnacle cyprids, freshwater cnidaria and echinoderms such as sea cucumbers and sea stars. In this study, the first nanoscale characterization of sea urchin temporary adhesives was performed using atomic force microscopy (AFM)...
2018: Beilstein Journal of Nanotechnology
Dieter Vollath, Franz Dieter Fischer, David Holec
The surface energy, particularly for nanoparticles, is one of the most important quantities in understanding the thermodynamics of particles. Therefore, it is astonishing that there is still great uncertainty about its value. The uncertainty increases if one questions its dependence on particle size. Different approaches, such as classical thermodynamics calculations, molecular dynamics simulations, and ab initio calculations, exist to predict this quantity. Generally, considerations based on classical thermodynamics lead to the prediction of decreasing values of the surface energy with decreasing particle size...
2018: Beilstein Journal of Nanotechnology
Dirk König, Daniel Hiller, Noël Wilck, Birger Berghoff, Merlin Müller, Sangeeta Thakur, Giovanni Di Santo, Luca Petaccia, Joachim Mayer, Sean Smith, Joachim Knoch
Impurity doping of ultrasmall nanoscale (usn) silicon (Si) currently used in ultralarge scale integration (ULSI) faces serious miniaturization challenges below the 14 nm technology node such as dopant out-diffusion and inactivation by clustering in Si-based field-effect transistors (FETs). Moreover, self-purification and massively increased ionization energy cause doping to fail for Si nano-crystals (NCs) showing quantum confinement. To introduce electron- (n-) or hole- (p-) type conductivity, usn-Si may not require doping, but an energy shift of electronic states with respect to the vacuum energy between different regions of usn-Si...
2018: Beilstein Journal of Nanotechnology
Nan Guan, Andrey Babichev, Martin Foldyna, Dmitry Denisov, François H Julien, Maria Tchernycheva
The optimized design of a photonic platform based on a nanowire light emitting diode (LED) and a nanowire photodetector connected with a waveguide is proposed. The light coupling efficiency from the LED to the detector is optimized as a function of the geometrical parameters of the system using the finite difference time domain simulation tool Lumerical. Starting from a design reported in the literature with a coupling efficiency of only 8.7%, we propose an optimized photonic platform with efficiency reaching 65...
2018: Beilstein Journal of Nanotechnology
Nicolae Leopold, Andrei Stefancu, Krisztian Herman, István Sz Tódor, Stefania D Iancu, Vlad Moisoiu, Loredana F Leopold
Chloride-capped silver nanoparticles (Cl-AgNPs) allow for high-intensity surface-enhanced Raman scattering (SERS) spectra of cationic molecules to be obtained (even at nanomolar concentration) and may also play a key role in understanding some fundamental principles behind SERS. In this study, we describe a fast (<10 min) and simple protocol for obtaining highly SERS-active colloidal silver nanoparticles (AgNPs) with a mean diameter of 36 nm by photoconversion from AgCl precursor microparticles in the absence of any organic reducing or capping agent...
2018: Beilstein Journal of Nanotechnology
Oleksandr Stroyuk
This review covers the state-of-the-art in organo-inorganic lead-free hybrid perovskites (HPs) and applications of these exciting materials as light harvesters in photovoltaic systems. Special emphasis is placed on the influence of the spatial organization of HP materials both on the micro- and nanometer scale on the performance and stability of perovskite-based solar light converters. This review also discusses HP materials produced by isovalent lead(II) substitution with Sn2+ and other metal(II) ions, perovskite materials formed on the basis of M3+ cations (Sb3+ , Bi3+ ) as well as on combinations of M+ /M3+ ions aliovalent to 2Pb2+ (Ag+ /Bi3+ , Ag+ /Sb3+ , etc...
2018: Beilstein Journal of Nanotechnology
Deepika Jhajhria, Dinesh K Pandya, Sujeet Chaudhary
The static and dynamic magnetization response of the CoFeB/IrMn/CoFeB trilayer system with varying thickness of the antiferromagnetic (AF) IrMn layer is investigated using magnetization hysteresis ( M - H ) and ferromagnetic resonance (FMR) measurements. The study shows that the two CoFeB layers are coupled via a long-range dynamic exchange effect through the IrMn layer up to a thickness of 6 nm. It is found that with the increase in IrMn layer thickness a nearly linear enhancement of the effective magnetic damping constant occurs, which is associated with the simultaneous influence of spin pumping and interlayer exchange coupling effects...
2018: Beilstein Journal of Nanotechnology
Janning F Herrmann, Christiane Höppener
Plasmonic nanoantennas have found broad applications in the fields of photovoltaics, electroluminescence, non-linear optics and for plasmon enhanced spectroscopy and microscopy. Of particular interest are fundamental limitations beyond the dipolar approximation limit. We introduce asymmetric gold nanoparticle antennas (AuNPs) with improved optical near-field properties based on the formation of sub-nanometer size gaps, which are suitable for studying matter with high-resolution and single molecule sensitivity...
2018: Beilstein Journal of Nanotechnology
Evelyne Salançon, Bernard Tinland
Using nanopipettes with very small apertures (<10 nm) is a good way to improve the spatial resolution in scanning conductance experiments, to monitor single-molecule delivery and to strain long molecules stretching during translocation. However, such nanopipettes can be difficult to fill. Here we describe a dynamic microdistillation technique that successfully fills all nanopipettes, whatever their shape or tip radius. Even elongated or bent nanopipettes with a small-angle tip are completely filled using this new technique...
2018: Beilstein Journal of Nanotechnology
Samuel D Escribano, Alfredo Levy Yeyati, Elsa Prada
Majorana modes emerge in non-trivial topological phases at the edges of specific materials such as proximitized semiconducting nanowires under an external magnetic field. Ideally, they are non-local states that are charge-neutral superpositions of electrons and holes. However, in nanowires of realistic length their wave functions overlap and acquire a finite charge that makes them susceptible to interactions, specifically with the image charges that arise in the electrostatic environment. Considering a realistic three-dimensional model of the dielectric surroundings, here we show that, under certain circumstances, these interactions lead to a suppression of the Majorana oscillations predicted by simpler theoretical models, and to the formation of low-energy quantum-dot states that interact with the Majorana modes...
2018: Beilstein Journal of Nanotechnology
Muhammad Imran, Nunzio Motta, Mahnaz Shafiei
Electrospun one-dimensional (1D) nanostructures are rapidly emerging as key enabling components in gas sensing due to their unique electrical, optical, magnetic, thermal, mechanical and chemical properties. 1D nanostructures have found applications in numerous areas, including healthcare, energy storage, biotechnology, environmental monitoring, and defence/security. Their enhanced specific surface area, superior mechanical properties, nanoporosity and improved surface characteristics (in particular, uniformity and stability) have made them important active materials for gas sensing applications...
2018: Beilstein Journal of Nanotechnology
Mohsen Rahmani, Chennupati Jagadish
No abstract text is available yet for this article.
2018: Beilstein Journal of Nanotechnology
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