Lead-free hybrid perovskites for photovoltaics

• Oleksandr Stroyuk

Beilstein J. Nanotechnol. 2018, 9, 2209–2235, doi:10.3762/bjnano.9.207

Recent highlights in nanoscale and mesoscale friction

• Andrea Vanossi,
• Dirk Dietzel,
• Andre Schirmeisen,
• Ernst Meyer,
• Rémy Pawlak,
• Thilo Glatzel,
• Marcin Kisiel,
• Shigeki Kawai and
• Nicola Manini

Beilstein J. Nanotechnol. 2018, 9, 1995–2014, doi:10.3762/bjnano.9.190

• surface-force balance and an impressive evidence of layering effects on friction was demonstrated [114]. RTILs are being also investigated as additives in liquid lubrication [115]. Modeling has investigated the role of the molecular shape of the ions [116][117] and the layer-by-layer squeeze-out

• standard phenomenological theories of frictional interfaces, which are essential for modeling macroscopic frictional dynamics, are not yet fully linked to the atomistic processes and interfacial geometries at the atomistic scales. Bridging over the widely separated time and length scales by establishing

• quantitative connections between small-scale processes and macroscopically observed phenomena is a major challenge of current tribology in particular, and, more in general, of materials modeling [196][197][198][199][200]. A first line of ongoing research efforts focuses on enriching the descriptions of

The role of the Ge mole fraction in improving the performance of a nanoscale junctionless tunneling FET: concept and scaling capability

• Hichem Ferhati,
• Fayçal Djeffal and
• Toufik Bentrcia

Beilstein J. Nanotechnol. 2018, 9, 1856–1862, doi:10.3762/bjnano.9.177

• Figure 1, L is the channel length, tch refers to the channel thickness, Nd is the doping concentration of the channel, and Ls and Ld denote the extension lengths of source and drain, respectively. The accurate modeling of the nanoscale DG-HJ-JL TFET requires taking into account quantum-confinement

• effects, which lead to some modeling bottlenecks associated with the models of the carrier density gradient. Furthermore, since the investigated transistor is considered as a quantum mechanical device, complicated systems of equations resulted from the necessity of considering the band-to-band quantum

• tunneling effects. These nonlinear equations impose many mathematical difficulties, which complicate the analytical modeling of the nanoscale device performance. Numerical approaches are used to deal with the above outlined problems. The ATLAS 2D device simulator using the S-PISCES module has emerged

Increasing the performance of a superconducting spin valve using a Heusler alloy

• Andrey A. Kamashev,
• Aidar A. Validov,
• Joachim Schumann,
• Vladislav Kataev,
• Bernd Büchner,
• Yakov V. Fominov and
• Ilgiz A. Garifullin

Beilstein J. Nanotechnol. 2018, 9, 1764–1769, doi:10.3762/bjnano.9.167

• present the results of theoretical modeling. Parameters used for fitting of the theory to the experimental results [17]. Supporting Information Supporting Information File 250: Fabrication of the SSV heterostructures. Acknowledgements A. K. gratefully acknowledges the Leibniz - DAAD Fellowship. Ya. F

Josephson effect in junctions of conventional and topological superconductors

• Alex Zazunov,
• Albert Iks,
• Miguel Alvarado,
• Alfredo Levy Yeyati and
• Reinhold Egger

Beilstein J. Nanotechnol. 2018, 9, 1659–1676, doi:10.3762/bjnano.9.158

• spinful nanowire model of [2][3] for modeling the TS wire is that the angle between the local Zeeman field B and the MBS spin polarization does not have to be introduced as phenomenological parameter but instead results from the calculation [43]. It is thus interesting to study the Josephson current in S

• kept when modeling the TS wire. However, we will also hint at how one can treat the general case. For the two S leads, boundary fermion fields are contained in Nambu spinors as in Equation 6, where their bGF follows with the Nambu matrix g(ω) in Equation 6 as We again use Pauli matrices τx,y,z and

Robust topological phase in proximitized core–shell nanowires coupled to multiple superconductors

• Tudor D. Stanescu,
• Anna Sitek and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1512–1526, doi:10.3762/bjnano.9.142

• superconducting phases a more detailed modeling of the hybrid structure (possibly, at the microscopic level) is necessary. To corroborate our findings regarding the effect of a phase difference, we consider the square wire corresponding to the phase diagram shown in Figure 5 coupled to four separate

Nanoporous silicon nitride-based membranes of controlled pore size, shape and areal density: Fabrication as well as electrophoretic and molecular filtering characterization

• Axel Seidenstücker,
• Stefan Beirle,
• Fabian Enderle,
• Paul Ziemann,
• Othmar Marti and
• Alfred Plettl

Beilstein J. Nanotechnol. 2018, 9, 1390–1398, doi:10.3762/bjnano.9.131

• membranes can be explained by modeling the membrane as a parallel connection of N nanopores (experimentally: N ≈ 107) leading to a total resistance of: where Rpore is the resistance of a single nanopore. Its value was successfully approximated by neglecting the influence of surface charges on the pore wall

Electrostatically actuated encased cantilevers

• Benoit X. E. Desbiolles,
• Gabriela Furlan,
• Adam M. Schwartzberg,
• Paul D. Ashby and
• Dominik Ziegler

Beilstein J. Nanotechnol. 2018, 9, 1381–1389, doi:10.3762/bjnano.9.130

• experimentally determined amplitude can be expressed as = 101 pm V−2|Udc − UCPD|Uac. A comparison with modeled results is given in section Modeling. We demonstrate imaging capability in air using electrostatic excitation in Figure 3c. A 3D rendering of the recorded topography shows copper grains evaporated onto

• deflection is given by yexp = −1.48 pm V−2 (Udc − UCPD)2. Modeling Despite the complex geometry of our drive electrode, we demonstrate that a simple parallel plate capacitor model can accurately describe the observed static deflection and oscillation amplitudes. After geometrical modeling of the capacitance

• gradient, we compute the expected deflection and amplitudes for static, harmonic and sub-harmonic excitation and compare them to our experimental results. Geometric modeling of the capacitance gradient Figure 6 shows a schematic of the longitudinal (Figure 6a) and transverse (Figure 6b) cross section of

Disorder-induced suppression of the zero-bias conductance peak splitting in topological superconducting nanowires

• Jun-Tong Ren,
• Hai-Feng Lü,
• Sha-Sha Ke,
• Yong Guo and
• Huai-Wu Zhang

Beilstein J. Nanotechnol. 2018, 9, 1358–1369, doi:10.3762/bjnano.9.128

• symmetric lead-wire coupling strength ΓL = ΓR = 0.3 meV. The bias voltage V across the whole device will shift the chemical potential μL(μR) in the leads to ±V/2. In modeling the disorder effect on the quantum transport in mesoscopic devices, the numerical results need to be averaged over enough random

Chemistry for electron-induced nanofabrication

• Petra Swiderek,
• Hubertus Marbach and
• Cornelis W. Hagen

Beilstein J. Nanotechnol. 2018, 9, 1317–1320, doi:10.3762/bjnano.9.124

• deposits. Modeling by different types of simulations is also an important approach to gain a deeper understanding and hopefully better control over FEBID processes. The quality of a deposit depends not only on the chemical properties and processes mentioned so far but also on precursor adsorption states

Formation mechanisms of boron oxide films fabricated by large-area electron beam-induced deposition of trimethyl borate

• Aiden A. Martin and
• Philip J. Depond

Beilstein J. Nanotechnol. 2018, 9, 1282–1287, doi:10.3762/bjnano.9.120

• previous studies of TEOS. This knowledge is critical for optimization of precursor chemistry in other materials systems and for future modeling efforts. Experimental EBID experiments were performed on a silicon substrate (100, n-type, P-doped, native oxide surface, MTI Corporation) with TMB precursor

The electrical conductivity of CNT/graphene composites: a new method for accelerating transmission function calculations

• Olga E. Glukhova and
• Dmitriy S. Shmygin

Beilstein J. Nanotechnol. 2018, 9, 1254–1262, doi:10.3762/bjnano.9.117

• investigated single-layer composite films and the results of modelling. Data of investigated two-layer composite films and the results of modeling. Acknowledgements The research described in this paper was supported by the grant of the Russian Science Foundation #15-29-01025 and by the Russian Presidential

Atomistic modeling of tribological properties of Pd and Al nanoparticles on a graphene surface

• Alexei Khomenko,
• Miroslav Zakharov,
• Denis Boyko and
• Bo N. J. Persson

Beilstein J. Nanotechnol. 2018, 9, 1239–1246, doi:10.3762/bjnano.9.115

• the friction dynamics of metallic nanoparticles [14] makes it virtually impossible to construct a general and reliable analytical theory of the phenomena under consideration. Therefore, computer modeling, in particular molecular dynamics (MD), is a useful tool for the theoretical study of friction and

• , morphology and orientation [10][11][13][14][17]. For atomistic modeling the material-dependent potential energy is needed. Here we use empirical potentials where the potential energy can be represented as a function of the atomic positions. For aluminum and palladium an empirical many-body potential is

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

• case the metal particles are treated quasistatically as dipole scatterers. The analytical formula for dipole scatterers in a dielectric matrix is given by the Maxwell–Garnett (MG) approach. A large uncertainty in modeling the dielectric function of the FEBID composite stems from the unknown optical

Circular dichroism of chiral Majorana states

• Javier Osca and
• Llorenç Serra

Beilstein J. Nanotechnol. 2018, 9, 1194–1199, doi:10.3762/bjnano.9.110

• (λ) is modeling a coupled bilayer system in which quasiparticles move. The set of Hamiltonian parameters is m0, m1, ΔB, μ, α, Δp and Δm. The latter two are given in terms of the pairing interaction in the two layers, Δt and Δb, by Hybridization of the two surfaces is represented by parameters m0 and

Thermoelectric current in topological insulator nanowires with impurities

• Sigurdur I. Erlingsson,
• Jens H. Bardarson and
• Andrei Manolescu

Beilstein J. Nanotechnol. 2018, 9, 1156–1161, doi:10.3762/bjnano.9.107

• experimental reach. Modeling of impurities The anomalous current introduced above relies on non-monotonic steps in the transmission function. For ballistic nanowires the steps are sharp, but in the presence of impurities the steps will get distorted. In order to simulate transport in a realistic nanowires, we

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

• temperature changes. Characteristic temperatures determined from the slope changes of the Δ(T) plot appeared to be very good guess values for the phase transition temperatures. Keywords: non-linear optics; organic semiconductors; spectroscopic ellipsometry; theoretical modeling; thin films; Introduction The

Theoretical study of strain-dependent optical absorption in a doped self-assembled InAs/InGaAs/GaAs/AlGaAs quantum dot

• Tarek A. Ameen,
• Hesameddin Ilatikhameneh,
• Archana Tankasala,
• Yuling Hsueh,
• James Charles,
• Jim Fonseca,
• Michael Povolotskyi,
• Jun Oh Kim,
• Sanjay Krishna,
• Monica S. Allen,
• Jeffery W. Allen,
• Rajib Rahman and
• Gerhard Klimeck

Beilstein J. Nanotechnol. 2018, 9, 1075–1084, doi:10.3762/bjnano.9.99

• MOdeling tool in version 5 (“NEMO5”) [16][17][18][19][20][21][22]. Theoretical Model Atomistic strain model The Harmonic Keating strain model, introduced in [6], has the elastic energy given by where rmn is the displacement vector from atom m to atom n for the strained crystal as shown in Figure 3, while

An implementation of spin–orbit coupling for band structure calculations with Gaussian basis sets: Two-dimensional topological crystals of Sb and Bi

• Sahar Pakdel,
• Mahdi Pourfath and
• J. J. Palacios

Beilstein J. Nanotechnol. 2018, 9, 1015–1023, doi:10.3762/bjnano.9.94

• , however, are usually restricted to the description of valence electrons, implicitly by assuming a minimal basis set of spd orbitals. The SOC is included by adding the matrix elements of the operator where λ is taken as an atomic parameter [8]. Although the simplicity of TB modeling is appealing, this

Dynamics and fragmentation mechanism of (C₅H₄CH₃)Pt(CH₃)₃ on SiO₂ surfaces

• Kaliappan Muthukumar,
• Harald O. Jeschke and
• Roser Valentí

Beilstein J. Nanotechnol. 2018, 9, 711–720, doi:10.3762/bjnano.9.66

• the equations of motion. For these simulations, we have used a reduced (2 × 2 × 2) SiO2 supercell in order to reduce the computational time. For reaction modeling studies, all species (transition states (TS) and intermediates (INT)) in the proposed reaction paths given below in Scheme 1 were traced at

• , it can be speculated that a design of suitable precursors for electron beam induced deposition might be more efficient than the use of traditional ALD precursors. With our reaction modeling studies, possible pathways by which the precursor molecule can fragment on SiO2 surfaces were also explored

Facile phase transfer of gold nanorods and nanospheres stabilized with block copolymers

• Yaroslav I. Derikov,
• Georgiy A. Shandryuk,
• Raisa V. Talroze,
• Alexander A. Ezhov and
• Yaroslav V. Kudryavtsev

Beilstein J. Nanotechnol. 2018, 9, 616–627, doi:10.3762/bjnano.9.58

• , while PS blocks form coronas preventing nanorod aggregation. Modeling the extinction spectra of Au nanorods Two bands in the optical absorbance spectra (Figure 1b) of the Au nanorods are attributed to the transverse (TE) and longitudinal (TM) plasmon modes, respectively [40]. The position of the former

Lyapunov estimation for high-speed demodulation in multifrequency atomic force microscopy

• David M. Harcombe,
• Michael G. Ruppert,
• Michael R. P. Ragazzon and
• Andrew J. Fleming

Beilstein J. Nanotechnol. 2018, 9, 490–498, doi:10.3762/bjnano.9.47

• harmonic imaging with amplitude and phase on both a stiff and compliant sample. Lyapunov Filter System modeling A single-frequency cantilever deflection signal is modeled as a sine wave with carrier frequency fc, time-varying amplitude A(t) and phase (t) of the form For readability, explicit dependencies

Optimal fractal tree-like microchannel networks with slip for laminar-flow-modified Murray’s law

• Dalei Jing,
• Shiyu Song,
• Yunlu Pan and
• Xiaoming Wang

Beilstein J. Nanotechnol. 2018, 9, 482–489, doi:10.3762/bjnano.9.46

• studied. Modeling Generation of fractal tree-like microchannel networks For different applications of a fractal tree-like branched network, a typical structure similar to that shown in Figure 2 has been widely used [6][7][8][9][10][11][12][13][14][15][16][17][18]. In the present work, a similar structure

• -like branched network generated in this manner is a symmetric and self-similar network. Theoretical model In this section, the pressure-driven flow in the fractal tree-like microchannel network generated in the last section will be modeled. Before the modeling, the following assumptions are made. (1

Growth model and structure evolution of Ag layers deposited on Ge films

• Arkadiusz Ciesielski,
• Lukasz Skowronski,
• Ewa Górecka,
• Jakub Kierdaszuk and
• Tomasz Szoplik

Beilstein J. Nanotechnol. 2018, 9, 66–76, doi:10.3762/bjnano.9.9

• the grain boundary voids, thus increasing the effective density (Figure 2, right). It is also worth noting, that in the case of modeling results of XRR measurements performed 3 days after the deposition (Figure 3a,c,e,g), it was necessary to consider a separate Ge interlayer between SiO2 substrate and

• very large grains (see Figure 2c), which taken into account the increase of the surface roughness of that sample to over 4 nm, which is similar to the value extracted from the XRR model. More information about XRR modeling can be found in [32] and references therein. The wide-angle X-ray diffraction

Study of the vertically aligned in-plane switching liquid crystal mode in microscale periodic electric fields

• Artur R. Geivandov,
• Mikhail I. Barnik,
• Irina V. Kasyanova and
• Serguei P. Palto

Beilstein J. Nanotechnol. 2018, 9, 11–19, doi:10.3762/bjnano.9.2

• studied various geometries using our modeling software and report the results for E7 LC material in the next section. In the polarized-light microscopy photos of VA-IPS cells in Figure 5 thin black stripes in the middle between the electrodes are clearly seen [9]. In Figure 5a the black stripes are quite

• faint compared to the black chromium electrodes, while in Figure 5b with a larger gap between the electrodes they are around 1 μm in width. Numerical modeling of the VA-IPS mode The simulations are done using LCD TDK software developed by one of the authors (S. P. Palto). The software is based on

• used for modeling. Experimental LC cell geometry. Experimentally measured electrooptical response for (a) E7 and (b) ZLI 1957/5 LC cells with chromium electrodes: w/g = 0.5 (p = 6 μm), d ≈ 3.5 μm; the driving voltage waveform is shown in the bottom graphs. The response curves show the transmittance