Atomic defect classification of the H–Si(100) surface through multi-mode scanning probe microscopy

• Jeremiah Croshaw,
• Thomas Dienel,
• Taleana Huff and
• Robert Wolkow

Beilstein J. Nanotechnol. 2020, 11, 1346–1360, doi:10.3762/bjnano.11.119

• -terminated tips In Figure 3, we compare AFM line profiles taken across the defect of interest (blue) and a corresponding defect-free region (grey) with a simple theoretical structure optimized by molecular dynamics calculations (see Methods for parameters). A preliminary comparison of Figure 3 with the

Structural and electronic properties of SnO₂ doped with non-metal elements

• Jianyuan Yu,
• Yingeng Wang,
• Yan Huang,
• Xiuwen Wang,
• Jing Guo,
• Jingkai Yang and
• Hongli Zhao

Beilstein J. Nanotechnol. 2020, 11, 1321–1328, doi:10.3762/bjnano.11.116

• SnO2 doped with non-metal elements (F, S, C, B, and N) were studied using first-principles calculations. The theoretical results show that doping of non-metal elements cannot change the structure of SnO2 but result in a slight expansion of the lattice volume. The most obvious finding from the analysis

• reflectivity in the infrared region, and the reflectance of the crystals doped with N, C, S, and B decreased sequentially. Based on this theoretical calculations, F-doped SnO2 is found to be the best photoelectric material for preparing low-emissivity coatings. Keywords: density functional theory (DFT); doped

• . When the concentration of the precursor solution was adjusted to 0.15 M and the substrate temperature was 773 K, a film with a resistivity of 1.2 × 10−4 Ω·cm was obtained [10]. Theoretical calculations, based on first principles, show that the doping of N into the SnO2 crystal structure can introduce

Nonadiabatic superconductivity in a Li-intercalated hexagonal boron nitride bilayer

• Kamila A. Szewczyk,
• Izabela A. Domagalska,
• Artur P. Durajski and
• Radosław Szczęśniak

Beilstein J. Nanotechnol. 2020, 11, 1178–1189, doi:10.3762/bjnano.11.102

• in Li-hBN is characterized by much lower values of the critical temperature (TLOVCC ∈ {19.1, 15.5, 11.8} K, for μ* ∈ {0.1, 0.14, 0.2}, respectively) than would result from calculations not taking this effect into account (TMEC∈ {31.9, 26.9, 21} K). From the technological point of view, the low value

• of TC limits the possible applications of Li-hBN. The calculations were carried out under the classic Migdal–Eliashberg formalism (ME) and the Eliashberg theory with lowest-order vertex corrections (LOVC). We show that the vertex corrections of higher order (λ3) lower the value of TLOVCC by a few

• ] and quantum information technology [44][45]. Currently, the most promising research seems to be the properties of the superconducting state in Li-intercalated hexagonal boron nitride bilayer (Li-hBN) compounds. Based on DFT calculations, it has been shown that the critical temperature (TC) of the

Scanning tunneling microscopy and spectroscopy of rubrene on clean and graphene-covered metal surfaces

• Karl Rothe,
• Alexander Mehler,
• Nicolas Néel and
• Jörg Kröger

Beilstein J. Nanotechnol. 2020, 11, 1157–1167, doi:10.3762/bjnano.11.100

• calculations [42] were performed for the HOMO alone. However, both vibronic excitations mainly involve tetracene stretching vibrations and both the HOMO and the LUMO are close to the tetracene backbone [43][44]. Therefore, vibronic progression induced by one of these vibrational modes is likely to occur in the

Straightforward synthesis of gold nanoparticles by adding water to an engineered small dendrimer

• Sébastien Gottis,
• Régis Laurent,
• Vincent Collière and
• Anne-Marie Caminade

Beilstein J. Nanotechnol. 2020, 11, 1110–1118, doi:10.3762/bjnano.11.95

• chemical signal. In addition, it has been shown that the 2JPP coupling constant values decrease when the electron-withdrawing power of the substituents decreases [55]. The density functional theory (DFT) calculations on free and Au-complexed P=N–P=S linkages have shown that a charge is transferred from the

Monolayers of MoS₂ on Ag(111) as decoupling layers for organic molecules: resolution of electronic and vibronic states of TCNQ

• Asieh Yousofnejad,
• Gaël Reecht,
• Nils Krane,
• Christian Lotze and
• Katharina J. Franke

Beilstein J. Nanotechnol. 2020, 11, 1062–1071, doi:10.3762/bjnano.11.91

• unoccupied molecular orbital (LUMO) of tetracyanoquinodimethane (TCNQ) molecules is significantly narrower than on the bare substrate and that it is accompanied by a characteristic satellite structure. Employing simple calculations within the Franck–Condon model, we reveal their vibronic origin and identify

• been found in calculations. It has been interpreted as a hybrid metal–MoS2 or an interface state [38]. The conduction band minimum, which is expected to lie at the point for quasi free-standing as well as metal-supported single-layer MoS2 [29][42][43][44], is hardly visible in the tunneling spectra

• , we corroborate this assignment by simulating constant-height dI/dV maps of a free, flat-lying molecule. We first calculated the gas-phase electronic structure using density functional theory (DFT) calculations with the B3PW91 functional and the 6-31g(d,p) basis set as implemented in the Gaussian 09

Excitonic and electronic transitions in Me–Sb₂Se₃ structures

• Nicolae N. Syrbu,
• Victor V. Zalamai,
• Ivan G. Stamov and
• Stepan I. Beril

Beilstein J. Nanotechnol. 2020, 11, 1045–1053, doi:10.3762/bjnano.11.89

• . Several studies have shown that the bandgap is established due to allowed transitions that happen within 1.0 and 1.9 eV [6][8][10], whereas other studies show that the bandgap is determined by forbidden transitions [21][22][23]. In addition, the energy band structure and the theoretical calculations in

• the reflection spectra for both Е||с and Е⟂с polarization cases at 300 K. The calculations showed that for the polarization Е||с the background dielectric constant (εb) is equal to 7.5, the energy of the transversal exciton (ωТ) is 1.192 eV, the longitudinal-transversal splitting (ωLT) is 15 meV, the

• damping factor (γ) is 110 and the translational mass of the exciton (M) is 3.5m0 (Table 2). For the excitonic series С the following parameters were calculated: ωТ = 1.310 eV, ωLT = 17 meV, γ = 150 and M = 3.9m0. For the E⟂c polarization case the calculations of the reflection spectra profiles gave the

A new photodetector structure based on graphene nanomeshes: an ab initio study

• Babak Sakkaki,
• Hassan Rasooli Saghai,
• Ghafar Darvish and
• Mehdi Khatir

Beilstein J. Nanotechnol. 2020, 11, 1036–1044, doi:10.3762/bjnano.11.88

• Abstract Recent experiments suggest graphene-based materials as candidates in future electronic and optoelectronic devices. In this paper, we propose to investigate new photodetectors based on graphene nanomeshes (GNMs). Density functional theory (DFT) calculations are performed to gain insight into

• makes it suitable for optical devices. Keywords: absorption spectra; DFT calculations; graphene nanomesh; graphene nanoribbon; photodetectors; Introduction Graphene monolayers with honeycomb crystal structure have unique electrical and optical properties and have received a lot of attention recently

• ]. In this paper, for the first time, we study a new GNM-based photodetector using computational modeling. In order to do a complete device simulation, we initially perform ab initio DFT calculations to investigate the electronic and optical properties of the several materials used in devices channels

Effect of magnetic field, heat generation and absorption on nanofluid flow over a nonlinear stretching sheet

• Santoshi Misra and
• Govardhan Kamatam

Beilstein J. Nanotechnol. 2020, 11, 976–990, doi:10.3762/bjnano.11.82

• prime (´) denotes differentiation with respect to η, and the physical parameters involved in the equations are defined as follows: The abbreviations used for the calculations are summarized in Table 1. Solving a system of first-order differential equations The nonlinear and coupled partial differential

Three-dimensional solvation structure of ethanol on carbonate minerals

• Hagen Söngen,
• Ygor Morais Jaques,
• Peter Spijker,
• Christoph Marutschke,
• Stefanie Klassen,
• Ilka Hermes,
• Ralf Bechstein,
• Lidija Zivanovic,
• John Tracey,
• Adam S. Foster and
• Angelika Kühnle

Beilstein J. Nanotechnol. 2020, 11, 891–898, doi:10.3762/bjnano.11.74

• isolated ethanol molecule on calcite obtained with DFT calculations [13]. Consequently, the hydrocarbon chains of the ethanol molecules point away from the surface. This results in one ethanol molecule per CaCO3 at the calcite (10.4) surface. The ordered first layer of ethanol molecules above the calcite

• distance is in good agreement with the above-cited previous calculations of ethanol interfaces. Moreover, observing no order in the upper layers fits well to the MD simulations from previous theoretical studies, which do not indicate significant lateral order in the layers above the first layer for the

Simulations of the 2D self-assembly of tripod-shaped building blocks

• Łukasz Baran,
• Wojciech Rżysko and
• Edyta Słyk

Beilstein J. Nanotechnol. 2020, 11, 884–890, doi:10.3762/bjnano.11.73

• structures, which are not reproducible with off-lattice simulations. Acknowledgements Calculations were carried out at the Academic Computer Centre in Gdansk. a–d) Schematic representation of the models used in this work. Silver and red circles correspond to the components of the backbone and “phantom

A Josephson junction based on a highly disordered superconductor/low-resistivity normal metal bilayer

• Pavel M. Marychev and
• Denis Yu. Vodolazov

Beilstein J. Nanotechnol. 2020, 11, 858–865, doi:10.3762/bjnano.11.71

• of a single S layer at zero temperature). Our calculations show, that the proper choice of the thickness of the N layer leads both to nonhysteretic current–voltage characteristics even at low temperatures and a relatively large product IcRn. Keywords: normal metal–superconductor bilayer; Josephson

• found from the self-consistings solution of Equation 1–Equation 3 and Equation 5. In numerical calculations we use dimensionless units. The magnitude of the order parameter is normalized by kBTc0 = Δ(0)/1.76, lengths are in units of ≈ 1.33ξ(0), where is the superconducting coherence length at T = 0

• , and the current is in units of the depairing current Idep of the superconductor at T = 0. To calculate the CPR we numerically solve Equation 1–Equation 3 and Equation 5 by using an iteration procedure with fixed δϕ. When self-consistency is achieved (we stop the calculations when the maximal relative

Agglomerates of nanoparticles

• Dieter Vollath

Beilstein J. Nanotechnol. 2020, 11, 854–857, doi:10.3762/bjnano.11.70

• approximation. Taking into account the boundary conditions, the parameters for the Weibull distribution function were determined by an iteration process using nested intervals. The calculations were performed for 102, 103, and 104 particles. Depending on the starting values, the resulting distribution function

• kinds of the probability distribution differ in the sign of the enthalpy of interaction. Table 1 displays the detailed results of the calculation for different sizes of the ensemble of particles. The calculations were performed for three different numbers of particles in the ensemble. The exact number

• maximum of the distribution function is either at the state of non-agglomerated particles or at the entropy and size of the largest particle agglomerates. The calculations show that, depending on the number of particles within the ensemble, the size of the largest agglomerate within an ensemble follows a

Adsorption behavior of tin phthalocyanine onto the (110) face of rutile TiO₂

• Lukasz Bodek,
• Mads Engelund,
• Aleksandra Cebrat and
• Bartosz Such

Beilstein J. Nanotechnol. 2020, 11, 821–828, doi:10.3762/bjnano.11.67

• [6], CuPc [7][8][9][10], ZnPc [11], FePc [12] and H2Pc [13]), while their nonplanar counterparts such as SnPc have been rarely probed [14]. Spectroscopy studies or density functional theory (DFT) calculations of molecular species adsorbed onto titanium dioxide can be an arduous task, especially for

• Kα) combined with a Scienta EAC2200 Nanosam 570 analyzer. Ti 2p peaks were used for global calibration of the XPS spectra. A Shirley function was used for background correction during XPS data analysis. Calculations were performed by employing density-functional theory (DFT) using the SIESTA code [15

• assume that the shape asymmetry of SnPc may also appear as a result of the presence of the surrounding molecules, or it can arise from the corrugated nature of the rutile (110) surface including its defects. To confirm the identification of Sn-up and Sn-down geometries, we performed DFT calculations. A

A set of empirical equations describing the observed colours of metal–anodic aluminium oxide–Al nanostructures

• Cristina V. Manzano,
• Jakob J. Schwiedrzik,
• Gerhard Bürki,
• Laszlo Pethö,
• Johann Michler and
• Laetitia Philippe

Beilstein J. Nanotechnol. 2020, 11, 798–806, doi:10.3762/bjnano.11.64

• colour model including luminance (Y) and chromaticity (xy) using the CIE 1931 colour space [12], were obtained from the UV–vis reflectance measurements of the nanostructures according to the detailed description in [23]. For these calculations, only the wavelength range of 400–700 nm was considered. (a

Light–matter interactions in two-dimensional layered WSe₂ for gauging evolution of phonon dynamics

• Avra S. Bandyopadhyay,
• Chandan Biswas and
• Anupama B. Kaul

Beilstein J. Nanotechnol. 2020, 11, 782–797, doi:10.3762/bjnano.11.63

• . The Raman band for Si at 520.7 cm−1 was used as a reference to calibrate the spectrometer. The laser spot size and spatial resolution were calculated to be ≈2.6 µm and 1.3 µm respectively and the supporting calculations are outlined in Section 1 of the Supporting Information File 1. The WSe2

Nickel nanoparticles supported on a covalent triazine framework as electrocatalyst for oxygen evolution reaction and oxygen reduction reactions

• Secil Öztürk,
• Yu-Xuan Xiao,
• Dennis Dietrich,
• Beatriz Giesen,
• Juri Barthel,
• Jie Ying,
• Xiao-Yu Yang and
• Christoph Janiak

Beilstein J. Nanotechnol. 2020, 11, 770–781, doi:10.3762/bjnano.11.62

• calculations based on N2 at 77 K on carbon with slit pores. Thermogravimetric analysis (TGA) was done with a Netzsch TG 209 F3 Tarsus device equipped with an Al crucible applying a heating rate of 10 K/min under inert atmosphere. Elemental analyses (CHN) were performed with a Perkin Elmer 2400 apparatus. Flame

Hexagonal boron nitride: a review of the emerging material platform for single-photon sources and the spin–photon interface

• Stefania Castelletto,
• Faraz A. Inam,
• Shin-ichiro Sato and
• Alberto Boretti

Beilstein J. Nanotechnol. 2020, 11, 740–769, doi:10.3762/bjnano.11.61

• indirect bandgaps. Bandgap energy values largely varying from 3.6 eV to 7.1 eV have been reported in the literature [84][85][86]. Theoretical calculations for the h-BN band structure also show significant differences in the eV values. Some density functional theory (DFT) in the local-density-approximation

• (LDA) computations suggests a lower indirect gap around 4 eV. Calculations with other methods suggest a higher value of about 5.95 eV [87]. In experiments, the variability of the properties is even larger. For example, stacking influences the electronic properties of h-BN [86]. The indirect bandgap is

• at 685 nm and 767 nm showed two resonant excitation wavelengths of 494 nm and 528 nm. DFT calculations suggest that the wide range of PL emission from UV to NIR is attributed to different types of defect structures. However, the single-photon emission from UV and NIR peaks has not been demonstrated

Effect of substitutional defects on resonant tunneling diodes based on armchair graphene and boron nitride nanoribbons lateral heterojunctions

• Majid Sanaeepur

Beilstein J. Nanotechnol. 2020, 11, 688–694, doi:10.3762/bjnano.11.56

• performance of RTDs based on Gr/hBN heterojunctions [26][27][28][29][30][31][32][33]. Formation energy calculations have revealed that point defects occur preferentially at the interfaces of graphene and hBN domains rather than in the middle of these domains, and that substitutional defects are dominant [30

• considers the interfaces of the Gr/hBN regions are parallel to the transport direction so that there are no bandgap variations in the transport direction. Since the electron transport is in zigzag direction, spin-polarized transport calculations are utilized. Instead, in the study presented here, the

• electron transport is in armchair direction, which is not spin-polarized. Therefore, nonequilibrium Green’s functions with tight-binding Hamiltonians (without considering spin degree of freedom) are utilized for electronic transport calculations. Furthermore, in the proposed RTD there are four GNR/BNNR

Evolution of Ag nanostructures created from thin films: UV–vis absorption and its theoretical predictions

• Robert Kozioł,
• Marcin Łapiński,
• Paweł Syty,
• Damian Koszelow,
• Wojciech Sadowski,
• Józef E. Sienkiewicz and
• Barbara Kościelska

Beilstein J. Nanotechnol. 2020, 11, 494–507, doi:10.3762/bjnano.11.40

• appears around 350 nm, which probably corresponds to the quadrupole resonance. For calculations leading to a better illustration of absorption, scattering and overall absorption of light in Ag nanoparticles, the Mie theory is employed. Absorbance and the distribution of the electromagnetic field around

• the nanostructures are calculated by finite-difference time-domain (FDTD) simulations. For calculations a novel approach based on modelling the whole sample with a realistic shape of the nanoparticles, instead of full spheres, was used. This led to a very good agreement with the experiment. Keywords

• corroborated by FDTD calculations showing the distribution of the electromagnetic field around the Ag nanoparticles, as well as the calculated absorbance. Analytical solutions of the electromagnetic field distribution in plasmonic platforms are known for very simple nanoparticles with spherical or cylindrical

Interfacial charge transfer processes in 2D and 3D semiconducting hybrid perovskites: azobenzene as photoswitchable ligand

• Nicole Fillafer,
• Tobias Seewald,
• Lukas Schmidt-Mende and
• Sebastian Polarz

Beilstein J. Nanotechnol. 2020, 11, 466–479, doi:10.3762/bjnano.11.38

• system of a semiconductor. Torres et al. reported calculations of a charge-transfer complex of para-methyl red/TiO2 in the gas phase where the isomerisation is fully quenched. The photoexcited state is oxidized immediately through a charge transfer from the azobenzene to TiO2 and no conformational change

• characterized with NMR (1H, 13C) and electro-spray ionisation mass spectroscopy (ESIMS) the results of which can be found in Supporting Information File 1 (Figures S1–S4). Several methods were used to investigate the properties of the ligands in the absence of the perovskite as reference. DFT calculations were

• performed to obtain information about the geometry of the molecules (Supporting Information File 1, Figure S5) the results of which are summarized in Table 1. According to these calculations, the distance between the π-conjugated part and the ammonium group ranges from 2.5 up to 17.6 Å. The position of the

Current measurements in the intermittent-contact mode of atomic force microscopy using the Fourier method: a feasibility analysis

• Berkin Uluutku and
• Santiago D. Solares

Beilstein J. Nanotechnol. 2020, 11, 453–465, doi:10.3762/bjnano.11.37

• the equation. The results are in agreement with each other. Both the power spectrum and the predicted peaks are normalized. The figure also shows that the first harmonic (70 kHz), is the strongest peak in the spectrum, although the decay of the higher harmonic values is not rapid. Our calculations

• peaks are not visible in the spectrum with linear vertical axis. However, they are ever present and can be seen in a logarithmic plot (b), where the second harmonic is almost 1000 times smaller than the first harmonic. Power spectrum of the current from analytical calculations and numerical cantilever

• results fall almost on top of each other and are visually indistinguishable. The average difference between the single- and two-cosine calculations for the first 50 harmonics is 0.18%. Both calculations are normalised. a) Power spectrum of the tip trajectory for the realistic simulation with the Hertzian

Atomic-resolution imaging of rutile TiO₂(110)-(1 × 2) reconstructed surface by non-contact atomic force microscopy

• Daiki Katsube,
• Shoki Ojima,
• Eiichi Inami and
• Masayuki Abe

Beilstein J. Nanotechnol. 2020, 11, 443–449, doi:10.3762/bjnano.11.35

• the symmetric Ti2O3 model based on DFT calculations [24]. These two structural models have been widely accepted. Mochizuki et al. reported total reflection high-energy positron diffraction results for the (1 × 2) surface, which supported the asymmetric Ti2O3 model [25]. In contrast, our previous study

Electrochemically derived functionalized graphene for bulk production of hydrogen peroxide

• Munaiah Yeddala,
• Pallavi Thakur,
• Anugraha A and
• Tharangattu N. Narayanan

Beilstein J. Nanotechnol. 2020, 11, 432–442, doi:10.3762/bjnano.11.34

• at 0.358 V (vs RHE, from Figure 4a). Supporting Information The supporting information includes additional TEM images, a detailed description of the quantification of H2O2, deconvoluted XPS spectra of O 1s, AFM analysis, FTIR spectra, ECSA calculations, and RRDE analysis for all EEG samples

DFT calculations of the structure and stability of copper clusters on MoS₂

• Cara-Lena Nies and
• Michael Nolan

Beilstein J. Nanotechnol. 2020, 11, 391–406, doi:10.3762/bjnano.11.30

• onto the monolayer, and calculations using different van der Waals (vdW) corrections show that the adsorption is driven by vdW interactions. The metal chains prefer to adsorb in the armchair conformation and cause a break of the hexagonal symmetry of graphene. Despite slightly contradictory results

• (DOS) analysis shows the emergence of mid-gap states, indicating that the system is changing from semiconducting to metallic as Cu atoms are adsorbed, making it suitable for application as a Cu diffusion barrier. Computational Methods All calculations, for bulk MoS2 and the 2D monolayer, were carried

• augmented wave potential (PAW) [36]. In the geometry relaxation calculations, all forces acting on the atoms were converged to within 0.02 eV/Å. The bulk structure of MoS2 used in this study was chosen from the “Materials Project” database [37]. The bulk material contains two layers of MoS2. The geometry