Absence of free carriers in silicon nanocrystals grown from phosphorus- and boron-doped silicon-rich oxide and oxynitride

• Daniel Hiller,
• Julian López-Vidrier,
• Keita Nomoto,
• Michael Wahl,
• Wolfgang Bock,
• Tomáš Chlouba,
• František Trojánek,
• Sebastian Gutsch,
• Margit Zacharias,
• Dirk König,
• Petr Malý and
• Michael Kopnarski

Beilstein J. Nanotechnol. 2018, 9, 1501–1511, doi:10.3762/bjnano.9.141

• -atoms for samples with 0.6–0.7 atom % P. It appears more consistent with the available data that P-induced defects (e.g., from interstitial P in the Si NCs or SiOx:P-related states at the surface) cause the PL quenching, as supported by density functional theory (DFT) calculations [29][41]. In that

• also not observed before the B-concentrations exceed >1 atom %, as shown in Figure 3c, and the same argumentation holds true for B-induced defects with states in the fundamental gap of Si NCs, as determined by DFT [30]. The as-measured PL peak intensity of the SRO:B sample set (open purple circles) is

• %. This circumstance together with the absence of the spectral behaviour expected for doped NCs indicates that dopant-induced defects are the origin of PL quenching, in accordance with theoretical DFT predictions. Low-temperature PL spectroscopy and transient transmission measurements show no indications

Predicting the strain-mediated topological phase transition in 3D cubic ThTaN₃

• Chunmei Zhang and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1399–1404, doi:10.3762/bjnano.9.132

• of the N atom [12][29][30]. Computational Methods First-principles calculations were performed based on density functional theory (DFT) as implemented in the plane wave basis VASP code [31][32][33]. A generalized gradient approximation (GGA) in the Perdew, Burke, and Ernzerhof (PBE) form exchange

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

• that includes multilayer precursor coverage to describe FEBID processes at lower temperatures or with less volatile precursors [30]. Using density functional theory (DFT) calculations, new light was also shed on an experimentally well investigated precursor, namely (CH3–C5H4)Pt(CH3)3. The interaction

Induced smectic phase in binary mixtures of twist-bend nematogens

• Anamarija Knežević,
• Irena Dokli,
• Marin Sapunar,
• Suzana Šegota,
• Ute Baumeister and
• Andreja Lesac

Beilstein J. Nanotechnol. 2018, 9, 1297–1307, doi:10.3762/bjnano.9.122

• . b) A sketch of intercalated smectic phase of a BB–CBI mixture comprising the ratio of two molecules of BB versus one molecule of CBI (blue square). The phase behaviour and molecular length, L, obtained at the B3LYP/6-31G level of density functional theory (DFT). The phase transition temperature (°C

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

• modern computing tools. The non-equilibrium Green function (NEGF) method with density functional tight-binding (DFTB) scheme or density functional theory (DFT) scheme is used to calculate the electrical conductance of molecular structures consisting of atoms of various elements with high accuracy [8

• the DFT method in the tight-binding approximation [10][11][12] within the Kvazar software package [13]; the parametrization pbc-0-3 was used [14][15][16]. The electrical conductance is described by the expression: where T(E) is the transmission function characterizing the quantum mechanical

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

• , electronic and optical properties using density functional theory (DFT), hybrid functional and Bethe–Salpeter equation (BSE) approaches. We find that the exfoliation of single-layer SiAs2 and GeAs2 is highly feasible and in principle could be carried out experimentally by mechanical cleavage due to the

• . Furthermore, band-gap tuning is also possible by application of tensile strain. Our results highlight a new family of 2D materials with great potential for solar cell applications. Keywords: density functional theory (DFT); photovoltaic applications; solar cell; two-dimensional semiconductors; Introduction

• . Computational Details Density functional theory (DFT) using plane wave Vienna ab initio simulation package (VASP) code is used for first-principle calculations for this study [11][12]. The geometry optimisation is done with generalized gradient approximation in the Perdew–Burke–Ernzerhof form (GGA-PBE) exchange

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

• models are needed to enable such large-scale device simulations. Early works on tight-binding models started from analytical effective mass extractions from the usually only numerically defined model [12]. Later semi-automatic mapping methods using genetic algortithms were introduced [13] followed by DFT

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

• parameters to the specific structural variations which also needs to be parametrized [10]. On the opposite side of sophistication, the electronic structure of topological materials can be evaluated through density functional theory (DFT). According to the type of basis sets, DFT codes fall into two broad

• for the interstitial or valence electrons, while approaching the core electrons differently. Since localized orbitals are convenient for a number of reasons, for instance for quantum transport calculations [15][16], a Kohn–Sham Hamiltonian obtained from plane-wave DFT codes may be transformed into a

• present an implementation of SOC for DFT calculations based on Gaussian-type localized basis sets, attempting to bridge the gap between the simplicity of TB Hamiltonians with their one-parameter implementation of SOC and the accuracy and transferability of a DFT-level description of the band structure. We

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

• surface potential changes on the hybrid system. In summary, interface-induced organized structures atop 2D materials may have an important impact on both design and operation of π-conjugated nanomaterial-based hybrid systems. Keywords: DFT calculations; graphene; organic semiconductors; scanning probe

A review of carbon-based and non-carbon-based catalyst supports for the selective catalytic reduction of nitric oxide

• Shahreen Binti Izwan Anthonysamy,
• Syahidah Binti Afandi,
• Mehrnoush Khavarian and
• Abdul Rahman Bin Mohamed

Beilstein J. Nanotechnol. 2018, 9, 740–761, doi:10.3762/bjnano.9.68

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

• /bjnano.9.66 Abstract The interaction of trimethyl(methylcyclopentadienyl)platinum(IV) ((C5H4CH3)Pt(CH3)3) molecules on fully and partially hydroxylated SiO2 surfaces, as well as the dynamics of this interaction were investigated using density functional theory (DFT) and finite temperature DFT-based

• have made a series of DFT studies in which we considered fully and partially hydroxylated SiO2 surfaces as a representative for untreated and electron beam pretreated substrates and investigated the adsorption [9][10] and dynamics of several carbonyl precursors [11]. (C5H4CH3)Pt(CH3)3, in which Pt

• ligand exchange process [13]. Recently, examination of the behavior of this molecule on fully hydroxylated SiO2 surfaces has shown that the molecule remains physisorbed [14]. These static T = 0 K DFT computations provide insights on the bonding of (C5H4CH3)Pt(CH3)3 to this surface, but are limited to the

Sensing behavior of flower-shaped MoS₂ nanoflakes: case study with methanol and xylene

• Maryam Barzegar,
• Masoud Berahman and
• Azam Iraji zad

Beilstein J. Nanotechnol. 2018, 9, 608–615, doi:10.3762/bjnano.9.57

• considered in a double-zetta polarized scheme with a mesh cut-off sampling of 75 Ry for optimization and study [32]. The Monkhorst–Pack mesh with 21 × 21 × 1 sampling was used for the investigation. The optimization process continued until the force on each atom was lower than 0.01 eV. The Grimme-DFT-D2

Electron interactions with the heteronuclear carbonyl precursor H₂FeRu₃(CO)₁₃ and comparison with HFeCo₃(CO)₁₂: from fundamental gas phase and surface science studies to focused electron beam induced deposition

• Ragesh Kumar T P,
• Paul Weirich,
• Lukas Hrachowina,
• Marc Hanefeld,
• Ragnar Bjornsson,
• Helgi Rafn Hrodmarsson,
• Sven Barth,
• D. Howard Fairbrother,
• Michael Huth and
• Oddur Ingólfsson

Beilstein J. Nanotechnol. 2018, 9, 555–579, doi:10.3762/bjnano.9.53

Gas-sensing behaviour of ZnO/diamond nanostructures

• Marina Davydova,
• Alexandr Laposa,
• Jiri Smarhak,
• Alexander Kromka,
• Neda Neykova,
• Josef Nahlik,
• Jiri Kroutil,
• Jan Drahokoupil and
• Jan Voves

Beilstein J. Nanotechnol. 2018, 9, 22–29, doi:10.3762/bjnano.9.4

• hybrid ZnO NRs/NCD sensor showed a remarkably enhanced NO2 response compared to the ZnO NRs sensor. Further, inspired by this special hybrid structure, the simulation of interaction between the gas molecules (NO2 and CO2) and hybrid ZnO NRs/NCD sensor was studied using DFT calculations. Keywords

• : density functional theory (DFT); gas sensor; interdigital electrodes; nanocrystalline diamond; sensitivity; zinc oxide (ZnO); Introduction Currently, a number of studies have been focused on developing gas sensors based on nanomaterials and/or nanostructures. Metal oxides are the most common sensing

• hybrid ZnO NRs/NCD sensor is carried out using density functional theory (DFT) calculations. Experimental Three different sensor designs were utilized with width and spacing of Au/Ti metal interdigital electrode (IDE) arrays of 100 μm. A schematic illustration of the sensor platforms is shown in Figure 1

The rational design of a Au(I) precursor for focused electron beam induced deposition

• Ali Marashdeh,
• Thiadrik Tiesma,
• Niels J. C. van Velzen,
• Sjoerd Harder,
• Remco W. A. Havenith,
• Jeff T. M. De Hosson and
• Willem F. van Dorp

Beilstein J. Nanotechnol. 2017, 8, 2753–2765, doi:10.3762/bjnano.8.274

• Al signal and the ring structure come from the supporting Al stub. DFT calculations on isolated molecules Figure 6 and Figure 7 show that ClAuCO is unstable in vacuum, decomposing rapidly to AuCl, while ClAuPMe3 and MeAuPMe3 are stable. To understand why the stability of these compounds varies so

• enough to be used as a precursor for chemical vapor or electron-induced deposition [12][51][52]. Concluding, the DFT calculations of the ground states of isolated molecules help to explain the stability of ClAuPF3, CF3AuCO and ClAuPMe3. MeAuPMe3 appears to be stabilized by a significant activation

• , the SEM analysis, the DFT calculations and the XRD measurements, we now understand the stability and volatility of Au(I) complexes at the molecular level. Regarding ClAuCO, DFT calculations on isolated molecules show that they are stabilized by at least +25.5 kcal/mol. On the other hand, periodic DFT

Ab initio study of adsorption and diffusion of lithium on transition metal dichalcogenide monolayers

• Xiaoli Sun and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2017, 8, 2711–2718, doi:10.3762/bjnano.8.270

• with high electronic and ion mobility and large energy storage capacity. Conclusion Using density functional theory (DFT) simulations, the stability and electronic properties of MX2 monolayers were investigated. TiX2, VSe2, CrX2, ZrX2 and HfX2 are energetically favourable in the 1T phase, and 1T-VS2

• . Simulation Details All the spin-polarized DFT calculations were performed with SIESTA code [62], in which norm-conserving pseudopotentials and a Perdew–Burcke–Ernzerhof functional was used to describe the electron–ion interaction and electron exchange correlation, respectively. Numerical atomic orbits were

Synthesis of [{AgO₂CCH₂OMe(PPh₃)}_n] and theoretical study of its use in focused electron beam induced deposition

• Jelena Tamuliene,
• Julian Noll,
• Peter Frenzel,
• Tobias Rüffer,
• Alexander Jakob,
• Bernhard Walfort and
• Heinrich Lang

Beilstein J. Nanotechnol. 2017, 8, 2615–2624, doi:10.3762/bjnano.8.262

• conditions was studied by DFT (B3LYP) calculations on monomeric [AgO2CCH2OMe(PPh3)]. At an energy of the secondary electrons up to 0.8 eV elimination of PPh3 occurs, giving Ag+ and O2CCH2OMe−. Likewise, by release of PPh3 from [AgO2CCH2OMe(PPh3)] the fragment [AgO2CCH2OMe]− is formed from which Ag+ and

• O2CCH2OMe− is generated, further following the first fragmentation route. However, at 1.3 eV the initial step is decarboxylation giving [AgCH2OMe(PPh3)], followed by Ag–P and Ag–C bond cleavages. Keywords: DFT; DSC; FEBID; silver(I) carboxylate; solid-state structure; TGA; Introduction Focused electron

• [{AgO2CCH2OMe(PPh3)}n] is a suitable FEBID precursor for silver deposition. Thus, we discuss the synthesis and the chemical and physical properties of [{AgO2CCH2OMe}n] and [{AgO2CCH2OMe(PPh3)}n]. DFT (B3LYP) studies were applied to predict the most favorable fragmentation pathways according to the lowest energy

Inelastic electron tunneling spectroscopy of difurylethene-based photochromic single-molecule junctions

• Youngsang Kim,
• Safa G. Bahoosh,
• Dmytro Sysoiev,
• Thomas Huhn,
• Fabian Pauly and
• Elke Scheer

Beilstein J. Nanotechnol. 2017, 8, 2606–2614, doi:10.3762/bjnano.8.261

• functional theory (DFT) for charge transport through C5F-ThM molecular junctions. DFT, as implemented in the TURBOMOLE software package [26], was employed for the calculations using the exchange-correlation functional PBE [27][28][29][30] and the def-SV(P) [31][32] basis set, which is of split-valence

• the separation between the Au electrodes. Having determined the junction geometries, we computed the elastic transmission functions of the single-molecule junctions for the open and closed molecular forms, as shown in Figure 2b. Since it is known that DFT with semilocal exchange-correlation

• functionals, as used here, tends to underestimate the HOMO–LUMO gaps of molecules and does not capture nonlocal surface polarization effects that are essential for an accurate description of metal–molecule level alignments, we use here the so-called DFT+Σ method [34][35]. By adding a self-energy correction

Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals: a density functional theory study

• Hao Tang,
• Nathalie Tarrat,
• Véronique Langlais and
• Yongfeng Wang

Beilstein J. Nanotechnol. 2017, 8, 2484–2491, doi:10.3762/bjnano.8.248

• The adsorption of the iron tetraphenylporphyrin (FeTPP) molecule in its deckchair conformation was investigated on Au(111), Ag(111) and Cu(111) surfaces by performing spin-polarized density functional theory (DFT) calculations taking into account both van der Waals (vdW) interaction and on-site

• junction, the line shape of zero-bias resonance of the adsorbed FeTPP molecule reversibly varies by adjusting the tip to surface distance, i.e., by mechanically squeezing the molecule. Density functional theory (DFT) calculations reveal that the spin state of the Fe centre undergoes a switch from S = 2 to

• shifts explain the direction of the charge transfer. In summary, by performing spin-polarized DFT and NEB calculations, we have identified two stable magnetic states of the free FeTPP molecule in its deckchair conformation (C2h). The two states (HS and IS) were separated by an activation barrier of 0.07

The interplay between spin densities and magnetic superexchange interactions: case studies of mono- and trinuclear bis(oxamato)-type complexes

• Azar Aliabadi,
• Bernd Büchner,
• Vladislav Kataev and
• Tobias Rüffer

Beilstein J. Nanotechnol. 2017, 8, 2245–2256, doi:10.3762/bjnano.8.224

• of experimentally determined spin density distributions via the approaches by Maki and McGarvey [48] and Morton and Preston [49] according to the above described procedure are summarized in Figure 7. Furthermore and for comparison, DFT-calculated values of 2, 4, 6, 8 and 10 are given as well. One can

• and discussed together with the DFT results and to be critically evaluated with respect to geometrical features of the studied molecular complexes. In particular, the approach of Maki and McGarvey [48] implies a square planar geometry of the molecule, a condition that is not always fulfilled. A

Au₅₅, a stable glassy cluster: results of ab initio calculations

• Dieter Vollath,
• David Holec and
• Franz Dieter Fischer

Beilstein J. Nanotechnol. 2017, 8, 2221–2229, doi:10.3762/bjnano.8.222

• on the structure of the Au55 nanocluster highlights the necessity to look again at this problem using up-to-date theoretical methods. Therefore, quantum-mechanical calculations within the density functional theory (DFT) framework as implemented in the Vienna ab initio simulation package (VASP) [24

• bulk n·εbulk. This approach was introduced by Medasani et al. [30] to calculate the surface energy of silver clusters using DFT calculations. In their study, the surface energy γ was defined as The quantity a represents the surface area of the cluster. At the first view, this approach seems logical and

Comprehensive investigation of the electronic excitation of W(CO)₆ by photoabsorption and theoretical analysis in the energy region from 3.9 to 10.8 eV

• Mónica Mendes,
• Khrystyna Regeta,
• Filipe Ferreira da Silva,
• Nykola C. Jones,
• Søren Vrønning Hoffmann,
• Gustavo García,
• Chantal Daniel and
• Paulo Limão-Vieira

Beilstein J. Nanotechnol. 2017, 8, 2208–2218, doi:10.3762/bjnano.8.220

• of relevance to estimate neutral dissociation cross sections of W(CO)6, a precursor molecule in focused electron beam induced deposition (FEBID) processes, from electron scattering measurements. Keywords: cross sections; density functional theory (DFT) calculations; focused electron beam induced

• -dependent density functional theory (TDDFT) calculations [15], and electron momentum spectroscopy calculations [16] have been carried out. Other relevant studies include DFT calculations on the structure of W(CO)6 and its behaviour in infrared spectroscopy [17], as well as Raman [18] and infrared [18][19

• functional theory (DFT) level with B3LYP functional [35] with all electron and triple-ζ polarized basis sets in vacuum [36], leading to W–C and C–O bond lengths of 2.069 Å and 1.144 Å (1.141 Å from [15]), respectively. The metal bond length is slightly overestimated with respect to previous results yielding

Ester formation at the liquid–solid interface

• Nguyen T. N. Ha,
• Thiruvancheril G. Gopakumar,
• Nguyen D. C. Yen,
• Carola Mende,
• Lars Smykalla,
• Maik Schlesinger,
• Roy Buschbeck,
• Tobias Rüffer,
• Heinrich Lang,
• Michael Mehring and
• Michael Hietschold

Beilstein J. Nanotechnol. 2017, 8, 2139–2150, doi:10.3762/bjnano.8.213

• reaction path and energy barrier, a "nudged elastic band" calculation was done using DFT with the program code GPAW [37]. The molecule was placed in a large box with non-periodic boundary conditions and 7 Å of vacuum in each direction. The starting and end geometry (reactants and products) are first

• temperature for 10 min and then the substrate was cooled down to room temperature for STM imaging. DFT calculations were carried out using the grid-based projector augmented wave method (GPAW) [37]. The PBE exchange-correlation functional [38] and the LCAO mode [37] with the standard double-zeta-polarized

• should be almost parallel to the A axis. Energy diagram of the reaction path of TMA and undecanol to form TMA–undecyl ester and water for isolated molecules (gas phase) calculated using DFT (PBE). The corresponding geometry of the molecules in the simulation is shown for each energy point marked in the

Electronic structure, transport, and collective effects in molecular layered systems

• Torsten Hahn,
• Tim Ludwig,
• Carsten Timm and
• Jens Kortus

Beilstein J. Nanotechnol. 2017, 8, 2094–2105, doi:10.3762/bjnano.8.209

• phthalocyanine (F16CoPc/MnPc) heterostructure, are investigated by means of density functional theory (DFT) and the non-equilibrium Green’s function (NEGF) approach. Furthermore, a master-equation-based approach is used to include electronic correlations beyond the mean-field-type approximation of DFT. We

• describe the essential theoretical tools to obtain the parameters needed for the master equation from DFT results. Finally, an interacting molecular monolayer is considered within a master-equation approach. Keywords: electron correlation; electronic structure; quantum transport; spin transport

• molecule but also between neighboring molecules in a film [15], where they can lead to ordering phenomena. Our paper is organised as follows. First we will present the methodical background and results of our theoretical investigations on different phthalocyanine heterostructures by using the DFT-NEGF

Adsorbate-driven cooling of carbene-based molecular junctions

• Giuseppe Foti and
• Héctor Vázquez

Beilstein J. Nanotechnol. 2017, 8, 2060–2068, doi:10.3762/bjnano.8.206

• a first-principles, self-consistent description of the junction out of equilibrium based on density functional theory (DFT) and non-equilibrium Green’s functions (NEGF). We show how the change in the electronic structure of the junction induced by the presence of the adsorbate promotes the cooling

• cooling dynamics of a NHC-based molecular junction. We calculated the bias-dependent rates of emission and absorption of molecular vibrations using first principles methods based on DFT-NEGF. We considered an electron-withdrawing NH2 species adsorbed in the vicinity of the molecule on one of the