Investigation of CVD graphene as-grown on Cu foil using simultaneous scanning tunneling/atomic force microscopy

• Majid Fazeli Jadidi,
• Umut Kamber,
• Oğuzhan Gürlü and
• H. Özgür Özer

Beilstein J. Nanotechnol. 2018, 9, 2953–2959, doi:10.3762/bjnano.9.274

• complicated as it could be interpreted as a map of the local charge density of states of the surface at the Fermi level [6]. Therefore, depending on tip type and its electronic charge state, different relative contrasts of the atoms on the surface, including even reversal of contrast, are obtained in STM

• inequivalent. Since, b atoms have a greater contribution to the density of states close to Fermi energy compared to a atoms, they are imaged as bright spots at low bias voltages based on the STM investigations. These b atoms form a new larger triangular structure in STM images (two lattice points in this

• slight difference in two different regions. Also, there is a small gradual increase in height starting midway through the STM image, which suggests a change in overall local density of states (LDOS) or topography. Line profiles of the force and STM topography in the two regions are given in the figure

Intrinsic ultrasmall nanoscale silicon turns n-/p-type with SiO₂/Si₃N₄-coating

• Dirk König,
• Daniel Hiller,
• Noël Wilck,
• Birger Berghoff,
• Merlin Müller,
• Sangeeta Thakur,
• Giovanni Di Santo,
• Luca Petaccia,
• Joachim Mayer,
• Sean Smith and
• Joachim Knoch

Beilstein J. Nanotechnol. 2018, 9, 2255–2264, doi:10.3762/bjnano.9.210

• Moore’s law to reach the Si-crystallization limit of ca. 1.5 nm [15]. In our present work, we prove by hybrid-density functional theory (h-DFT) simulations and synchrotron-based long-term ultraviolet photoelectron spectroscopy (UPS) that usn-Si indeed can have a massive ΔE of their electronic density of

• states (DOS) when embedded in SiO2 or Si3N4. We use further h-DFT results of a Si-nanowire (NWire) covered in SiO2 and Si3N4 to examine the device behaviour of an undoped Si-NWire FET based solely on CMOS-compatible materials (e.g., Si, SiO2, Si3N4) using the nonequilibrium Green’s function (NEGF

Dumbbell gold nanoparticle dimer antennas with advanced optical properties

• Janning F. Herrmann and
• Christiane Höppener

Beilstein J. Nanotechnol. 2018, 9, 2188–2197, doi:10.3762/bjnano.9.205

• additionally, which is usually blue-shifted from the LSPR. As a consequence of these dependencies, the effective local density of states (LDOS) varies. The observed spectral variations for geometrically similar dimers are likely correlated to the spread in the fluorescence enhancement factor. In principle

Spin-coated planar Sb₂S₃ hybrid solar cells approaching 5% efficiency

• Pascal Kaienburg,
• Benjamin Klingebiel and
• Thomas Kirchartz

Beilstein J. Nanotechnol. 2018, 9, 2114–2124, doi:10.3762/bjnano.9.200

• absorption coefficient of a thin-film is measured over several orders of magnitude [52][53] which cannot be achieved by standard transmission–reflection measurements using an UV–vis photospectrometer. The large dynamic range of PDS makes it a powerful tool for to study the density of states in the sub

• attributed to interference in the smooth films – which did not fully cancel out during data analysis – instead of actual variations in the materials’ density of states in the sub-bandgap region. The negative impact of the increased defect density on device performance is confirmed by comparing solar cells

Metal-free catalysis based on nitrogen-doped carbon nanomaterials: a photoelectron spectroscopy point of view

• Mattia Scardamaglia and
• Carla Bittencourt

Beilstein J. Nanotechnol. 2018, 9, 2015–2031, doi:10.3762/bjnano.9.191

• zero-gap semiconductor). This peculiarity represents one of the biggest challenges for its use in concrete applications, because it results in a very low density of states (DOS) at the Fermi level for typical doping levels, making graphene an intrinsically inert material. To overcome these issues

• , several strategies have been employed to tailor the properties of graphene. Being very sensitive to local perturbations, any modification of the lattice or adsorption of foreign atoms or molecules produce sudden evident changes in the density of states that can be monitored by the shift of the Dirac cone

• the electronic states of graphene. In general, point defects generate localized states at the Fermi level, easily identifiable as protrusion by scanning tunneling microscopy (STM) [56], while carbon vacancies are responsible for an opening of the energy gap [57]. The increase in the density of states

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

• combined using Matthiessen’s formula. Accordingly, the Lombardi model (CVT) is used to express the carrier mobility in the channel [27]. Moreover, the intrinsic parameters of the materials (Si, Si1−xGex and Ge) such as band gap, mobility and the density of states were considered to be dependent on the Ge

Improving the catalytic activity for hydrogen evolution of monolayered SnSe_2(1−x)S_2x by mechanical strain

• Sha Dong and
• Zhiguo Wang

Beilstein J. Nanotechnol. 2018, 9, 1820–1827, doi:10.3762/bjnano.9.173

• increases upon application of tensile strain because the valence band and conduction band move upward and downward in energy, respectively. Previous reports showed that H adsorption depends on the density of states near the Fermi energy level [57][58], with the adsorption being enhanced as the d-band centre

A zero-dimensional topologically nontrivial state in a superconducting quantum dot

• Pasquale Marra,
• Alessandro Braggio and
• Roberta Citro

Beilstein J. Nanotechnol. 2018, 9, 1705–1714, doi:10.3762/bjnano.9.162

• electron dispersion in the two superconducting leads. In the following we furthermore assume that the bare electron dispersion varies in the interval [−D,D] and that the density of states is ρ0 = 1/(2D) with 2D the total bandwidth. The tunneling between the dot and the leads is described by the tunnel

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

• and take real-valued tunnel amplitudes λS/TS, see Figure 1a, using a gauge where the superconducting phase difference appears via the QD–TS tunneling term. These tunnel amplitudes contain density-of-states factors for the respective leads. The operator expression for the current flowing through the

Free-radical gases on two-dimensional transition-metal disulfides (XS₂, X = Mo/W): robust half-metallicity for efficient nitrogen oxide sensors

• Chunmei Zhang,
• Yalong Jiao,
• Fengxian Ma,
• Sri Kasi Matta,
• Steven Bottle and
• Aijun Du

Beilstein J. Nanotechnol. 2018, 9, 1641–1646, doi:10.3762/bjnano.9.156

• . The binding position and adsorption energy are analyzed in detail. In terms of the projected density of states (PDOS) and orbital contribution, our results offer a deep insight into the Fermi-level pinning mechanism. In addition, we expand the calculations to other 2D layered materials including GaS

Interplay between pairing and correlations in spin-polarized bound states

• Szczepan Głodzik,
• Aksel Kobiałka,
• Anna Gorczyca-Goraj,
• Andrzej Ptok,
• Grzegorz Górski,
• Maciej M. Maśka and
• Tadeusz Domański

Beilstein J. Nanotechnol. 2018, 9, 1370–1380, doi:10.3762/bjnano.9.129

• -of-plane spin–orbit field, respectively, and satisfy . Solving numerically the BdG equations (Equation 6) we can determine the local order parameter χi and occupancy niσ where f(ω) = [1 + exp(ω/kBT)]−1. In what follows, we shall inspect the spin-resolved local density of states For its numerical

• observe a constructive influence of the Majorana quasiparticle on opposite-spin ↓ electrons. Figure 9 shows evolution of the spectral function ρ↑(ω) for various couplings tm. In the weak-coupling limit we clearly observe a reduction (by half) of the initial density of states. With increasing tm the

Andreev spectrum and supercurrents in nanowire-based SNS junctions containing Majorana bound states

• Jorge Cayao,
• Annica M. Black-Schaffer,
• Elsa Prada and
• Ramón Aguado

Beilstein J. Nanotechnol. 2018, 9, 1339–1357, doi:10.3762/bjnano.9.127

• , a highly transmissive interface between the nanowire and the superconductor is required, so that electrons can tunnel between these two systems [13][14][15][16]. This results in a superconducting nanowire, with a well-defined induced hard gap (namely, without residual quasiparticle density of states

Inverse proximity effect in semiconductor Majorana nanowires

• Alexander A. Kopasov,
• Ivan M. Khaymovich and
• Alexander S. Mel'nikov

Beilstein J. Nanotechnol. 2018, 9, 1184–1193, doi:10.3762/bjnano.9.109

• resulting restrictions on the operation of Majorana-based devices. A strong paramagnetic effect for electrons entering the semiconductor together with spin–orbit coupling and van Hove singularities in the electronic density of states in the wire are responsible for the suppression of superconducting

• analogous to the one used in the phenomenological model. On top of that it gives the gap dependence on the transparency of the interface between the wire and the s-wave superconductor and chemical potential via density of states (DOS). Another important point is that the exchange of electrons between the

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

• velocity vn(E) and density of states ρn(E) of a given mode n at energy E [36]. This product is a constant vn(E)ρn(E) = 1/h, irrespective of the form of εn(k), which leads to the well-known conductance quantum e2/h. For infinitely long, ballistic systems all channels are perfectly transmitted Tn = 1, so one

Cyclodextrin inhibits zinc corrosion by destabilizing point defect formation in the oxide layer

• Abdulrahman Altin,
• Maciej Krzywiecki,
• Adnan Sarfraz,
• Cigdem Toparli,
• Claudius Laska,
• Philipp Kerger,
• Aleksandar Zeradjanin,
• Karl J. J. Mayrhofer,
• Michael Rohwerder and
• Andreas Erbe

Beilstein J. Nanotechnol. 2018, 9, 936–944, doi:10.3762/bjnano.9.86

• , defect levels affect the VBonset and VBmax energy positions differently, consequently altering the density of states in the VB region. Altered density of states leads to different charge carrier densities at the interface and a decrease in potential barrier for charge dislocation.) From the magnitude of

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

• and copper [19] which are terminated after the transfer. Besides, this may lead to different values of the average graphene–substrate distance resulting in deviation of the density of states (DOS) from a simple Dirac cone [16] and a consequent shift of the Dirac point energy, leading to different

Revealing the interference effect of Majorana fermions in a topological Josephson junction

• Jie Liu,
• Tiantian Yu and
• Juntao Song

Beilstein J. Nanotechnol. 2018, 9, 520–529, doi:10.3762/bjnano.9.50

• the local density of states (DOS) in a topological Josephson junction. We show that the well-known 4π Josephson effect originates from the interference effect between two Majorana fermions (MFs) that are localized at the Josephson junction. In addition, the DOS for electrons (holes) shows the 4π

• interference effect of the MFs as well as the DOS by combining Andreev reflection with the electron transmission process. Keywords: density of states; fractional Josephson effect; Majorana fermion; Introduction After Kitaev reported that Majorana fermions (MFs) can appear as quasi-particle states at the ends

• topological superconductors as shown in Figure 1a. Unlike previous studies, we focus on the density of states (DOS) for both the electron part and the hole part. The essential property of the MFs is that the wave function of the electron part must be conjugated with the wave function of the hole part, which

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

• adsorbed FeTPP in the deckchair conformation (C2h). In the following we check the strength of different interactions involved in the adsorption of this HS FeTPP on the Au(111) surface as well as the charge transfer, work function modification and the projected density of states (PDOS) variations. In the

• contributes to electronic states around the Fermi level. We compare here the spin-resolved density of states projected (PDOS) onto the d-orbitals of Fe in the HS state before and after adsorption (with FeTPP adsorbed at the fcc site of Au(111) surface) (Figure 7). In these cases, only one orbital () is doubly

• this restriction was tested on the reference configuration (FeTPP at the hollow-fcc site of Au(111)) with a (5 × 5 × 1) Monkhorst–Pack k-point mesh. This comparison gives a difference lower than 1% for the total energy and the bond length. The difference in density of states and local electrostatic

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

• deposited solution due to enforced evaporation as well as to an increased mobility of the molecules [35]. Figure 6 shows simulated constant height mode STM images obtained from a calculated local density of states (LDOS) of the free monoester molecule. Both HOMO and LUMO show a strong intensity close to the

Substrate and Mg doping effects in GaAs nanowires

• Perumal Kannappan,
• Nabiha Ben Sedrine,
• Jennifer P. Teixeira,
• Maria R. Soares,
• Bruno P. Falcão,
• Maria R. Correia,
• Nestor Cifuentes,
• Emilson R. Viana,
• Marcus V. B. Moreira,
• Geraldo M. Ribeiro,
• Alfredo G. de Oliveira,
• Juan C. González and
• Joaquim P. Leitão

Beilstein J. Nanotechnol. 2017, 8, 2126–2138, doi:10.3762/bjnano.8.212

• term cxT3/2 accounts for the effective density of states of the band involved, and cx is a fitting parameter. Different models were tested for each component of the two samples. The best one consists of the lower number of non-radiative de-excitation channels that allows us to well describe the thermal

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

• density of states as obtained from the DFT calculations. While the electronic structure of CoPc and F16CoPc is qualitative similar after surface contact, the manganese center in the F16CoPc/MnPc yields a larger local magnetic moment and more strongly occupied metal 3d states close to the Fermi level. Both

• stack. c), d) Density of states (DOS) of the molecule-Au(111) interfaces as obtained from the calculations. The overall DOS as well as the projections onto the molecule and metal centers are shown. I–V curves calculated within the DFT-NEGF method for the sandwich structure a) CoPc/CoPc and b) F16CoPc

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

• of NHC vibrational modes through i) electrostatic gating of molecular levels and ii) quenching of carbene density of states (DOS) as a function of the applied bias. We illustrate the connection between the gating of NHC states and the heating of the junction by comparing vibron populations as a

• - and right-projected DOS of the molecule while the gray curve is the density of states of the adsorbate. a) Left and right spectral functions at 0 V for a clean NHC (C, structure shown in Figure 1a,b) and with a NH2 group adsorbed on the left electrode, (CA, structure in Figure 1c,d). For the latter we

Coexistence of strongly buckled germanene phases on Al(111)

• Weimin Wang and
• Roger I. G. Uhrberg

Beilstein J. Nanotechnol. 2017, 8, 1946–1951, doi:10.3762/bjnano.8.195

• bilayer germanene on Cu(111) at room temperature. Scanning tunneling spectroscopy showed a “V” shaped density of states, which was also observed by Zhang et al. [12], who synthesized germanene on MoS2 at room temperature. Al(111) was chosen as a substrate to deposit germanene by Derivaz et al. [13] with

• the motivation that it is a simple unreconstructed metal with surface density of states dominated by s-electrons. A monolayer of Ge formed at a “magic” temperature (in a range of 20 °C around 87 °C) was interpreted as a germanene layer. Well-resolved STM images showed a honeycomb arrangement of blobs

• within 0.01 eV/Å. Simulated STM images were generated from local density of states according to the Tersoff–Hamann approach [17]. The charge transfer was calculated by the Bader scheme within VASP. (a) LEED pattern obtained at an electron energy of 55 eV from Al(111) with 0.6 ML of Ge deposited at a rate

Spin-dependent transport and functional design in organic ferromagnetic devices

• Guichao Hu,
• Shijie Xie,
• Chuankui Wang and
• Carsten Timm

Beilstein J. Nanotechnol. 2017, 8, 1919–1931, doi:10.3762/bjnano.8.192

• spin filtering is realized in this bias range. The second peak of the SP appears at about 1.8 V but the SP is reduced to about 40%. In order to understand the spin filtering effect, we have calculated the spin-resolved density of states (DOS) of π-orbitals from the Green’s function with DOSσ(E,V) = −(1

• ], copyright 2007 American Physical Society. Density of states of the OF device at a bias of 0.8 V. Here, the Fermi energy of the electrodes is taken to be EF = 1.5 eV, which for a bias voltage of V = 0.8 V leads to the indicated chemical potentials μL,R = EF ± 0.4 eV. Reproduced with permission from [31

• ], copyright 2007 American Physical Society. Density of states of (a) Co and (b) the OF poly-BIPO. The molecular length is 20 sites. (c) Schematic of the magnetization configurations C1, C2, C3, and C4 in the ferromagnet/OF/ferromagnet device. Reproduced with permission from [32], copyright 2014 AIP Publishing

Structural model of silicene-like nanoribbons on a Pb-reconstructed Si(111) surface

• Agnieszka Stępniak-Dybala and
• Mariusz Krawiec

Beilstein J. Nanotechnol. 2017, 8, 1836–1843, doi:10.3762/bjnano.8.185

• values of Φ then Pb areas, in full agreement with the experimental results. To shed light on electronic properties, we provide a comparison of the measured dI/dV characteristics and calculated density of states (DOS) in Figure 5. Again, the theoretical results reproduce well the experimental data. The

• density of states of Si NR system in the absence (red line) and in the presence of Pb atoms (black line). Note that the system is metallic. Relative surface energies γNR(Si) and BP–BP distance dBP of structural models of Si NRs on the Si(111) surface. γNR(Si), defined by Equation 1, is measured with