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

• measurements immediately after the deposition process as well as 10 days later. The results are presented in Figure 8. There are two characteristic bands in the Raman spectra. The band centered at 270 cm−1 most likely originates from the confined optical phonon in ultra-small germanium nanoclusters, while the

• band at around 160 nm is a combination of bands originating from transverse acoustic, longitudinal acoustic, longitudinal optical and transverse optical phonon modes in the amorphous Ge Raman spectrum [29][30][31]. This indicates a mixture of nanocrystalline and amorphous Ge. The bands are clearly

CdSe nanorod/TiO₂ nanoparticle heterojunctions with enhanced solar- and visible-light photocatalytic activity

• Fakher Laatar,
• Hatem Moussa,
• Halima Alem,
• Lavinia Balan,
• Emilien Girot,
• Ghouti Medjahdi,
• Hatem Ezzaouia and
• Raphaël Schneider

Beilstein J. Nanotechnol. 2017, 8, 2741–2752, doi:10.3762/bjnano.8.273

• their dispersion in TiO2 particles. Raman spectroscopy was further used to confirm the structures of CdSe/TiO2 composites. Two peaks located at 206 and 414 cm−1 corresponding to the longitudinal optical (LO) phonon and its overtone (2LO) can be observed for CdSe NRs (Figure S2, Supporting Information

Fabrication of CeO₂–MO_x (M = Cu, Co, Ni) composite yolk–shell nanospheres with enhanced catalytic properties for CO oxidation

• Ling Liu,
• Jingjing Shi,
• Hongxia Cao,
• Ruiyu Wang and
• Ziwu Liu

Beilstein J. Nanotechnol. 2017, 8, 2425–2437, doi:10.3762/bjnano.8.241

• on various parameters, including the crystal defects, oxygen vacancies, phonon confinement, and inhomogeneous strain related to the reduced ceria [31][32]. Herein, the shift can be related to the interaction between the MOx species and CeO2 surface, which leads to lengthening and weakening of the M–O

Changes of the absorption cross section of Si nanocrystals with temperature and distance

• Michael Greben,
• Petro Khoroshyy,
• Sebastian Gutsch,
• Daniel Hiller,
• Margit Zacharias and
• Jan Valenta

Beilstein J. Nanotechnol. 2017, 8, 2315–2323, doi:10.3762/bjnano.8.231

• the function presented in Equation 20 (Figure 4b) for our ML structures. Temperature dependence of the ACS Contrary to the common assumption, the ACS should be generally considered as temperature-dependent [5][29]. There are two mechanisms responsible for this dependence. First, for the phonon

• -assisted transitions the occupation number of phonons is an exponential function [1] of temperature containing the Bose–Einstein statistical factor: where Ωph is the typical (average) phonon energy and kB is the Boltzmann constant. Second, with varying temperatures the band gap of a NC is shifting. This

• changes the effective DOS at a certain energy. Following the phenomenological expression proposed by Cardona’s group [30] we can write: where B is a temperature-independent constant related to the strength of the electron–phonon interaction, and Egap,0 corresponds to the band gap at 0 K. The ACS is equal

Velocity dependence of sliding friction on a crystalline surface

• Christian Apostoli,
• Giovanni Giusti,
• Jacopo Ciccoianni,
• Gabriele Riva,
• Rosario Capozza,
• Rosalie Laure Woulaché,
• Andrea Vanossi,
• Emanuele Panizon and
• Nicola Manini

Beilstein J. Nanotechnol. 2017, 8, 2186–2199, doi:10.3762/bjnano.8.218

• , representing a crystalline substrate. This interaction converts a part of the kinetic energy of the slider into phonon waves in the substrate. As a result, the slider experiences a friction force. As a function of the slider speed, we observe dissipation peaks at specific values of the slider speed, whose

• nature we understand by means of a Fourier analysis of the excited phonon modes. By relating the phonon phase velocities with the slider velocity, we obtain an equation whose solutions predict which phonons are being excited by the slider moving at a given speed. Keywords: atomic-scale friction; contact

• ][29][30][31][32][33][34][35]. The main difficulty here is to provide a satisfactory implementation of the thermostat that not only provides a correct canonical dynamics in equilibrium conditions, but also manages to dispose of the extra excitation energy carried by the traveling phonon waves generated

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

• the lattice and the electron–phonon interaction promote the broadening and the redshift of the energy levels, which leads to a reduction of the bandgap [46][62][63]. Among the several theoretical models available in the literature, one that probably better describes the temperature dependence of the

• ). For two of the investigated nanowires, our values are in good agreement with a recent result (≈31 cm2/Vs) in p-type Si-doped GaAs nanowires, obtained by measuring the plasmon–phonon interactions using transmission Raman spectroscopy [59] and, on average, clearly higher than the reported value (0.417

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

• polarization basis for gold and a double-ζ plus polarization basis for nitrogen, hydrogen and carbon atoms. Exchange–correlation is described with the generalized gradient approximation (GGA) [32]. For the calculation of the electron–phonon coupling matrix we use the Inelastica code [33] with the M(Γ

• ) approximation [34], which consists of calculating the electron–phonon coupling matrix M in just one point of the Brillouin zone (Γ) for both electrons and phonons. The dynamical region includes the molecule, the Au atoms forming electrode terminations and the adsorbate atoms. The position of the molecule, tip

• , for high energy modes (E ≥ 70 meV), the numerator can be well approximated by the emission rate Re,λ(Vb) since, assuming a low phonon-bath temperature, . Also, the denominator J + Ra,λ(Vb) − Re,λ(Vb) does not change much for carbene modes over the whole bias range considered. Figure S6 in Supporting

Oxidative stabilization of polyacrylonitrile nanofibers and carbon nanofibers containing graphene oxide (GO): a spectroscopic and electrochemical study

• İlknur Gergin,
• Ezgi Ismar and
• A. Sezai Sarac

Beilstein J. Nanotechnol. 2017, 8, 1616–1628, doi:10.3762/bjnano.8.161

• electron–phonon interactions of the material [51]. ATR-FTIR spectroscopy of oxidized PAN/GO nanofibers The ATR-FTIR results show a broad OH stretching peak of GO around 3300 cm−1 [57] and the C–H vibrations of the CH, CH2 and CH3 structures of oxidized polyacrylonitrile around 2920 cm−1 [38][40]. Through

Calcium fluoride based multifunctional nanoparticles for multimodal imaging

• Marion Straßer,
• Joachim H. X. Schrauth,
• Sofia Dembski,
• Daniel Haddad,
• Bernd Ahrens,
• Stefan Schweizer,
• Bastian Christ,
• Alevtina Cubukova,
• Marco Metzger,
• Heike Walles,
• Peter M. Jakob and
• Gerhard Sextl

Beilstein J. Nanotechnol. 2017, 8, 1484–1493, doi:10.3762/bjnano.8.148

• favorable chemical and mechanical properties. They seem to be perfect materials as fluorescence host matrix owing to their low phonon energies and they subsequently minimize the quenching of the excited state of rare-earth ions. In contrast to chloride or bromide hosts, fluorides are completely air stable

• biocompatible agents for bone and teeth reconstruction [23]. Calcium fluoride exhibits a wide transparent spectral window (190–1100 nm), large band gap (approx. 12 eV), low refractive index and low phonon energy [14]. Because of the high stability and flexibility of the fluorite structure, a number of various

Comprehensive Raman study of epitaxial silicene-related phases on Ag(111)

• Dmytro Solonenko,
• Ovidiu D. Gordan,
• Guy Le Lay,
• Dietrich R. T. Zahn and
• Patrick Vogt

Beilstein J. Nanotechnol. 2017, 8, 1357–1365, doi:10.3762/bjnano.8.137

• cm−1 with a shoulder around 350 cm−1. Narrow phonon modes indicative of crystalline order are not observed in this case. At a temperature of 220 °C at which (3×3)/(4×4) epitaxial silicene is formed, the prototypical phase with C6v symmetry is identified by the presence of narrow A1 and A2 modes at

• band at 520 cm−1 with a FWHM of 8 cm−1. This mode is similar to the L(T)O phonon mode of diamond-like silicon, clearly indicating the formation of Si crystallites. Additionally, the second-order TO phonon mode around 900 cm−1 (Figure 2, top spectrum) supports the bulk-like nature of the structures

• formed. The fact that the intensity of the L(T)O phonon mode gets higher for deposition at 350 °C demonstrates that the sizes of the crystallites enlarge with increasing deposition temperatures. However, this temperature is still low compared to the growth temperature of crystalline Si, which usually

3D continuum phonon model for group-IV 2D materials

• Morten Willatzen,
• Lok C. Lew Yan Voon,
• Appala Naidu Gandi and
• Udo Schwingenschlögl

Beilstein J. Nanotechnol. 2017, 8, 1345–1356, doi:10.3762/bjnano.8.136

• anisotropy and flexural modes perpendicular to the layers and can thus be applied to any two-dimensional material. In this paper, we use the model to not only compare the phonon spectra among the group-IV materials but also to study whether these phonons differ from those of a compound material such as

• molybdenum disulfide. The origin of quadratic modes is clarified. Mode coupling for both graphene and silicene is obtained, contrary to previous works. Our model allows us to predict the existence of confined optical phonon modes for the group-IV materials but not for molybdenum disulfide. A comparison of

• the long-wavelength modes to density-functional results is included. Keywords: graphene; molybdenum disulfide; phonon; silicene; two-dimensional materials; Introduction Phonon spectra in two-dimensional (2D) nanomaterials have almost exclusively been computed using density-functional theory (DFT

Two-dimensional silicon and carbon monochalcogenides with the structure of phosphorene

• Dario Rocca,
• Ali Abboud,
• Ganapathy Vaitheeswaran and
• Sébastien Lebègue

Beilstein J. Nanotechnol. 2017, 8, 1338–1344, doi:10.3762/bjnano.8.135

• computing phonon dispersion curves, in this work we show that carbon and silicon monochalcogenides are dynamically stable in a puckered structure. Additionally, we compute band structures using the quantitatively accurate HSE06 hybrid functional [29] and we evaluate effective masses, whose anisotropy

• paper have been performed using the Quantum Espresso package [30], which is based on a plane-wave basis set and pseudopotentials. The Perdew–Burke–Ernzerhof (PBE) [31] functional has been used to optimize the structure and to compute phonon dispersion spectra. After optimizing the structure with a force

• threshold of at least 10−4 Ry/Bohr the phonon curves have been computed by using density functional perturbation theory [32]. The kinetic-energy cut-off convergence has been carefully tested for each system and a 12 × 12 × 1 k-point grid was used (supposing that the z direction is perpendicular to the two

Metal oxide nanostructures: preparation, characterization and functional applications as chemical sensors

• Dario Zappa,
• Angela Bertuna,
• Elisabetta Comini,
• Navpreet Kaur,
• Nicola Poli,
• Veronica Sberveglieri and
• Giorgio Sberveglieri

Beilstein J. Nanotechnol. 2017, 8, 1205–1217, doi:10.3762/bjnano.8.122

• mat. Raman spectrum of NiO nanowires (Figure 2) shows several bands above 400 cm−1. The first four bands at 584 cm−1, 740 cm−1, 903 cm−1 and 1100 cm−1 have vibrational origin. The first band at 584 cm−1 corresponds to one phonon TO (transverse mode) and LO (longitudinal mode), 740 cm−1 to the two

• phonon 2TO modes, 903 cm−1 to the TO+LO and 1100 cm−1 is related to the 2LO modes. One last strong band was observed at 1482 cm−1 and it belongs to magnon (2M) scattering [5]. The extra peak that appears in the spectra below 450 cm−1 belongs to the alumina substrate. Concerning SnO2, three major peaks

Fully scalable one-pot method for the production of phosphonic graphene derivatives

• Kamila Żelechowska,
• Marta Prześniak-Welenc,
• Marcin Łapiński,
• Izabela Kondratowicz and
• Tadeusz Miruszewski

Beilstein J. Nanotechnol. 2017, 8, 1094–1103, doi:10.3762/bjnano.8.111

• first-order scattering of the E2g mode at 1578 cm−1 and broad D band at 1350 cm−1. The overtone 2D band can be seen in the range from 2700 to 3000 cm−1. The D band is attributed to phonon branches around K and together with its overtone 2D band both are dispersive bands observed in graphite-derived

Near-field surface plasmon field enhancement induced by rippled surfaces

• Mario D’Acunto,
• Francesco Fuso,
• Ruggero Micheletto,
• Makoto Naruse,
• Francesco Tantussi and
• Maria Allegrini

Beilstein J. Nanotechnol. 2017, 8, 956–967, doi:10.3762/bjnano.8.97

• , permittivity of the environment, ε = 1 (air). Supporting Information Supporting Information File 172: Additional Green’s function calculations. Acknowledgements The authors would like to thank the bilateral Italy-Japan project, CNR-JSPS “Fluctutation-phonon-mediated assisted nanophotonic fabrication and

In-situ monitoring by Raman spectroscopy of the thermal doping of graphene and MoS₂ in O₂-controlled atmosphere

• Aurora Piazza,
• Filippo Giannazzo,
• Gianpiero Buscarino,
• Gabriele Fisichella,
• Antonino La Magna,
• Fabrizio Roccaforte,
• Marco Cannas,
• Franco Mario Gelardi and
• Simonpietro Agnello

Beilstein J. Nanotechnol. 2017, 8, 418–424, doi:10.3762/bjnano.8.44

• , in addition to a thermal effect, an effect attributable to a p-type doping through oxygen. The thermal broadening of the line shape, found during thermal treatments by in situ Raman measurements, can be related to thermal phonon effects. The absence of a band shift results from the balance between a

Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles

• Anurag Roy,
• Partha Pratim Das,
• Mukta Tathavadekar,
• Sumita Das and
• Parukuttyamma Sujatha Devi

Beilstein J. Nanotechnol. 2017, 8, 210–221, doi:10.3762/bjnano.8.23

• longitudinal optical (LO) phonon modes of CdS, respectively. The peak 876 cm−1 is assigned to a combination of (1LO + 2LO) [37][38]. The UV–vis absorption spectrum of CdS NPs exhibited an absorption edge (λe) at ≈480 nm (Figure 2c) which further depicted an average nanoparticle size of 4.71 nm as derived from

Electron energy relaxation under terahertz excitation in (Cd_1−xZn_x)₃As₂ Dirac semimetals

• Alexandra V. Galeeva,
• Ivan V. Krylov,
• Konstantin A. Drozdov,
• Anatoly F. Knjazev,
• Alexey V. Kochura,
• Alexander P. Kuzmenko,
• Vasily S. Zakhvalinskii,
• Sergey N. Danilov,
• Ludmila I. Ryabova and
• Dmitry R. Khokhlov

Beilstein J. Nanotechnol. 2017, 8, 167–171, doi:10.3762/bjnano.8.17

• electrons excited by the incident terahertz radiation occurs mainly via the interelectron interaction since the optical phonon energy is higher than the laser quantum energy used. Consequently, the strong enhancement of the thermalization time in topological insulators compared to the trivial insulators is

Obtaining and doping of InAs-QD/GaAs(001) nanostructures by ion beam sputtering

• Sergei N. Chebotarev,
• Alexander S. Pashchenko,
• Leonid S. Lunin,
• Elena N. Zhivotova,
• Georgy A. Erimeev and
• Marina L. Lunina

Beilstein J. Nanotechnol. 2017, 8, 12–20, doi:10.3762/bjnano.8.2

• fabricated at different ion current densities. The shift of the peaks is caused, first of all, by the reduction of elastic stress in the layers with QDs and, then, by an increase in the average QD size. The peaks drift to LO phonon scattering on unstrained single-crystal indium arsenide at 242 cm−2. Note

Effect of Anderson localization on light emission from gold nanoparticle aggregates

• Mohamed H. Abdellatif,
• Marco Salerno,
• Gaser N. Abdelrasoul,
• Ioannis Liakos,
• Alice Scarpellini,
• Sergio Marras and
• Alberto Diaspro

Beilstein J. Nanotechnol. 2016, 7, 2013–2022, doi:10.3762/bjnano.7.192

• . Another effective process is the carrier–phonon scattering, but this process is as fast as in the bulk, so it cannot contribute to the enhancement of the PL. Coulomb scattering is another nonradiative process, but it is faster in nanoparticles than in bulk metal because of the size-dependent screening

Active and fast charge-state switching of single NV centres in diamond by in-plane Al-Schottky junctions

• Christoph Schreyvogel,
• Vladimir Polyakov,
• Sina Burk,
• Helmut Fedder,
• Andrej Denisenko,
• Felipe Fávaro de Oliveira,
• Ralf Wunderlich,
• Jan Meijer,
• Verena Zuerbig,
• Jörg Wrachtrup and
• Christoph E. Nebel

Beilstein J. Nanotechnol. 2016, 7, 1727–1735, doi:10.3762/bjnano.7.165

• show fluorescence upon optical excitation, whereas NV0 and NV− show a zero phonon line at 575 nm at 637 nm, respectively, with their corresponding phonon side bands [8]. A PL-intensity mapping performed on the surface shows bright spots originating from NV luminescence (Figure 1a). An analysing of PL

• surface (black spectrum in Figure 3), since the NV centre is in the NV+ state which shows no fluorescence. Upon applying a reverse bias voltage of +15 V, the measured spectrum clearly shows NV0 emission with the characteristic zero phonon line at 575 nm and its phonon side band (red spectrum in Figure 3

• ). By increasing the reverse bias voltage to +20 V, the measured spectrum shows NV− emission with the characteristic zero phonon line at 637 nm and its phonon side band (blue spectrum in Figure 3). After switching off the applied bias voltage, the recorded PL-spectrum revealed only the previously

Fingerprints of a size-dependent crossover in the dimensionality of electronic conduction in Au-seeded Ge nanowires

• Maria Koleśnik-Gray,
• Gillian Collins,
• Justin D. Holmes and
• Vojislav Krstić

Beilstein J. Nanotechnol. 2016, 7, 1574–1578, doi:10.3762/bjnano.7.151

• , two regimes were identified for large (lightly doped) and small (stronger doped) nanowires in which the charge-carrier drift is dominated by electron-phonon and ionized-impurity scattering, respectively. This goes in hand with the finding that the electrostatic properties for radii below ca. 37 nm

•  3a). In the case of mobility (Figure 3b), between ≤1015 and ≈1016 cm−3 μNW(Nd) ≈ Nd, indicating that lattice phonon scattering is the main mechanism limiting the carrier drift [25]. The dominance of electron phonon scattering within this density range suggests that the free holes behave similar to

Localized surface plasmons in structures with linear Au nanoantennas on a SiO₂/Si surface

• Ilya A. Milekhin,
• Sergei A. Kuznetsov,
• Ekaterina E. Rodyakina,
• Alexander G. Milekhin,
• Alexander V. Latyshev and
• Dietrich R. T. Zahn

Beilstein J. Nanotechnol. 2016, 7, 1519–1526, doi:10.3762/bjnano.7.145

• between plasmonic excitations of gold nanoantennas and optical phonons in SiO2 leads to the appearance of new plasmon–phonon modes observed in the infrared transmission spectra the frequencies of which are well predicted by the simulations. Keywords: nanoantenna array; localised surface plasmon resonance

• ; plasmon–phonon interaction; phonons; SiO2; Introduction Plasmonic metamaterials remain the object of keen interest both in fundamental and applied research due to their unique optical properties including negative and zero refraction, focusing, filtering, polarization manipulation, etc. [1][2][3][4

• response of various thin films and adsorbents due to coincidence of LSPR energies in the nanoantenna and vibrational states of a studied substance [28][29][30]. When the LSPR energy in metal nanostructures is close to the optical phonon energy of investigated substances or thin films, the effects of

Electric field induced structural colour tuning of a silver/titanium dioxide nanoparticle one-dimensional photonic crystal

• Eduardo Aluicio-Sarduy,
• Simone Callegari,
• Diana Gisell Figueroa del Valle,
• Andrea Desii,
• Ilka Kriegel and
• Francesco Scotognella

Beilstein J. Nanotechnol. 2016, 7, 1404–1410, doi:10.3762/bjnano.7.131

• electrons release their energy to the lattice via electron–phonon scattering. iii) The hot lattice releases its energy to the environment within hundreds of ps. With the temporal resolution of our setup, which is about 150 fs, we could not observe the electron–electron scattering, but the dynamic of the

• resonance at 450 nm reported in Figure 3b is related to the electron–phonon scattering. This picosecond-scale dynamic is followed by a very weak phonon–phonon scattering. The photonic band gap (around 620 nm) does not show any particular dynamic (not shown here), as expected. The combination of a metal and

Diameter-driven crossover in resistive behaviour of heavily doped self-seeded germanium nanowires

• Stephen Connaughton,
• Maria Koleśnik-Gray,
• Richard Hobbs,
• Olan Lotty,
• Justin D. Holmes and
• Vojislav Krstić

Beilstein J. Nanotechnol. 2016, 7, 1284–1288, doi:10.3762/bjnano.7.119

• therefore the quantum regime is entered. As dominating resistivity contributions, we considered phonon and (remote) Coulomb scattering from the charge traps at the core/shell interface (Supporting Information File 1). Surface roughness scattering was neglected within our diameter range, as previous reports