Functionalization of vertically aligned carbon nanotubes

• Eloise Van Hooijdonk,
• Carla Bittencourt,
• Rony Snyders and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2013, 4, 129–152, doi:10.3762/bjnano.4.14

• functionalization, and also dry gas-phase functionalization. Before presenting these methods, we briefly discuss different ways to synthesize vertically aligned carbon nanotubes and the existing approaches to obtain patterning of vertically aligned carbon nanotubes. A part of this review is also dedicated to a

• layer deposition (ALD). First the VA-CNTs were modified by chemical functionalization with a trimethylaluminium (TMA) monolayer or ex-situ Ar, O2 or Ar/O2 RF-plasma functionalization. Then, platinum was deposited by ALD. The gas-phase functionalization route was preferred in order to control the

Controlled deposition and combing of DNA across lithographically defined patterns on silicon

• Zeinab Esmail Nazari and
• Leonid Gurevich

Beilstein J. Nanotechnol. 2013, 4, 72–76, doi:10.3762/bjnano.4.8

• molecules across lithographically defined patterns. The technique involves surface modification of Si/SiO2 substrates with a hydrophobic silane by using gas-phase deposition. Thereafter, DNA molecules are aligned by dragging the droplet on the hydrophobic substrate with a pipette tip. Using this procedure

• substrates are coated with a thin layer of a hydrophobic silane by gas-phase deposition. Figure 1 is a representation of the combing procedure used in this experiment. In the method proposed here, the applied meniscus force is large enough to allow efficient combing of DNA across nanofabricated patterns as

• –peptide conjugates, while the original recipe was proven to be ineffective for combing these materials [11]. Figure 3 represents the topography of combed dsDNA conjugated with various peptides. Combing across nanoelectrodes was also possible for DNA–peptide conjugates (Figure 3e). The gas-phase deposition

Structural and electronic properties of oligo- and polythiophenes modified by substituents

• Simon P. Rittmeyer and
• Axel Groß

Beilstein J. Nanotechnol. 2012, 3, 909–919, doi:10.3762/bjnano.3.101

• predicted a dihedral angle of 17.5° with a very flat rotational potential for angles from 0° to 30° whereas Almenningen et al. obtained an angle of about 34° using gas-phase electron diffraction [37]. There are known problems when using GGA-DFT to compute rotational barriers especially for conjugated

Diamond nanophotonics

• Katja Beha,
• Helmut Fedder,
• Marco Wolfer,
• Merle C. Becker,
• Petr Siyushev,
• Mohammad Jamali,
• Anton Batalov,
• Christopher Hinz,
• Jakob Hees,
• Lutz Kirste,
• Harald Obloh,
• Etienne Gheeraert,
• Boris Naydenov,
• Ingmar Jakobi,
• Florian Dolde,
• Sébastien Pezzagna,
• Daniel Twittchen,
• Matthew Markham,
• Daniel Dregely,
• Harald Giessen,
• Jan Meijer,
• Fedor Jelezko,
• Christoph E. Nebel,
• Rudolf Bratschitsch,
• Alfred Leitenstorfer and
• Jörg Wrachtrup

Beilstein J. Nanotechnol. 2012, 3, 895–908, doi:10.3762/bjnano.3.100

• -collection efficiency and directed emission is demonstrated by solid immersion lenses and micropillar cavities. Thereafter, the coupling of diamond nanocrystals to the guided modes of micropillar resonators is discussed along with experimental results. Finally, we present a gas-phase-doping approach to

• advantage of our gas-phase-doping approach is that it offers a targeted dopant addition. The dopant concentration in the gas phase can be adjusted either by the temperature of the precursor material in the dopant reservoir or by the carrier gas flux. The reproducibility of our doping approach was verified

• was hence ascribed to impurities originating from the filament material and accordingly from the cathode material of the reactor systems. The observation of the W5-luminescence in diamond layers grown with the addition of W(CO)6 confirms the previous assignment. The gas-phase doping approach offered

Influence of the diameter of single-walled carbon nanotube bundles on the optoelectronic performance of dry-deposited thin films

• Kimmo Mustonen,
• Toma Susi,
• Antti Kaskela,
• Patrik Laiho,
• Ying Tian,
• Albert G. Nasibulin and
• Esko I. Kauppinen

Beilstein J. Nanotechnol. 2012, 3, 692–702, doi:10.3762/bjnano.3.79

• synthesized under previously optimized conditions at 880 °C with the introduction of 1500 ppm CO2. The SWCNTs were collected from the gas phase by filtering the flow at the reactor outlet through 10 mm diameter nitrocellulose disk filters (Millipore, HAWP, 0.45 µm pore diameter). In addition to the HWG

Zeolites as nanoporous, gas-sensitive materials for in situ monitoring of DeNO_x-SCR

• Thomas Simons and
• Ulrich Simon

Beilstein J. Nanotechnol. 2012, 3, 667–673, doi:10.3762/bjnano.3.76

• desorption from catalytic conversion under SCR-like conditions by IS on zeolite H-ZSM 5 with a Si/Al ratio of 80. We demonstrated that in situ monitoring of the NH3 conversion with NOx becomes feasible when the zeolite is loaded with NH3 first and NOx is applied to the gas phase afterwards [34]. In this

Polymer blend lithography: A versatile method to fabricate nanopatterned self-assembled monolayers

• Cheng Huang,
• Markus Moosmann,
• Jiehong Jin,
• Tobias Heiler,
• Stefan Walheim and
• Thomas Schimmel

Beilstein J. Nanotechnol. 2012, 3, 620–628, doi:10.3762/bjnano.3.71

• mask can be alternatively dissolved in THF, following the protocol described above for acetic acid. For the three-phase template the (3-aminopropyl)triethoxysilane (APTES, Aldrich) SAM was deposited onto the silicon surface inside the holes of the lithographic mask in the gas phase, shown in Figure 5a

Focused electron beam induced deposition: A perspective

• Michael Huth,
• Fabrizio Porrati,
• Christian Schwalb,
• Marcel Winhold,
• Roland Sachser,
• Maja Dukic,
• Jonathan Adams and
• Georg Fantner

Beilstein J. Nanotechnol. 2012, 3, 597–619, doi:10.3762/bjnano.3.70

• used in FEBID. In particular, one has to keep in mind that dissociation cross sections obtained on precursor molecules in the gas phase do not necessarily provide a suitable basis for a quantitative description of precursors in an adsorbed state. The coupling to the substrate provides additional

Spontaneous dissociation of Co₂(CO)₈ and autocatalytic growth of Co on SiO₂: A combined experimental and theoretical investigation

• Kaliappan Muthukumar,
• Harald O. Jeschke,
• Roser Valentí,
• Evgeniya Begun,
• Johannes Schwenk,
• Fabrizio Porrati and
• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 546–555, doi:10.3762/bjnano.3.63

• result of geometry optimization and are discussed in the text. Calculated Bader charges for Co2(CO)8 in units of electrons in the gas phase and for the adsorbate on SiO2 surfaces. The numbers in parenthesis identify the CO ligand as shown in Figure 5a and Figure 7. Values indicated by an asterisk

Imaging ultra thin layers with helium ion microscopy: Utilizing the channeling contrast mechanism

• Gregor Hlawacek,
• Vasilisa Veligura,
• Stefan Lorbek,
• Tijs F. Mocking,
• Antony George,
• Raoul van Gastel,
• Harold J. W. Zandvliet and
• Bene Poelsema

Beilstein J. Nanotechnol. 2012, 3, 507–512, doi:10.3762/bjnano.3.58

• , the BSHe data presented here was recorded with lower PEs between 10 keV and 20 keV. This results in a better signal-to-noise ratio for the BSHe images. Patterns of self-assembled monolayers (SAM) were created by using a PDMS stamp and gas-phase silanization. Orthogonal stripes with an identical width

Macromolecular shape and interactions in layer-by-layer assemblies within cylindrical nanopores

• Thomas D. Lazzara,
• K. H. Aaron Lau,
• Wolfgang Knoll,
• Andreas Janshoff and
• Claudia Steinem

Beilstein J. Nanotechnol. 2012, 3, 475–484, doi:10.3762/bjnano.3.54

• was adsorbed on the unfunctionalized surface. AAO substrates were O2 plasma cleaned for 2 min immediately prior to gas-phase silanization to increase the surface density of OH groups. The glass slide substrates to be silanized were inserted into a glass staining jar and 50 µL of APTES were added in a

Forming nanoparticles of water-soluble ionic molecules and embedding them into polymer and glass substrates

• Stella Kiel,
• Olga Grinberg,
• Nina Perkas,
• Jerome Charmet,
• Herbert Kepner and
• Aharon Gedanken

Beilstein J. Nanotechnol. 2012, 3, 267–276, doi:10.3762/bjnano.3.30

• the alkali metals arose from the gas phase of the bubbles. The ions reached the hot center of the bubble by the flow of the liquid towards the center upon their collapse. In our case, cavitation occurs not only in pure liquid, but also in liquid near a solid surface (glass slides) and it was found

Electron-beam patterned self-assembled monolayers as templates for Cu electrodeposition and lift-off

• Zhe She,
• Andrea DiFalco,
• Georg Hähner and
• Manfred Buck

Beilstein J. Nanotechnol. 2012, 3, 101–113, doi:10.3762/bjnano.3.11

• which Cu deposition was suppressed. It is noted that the doses needed to produce good contrast in our electrochemical experiment are substantially higher compared to those reported in the literature. For example, for Ni deposited from the gas phase about 45 mC/cm2 was used [54]. In electrochemical

Transmission eigenvalue distributions in highly conductive molecular junctions

• Justin P. Bergfield,
• Joshua D. Barr and
• Charles A. Stafford

Beilstein J. Nanotechnol. 2012, 3, 40–51, doi:10.3762/bjnano.3.5

• ][12] to transport through SMJs utilized a semiempirical Hamiltonian [13] for the π-electrons, which accurately describes the gas-phase spectra of conjugated organic molecules. Although this approach should be adequate to describe molecules weakly coupled to metal electrodes, e.g., by thiol linkages

• is derived from Maxwell’s equations, and hence can be readily generalized to include screening of intramolecular Coulomb interactions due to nearby metallic electrodes. Effective Hamiltonian This allows the effective Hamiltonian for the π-electrons in gas-phase benzene to be expressed as where t is

• correct up to fifth order in the interatomic distance. Benzene The adjustable parameters in our Hamiltonian for gas-phase benzene are the nearest-neighbor tight-binding matrix element t, the on-site repulsion U, the dielectric constant , and the π-orbital quadrupole moment Q. These were renormalized by

Self-assembled monolayers and titanium dioxide: From surface patterning to potential applications

• Yaron Paz

Beilstein J. Nanotechnol. 2011, 2, 845–861, doi:10.3762/bjnano.2.94

• often observed both in the liquid phase and in the gas phase, suggesting, albeit not proving [11][12] the need for adsorption as a prerequisite for photocatalysis. Self-assembled monolayers (SAMs) being chemisorbed in an ordered manner on surfaces such as metals (Au, Ag), oxides (SiO2, Al2O3, TiO2) and

• grafting density with respect to chemisorption by conventional methods (2.8–3.0 molecules per nm2 versus 4.3–4.8 molecules per nm2). It is worth mentioning that a study on organosilane monolayers formed on the surfaces of zirconia and titania (anatase and rutile), by a gas–phase process employing

• chains in the LB film plays a role in improving the capturing of the spheres. Atomic-layer deposition (ALD) is a gas–phase thin-film deposition method employing self-terminating surface reactions, leading to a linear correlation between the thickness of the layer and the number of deposition cycles

Template-assisted formation of microsized nanocrystalline CeO₂ tubes and their catalytic performance in the carboxylation of methanol

• Jörg J. Schneider,
• Meike Naumann,
• Christian Schäfer,
• Armin Brandner,
• Heiko J. Hofmann and
• Peter Claus

Beilstein J. Nanotechnol. 2011, 2, 776–784, doi:10.3762/bjnano.2.86

• stability. We observed partial destruction of the 1-D structure during the catalytic reactions in the liquid reaction phase of the batch reactor setup. Currently we are setting up a gas-phase reaction system in order to study the DMC formation under gas phase conditions, with an aim to minimize the

Towards quantitative accuracy in first-principles transport calculations: The GW method applied to alkane/gold junctions

• Mikkel Strange and
• Kristian S. Thygesen

Beilstein J. Nanotechnol. 2011, 2, 746–754, doi:10.3762/bjnano.2.82

• found here [56]. For calculations of the molecules in the gas-phase, we include 16 Å of vacuum between molecules in the repeated supercells. All transport calculations where performed according to the method described in detail in [24]. In brief, we employ a basis set of numerical atomic orbitals

• Table 2 we list the energy of the HOMO and HOMO–2 calculated with DFT-PBE, Hartree–Fock (HF), and GW for the molecules in the gas-phase and in the junction. In the gas-phase, all three methods predict the HOMO energy to be almost independent of molecular length. This is clearly due to its end-group

• levels to shift downwards even more than for the isolated molecules, i.e., the gap will shrink relative to its gas-phase value. It has been shown previously that DFT in (semi)local approximations and Hartree–Fock completely miss this important effect [26][27][28]. In Figure 2c and Figure 2d, we show the

Generation and agglomeration behaviour of size-selected sub-nm iron clusters as catalysts for the growth of carbon nanotubes

• Ravi Joshi,
• Benjamin Waldschmidt,
• Jörg Engstler,
• Rolf Schäfer and
• Jörg J. Schneider

Beilstein J. Nanotechnol. 2011, 2, 734–739, doi:10.3762/bjnano.2.80

• crystal [6]. Size-defined, sub-nm, ligand-free metal clusters would be an interesting synthetic alternative to obtain CNTs with controlled diameter. However, such small metal clusters can only be generated by gas-phase techniques, typically in a ligand-free environment as naked clusters. A controlled

Formation of SiC nanoparticles in an atmospheric microwave plasma

• Martin Vennekamp,
• Ingolf Bauer,
• Matthias Groh,
• Evgeni Sperling,
• Susanne Ueberlein,
• Maksym Myndyk,
• Gerrit Mäder and
• Stefan Kaskel

Beilstein J. Nanotechnol. 2011, 2, 665–673, doi:10.3762/bjnano.2.71

• mN/m [25], and the molar volume is usually assumed to be that of the bulk material. Hence, in order to determine the minimal nanoparticle size during the microwave synthesis we made the following arbitrary assumption: The partial pressure of the SiC species in the gas phase over the SiC nanoparticles

• the Lifshitz–Slyozov–Wagner (LSW) theory [26][27], which has also been adopted for description of the growth of nanoparticles from the gas phase [28]. The surface kinetics in a plasma is increased [29], driving the growth process into a diffusion limit. The particle growth rate is therefore given by

Femtosecond time-resolved photodissociation dynamics of methyl halide molecules on ultrathin gold films

• Mihai E. Vaida,
• Robert Tchitnga and
• Thorsten M. Bernhardt

Beilstein J. Nanotechnol. 2011, 2, 618–627, doi:10.3762/bjnano.2.65

• systems, which have been studied in great detail in the gas phase (see, e.g., [3][4][5][6][7]) as well on several metallic and nonmetallic solid substrates (see, e.g., [8][9][10][11][12][13][14]). The adsorption of methyl iodide on a gold surface has been previously investigated [9][11]. However, nothing

• slightly perturbed from the gas phase. In contrast, the excited state is strongly bound to the metal surface, which facilitates the recapturing of the ground state before the C–I bond stretches considerably. As a consequence, the molecule will almost instantaneously relax back to the ground state after

Nanostructured, mesoporous Au/TiO₂ model catalysts – structure, stability and catalytic properties

• Matthias Roos,
• Dominique Böcking,
• Kwabena Offeh Gyimah,
• Gabriela Kucerova,
• Joachim Bansmann,
• Johannes Biskupek,
• Ute Kaiser,
• Nicola Hüsing and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2011, 2, 593–606, doi:10.3762/bjnano.2.63

• at 80 °C and comparable gas-phase compositions. The much lower reaction orders in the above two studies can be explained by the lower reaction temperatures in those cases. Considering the steep increase of the total reaction order with temperature, by almost 100% upon increasing from 90 °C to 135 °C

Towards a scalable and accurate quantum approach for describing vibrations of molecule–metal interfaces

• David M. Benoit,
• Bruno Madebene,
• Inga Ulusoy,
• Luis Mancera,
• Yohann Scribano and
• Sergey Chulkov

Beilstein J. Nanotechnol. 2011, 2, 427–447, doi:10.3762/bjnano.2.48

• efficient computational tool. We also present results on the vibrational spectrum of hydrogen fluoride on pyrene, on the thiophene molecule in the gas phase, and on small neutral gold clusters. Keywords: computational scaling; grid computing; molecule–metal interactions; periodic density functional theory

• ) that can be further exploited in the vibrational correlation treatment to construct efficient algorithms, as will be shown later in the paper. Our local VSCF implementation Our aim is to develop a program to compute accurate vibrational frequencies of polyatomic system in the gas phase, condensed phase

• the VSCF/VCI level of vibrational theory and using the STA approach we obtain 3477 cm−1 which corresponds to a shift of −135 cm−1 from the gas-phase molecule stretch frequency, ν(HF) = 3612 cm−1 from the 1-D vibrational solutions. To the best of our knowledge the HF-stretch frequency of hydrogen

Influence of water on the properties of an Au/Mpy/Pd metal/molecule/metal junction

• Jan Kučera and
• Axel Groß

Beilstein J. Nanotechnol. 2011, 2, 384–393, doi:10.3762/bjnano.2.44

• structure with every second water molecule bound to the metal surface via the oxygen atom. The other water molecules have one hydrogen atom either pointing away from the surface (Hup) or towards the surface (Hdown). In such an arrangement the adsorption energy related to one H2O in the gas phase is higher

• gas phase. In order to check whether this is a consequence of the lowered coordination of the Pd atoms in the monolayer, or of the changes induced by the N–Pdb interaction, we considered a free-standing palladium (111) monolayer using a (3 × 3) unit cell. Within this model, we first calculated the

• energy gain per H2O molecule upon adsorption with respect to a H2O molecule in the gas phase. Bader analysis of the total electronic charge depletion/accumulation in the Au slab, the 4-mercaptopyridine molecule, the palladium layer (in parenthesis: Charge localized on the Pdb atom only), and the water

Studies towards synthesis, evolution and alignment characteristics of dense, millimeter long multiwalled carbon nanotube arrays

• Pitamber Mahanandia,
• Jörg J. Schneider,
• Martin Engel,
• Bernd Stühn,
• Somanahalli V. Subramanyam and
• Karuna Kar Nanda

Beilstein J. Nanotechnol. 2011, 2, 293–301, doi:10.3762/bjnano.2.34

• methodology, the experimental set up was modified such that the precursor mixture vaporized and the gas-phase precursor species were driven to the hot reaction zone without any additional transport gas. In the hot reaction zone, the precursor mixture pyrolyzed into carbon species and iron, resulting in the

Effect of large mechanical stress on the magnetic properties of embedded Fe nanoparticles

• Srinivasa Saranu,
• Sören Selve,
• Ute Kaiser,
• Luyang Han,
• Ulf Wiedwald,
• Paul Ziemann and
• Ulrich Herr

Beilstein J. Nanotechnol. 2011, 2, 268–275, doi:10.3762/bjnano.2.31

• Deposition and structure of the Fe nanoparticles The Fe nanoparticles used in this study were prepared by plasma-assisted gas phase condensation [14]. This method allows deposition of both, elemental [15] and alloy clusters with rather narrow size distributions. By combination with a film deposition