Gas sensing with gold-decorated vertically aligned carbon nanotubes

• Prasantha R. Mudimela,
• Mattia Scardamaglia,
• Oriol González-León,
• Nicolas Reckinger,
• Rony Snyders,
• Eduard Llobet,
• Carla Bittencourt and
• Jean-François Colomer

Beilstein J. Nanotechnol. 2014, 5, 910–918, doi:10.3762/bjnano.5.104

• CVD reactor using C2H4 as carbon source. Si wafers with native SiO2 were used as substrates. Al2O3 (30 nm) were used as buffer layer on wafer pieces and Fe (6 nm) used as active catalyst. The multilayer system composed of Si/native SiO2/Al2O3/Fe will be called from now the catalyst. The Al2O3 and Fe

Antimicrobial properties of CuO nanorods and multi-armed nanoparticles against B. anthracis vegetative cells and endospores

• Pratibha Pandey,
• Merwyn S. Packiyaraj,
• Himangini Nigam,
• Gauri S. Agarwal,
• Beer Singh and
• Manoj K. Patra

Beilstein J. Nanotechnol. 2014, 5, 789–800, doi:10.3762/bjnano.5.91

• from 10 to 100 mg per 2000 cells. Haggstrom et al. [14] have reported sporicidal activity of corrosive halogen adducts of nanometer-scaled active metal oxides Al2O3, TiO2 and CeO2 in a solid based interaction on microfiltration membranes. The ratio of bacterial agents to metal oxide is not clear from

Carbon dioxide hydrogenation to aromatic hydrocarbons by using an iron/iron oxide nanocatalyst

• Hongwang Wang,
• Jim Hodgson,
• Tej B. Shrestha,
• Prem S. Thapa,
• David Moore,
• Xiaorong Wu,
• Myles Ikenberry,
• Deryl L. Troyer,
• Donghai Wang,
• Keith L. Hohn and
• Stefan H. Bossmann

Beilstein J. Nanotechnol. 2014, 5, 760–769, doi:10.3762/bjnano.5.88

• ] and copper [22] had significant effect on both the reactivity and selectivity of the iron-based catalysts. Higher olefins and aliphatic hydrocarbons, as well as improved CO2 conversion, were achieved. Al2O3 was found to be an excellent structural promoter to sustain the catalyst activity of iron-based

En route to controlled catalytic CVD synthesis of densely packed and vertically aligned nitrogen-doped carbon nanotube arrays

• Slawomir Boncel,
• Sebastian W. Pattinson,
• Valérie Geiser,
• Milo S. P. Shaffer and
• Krzysztof K. K. Koziol

Beilstein J. Nanotechnol. 2014, 5, 219–233, doi:10.3762/bjnano.5.24

• 5 × 108 nanotubes per mm2 while the highest value of areal density of MWCNTs reported up-to-date was 4.9 × 108 nanotubes per mm2 [58]. However, this value was found for the hydrogen-assisted growth from ethylene with an Fe/Al2O3 catalyst that was pre-treated with hydrogen. This synthesis yielded

3D-nanoarchitectured Pd/Ni catalysts prepared by atomic layer deposition for the electrooxidation of formic acid

• Loïc Assaud,
• Evans Monyoncho,
• Kristina Pitzschel,
• Anis Allagui,
• Matthieu Petit,
• Margrit Hanbücken,
• Elena A. Baranova and
• Lionel Santinacci

Beilstein J. Nanotechnol. 2014, 5, 162–172, doi:10.3762/bjnano.5.16

• detection mode was used to enhance the chemical contrast of the image shown in Figure 3. The NiO deposit (red color in the figure) is clearly visible within the Al2O3 pores. The NiO film is approximately 10 nm thick after 1000 ALD cycles. The TEM picture presented in Figure 4 shows the as-grown NiO layer

• have been investigated for the electrooxidation of formic acid in 0.5 M H2SO4. The deposition of nickel oxide from NiCp2 and O3 precursors on high aspect ratio nanoporous Al2O3 has been demonstrated. Although the chemical composition analysis of the NiO layers has not shown that the reductive treatment

• constant voltage, U, of 40 V in oxalic acid. A chemical dissolution was performed between the two anodizations to remove the disordered sacrificial Al2O3 layer. The resulting alumina membrane is ordered on a large scale area (ca. 10 cm2); the pore diameter is 40 nm and the length of the pores is about 5 μm

Quantum size effects in TiO₂ thin films grown by atomic layer deposition

• Massimo Tallarida,
• Chittaranjan Das and
• Dieter Schmeisser

Beilstein J. Nanotechnol. 2014, 5, 77–82, doi:10.3762/bjnano.5.7

• spectra were also observed in very thin TiO2 films that were grown by reactive evaporation in oxygen atmosphere at room temperature on SiO2 [18], Al2O3 [19] and MgO [20]. There, XAS spectra at the Ti-L2,3 absorption edge were analyzed within the charge-transfer multiplet (CTM) model. Within the CTM theory

• -field and pdσ at the TiO2 interface with either MgO, Al2O3 or SiO2, attributing the line shape of the Ti-L2,3 spectra to structural modifications of TiO2, changing the Slater integrals would have induced to attribute the line-shape variations to a changed Ti 3d/O 2p hybridization (and covalency) in very

Challenges in realizing ultraflat materials surfaces

• Takashi Yatsui,
• Wataru Nomura,
• Fabrice Stehlin,
• Olivier Soppera,
• Makoto Naruse and
• Motoichi Ohtsu

Beilstein J. Nanotechnol. 2013, 4, 875–885, doi:10.3762/bjnano.4.99

• ), because the land structures of 100 nm in height were etched by using this process. Dressed photon–phonon desorption A DPP desorption process has also been developed for smoothing the surfaces of transparent ceramics such as alumina (Al2O3), which is a hard polycrystalline ceramic [44]. Alumina can be used

• as a low-loss gain medium for ceramic lasers [45] that are used in laser-driven spark plugs for ignition systems in automobile engines [46]. We expect that the surface roughness (e.g., scratches) of such media could be reduced by sputtering with Al2O3 nanoparticles, followed by DPP desorption [47

• ]. In this study, radio frequency (RF) sputtering was used to deposit Al2O3 nanoparticles on an alumina substrate. In the case of conventional RF sputtering, the migration length of the Al2O3 nanoparticles on the substrate surface depends on the Schwöbel barrier [48] in the free energy profile. The

Synthesis and electrochemical performance of Li₂Co_1−xM_xPO₄F (M = Fe, Mn) cathode materials

• Nellie R. Khasanova,
• Oleg A. Drozhzhin,
• Stanislav S. Fedotov,
• Darya A. Storozhilova,
• Rodion V. Panin and
• Evgeny V. Antipov

Beilstein J. Nanotechnol. 2013, 4, 860–867, doi:10.3762/bjnano.4.97

• consisted of Al2O3/C/PVdF in a ratio of 80/10/10, in order to imitate the effect of the carbon- and binding electrode components at high potentials. Because the loading mass and the effective surface area of the active material on the electrodes that were used for electrolyte testing were similar in all

• 3D-Li2MPO4F, positions of Li atoms are denoted. Cyclovoltammetry curves (first cycle) of 1 M LiPF6 in EC/DMC (black) and 1 M LiBF4 in TMS (red) at scan rate of 0.1 mV·s−1. (a) Aluminum electrode, (b) idle electrode consisting of Al2O3/C/PVdF in an 80/10/10 ratio. Powder XRD patterns of Li2CoPO4F/C (a

Synthesis of boron nitride nanotubes from unprocessed colemanite

• Saban Kalay,
• Zehra Yilmaz and
• Mustafa Çulha

Beilstein J. Nanotechnol. 2013, 4, 843–851, doi:10.3762/bjnano.4.95

• catalyst. For this purpose Fe, Al or Mg are widely used in the synthesis of BNNT [3][6]. In this study, four types of catalysts, namely ZnO, Al2O3, Fe3O4, and Fe2O3, were investigated for their performances. Figure 1a–d shows 4 SEM images of reaction mixtures under the same experimental conditions but each

• when ZnO (data not shown) or Al2O3 (Figure 1b) was used. For the initiation of the synthesis reaction the catalyst in the reaction mixture must be as close as possible to the reaction mixture surface to interact with NH3 gas. Since these metal oxides stay buried under the colemanite due to the density

• (Figure 4d). Peaks were observed at 2θ angles of 26.8° and 41.8° belonging to hexagonal BN. There are not any crystalline phase peaks originating from CaO, SiO2, Al2O3, MgO, SrO or Na2O in colemanite and the Fe2O3 catalyst. UV–vis, FTIR and Raman analysis of BNNTs The BNNTs were analyzed with UV–vis

Synthesis of indium oxi-sulfide films by atomic layer deposition: The essential role of plasma enhancement

• Cathy Bugot,
• Nathanaëlle Schneider,
• Daniel Lincot and
• Frédérique Donsanti

Beilstein J. Nanotechnol. 2013, 4, 750–757, doi:10.3762/bjnano.4.85

• generated, has been the key for the development of fast thin-film deposition processes at low temperature. It is widely used to enhance the thin-film deposition of materials such as Al2O3, ZnO, Ta2O5, TiN, TaN and SiNx [19]. In this study, ALD and PEALD have been used to synthesize In2(S,O)3 thin films and

Ellipsometry and XPS comparative studies of thermal and plasma enhanced atomic layer deposited Al₂O₃-films

• Jörg Haeberle,
• Karsten Henkel,
• Hassan Gargouri,
• Franziska Naumann,
• Bernd Gruska,
• Michael Arens,
• Massimo Tallarida and
• Dieter Schmeißer

Beilstein J. Nanotechnol. 2013, 4, 732–742, doi:10.3762/bjnano.4.83

• , Germany 10.3762/bjnano.4.83 Abstract We report on results on the preparation of thin (<100 nm) aluminum oxide (Al2O3) films on silicon substrates using thermal atomic layer deposition (T-ALD) and plasma enhanced atomic layer deposition (PE-ALD) in the SENTECH SI ALD LL system. The T-ALD Al2O3 layers were

• not influenced significantly. Initial state energy shifts in all PE-ALD samples are observed which we attribute to a net negative charge within the films. Keywords: Al2O3; ALD; ellipsometry; PE-ALD; XPS; Introduction Thin aluminum oxide (Al2O3) layers deposited by atomic layer deposition (ALD) have

• [8] or corrosion protection [9]. Recently, there is a growing activity in covering photo-electrodes or electrodes by ultra-thin Al2O3 ALD layers for electrochemical energy generation and storage systems [10] in order to enhance the efficiency and durability of such devices. This includes for example

Surface passivation and optical characterization of Al₂O₃/a-SiC_x stacks on c-Si substrates

• Gema López,
• Pablo R. Ortega,
• Cristóbal Voz,
• Isidro Martín,
• Mónica Colina,
• Anna B. Morales,
• Albert Orpella and
• Ramón Alcubilla

Beilstein J. Nanotechnol. 2013, 4, 726–731, doi:10.3762/bjnano.4.82

• study the surface passivation of aluminum oxide/amorphous silicon carbide (Al2O3/a-SiCx) stacks on both p-type and n-type crystalline silicon (c-Si) substrates as well as the optical characterization of these stacks. Al2O3 films of different thicknesses were deposited by thermal atomic layer deposition

• experimentally determined the optimum thickness of the stack for photovoltaic applications by minimizing the reflection losses over a wide wavelength range (300–1200 nm) without compromising the outstanding passivation properties of the Al2O3 films. The upper limit of the surface recombination velocity (Seff,max

• ) was evaluated at a carrier injection level corresponding to 1-sun illumination, which led to values below 10 cm/s. Reflectance values below 2% were measured on textured samples over the wavelength range of 450–1000 nm. Keywords: aluminum oxide (Al2O3); antireflection coating; atomic layer deposition

Preparation of electrochemically active silicon nanotubes in highly ordered arrays

• Tobias Grünzel,
• Young Joo Lee,
• Karsten Kuepper and
• Julien Bachmann

Beilstein J. Nanotechnol. 2013, 4, 655–664, doi:10.3762/bjnano.4.73

• Al2O3 closing the pore extremities was opened in 5 wt % H3PO4 (45 °C, 10 min), after which the samples were dried for 4 h at 400 °C in air. Thermal reductions of SiO2 and subsequent steps When flat films (thermal oxide layer on Si wafer pieces) were used as a starting material, their thickness was

Ferromagnetic behaviour of Fe-doped ZnO nanograined films

• Boris B. Straumal,
• Svetlana G. Protasova,
• Andrei A. Mazilkin,
• Thomas Tietze,
• Eberhard Goering,
• Gisela Schütz,
• Petr B. Straumal and
• Brigitte Baretzky

Beilstein J. Nanotechnol. 2013, 4, 361–369, doi:10.3762/bjnano.4.42

• ZnO itself. We carefully measured the magnetization curves for bare Al2O3 substrates and subtracted them from data for the substrates including ZnO films. The films were transparent and sometimes with a very slight greenish finish. The films had a thickness between 50 and 200 nm, determined using edge

Near-field effects and energy transfer in hybrid metal-oxide nanostructures

• Ulrich Herr,
• Barat Achinuq,
• Cahit Benel,
• Giorgos Papageorgiou,
• Manuel Goncalves,
• Johannes Boneberg,
• Paul Leiderer,
• Paul Ziemann,
• Peter Marek and
• Horst Hahn

Beilstein J. Nanotechnol. 2013, 4, 306–317, doi:10.3762/bjnano.4.34

• investigated by modification of the surface of the nanophosphors. Stable oxides may be considered as a suitable solution for such a coating. In principle, two options may be considered in the present context. A coating with a wide-band-gap oxide material, such as Al2O3, could passivate the surface and confine

• using organic surfactants. Results of the ALD post-processing of TiO2:Eu nanoparticles are shown in Figure 7 and Figure 8. Figure 7 shows a STEM image of TiO2:Eu nanoparticles coated with 3 nm of Al2O3. In addition, a thin layer of TiO2 was added at the end of the process in order to test the

• possibility of generating multishell structures. One can clearly distinguish the TiO2:Eu core from the shell in Figure 7, but it is not possible to distinguish between the Al2O3 and the TiO2 part of the shell. Figure 8 shows a high-resolution TEM image of TiO2 nanoparticles coated with Al2O3. Lattice fringes

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

• catalytic system composed of thin Al2O3/Fe metal layers proposed by K. Hata, and co-workers [26][27]. In 2012, Zhu et al. [53] reported the synthesis of a hybrid material formed by VA-SWCNTs covalently bonded to graphene. The synthesis strategy is as follows. A sandwich consisting of a graphene substrate

Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

• Lu-Cun Wang,
• Yi Zhong,
• Haijun Jin,
• Daniel Widmann,
• Jörg Weissmüller and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 111–128, doi:10.3762/bjnano.4.13

• reaction temperature of 30 °C, without applying any pretreatment prior to the measurements. The catalysts were diluted with α-Al2O3 in order to obtain differential reaction conditions, with reactant conversions of below 15% throughout the measurements. The temperature of the catalyst bed was measured by a

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

• produced by vaporization from a resistively heated iron wire (current 2.7 A, diameter 250 μm, purity 99.95%, Goodfellow, USA) in a H2/Ar (7/93 mol ratio) flow of 480 cm3·min−1 inside an aluminium oxide (Al2O3) tube (inner diameter 16 mm). Particles formed and grew through vapor nucleation–condensation and

• coagulation processes inside an Al2O3 tube reactor (inner diameter 22 mm) and were mixed with 500 cm3·min−1 CO, together with 1300 ppm of CO2, in the heated section of the furnace. The mixing zone resided 29 cm from the bottom inlet of the reactor, corresponding to wall temperatures of 460–700 °C. The aerosol

Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor

• Wolfgang Molnar,
• Alois Lugstein,
• Tomasz Wojcik,
• Peter Pongratz,
• Norbert Auner,
• Christian Bauch and
• Emmerich Bertagnolli

Beilstein J. Nanotechnol. 2012, 3, 564–569, doi:10.3762/bjnano.3.65

• precursor gas flow was stopped, and the quartz tube was purged with He for a further 5 min before the sample was removed from the APCVD system. For contacting the NWs, 200 × 200 µm2 Au pads were structured on a highly doped Si (100) wafer, capped with 80 nm Al2O3, by photolithography and lift-off techniques

Surface functionalization of aluminosilicate nanotubes with organic molecules

• Wei Ma,
• Weng On Yah,
• Hideyuki Otsuka and
• Atsushi Takahara

Beilstein J. Nanotechnol. 2012, 3, 82–100, doi:10.3762/bjnano.3.10

• [Al2O3·SiO2·2H2O] [22]. The schematic representation of imogolite is shown in Figure 1. The gas adsorption data of N2, CO2, and CH4 concluded that imogolite possesses an inner-pore diameter of 1 nm [23]. The wall structure of imogolite comprises a layer of gibbsite on the outer wall, and a layer of

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

• groups/nm2 for H3Si(CH2)8SiH3. Unlike organosilane SAMs, whose tendency to form on TiO2 and SiO2 is quite similar, SAMs having phosphonic acid as their connecting head group are not formed on silicon dioxide but are formed easily from aqueous solutions on TiO2, Al2O3, Ta2O5 and Nb2O5 [27]. FTIR

• deposition of boehmite (AlOOH·nH2O) on the exposed TiO2 domains. Then, a heat-treatment step converted the boehmite into Al2O3, while oxidizing the SAMs, forming a patterned TiO2–boehmite surface. A hydrophobic SAM was then attached to both types of domains, which then went through a second step of exposure

Detection of interaction between biomineralising proteins and calcium carbonate microcrystals

• Hanna Rademaker and
• Malte Launspach

Beilstein J. Nanotechnol. 2011, 2, 222–227, doi:10.3762/bjnano.2.26

• -ray measurement. The specific surface area of the microcrystals was determined by the BET gas adsorption method (see, e.g., [4]) with N2 as adsorptive at a temperature of 77 K (BELsorp-miniII). Preparation of proteins Shells of Haliotis laevigata were sand blasted (Sigg Strahlmittel, WA 70, with Al2O3

Magnetic interactions between nanoparticles

• Steen Mørup,
• Mikkel Fougt Hansen and
• Cathrine Frandsen

Beilstein J. Nanotechnol. 2010, 1, 182–190, doi:10.3762/bjnano.1.22

• after grinding for different periods of time together with nanoparticles of η-Al2O3 [45]. At room temperature, the spectrum of the as-prepared sample shows a sextet with very broad lines, typical for samples in which the superparamagnetic relaxation is suppressed by inter-particle interactions. At 80 K

• nanoparticles, Phys. Rev. B 2000, 62, 1124. Copyright (2000) by the American Physical Society. Mössbauer spectra of 8 nm hematite nanoparticles ground in a mortar with η-Al2O3 nanoparticles for the indicated periods of time. (a) Spectra obtained at room temperature. (b) Spectra obtained at 80 K. Reprinted with

Flash laser annealing for controlling size and shape of magnetic alloy nanoparticles

• Damien Alloyeau,
• Christian Ricolleau,
• Cyril Langlois,
• Yann Le Bouar and
• Annick Loiseau

Beilstein J. Nanotechnol. 2010, 1, 55–59, doi:10.3762/bjnano.1.7

• pulsed laser beam, without changing the NPs composition. These developments open up a new way to design magnetic alloys NPs with ideal morphologies and size for magnetic studies and applications. Results and Discussion CoPt NP thin films on amorphous alumina (a-Al2O3) were produced by pulsed laser

• deposition (PLD) in a high vacuum chamber [21][22]. a-Al2O3 and the metals are deposited by PLD using a KrF excimer laser at 248 nm with a pulse duration of 25 ns at a repetition rate of 5 Hz. Substrates were commercial transmission electron microscopy (TEM) grids on which an amorphous carbon layer with a

• thickness of 10 nm was deposited. On the top of the amorphous carbon, a 3 nm layer of a-Al2O3 was deposited. Then, cobalt and platinum were alternatively deposited using pure Co and Pt targets irradiated with an energy density of 4.4 J/cm2 in order to obtain Co50Pt50 NPs. The crystalline structure of as