bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dislocation imaging for electronics application crystal selection
Authors: Secroun Aurélia , Brinza Ovidiu , Tardieu André , Achard Jocelyn , Silva François , Bonnin Xavier , De Corte Katrien , Anthonis Ans , Newton Mark E. , Ristein Jürgen , Geithner Peter , Gicquel Alix 
Published: November 2007

AbstractHigh power electronics are today a real challenge for large band gap materials. Devices as simple as switches have to work at ever higher powers and demand material with exceptional properties: in particular, a high breakdown voltage (at least a few 106 V/cm), a high mobility‐lifetime product (at least 10–3 cm2/V), and a relatively fast response. As far as diamond is concerned, only thick (100 µm) monocrystalline free‐standing films of very good quality are expected to fulfill these requirements. Today's growth techniques still create many defects within the crystal that may deteriorate its electrical properties. It is thus our concern to identify which defects are involved and to find a strategy to select films with properties best suited for our power switching applications. Here, it is shown that nitrogen impurities are one major defect that control electrical properties as soon as 1 ppb is contained in the film and that, for lower values, dislocations seem to play a role. Besides, it is shown that the choice of substrate is involved in the formation of those dislocations within the grown film. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Industrial production of multiwalled carbon nanotubes
Authors: Bierdel M. , Buchholz S. , Michele V. , Mleczko L. , Rudolf R. , Voetz M. , Wolf A. 
Published: November 2007

AbstractCarbon Nanotubes are currently being synthesized by different methods. The methods differ largely by the achievable space‐time yield, amorphous carbon content and carbon purity. High space‐time yields can only be achieved by CVD processes. Though usually low contents of amorphous carbon are observed in CVD processes, C‐purity is generally decreased due to catalyst residues. Bayer Technology Services has developed a high‐yield process for multi‐walled carbon nanotubes (MWNT, trade name Baytubes®) based on a CCVD process starting from light hydrocarbons. The produced Baytubes® are characterized by a very high graphite content and an excellent purity (carbon content >95 wt%). Due to their high purity and quality, Baytubes® can be employed directly in further processing. The Baytubes® were incorporated into different polymers and also into liquids. The primary feature for good mechanical and electrical properties of the polymer composites is a full dispersion of the CNT in the polymer matrix. TEM analysis is an important method to investigate the CNT dispersion on the nanometer scale. But it is also necessary to combine different methods to ensure a good and constant dispersion quality. Thus, different analysis methods were developed by BTS during product development. Process scale‐up is under way and a nominal production capacity of 60 tons per year has already been commissioned. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrochemically modified single‐walled carbon nanotubes
Authors: Burghard M. , Maroto A. , Balasubramanian K. , Assmus T. , Forment‐Aliaga A. , Lee E. J. H. , Weitz R. T. , Scolari M. , Nan F. , Mews A. , Kern K. 
Published: November 2007

AbstractWe report on the properties of electrochemically modified SWCNTs bearing a functional organic layer and a low density of noble metal nanoparticles, respectively. First, a novel approach to nanoscale pH sensors is demonstrated which involves the gentle modification of individual metallic tubes via covalent attachment of amino‐substituted phenyl groups. Furthermore, gold particles with sizes of a few tens of nanometres deposited onto individual SWCNTs were found to locally enhance the Raman signals of the underlying nanotube. The enhancement imparted by individual gold particles was estimated to be two orders of magnitude. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
DNA–carbon nanotube interactions and nanostructuring based on DNA
Authors: Vogel Stephanie R. , Müller Katharina , Plutowski Ulrich , Kappes Manfred M. , Richert Clemens 
Published: November 2007

AbstractThe unusual properties of single‐walled carbon nanotubes (SWCNTs) make them attractive for applications in the realm of molecular electronics, but also cause severe experimental difficulties in the purification and handling of these materials. One important step toward routine use of SWCNTs is the development of concentrated, monodisperse suspensions that are suitable for conventional manipulation and chromatography. We have studied the effect of the structure of oligodeoxynucleotides on their ability to generate such suspensions of SWCNTs, as well as the ability to release the nanotubes site‐selectively after (local) heating. Interestingly, short DNA strands were found to be better “surfactants” for the solubilization process than longer ones. The kinetic stability data suggest that the affinity of oligodeoxynucleotides for SWCNTs is greater than that for complementary DNA strands. The implications of this finding for DNA‐based nanostructuring are discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Body emission characteristics from lateral single‐walled carbon nanotube emitters
Authors: Lee W. Y. , Yang F. , Fan L. S. , Tsai C. H. 
Published: November 2007

AbstractThe uniform body emission properties of lateral single‐walled carbon nanotubes (SWNTs) emitters grown by chemical vapor deposition are reported. Lateral SWNTs lying on the substrate were found to possess a turn‐on field of at least 1.67 V/μm and a field enhancement factor of 5223 at most. A flat panel display requiring 1 mA/cm2 was carried out at 4.7 V/μm. The large area uniform luminescence was obtained due to the uniform electrical field intensities throughout the body of SWNTs according to a calculation of electrical field distribution. Good field emission characteristics with a simple process could be more applicable for display applications. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Bond‐curvature effect on burning of single‐wall carbon nanotubes
Authors: Miyata Y. , Kawai T. , Miyamoto Y. , Yanagi K. , Maniwa Y. , Kataura H. 
Published: November 2007

AbstractChirality dependent burning of single‐wall carbon nanotubes (SWCNTs) was monitored using optical absorption and photoluminescence spectroscopy for the HiPco and the CoMoCAT SWCNTs. Results have indicated that nanotubes with a higher chiral angle and smaller diameter decomposed more rapidly through thermal oxidation in air. A “local curvature radius” along the C–C bond is found to be a major rate‐determining factor in the combustion process of SWCNTs. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of highly crystalline C60 thin films and their field‐effect mobility
Authors: Birendra Singh Th. , Yang H. , Plochberger B. , Yang L. , Sitter H. , Neugebauer H. , Sariciftci N. S. 
Published: November 2007

AbstractTransistors fabricated from C60 films grown by hot wall epitaxy at elevated substrate temperature of 250 °C, show charge carrier mobility of ∼6 cm2/Vs. When grown at substrate temperature of 25 °C, mobilities of only 0.6–1 cm2/Vs are obtained. The C60 films were characterized using grazing‐incidence X‐ray diffraction and show increased crystalline properties when grown at elevated substrate temperature. The improvement in the charge carrier mobility is attributed to the higher crystalline nature of the thin films. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Computer modeling of electronic structure of single‐wall carbon nanotubes affected by pressure
Authors: Osadchy A. V. , Obraztsova E. D. 
Published: November 2007

AbstractIn this paper, a principal calculation of the electronic structure of single‐wall carbon nanotubes at different pressure values has been performed. The simulations have been done for nanotubes aggregated in ropes. The pressure has been modeled by changing the distances between neighbor nanotubes in the rope. The results of the calculations show that the pressure increase leads to a decrease of energy of allowed optical transitions in nanotubes. This result corresponds to the experimental data published. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High pressure Raman study of the second‐order vibrational modes of single‐ and double‐walled carbon nanotubes
Authors: Papagelis K. , Andrikopoulos K. S. , Arvanitidis J. , Christofilos D. , Galiotis C. , Takenobu T. , Iwasa Y. , Kataura H. , Ves S. , Kourouklis G. A. 
Published: November 2007

AbstractThe pressure response of the second‐order Raman G′ band of bundled double‐ (DWCNTs) and single‐wall carbon nanotubes (SWCNTs) has been investigated by means of Raman spectroscopy using the 632.8 nm excitation. The different pressure responses of the G′ peak in SWCNTs and its corresponding components associated with the inner and the outer tubes in DWCNTs can be attributed to the different diameters of the resonantly probed tubes and the strength of the inner‐outer tube interaction. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ferrocene encapsulated in single‐wall carbon nanotubes: a precursor to secondary tubes
Authors: Shiozawa Hidetsugu , Pichler Thomas , Pfeiffer Rudolf , Kuzmany Hans , Kataura Hiromichi 
Published: November 2007

AbstractWe demonstrate filling of single‐wall carbon nanotubes with ferrocene. Encapsulated ferrocenes are utilized as a precursor to secondary inner tubes and iron dopant. The reaction pathway is traced by Raman and photoemission spectroscopy. From a comparison to the inner‐tube growth from C60 fillers we propose different mechanisms for the inner‐tube growth from fullerene and non‐fullerene precursors. This work pioneers a new chemistry using carbon nanotubes as a nano reaction furnace. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extreme thermal stability of carbon nanotubes
Authors: Begtrup G. E. , Ray K. G. , Kessler B. M. , Yuzvinsky T. D. , Garcia H. , Zettl A. 
Published: November 2007

AbstractThe versatility of carbon–carbon bonding creates a wealth of extraordinary physical properties. Of the two common allotropes of carbon, diamond (sp‐3 bonded) exhibits record thermal conductivity but is meta‐stable and transits to graphite at elevated temperatures. Graphite (sp‐2) is electrically conducting but sublimes at temperatures as low as 2400 K. Carbon nanotubes (also sp‐2) capitalize on the extraordinary strength of the sp‐2 hybridized carbon–carbon bond and exhibit high electrical and thermal conductivities as well as tremendous mechanical strength. Here we report a new technique to measure the thermal properties of nanosystems. We apply this technique to determine the ultimate high temperature breakdown of multiwalled carbon nanotubes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanofoam as a potential hydrogen storage material
Authors: Blinc R. , Arčon D. , Umek P. , Apih T. , Milia F. , Rode A. V. 
Published: November 2007

AbstractHydrogen based fuel cells are considered to be an important future alternative to fossile based energy sources such as oil, natural gas and coal. For many applications such a hydrogen driven cars, the limiting factor is the weight of the hydrogen fuel storage device which seems to be excessive for hydrogen stored in metals. This is the reason for the search for ultralight hydrogen storage materials such as carbon nanotubes or graphite layers. Here we report on the investigation of the basic mechanism of H‐carbonaceous interactions leading to hydrogen storage. The system has an ultra‐low density of 2–10 mg/cm3 and a large surface area 300–400 m2/g. Electron diffraction showed the presence of hyperbolic “schwarzite” layers making the system suitable for hydrogen storage. Preliminary proton NMR experiments showed that hydrogen can indeed be reversibly stored in carbon nanofoam at room temperature and that the corresponding proton spin lattice relaxation time T1 of the stored hydrogen is 400 ms. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Single‐walled carbon nanotubes as nanotest tubes
Authors: Borowiak‐Palen E. 
Published: November 2007

AbstractIn this study a wet‐chemistry procedure to perform a metathesis reaction in the interior of single‐walled carbon nanotube (SWCNT) is shown. Initially, AgNO3 was placed into the tube interior. The AgNO3 filling was then transformed into AgCl through a metathesis reaction involving a treatment step with HCl. The reaction highlights the potential application of SWCNT as nanotest tubes. This was further demonstrated by the successful development of a facile and efficient wet‐chemistry route to purge the AgCl filling from the interior of the SWCNT. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Filling of carbon nanotubes for bio‐applications
Authors: Costa S. , Borowiak‐Palen E. , Bachmatiuk A. , Rümmeli M. H. , Gemming T. , Kaleńczuk R. J. 
Published: November 2007

AbstractCarbon nanotubes (CNT) provide a smart carrier system on the nanometer scale. The system can be used as a template for ferromagnetic fillers. Such a molecular hybrid is a promising potential candidate for the controlled heating of tumour tissue at the cellular level. This is a key reason why it is important to optimize the synthesis route of metal filled carbon nanotubes with regards bulk scale synthesis and purity. In the current study we present multiwalled carbon nanotubes filled with α‐iron phase (Fe‐MWCNT). The influence of acid treatment on the stability of the filling and the sample purity is also presented. High resolution transmission microscopy, its Energy dispersive X‐Ray spectroscopy (EDX) and electron energy‐loss spectroscopy (EELS) modes have been applied for the analysis of the morphology and chemical composition of the samples. The phase of iron nanowires encapsulated into the carbon nanotubes was determined with selected area electron diffraction (SAED) on a local scale. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Method for continuous production of catalysts for synthesis of carbon nanotubes
Authors: Lima Márcio D. , Dettlaff Ursula , de Andrade Mônica J. , Skakalová Viera , Locatelli Andrei , Bergmann Carlos P. , Roth Siegmar 
Published: November 2007

AbstractA new method for continuous production of carbon nanotube (CNT) catalysts is proposed in this study. The method is a modification of the solution combustion synthesis and was called continuous solution combustion synthesis (CSCS). The method consists of the atomization of the modified combustion synthesis precursor solution in a pilot flame. A combustible, like ethanol, is added to the precursor solution to improve the evaporation of the solvent and the atomization. The ignition of the precursor solution is self‐sufficient. A fine and porous powder is produced. The powder, collected through an electrostatic precipitator, has superior performance as a carbon nanotube catalyst. When comparing the production of Fe–Mo/MgO catalyst synthesized by the continuous method with the conventional route, it was observed that the amount of carbon nanotubes increased by 52 wt%, and the G/D ratio was also higher. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural properties and electrochemical behavior of CNT‐TiO2 nanocrystal heterostructures
Authors: Frank Otakar , Kalbac Martin , Kavan Ladislav , Zukalova Marketa , Prochazka Jan , Klementova Mariana , Dunsch Lothar 
Published: November 2007

AbstractDifferent methods of preparation of CNT‐TiO2 (anatase) heterostructures have been tested in order to obtain information on the relationship between the preparation method, resulting structure of the material and its electrochemical behavior during Li+ insertion. The most complete TiO2 coverage of individual non‐functionalized MWCNT was achieved in block co‐polymer (Pluronic P123) templated TiO2 thin films. This heterostructure has the highest specific capacity of Li+ insertion into TiO2 lattice to form Lix TiO2 (688 C/g, x = 0.57), however, this was accompanied by the worst reversibility (76%). On the contrary, electrodeposited TiO2 on SWCNT covered only bundles of nanotubes and its Li+ insertion capacity was 507 C/g (x = 0.42). However, the reversibility for all electrodeposited samples was almost complete and varied around 98%. Furthermore, Li+ insertion behavior studied by the cyclic voltammetry technique showed unambiguously the presence of minute amounts of monoclinic TiO2(B) in addition to anatase in samples from both synthesis methods. Thirdly, non‐functionalized MWCNT have been mixed by phase pure anatase nanocrystals of average size 30 nm made by hydrolysis of Ti‐butoxide in ethanol dispersion of CNT. Electrochemical Li+ insertion showed x = 0.54 (charge capacity of 652 C/g) with 85% reversibility. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Combination of atomic force microscopy and photoluminescence microscopy for the investigation of individual carbon nanotubes on sapphire surfaces
Authors: Jester Stefan‐Sven , Kiowski Oliver , Lebedkin Sergei , Hennrich Frank , Fischer Regina , Stürzl Ninette , Hawecker Jacques , Kappes Manfred M. 
Published: November 2007

AbstractAtomic force microscopy (AFM) and photoluminescence (PL) spectroscopy were applied to characterize single walled carbon nanotubes (SWNTs) deposited on sapphire. The electronic properties and structure of luminescent semiconducting SWNTs can be probed by PL spectroscopy. The diameter, length, spatial position, and angular orientation of deposited SWNTs can be accurately determined by intermittent contact AFM. We describe an approach to combine and compare the spectroscopic (PL) and topographical (AFM) information for the same individual nanotubes as well as nanotube aggregates. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Theoretical Raman intensity of the radial breathing mode of single‐walled carbon nanotubes
Authors: Popov V. N. , Lambin P. 
Published: November 2007

AbstractThe atomistic calculations of the physical properties of perfect single‐walled carbon nanotubes can be performed successfully by use of the helical symmetry of the nanotubes. The efficiency of this approach is illustrated by calculations of the electronic band structure, lattice dynamics, and the resonant Raman intensity of the radial‐breathing mode for all nanotubes in the diameter range from 0.6 nm to 2.4 nm within a symmetry‐adapted nonorthogonal tight‐binding model. It is shown that the derived electron–phonon coupling and the Raman intensity are in fair agreement with recent Raman data on individual nanotubes. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Chemical vapor deposition of functionalized single‐walled carbon nanotubes with defined nitrogen doping
Authors: Ayala Paola , Freire Fernando L. , Rümmeli Mark H. , Grüneis Alexander , Pichler Thomas 
Published: November 2007

AbstractDefined n‐doping of carbon nanotubes can find potential application in nanoelectronics and sensors. An efficient doping can be achieved by substituting Carbon by heteroatoms such as Nitrogen. We explored the formation process of N doped single‐walled nanotubes within hot wall chemical vapor deposition employing different (C/N) feedstocks and catalysts. The process was optimized regarding the formation of substitutionally doped SWCNT and double wall CNTs. Analysis of N content and bonding environment is presented. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A nanoscaled contactless thermometer for biological systems
Authors: Vyalikh A. , Klingeler R. , Hampel S. , Haase D. , Ritschel M. , Leonhardt A. , Borowiak‐Palen E. , Rümmeli M. , Bachmatiuk A. , Kalenczuk R. J. , Grafe H.‐J. , Büchner B. 
Published: November 2007

AbstractWe report on a systematic approach to exploit the potential of filled carbon nanotubes (CNT) to act as sensors that might provide non‐invasive temperature control in biological systems on a cellular level. In this case the temperature is detected by measuring NMR parameters on the filling materials. The beneficial feature of a carbon nanotube is to provide protection of both (i) a human body against toxic adverse effects from the filling material and (ii) a filling material against chemical and biochemical exposure. The feasibility of this concept has been demonstrated on the example of the temperature‐dependent NMR frequency and relaxation time measured on the CNT filled with the appropriate sensor materials. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Manipulation of quantum information in N@C60 using electron and nuclear magnetic resonance
Authors: Ardavan Arzhang , Morton John J. L. , Benjamin Simon C. , Porfyrakis Kyriakos , Briggs G. Andrew D. , Tyryshkin Alexei M. , Lyon S. A. 
Published: November 2007

AbstractWe review recent progress towards implementing quantum information processing protocols using electron and nuclear magnetic resonance in the molecule 14N@C60. Using conventional spectrometers, we measure the errors inherent in quantum manipulations of spins. By applying composite pulses, we correct the dominant error to a high degree. Identifying a two qubit computational basis out of the electron and nuclear spin levels of 14N@C60, we implement an ultrafast phase gate on the nuclear qubit by exciting an electron spin transition. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
N@C60 quantum bit engineering
Authors: Harneit W. , Huebener K. , Naydenov B. , Schaefer S. , Scheloske M. 
Published: November 2007

AbstractWe report on some engineering aspects in the context of utilizing N@C60 molecules as quantum bits. Multi‐step recycling HPLC leads to 100% pure material. Symmetry breaking environments provide full addressing of the high‐dimensional Hilbert space. AFM‐tip induced local anodic oxidation of silicon can be used for arrangements of fullerenes on surfaces. Finally, electrically detected magnetic resonance is capable of coherent manipulation and read‐out of spin evolution of fullerenes at room temperature. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Carbon nanotubes for ultrafast photonics
Authors: Scardaci V. , Rozhin A. G. , Tan P. H. , Wang F. , White I. H. , Milne W. I. , Ferrari A. C. 
Published: November 2007

AbstractWe report characterization by absorption and photoluminescence excitation (PLE) spectroscopy of carbon nanotube solutions, which are then used for nanotube‐based composite preparation. PLE shows the presence of bundles in the solution. The composite show a saturation intensity of 5 MW/cm2 and is used in a fibre laser to generate pulses as short as 866 fs at about 1530 nm. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)