共查询到20条相似文献,搜索用时 31 毫秒
1.
R. Krupke F. Hennrich H.B. Weber D. Beckmann O. Hampe S. Malik M.M. Kappes H. v. Löhneysen 《Applied Physics A: Materials Science & Processing》2003,76(3):397-400
Single bundles of carbon nanotubes have been selectively deposited from suspensions onto sub-micron electrodes with alternating
electric fields. We show that it is possible to control the trapping of a single bundle by the use of Ag as electrode material
which, unlike Au, strongly interacts with the carboxyl functionalized carbon nanotubes. Excellent alignment of the bundles
between Au or Ag electrodes occurs at frequencies above 1 kHz, with superior contacts being formed with Ag electrodes.
Received: 22 May 2002 / Accepted: 21 June 2002 / Published online: 28 October 2002
RID="*"
ID="*"Corresponding author. Fax: +49-7247/82-6368, E-mail: ralph.krupke@int.fzk.de 相似文献
2.
Y. Chen M.J. Conway J.D. Fitzgerald 《Applied Physics A: Materials Science & Processing》2003,76(4):633-636
Multi-walled carbon nanotubes with cylindrical and bamboo-type structures are produced in a graphite sample after mechanical
milling at ambient temperature and subsequent thermal annealing up to 1400 °C. The ball milling produces a precursor structure
and the thermal annealing activates the nanotube growth. Different nanotubular structures indicate different formation mechanisms:
multi-wall cylindrical carbon nanotubes are probably formed upon micropores and the bamboo tubes are produced because of the
metal catalysts. A two-dimensional growth governed by surface diffusion is believed to be one important factor for the nanotube
growth. A potential industrial production method is demonstrated with advantages of large production quantity and low cost.
Received: 17 May 2002 / Accepted: 12 September 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +61-2/6125-8338, E-mail: ying.chen@anu.edu.au 相似文献
3.
G. Brown S.R. Bailey M. Novotny R. Carter E. Flahaut K.S. Coleman J.L. Hutchison M.L.H. Green J. Sloan 《Applied Physics A: Materials Science & Processing》2003,76(4):457-462
We describe here the high yield filling (i.e. >50%) of single walled nanotubes (SWNTs) with a variety of halides, achieved
according to various modified filling procedures. Both bundles and discrete SWNTs can be filled continuously up to lengths
of several hundred nm, often with filling yields approaching 60–70% or better. In addition some high yield filled SWNTs were
subjected to long-term washing in either boiling or room temperature. aqueous media, which does not remove the filling from
the tubules, but enables effective removal of water-soluble extraneous materials .
Received: 10 May 2002 / Accepted: 25 October 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +44-1865/272-690, E-mail: jeremy.sloan@chem.ox.ac.uk 相似文献
4.
Nanotube growth during annealing of mechanically milled Boron 总被引:1,自引:0,他引:1
J.D. Fitz Gerald Y. Chen M.J. Conway 《Applied Physics A: Materials Science & Processing》2003,76(1):107-110
Boron powder, finely ground in a tungsten carbide ball mill in an ammonia atmosphere, has been annealed at 1200 °C in flowing
nitrogen to produce small quantities of cylindrical BN nanotubes, both as isolated individuals and grouped into ropes. Thick-walled
conical BN tubes are abundant in specimens annealed for longer times, and their growth was catalysed once WC debris was converted
into W metal particles. Some catalytic effect of small W nanoparticles could be necessary for nanotube formation, though no
tip particles have been imaged here. Given the low temperature of mechanical milling and annealing, BN growth must involve
surface diffusion and solid-state reconfiguration. It could be possible to engineer desirable physical and chemical properties
by exploiting the variation in cylindrical versus conical BN structures as a function of annealing time.
Received: 19 December 2001 / Accepted: 3 April 2002 / Published online: 19 July 2002
RID="*"
ID="*"Corresponding author. Fax: +61-2/6125-8253, E-mail: john.fitzgerald@anu.edu.au 相似文献
5.
Giant field amplification in tungsten nanowires 总被引:5,自引:0,他引:5
Umnov A.G. Shiratori Y. Hiraoka H. 《Applied Physics A: Materials Science & Processing》2003,77(1):159-161
The original RF-sputtering-assisted technique to produce metal wires with tip-curvature radii at the nanometer scale was developed
and applied to tungsten. The wire tips were characterized by scanning electron microscopy. Field-emission tests of those wires
exhibit excellent performance and reliable processability. Very high field-amplification factors of 18000 were demonstrated.
Received: 1 November 2002 / Accepted: 30 November 2002 / Published online: 11 April 2003
RID="*"
ID="*"Corresponding author. Fax: +1-972/479-4482, E-mail: alexander.umnov@fla.fujitsu.com 相似文献
6.
Field emission from single-walled carbon nanotubes (SWNTs) aligned on a patterned gold surface is reported. The SWNT emitters
were prepared at room temperature by a self-assembly monolayer technique. SWNTs were cut into sub-micron lengths by sonication
in an acidic solution. Cut SWNTs were attached to the gold surface by the reaction between the thiol groups and the gold surface.
The field-emission measurements showed that the turn-on field was 4.8 V/μm at an emission current density of 10 μA/cm2. The current density was 0.5 mA/cm2 at 6.6 V/μm. This approach provides a novel route for fabricating CNT-based field-emission displays.
Received: 3 May 2002 / Accepted: 6 May 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +82-54/279-8298, E-mail: ce20047@postech.ac.kr 相似文献
7.
High-resolution electron microscopy of individual metallofullerene molecules on the dipole orientations in peapods 总被引:1,自引:0,他引:1
K. Suenaga T. Okazaki K. Hirahara S. Bandow H. Kato A. Taninaka H. Shinohara S. Iijima 《Applied Physics A: Materials Science & Processing》2003,76(4):445-447
Electron microscopy with atomic sensitivity enables us to obtain a direct image of the intra-molecular structure of metallofullerenes
encapsulated inside single-walled carbon nanotubes. By a comparison of high-resolution images with a simulation to extract
the relative atom positions for encaged metal atoms in each molecule, the distribution of the molecular orientations and interactions
between adjacent molecules in metallofullerene peapods have been statistically analyzed. The results are suggestive of strong
interactions between fullerene–fullerene and fullerene–tube in peapods at room temperature.
Received: 10 October 2002 / Accepted: 25 October 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +81-298/61-6310, E-mail: suenaga-kazu@aist.go.jp 相似文献
8.
R.L.D. Whitby W.K. Hsu C.B. Boothroyd K.S. Brigatti H.W. Kroto D.R.M. Walton 《Applied Physics A: Materials Science & Processing》2003,76(4):527-532
Time-dependent powder X-ray-diffraction analyses reveal that the conversion of WO3 into WS2 on carbon nanotube surfaces in the presence of H2S is a one-step process. The WS2 layers grow simultaneously along the tube in the radial and axial directions.
Received: 17 June 2002 / Accepted: 19 June 2002 / Published online: 15 January 2003
RID="*"
ID="*"Corresponding author. Fax: +44-1273/677-196, E-mail: d.walton@sussex.ac.uk 相似文献
9.
10.
K.H. Heinig T. Müller B. Schmidt M. Strobel W. Möller 《Applied Physics A: Materials Science & Processing》2003,77(1):17-25
We have investigated the synthesis of nanostructures, as well as the control of their size and location by means of ion beams.
The phase separation and interface kinetics under ion irradiation give new possibilities for controlling the growth of nanostructures.
Additionally, the chemical decomposition of the host matrix by collisional mixing can contribute to the self-organization
of nanostructures, especially at interfaces. It is shown how collisional mixing during ion implantation affects nanocrystal
(NC) synthesis and how ion irradiation through NCs modifies their size and size distribution. An analytical expression for
solute concentration around an ion-irradiated NC was found, which may be written like the well-known Gibbs–Thomson relation.
However, parameters have modified meanings, which has a significant impact on the evolution of NC ensembles. “Inverse Ostwald
ripening” of NCs, resulting in an unimodal NC size distribution, is predicted, which has been confirmed experimentally for
Au NCs in SiO2 and by kinetic lattice Monte Carlo simulations. At interfaces, the same ion-irradiation-induced mechanism may result in self-organization
of NCs into a thin δ-layer. Collisional decomposition of SiO2 may enhance the NC δ-layer formation in SiO2 at the Si/SiO2 interface. The distance of the self-organized NC δ-layer from the SiO2/Si interface renders the structure interesting for non-volatile memory applications.
Received: 11 November 2002 / Accepted: 12 November 2002 / Published online: 4 April 2003
RID="*"
ID="*"Corresponding author. Fax: +49-351-260-3285, E-mail: K.-H.Heinig@fz-rossendorf.de 相似文献
11.
Z.P. Huang D.Z. Wang J.G. Wen M. Sennett H. Gibson Z.F. Ren 《Applied Physics A: Materials Science & Processing》2002,74(3):387-391
The effect of pure nickel, iron and cobalt on growth of aligned carbon nanotubes was systematically studied by plasma-enhanced
hot-filament chemical vapor deposition. It is found that the catalyst has a strong effect on the nanotube diameter, growth
rate, wall thickness, morphology and microstructure. Ni yields the highest growth rate, largest diameter and thickest wall,
whereas Co results in the lowest growth rate, smallest diameter and thinnest wall. The carbon nanotubes catalyzed by Ni have
the best alignment and the smoothest and cleanest wall surface, whereas those from Co are covered with amorphous carbon and
nanoparticles on the outer surface. The carbon nanotubes produced from Ni catalyst also exhibit a reasonably good graphitization.
Therefore, Ni is considered as the most suitable catalyst for growth of aligned carbon nanotubes.
Received: 30 November 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
12.
J.H. Liao K.J. Chen L.N. Xu C.W. Ge J. Wang L. Huang N. Gu 《Applied Physics A: Materials Science & Processing》2003,76(4):541-543
The one-dimensional coagulation of gold colloidal particles dispersed in organic solvent was investigated with transmission
electron microscopy. The results indicate that the length of the nanoparticle chains can be modulated by changing the concentration
of the solutions. It was also demonstrated that the wetting of the substrate surface hardly influenced the morphology of the
nanoparticle chains, which revealed that the particle chains had been formed in the solution before deposition on the substrates.
A general theoretical interpretation is provided to explain the linear coagulation of gold colloidal particles, on the basis
of the asymmetrical distribution of the charges absorbed on the surface of the gold colloidal particles, as well as the action
of the solvent molecules.
Received: 8 April 2002 / Accepted: 1 July 2002 / Published online: 4 December 2002
RID="*"
ID="*"Corresponding author. Fax: +86-025/361-9983, E-mail: jhliao@seu.edu.cn 相似文献
13.
T. Okazaki T. Shimada K. Suenaga Y. Ohno T. Mizutani J. Lee Y. Kuk H. Shinohara 《Applied Physics A: Materials Science & Processing》2003,76(4):475-478
Electronic properties of Gd@C82 metallofullerene peapods, (Gd@C82)n@SWNTs, were investigated by electron energy-loss spectroscopy (EELS), scanning tunneling microscopy and spectroscopy (STM/STS),
and field-effect transistor (FET) transport measurements. The results indicate that the electronic structure of Gd@C82 metallofullerene peapods is completely different from that of intact single-walled nanotubes (SWNTs). For example, Gd@C82-peapod-FETs show ambipolar behavior which is not observed in the empty SWNT-FETs under our experimental conditions. Furthermore,
in semiconducting nanotubes the band gap can be varied from ∼0.5 to ∼0.1 eV using inserted Gd@C82 endohedral metallofullerenes with a spatial periodicity of 1.1 to 8.0 nm, depending on the density of the fullerenes. The
present findings suggest that metallofullerene peapods may point the way toward novel electronic devices.
Received: 6 September 2002 / Accepted: 25 October 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +81-52/789-1169, E-mail: noris@cc.nagoya-u.ac.jp 相似文献
14.
S.-H. Jung M.-R. Kim S.-H. Jeong S.-U. Kim O.-J. Lee K.-H. Lee J.-H. Suh C.-K. Park 《Applied Physics A: Materials Science & Processing》2003,76(2):285-286
Synthesis of multi-walled carbon nanotubes (MWNTs) by arc discharge in liquid nitrogen is reported. As liquid nitrogen substituted
both vacuum and cooling systems, high-quality MWNTs were produced at a low cost. The content of the MWNTs can be as high as
70% of the reaction product. Auger-spectroscopy analysis revealed that no nitrogen is incorporated in the MWNTs. This method
can be an economical route for the mass production of highly crystalline MWNTs.
Received: 5 July 2002 / Accepted: 8 July 2002 / Published online: 10 September 2002
RID="*"
ID="*"Corresponding author. Fax: +82-54/279-8298, E-mail: ce20047@postech.ac.kr 相似文献
15.
A.B. Fedotov P. Zhou A.N. Naumov V.V. Temnov V.I. Beloglazov N.B. Skibina L.A. Mel’nikov A.V. Shcherbakov A.P. Tarasevitch D. von der Linde A.M. Zheltikov 《Applied physics. B, Lasers and optics》2002,75(6-7):621-627
Photonic-molecule modes of a cobweb-microstructure fiber allow efficient nonlinear optical spectral broadening of nanojoule
femtosecond light pulses. Spectral widths of approximately 200 nm are achieved at the output of a 6-cm sample of such a fiber
for 40-fs Ti:sapphire laser pulses with an energy of a few nanojoules coupled into photonic-molecule modes. Higher values
of the group index and a lower group-velocity dispersion, attainable with higher-order photonic-molecule modes, allow the
efficiency of spectral broadening of femtosecond laser pulses to be increased relative to the efficiency of spectral broadening
in the fundamental photonic-molecule mode.
Received: 9 June 2002 / Revised version: 29 June 2002 / Published online: 22 November 2002
RID="*"
ID="*"Corresponding author. Fax: +7-095/939-3959, E-mail: zheltikov@top.phys.msu.su 相似文献
16.
W. Wang Z. Liu Y. Liu C. Xu C. Zheng G. Wang 《Applied Physics A: Materials Science & Processing》2003,76(3):417-420
Using a simple wet-chemical route, we synthesized CuO nanorods with diameters of ca. 5–15 nm and lengths of up to 400 nm.
The purity, crystallinity, morphology, structure features, and chemical composition of the as-prepared CuO nanorods were investigated
by powder X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron
spectroscopy, and Raman spectroscopy.
Received: 22 March 2002 / Accepted: 12 June 2002 / Published online: 28 October 2002
RID="*"
ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: wangqun@nju.edu.cn 相似文献
17.
Quasi one-dimensional systems of molecules of C60 encapsulated in (10/10) nanotubes were studied by both lattice-gas and Takashi–Gursey configurational integral methods of
statistical mechanics for both open and capped finite nanotubes as well as infinite nanotubes. From well-established potentials,
the energy, heat capacity compressibility, equation of state and absorption isotherms were computed as a function of temperature
and molecular density. The existing theories were extended to include the calculation of clustering, and the number of clusters
as a function of size was computed for a variety of temperatures and densities. For both models, all molecules are frozen
into a single cluster, and increasing the temperature results in a break-up into smaller clusters. The corresponding heat
capacity has a broad maximum, which is lower for the T–G model than for the lattice-gas model. The equations of state have
a similar form in both models and are identical at low temperatures. The absorption isotherms show that filling of the tubes
can take place at all temperatures of practical interest. Peapods are nearly ideal realizations of one-dimensional systems
whose thermodynamic and structural properties can be accurately obtained by statistical mechanics.
Received: 15 November 2001 / Accepted: 25 October 2002 / Published online: 10 March 2003
RID="*"
ID="*"Corresponding author. Fax: +1-215/573-2128, E-mail: lag@sol1.lrsm.upenn.edu
RID="**"
ID="**"Present address: Dept. of Physics, North Carolina State University, Raleigh, NC 27695, USA 相似文献
18.
T.B. Settersten A. Dreizler B.D. Patterson P.E. Schrader R.L. Farrow 《Applied physics. B, Lasers and optics》2003,76(4):479-482
This study reports on photochemical interferences affecting atomic oxygen detection using two-photon laser-induced fluorescence
at 226 nm. In contrast to previous studies in which molecular oxygen was proven to be the relevant photochemical precursor
molecule in a hydrogen-fueled flame, the present investigations were carried out in a laminar diffusion flame of methane and
air. The most significant interferences were found at the fuel side of the flame in the absence of molecular oxygen, and vibrationally
excited carbon dioxide was identified as the most probable precursor molecule for the photochemical production of oxygen atoms.
Received: 11 December 2002 / Revised version: 10 March 2003 / Published online: 16 April 2003
RID="*"
ID="*"Corresponding author. Fax: +1-925/294-2595, E-mail: tbsette@sandia.gov 相似文献
19.
Z. Siwy D. Dobrev R. Neumann C. Trautmann K. Voss 《Applied Physics A: Materials Science & Processing》2003,76(5):781-785
For the preparation of a single asymmetrically shaped nanopore in a polyimide membrane, Kapton foils were irradiated with
single heavy ions and subsequently etched from one side in sodium hypochlorite (NaOCl). The other side of the membrane was
protected from etching by a stopping medium containing a reducing agent for hypochlorite ions (OCl-). The resulting conical nanopore rectified ion current and exhibited a stable ion-current flow.
Received: 23 May 2002 / Accepted: 2 September 2002 / Published online: 15 January 2003
RID="*"
ID="*"Corresponding author. Fax: +49-6159/712-179, E-mail: Z.Siwy@gsi.de 相似文献
20.
R. Frömter H.P. Oepen J. Kirschner 《Applied Physics A: Materials Science & Processing》2003,76(6):869-871
The basics of the scanning electron microscope with polarization analysis are briefly reviewed, emphasizing the achievable
magnetic resolution and image contrast. The design of an optimized spin-polarization detector based on the well-established
LEED scattering principle is presented. Results of first tests are reported.
Received: 2 September 2002 / Accepted: 2 September 2002 / Published online: 5 March 2003
RID="*"
ID="*"Corresponding author. Fax: +49-40/42838-6368, E-mail: RFroemte@PHYSnet.Uni-Hamburg.de 相似文献