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1.
C. Schönenberger A. Bachtold C. Strunk J.-P. Salvetat L. Forró 《Applied Physics A: Materials Science & Processing》1999,69(3):283-295
We report equilibrium electric resistance R and tunneling spectroscopy (dI/dV)measurements obtained on single multi-wall nanotubes
contacted by four metallic Au fingers from above. At low temperature quantum interference phenomena dominate the magnetoresistance.
The phase-coherence (lφ)and elastic-scattering lengths (le)are deduced. Because le is of order of the circumference of the nanotubes, transport is quasi-ballistic. This result is supported by a dI/dV spectrum
which is in good agreement with the density of states (DOS) due to the one-dimensional subbands expected for a perfect single-wall
tube. As a function of temperature T the resistance increases on decreasing T and saturates at ≈1–10 Kfor all measured nanotubes.
R(T) cannot be related to the energy-dependent DOS of graphene but is mainly caused by interaction and interference effects.
On a relatively small voltage scale of the order ≈10 meV, a pseudogap is observed in dI/dV which agrees with Luttinger-liquid
theories for nanotubes. Because we have used quantum diffusion based on Fermi-liquid as well as Luttinger-liquid theory in
trying to understand our results, a large fraction of this paper is devoted to a careful discussion of all our results.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 4 August 1999 相似文献
2.
Application of scanning force microscopy in nanotube science 总被引:2,自引:0,他引:2
J. Muster G.S. Duesberg S. Roth M. Burghard 《Applied Physics A: Materials Science & Processing》1999,69(3):261-267
Recent developments in the application of scanning force microscopy in nanotube science are reviewed. The non-destructive
character of this technique allows the structural characterisation of (chemically modified) single- and multi-wall nanotubes
deposited on substrates for further investigations such as electrical transport measurements. Furthermore, SFM is now an established
tool for manipulation of nanotubes, which allows position control and determination of elastic constants such as the Young’s
modulus. Finally it is shown that very sharp and stable probes for scanning force microscopy can be made from nanotubes due
to their excellent stability and aspect ratio.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 29 July 1999 相似文献
3.
Synthesis, integration, and electrical properties of individual single-walled carbon nanotubes 总被引:4,自引:0,他引:4
J. Kong C. Zhou A. Morpurgo H.T. Soh C.F. Quate C. Marcus H. Dai 《Applied Physics A: Materials Science & Processing》1999,69(3):305-308
High-quality single-walled carbon nanotubes (SWNTs) are synthesized by chemical vapor deposition (CVD) of methane on silicon-dioxide
substrates at controlled locations using patterned catalytic islands. With the synthesized nanotube chips, microfabrication
techniques are used to reliably contact individual SWNTs and obtain low contact resistance. The combined chemical synthesis
and microfabrication approaches enable systematic characterization of electron transport properties of a large number of individual
SWNTs. Results of electrical properties of representative semiconducting and metallic SWNTs are presented. The lowest two-terminal
resistance for individual metallic SWNTs (≈5 μm long) is ≈16.5 kΩ measured at 4.2 K.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 14 July 1999 相似文献
4.
G.S. Duesberg J. Muster H.J. Byrne S. Roth M. Burghard 《Applied Physics A: Materials Science & Processing》1999,69(3):269-274
Production methods for carbon nanotubes are now well established and allow their synthesis on a scale of grams per day. For
many potential applications of this unique material, its purification still remains a crucial problem. In this article various
purification methods for single- and multi-wall carbon nanotubes are reviewed. These methods are compared in terms of their
capacity, efficiency, and effects on the tubes. In addition, the use of Raman spectroscopy for monitoring the chromatographic
purification of single-wall nanotubes is described.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 29 July 1999 相似文献
5.
C. Thomsen S. Reich H. Jantoljak I. Loa K. Syassen M. Burghard G.S. Duesberg S. Roth 《Applied Physics A: Materials Science & Processing》1999,69(3):309-312
The pressure dependence of the high-energy Raman modes in single- and multi-walled carbon nanotubes was measured in the range
0–10 GPa. We found the pressure coefficient to be linear in both materials but 25% smaller in MWNT. Given that the curvature
effects on vibrational properties of the rolled-up graphene sheets are small, we can explain this difference simply with elasticity
theory.
Received: 17 May 1999 / Accepted 18 May 1999 / Published online: 4 August 1999 相似文献
6.
Mechanical properties of carbon nanotubes 总被引:26,自引:0,他引:26
J.-P. Salvetat J.-M. Bonard N.H. Thomson A.J. Kulik L. Forró W. Benoit L. Zuppiroli 《Applied Physics A: Materials Science & Processing》1999,69(3):255-260
A variety of outstanding experimental results on the elucidation of the elastic properties of carbon nanotubes are fast appearing.
These are based mainly on the techniques of high-resolution transmission electron microscopy (HRTEM) and atomic force microscopy
(AFM) to determine the Young’s moduli of single-wall nanotube bundles and multi-walled nanotubes, prepared by a number of
methods. These results are confirming the theoretical predictions that carbon nanotubes have high strength plus extraordinary
flexibility and resilience. As well as summarising the most notable achievements of theory and experiment in the last few
years, this paper explains the properties of nanotubes in the wider context of materials science and highlights the contribution
of our research group in this rapidly expanding field. A deeper understanding of the relationship between the structural order
of the nanotubes and their mechanical properties will be necessary for the development of carbon-nanotube-based composites.
Our research to date illustrates a qualitative relationship between the Young’s modulus of a nanotube and the amount of disorder
in the atomic structure of the walls. Other exciting results indicate that composites will benefit from the exceptional mechanical
properties of carbon nanotubes, but that the major outstanding problem of load transfer efficiency must be overcome before
suitable engineering materials can be produced.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 29 July 1999 相似文献
7.
Field emission from carbon nanotubes: perspectives for applications and clues to the emission mechanism 总被引:15,自引:0,他引:15
J.-M. Bonard J.-P. Salvetat T. Stöckli L. Forró A. Châtelain 《Applied Physics A: Materials Science & Processing》1999,69(3):245-254
We report on the extensive characterization of carbon nanotube electron field emitters. We studied the emission behavior of
single-wall, closed and opened arc-discharge multi-wall, and catalytically grown multi-wall nanotubes, as single emitters
and in film form. The nanotube field emitters show excellent field emission properties, but significant differences were observed
between the different types of nanotubes. To obtain good performances as well as long emitter lifetimes, the nanotubes should
be multi-walled and have closed, well-ordered tips. Complementary results such as energy distribution and luminescence induced
by the field emission give further precious indications on the field emission mechanism. The large field amplification factor,
arising from the small radius of curvature of the nanotube tips, is partly responsible for the good emission characteristics.
Additional evidence however shows that the density of states at the tip is non-metallic, appearing in the form of localized
states with well-defined energy levels.
Received: 15 May 1999 / Accepted: 18 May 1999 / Published online: 29 July 1999 相似文献
8.
M.G. Mustafa A. Sen L. Paria 《The European Physical Journal C - Particles and Fields》1999,11(4):729-732
We show that requiring the quark partition function to be color singlet in the SU(3) color gauge group leads to reordering
of the thermodynamic potential in terms of the colorless multiquark modes (, qqq, , ) at any given temperature. These color-singlet structures are not bound states in a real sense, rather they are a combination
of constituent quarks only. In accord with the “preconfinement” property of QCD, under a suitable confining mechanism, these
could evolve into color-singlet hadrons/baryons at low temperatures. At fairly high temperatures, these multiquark color-singlet
structures exist in the plasma as hadronic modes, just as in the more familiar low-temperature phase. This suggests that there
exists a strong color correlation in the plasma at all temperatures.
Received: 25 May 1999 / Published online: 2 November 1999 相似文献
9.
R. Dinu M. Dinescu J.D. Pedarnig R.A. Gunasekaran D. Bäuerle S. Bauer-Gogonea S. Bauer 《Applied Physics A: Materials Science & Processing》1999,69(1):55-61
Ferroelectric SrBi2Ta2O9 (SBT) films were grown by pulsed-laser deposition (PLD) at different substrate temperatures and fluences. A correlation between
film structure and ferroelectric properties is established. The dielectric function ε′ of thin SBT films shows a Curie–Weiss behavior well below the peak temperature Tmax and relaxor-like behavior in the vicinity of Tmax. Domain walls have a strong influence on the dielectric and ferroelectric properties and on the polarization fatigue of SBT
films below 100 °C. The formation of ferroelectric phases is favored at lower substrate temperatures by incorporating Bi2O3 template layers into the structure.
Received: 18 March 1999 / Accepted: 19 March 1999 / Published online: 5 May 1999 相似文献
10.
P. M. Milazzo G. Vannini M. Bruno N. Colonna M. D’Agostino F. Gramegna G. V. Margagliotti P. F. Mastinu A. Moroni 《The European Physical Journal A - Hadrons and Nuclei》2000,7(3):355-360
The dependence of the nuclear temperatures of highly excited systems, extracted by means of the double ratios of the emitted
isotopes, on the experimental conditions is investigated. Experimental data obtained in the Xe+Cu 30 MeV/nucleon reaction
are used to study the sensitivity of the method and the effects of the energy thresholds on the obtained temperature values.
We find that the temperatures extracted using the He/Li ratios can be strongly influenced by the experimental energy thresholds
which are different for different elements. These distortions depend on the velocity of the emitting system and on the detection
angle and therefore particular care is needed in the choice of the detectors in those experiments in which velocities are
low and angles are large. The use of four isotopes of the same element make negligible such effects.
Received: 6 October 1999 / Accepted: 28 May 2000 相似文献
11.
C. Berger Y. Yi Z.L. Wang W.A. de Heer 《Applied Physics A: Materials Science & Processing》2002,75(3):363-365
Following the experiments of Frank et al. [1], which demonstrated quantum transport in multiwalled carbon nanotubes, there
have been several experiments that appear to contradict the main conclusion of that paper, which is that the transport of
a MWNT at room temperature is ballistic. Here we demonstrate that the intrinsic resistance of clean-arc-produced carbon nanotubes
is at most 200 Ω/ μm, which implies that the momentum mean free path is greater than 30 μm, which in turn is much larger than
the tube length. This implies that these tubes are ballistic, according to the standard definition of ballistic transport.
We also show that the contact resistance with mercury is quite large: a nanotube in contact with Hg over 100 nm of its length
still represents a 3000 Ω resistance.
Received: 14 September 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
12.
R. Martin-Lopez A. Dauscher H. Scherrer J. Hejtmanek H. Kenzari B. Lenoir 《Applied Physics A: Materials Science & Processing》1999,68(5):597-602
Homogeneous polycrystalline Bi100-xSbx (x=12, 15, 22) alloys were synthesized by mechanical alloying. The transport coefficients (electrical resistivity, thermal
conductivity, and thermopower) were measured, in the 77–300 K temperature range, on samples consolidated either by sintering
or extrusion. The thermoelectric figure of merit was deduced from the three coefficients. The temperature dependences are
discussed as a function of the alloys’ microstructures taking into account the qualitative effect of potential barriers. Extrusion
leads to better performing thermoelectric materials than does sintering. The highest figure of merit is reached for temperatures
around 150 K, a temperature at which no reliable thermoelectric material of long service life is available until now.
Received: 11 November 1998 / Accepted: 5 January 1999 / Published online: 24 March 1999 相似文献
13.
Synthesis of carbon nitride films by low-power inductively coupled plasma-activated transport reactions from a solid carbon source 总被引:1,自引:0,他引:1
C. Popov M.F. Plass A. Bergmaier W. Kulisch 《Applied Physics A: Materials Science & Processing》1999,69(2):241-244
Thin films of carbon nitride were prepared by low-power inductively coupled plasma chemical vapor deposition from a solid
carbon source by utilizing transport reactions. The maximum deposition rate achieved was 10 nm/min and depended mainly on
the substrate position in the reactor. The nitrogen fraction in the films was not so sensitive to the process parameters and
was at about 0.5 for all experiments as measured by Auger electron spectroscopy (AES) and elastic recoil detection (ERD) analysis.
The chemical bonding structure studied by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy
(XPS) showed the presence of triple, double and single bonds between carbon and nitrogen atoms.
Received: 12 May 1999 / Accepted: 12 May 1999 / Published online: 24 June 1999 相似文献
14.
S.I. Anisimov N.A. Inogamov A.M. Oparin B. Rethfeld T. Yabe M. Ogawa V.E. Fortov 《Applied Physics A: Materials Science & Processing》1999,69(6):617-620
Theoretical study of laser ablation is usually based on the assumption that the vapor is an ideal gas. Its flow is described
by gas dynamics equations [1, 2]. The boundary conditions at vaporization front are derived from the solution of the Boltzmann
equation that describes the vapor flow in the immediate vicinity of the vaporizing surface (so-called Knudsen layer) [1].
This model is applicable within the range of temperatures much lower than the critical temperature of target material. In
the present work, a general case is considered when the temperature of the condensed phase is comparable to or higher than
the critical temperature. The dynamics of both condensed and gaseous phases can be described in this case by the equations
of hydrodynamics. The dynamics of vaporization of a metal heated by an ultrashort laser pulse is studied both analytically
and numerically. The analysis reveals that the flow consists of two domains: thin liquid shell moving with constant velocity,
and thick low-density layer of material in two-phase state.
Received: 2 March 1999 / Accepted: 28 May 1999 / Published online: 21 October 1999 相似文献
15.
Effect of gas pressure on the growth and structure of carbon nanotubes by chemical vapor deposition 总被引:3,自引:0,他引:3
W.Z. Li J.G. Wen Y. Tu Z.F. Ren 《Applied Physics A: Materials Science & Processing》2001,73(2):259-264
The effect of gas pressure on the structure of carbon nanotubes (CNTs) has been systematically investigated in the chemical
vapor deposition process. The yield of CNTs (defined as the weight ratio of CNTs vs. catalyst) increases significantly with
the gas pressure, reaches 600% at 600 Torr, then decreases with further increase of gas pressure. At low reacting gas pressure
the CNTs have completely hollow cores, whereas at high pressure the CNTs have a bamboo structure. The density of the compartments
in the bamboo-structured CNTs increases dramatically with the increase of the gas pressure. This result shows that the structure
and yield of carbon nanotubes are strongly affected by the growth gas pressure.
Received: 10 May 2001 / Accepted: 10 May 2001 / Published online: 20 June 2001 相似文献
16.
C. Triché P. Verkerk G. Grynberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,5(2):225-228
We present an experimental study of the kinetic temperature of cesium atoms interacting with laser beams tuned on the blue
side of the transition. In the case of a three-dimensional four-beam molasses, temperatures as low as 800 nK were found. These low temperatures
are compatible with a good capture efficiency. The influence of other hyperfine transitions on the temperature is significant.
In the presence of a static magnetic field (antidot lattices), the temperatures are slightly higher but show a much weaker
dependence on the other hyperfine transitions.
Received: 14 May 1998 / Received in final form: 16 October 1998 / Accepted: 2 November 1998 相似文献
17.
C. Stockinger G. Heine W. Markowitsch W. Lang R. Adam R. Sobolewski R. Rössler J.D. Pedarnig D. Bäuerle 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(2):227-231
() thin films were photodoped with white light at various temperatures from 70 K to 290 K. Before and after the excitation,
the magnetoconductivity was measured in a magnetic field B
= 0.5 T, and the experimental results were fitted to the Aslamazov-Larkin theory of superconducting order-parameter fluctuations
to determine the superconducting coherence lengths, and . We observed that the photodoping process enhanced and and that the amount increased with the photodoping temperature increase. On the other hand, the superconducting anisotropy
/ decreased with increasing temperature. The photodoping effect enhances superconducting properties of partially oxygen-deficient
samples and is considerably increased by high doping temperatures.
Received 15 December 1999 and Received in final form 24 May 2000 相似文献
18.
We report on metal (Cr, Ni, or Pd)-induced solid-phase crystallization (MISPC) of plasma-enhanced chemical-vapor-deposited
hydrogenated amorphous silicon at annealing temperatures ≤600 °C. MISPC is found to significantly reduce the thermal budget
of crystallization at annealing temperatures as low as ∼400 °C. The lowest achievable annealing temperature is found to depend
on the metal type. The metal type is also found to influence grain size and the conductivity of the polycrystalline silicon.
Received: 21 June 1999 / Accepted: 20 October 1999 / Published online: 23 February 2000 相似文献
19.
Scanning tunneling microscopy of carbon nanotubes 总被引:1,自引:0,他引:1
W. Clauss 《Applied Physics A: Materials Science & Processing》1999,69(3):275-281
This article reports on the application of scanning tunneling microscopy for the study of surface structures and electronic
properties of carbon nanotubes. Geometric effects resulting from the cylindrical shape of the tubes as well as the particular
band structure of the graphitic crystal lattice can lead to a variety of contrast patterns. On the atomic scale, it is sometimes
possible to see the full honeycomb lattice structure but often different structures are observed. Besides distortions caused
by tip–sample interactions, we find that a complex superstructure superimposed on the simple atomic contrast pattern arises
from elastic scattering of the Fermi states at defects or impurities. From a careful analysis of high-resolution images it
is possible to extract information about elastic strain of individual tubes. A new combination of scanning tunneling and scanning
force microscopy enables near-atomic point resolution of the force signal the tubes can be identified without the need of
a conducting substrate. This imaging mode is a crucial step for the characterization of electronic devices based on individual
single-wall tubes. This mode can be further enhanced by the use of single-walled tubes as probe tips.
Received: 17 May 1999 / Accepted: 18 May 1999 / Published online: 4 August 1999 相似文献
20.
Pb diffusion in α-Zr matrix between 823 and 1123 K was measured using heavy ion Rutherford backscattering spectrometry (HIRBS)
technique. A deviation from the Arrhenius law was observed, with two different regions. At low temperatures the activation
energy Q is close to the expected value for a substitutional diffuser but the pre-exponential factor D0 is higher than expected. Close to the phase transition temperature the opposite occurs, with a low Q value. This behavior
is similar to the one observed for Hf and self-diffusion in α-Zr.
Received: 29 September 1998 / Accepted: 29 January 1999 / Published online: 28 April 1999 相似文献