共查询到20条相似文献,搜索用时 15 毫秒
1.
《Current Applied Physics》2015,15(11):1506-1511
We demonstrate the production of low-dimensional carbon nanomaterials using a solution plasma system and their application to flexible conductive paper. The solution plasma system consists of two graphite electrodes and a beaker filled with ferritin-mixed deionized water. Ferritin molecules are used as the growth catalyst of the carbon nanomaterials. A high voltage of 15 kV at a frequency of 25 kHz is supplied to the electrodes using an alternating-current power source. The effects of the graphite rod diameters and the concentration of ferritin molecules are comparatively investigated. The produced carbon nanomaterials are characterized using Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. We confirmed the synthesis of graphitic platelets, onion-like structures, and carbon nanotubes. Finally, we fabricated flexible conductive papers using the produced materials with a good electrical conductance. 相似文献
2.
We have theoretically investigated the first correction to conductance of armchair single wall carbon nanotubes (SWCNTs) with finite length, embedded between two electrodes, due to the presence of electron–transversal phonon interaction. The perturbative scheme has been used with finite length real space nearest neighbors tight binding method. Both radial breathing and tangential modes are investigated separately. It is found that not only the conductance correction crucially depends on source-drain voltage but also it strongly depends on the length and diameter of SWCNT. So, this work opens up opportunities to control the electrical conductance of SWCNT and increases yield of micro or nanodevices based on carbon nanotube. 相似文献
3.
By applying non-equilibrium Green's functions in combination with density-functional theory, we investigate electronic transport properties of C60 coupled to carbon nanotubes and Li electrodes. The results show that electronic transport properties of CNT-C60-CNT and Li-C60-Li systems are completely different. Nonlinear I-V characteristic, varistor-type behavior and negative differential resistance (NDR) phenomenon are observed when electrodes are carbon nanotubes. We discuss the mechanism of I-V characteristics of CNT-C60-CNT systems in details. Our results suggest conductance, energy level of Frontier molecular orbitals, energy gap between HOMO and LUMO, the coupling between molecular orbitals and electrodes are all playing critical roles in electronic transport properties. 相似文献
4.
We have developed a new theoretical formalism for phonon transport in nanostructures using the nonequilibrium phonon Green's function technique and have applied it to thermal conduction in defective carbon nanotubes. The universal quantization of low-temperature thermal conductance in carbon nanotubes can be observed even in the presence of local structural defects such as vacancies and Stone-Wales defects, since the long wavelength acoustic phonons are not scattered by local defects. At room temperature, however, thermal conductance is critically affected by defect scattering since incident phonons are scattered by localized phonons around the defects. We find a remarkable change from quantum to classical features for the thermal transport through defective carbon nanotubes with increasing temperature. 相似文献
5.
The temperature dependences of the thermal conductivity of planar and nanotubular supracrystalline structures have been calculated at temperatures below the Debye temperature using the Landauer approach for the ballistic conductance of one-dimensional conductors. The mathematical model based on this approach has been examined on carbon nanotubes and graphene. 相似文献
6.
We have calculated the differential conductance of metallic carbon nanotubes by the scatter matrix methon.It is found that the differential conductance of metallic nanotube-based devices oscillates as a function of the bias voltage between the two leads and the gate voltage.Oscillation period T is directly proportional to the reciprocal of nanotube length.In addition,we found that electronic transport properties are sensitive to variation of the length of the nanotube. 相似文献
7.
We have studied the resistance of single-wall carbon nanotubes measured in a four-point configuration with noninvasive voltage electrodes. The voltage drop is detected using multiwalled carbon nanotubes while the current is injected through nanofabricated Au electrodes. The resistance at room temperature is shown to be linear with the length as expected for a classical resistor. This changes at cryogenic temperature; the four-point resistance then depends on the resistance at the Au-tube interfaces and can even become negative due to quantum-interference effects. 相似文献
8.
J. Nygard D.H. Cobden M. Bockrath P.L. McEuen P.E. Lindelof 《Applied Physics A: Materials Science & Processing》1999,69(3):297-304
We review transport measurements on single-walled carbon nanotubes contacted by metal electrodes. At room temperature some
devices show transistor action similar to that of p-channel field effect transistors, while others behave as gate-voltage
independent wires. At low temperatures transport is usually dominated by Coulomb blockade. In this regime the quantum eigenstates
of the finite-length tubes can be studied. At higher temperatures power law behaviour is observed for the temperature and
bias dependence of the conductance. This is consistent with tunneling into a one-dimensional Luttinger liquid in a nanotube.
We also discuss recent developments in contacting nanotubes which should soon allow study of their intrinsic transport properties.
Received: 17 May 1999 / Accepted 18 May 1999 / Published online: 4 August 1999 相似文献
9.
Chiu HY Deshpande VV Postma HW Lau CN Mikó C Forró L Bockrath M 《Physical review letters》2005,95(22):226101
We report electrical transport experiments, using the phenomenon of electrical breakdown to perform thermometry, that probe the thermal properties of individual multiwalled carbon nanotubes. Our results show that nanotubes can readily conduct heat by ballistic phonon propagation. We determine the thermal conductance quantum, the ultimate limit to thermal conductance for a single phonon channel, and find good agreement with theoretical calculations. Moreover, our results suggest a breakdown mechanism of thermally activated C-C bond breaking coupled with the electrical stress of carrying approximately 10(12) A/m2. We also demonstrate a current-driven self-heating technique to improve the conductance of nanotube devices dramatically. 相似文献
10.
Boron (B)/phosphorus (P)-doped single-wall carbon nanotubes (B-PSWNTs) are studied by using the first-principle method based
on density function theory. Mayer bond order, band structure, electrons density and density of states are calculated. It concludes
that the B-PSWNTs have special band structure, which is quite different from BN nanotubes, and that metallic carbon nanotubes
will be converted to semiconductor due to boron/phosphorus co-doping, which breaks the symmetrical structure. The bonding
forms in B-PSWNTs are investigated in detail. Besides, Mulliken charge population and the quantum conductance are also calculated
to study the quantum transport characteristics of B-PSWNT hetero-junction. It is found that the position of p–n junction in
this hetero-junction will be changed as the applied electric field increase and it performs the characteristics of diode. 相似文献
11.
O. V. Kononenko V. N. Matveev Yu. A. Kasumov I. I. Khodos D. V. Matveev S. I. Bozhko V. T. Volkov M. A. Knyazev A. A. Firsov A. I. Il’yun 《Bulletin of the Russian Academy of Sciences: Physics》2010,74(7):991-993
Single-wall carbon nanotubes were synthesized on specified parts of oxidized silicon substrates by single acetylene burst
CVD and studied with high-resolution scanning electron and scanning probe micro-scopes. The resistance of individual nanotubes
and nanotube series was measured using devices fabricated by the deposition of Pd and Pd/Al electrodes on the obtained single-wall
nanotubes. The contact potential difference between Pd electrodes and carbon nanotubes was measured in the Kelvin mode of
a scanning probe microscope. 相似文献
12.
The effects of impurities and local structural defects on the conductance of metallic carbon nanotubes are calculated using an ab initio pseudopotential method within the Landauer formalism. Substitutionally doped boron or nitrogen produces quasibound impurity states of a definite parity and reduces the conductance by a quantum unit (2e(2)/h) via resonant backscattering. These resonant states show strong similarity to acceptor or donor states in semiconductors. The Stone-Wales defect also produces quasibound states and exhibits quantized conductance reduction. In the case of a vacancy, the conductance shows a much more complex behavior than the prediction from the widely used pi-electron tight-binding model. 相似文献
13.
Jørgensen HI Grove-Rasmussen K Novotný T Flensberg K Lindelof PE 《Physical review letters》2006,96(20):207003
We fabricated reproducible high transparency superconducting contacts consisting of superconducting Ti/Al/Ti trilayers to gated single-wall carbon nanotubes. The reported semiconducting single-wall carbon nanotubes have normal state differential conductance up to 3e2/h and exhibit clear Fabry-Perot interference patterns in the bias spectroscopy plot. We observed subharmonic gap structure in the differential conductance and a distinct peak in the conductance at zero bias, which is interpreted as a manifestation of the supercurrent. The gate dependence of this supercurrent as well as the excess current are examined and compared to the coherent theory of superconducting quantum point contacts with good agreement. 相似文献
14.
Electric field aligned, single-walled carbon nanotubes are grown between electrodes using thermal chemical vapour deposition (CVD) of methane. The growth occurs on a thin film layered catalyst of aluminium, iron and molybdenum patterned on top of electrodes. The nanotubes bridge 10 μm sized electrode gaps and have a typical diameter of less than 2 nm as measured by Raman spectroscopy and atomic force microscopy. We present electrical transport measurements on a directly grown nanotube which shows p-type semiconducting behaviour. 相似文献
15.
Kim J Kim JR Lee JO Park JW So HM Kim N Kang K Yoo KH Kim JJ 《Physical review letters》2003,90(16):166403
We report the observation of the resonant transport in multiwall carbon nanotubes in a crossed geometry. The resonant transport is manifested by an asymmetric peak in the differential conductance curve. The observed asymmetric conductance peak is well explained by the Fano resonance originating from the scattering at the contact region of the two nanotubes. The conductance peak depends sensitively on the external magnetic field and exhibits Aharonov-Bohm-type oscillation. 相似文献
16.
17.
The dynamic conductance of carbon nanotubes was investigated using the nonequilibrium Green's function formalism within the context of a tight-binding model. Specifically, we have studied the ac response of tubes of different helicities, both with and without defects, and an electronic heterojunction. Because of the induced displacement currents, the dynamic conductance of the nanotubes differs significantly from the dc conductance displaying both capacitive and inductive responses. The important role of photon-assisted transport through nanotubes is revealed and its implications for experiments discussed. 相似文献
18.
The transport properties of C14 monocyclic ring sandwiched between two Al(1 0 0) electrodes are investigated by first-principle calculations. The variation of the equilibrium conductance as the function of the separation distance between the molecule and the electrodes is studied. C14 monocyclic ring shows metallic behavior according to the calculated equilibrium conductance. Electron transmission occurs through the lowest unoccupied molecular orbital (LUMO). With gate-voltage applied, it is found that the positive and negative gate-voltages can bring very different effect on the variation of equilibrium conductance. We also calculate the effects of adsorbing other atoms on the carbon ring such as oxygen and sulfur atoms. The results indicate that adsorption of this kind of electron-accepting impurity will decrease the conductance of the system. 相似文献
19.
Christian J. -F. Dupraz Patrick Nickels Udo Beierlein Wendy U. Huynh Friedrich C. Simmel 《Superlattices and Microstructures》2003,33(5-6):369
This paper provides an overview of recent research developments in the field of nanoelectronics with organic materials such as carbon nanotubes and DNA-templated nanowires. Carbon nanotubes and gold electrodes are chemically functionalized in order to contact carbon nanotubes by self-assembly. The transport properties of these nanotubes are dominated by charging effects and display clear Coulomb blockade behaviour. A different approach towards nanoscale electronics is based on the molecular recognition properties of biomolecules such as DNA. As an example, DNA is stretched between electrodes using a molecular combing technique. A two-step metallization procedure leads to the formation of highly conductive gold nanowires. 相似文献
20.
Electronic properties of multi-defected zigzag single-walled carbon nanotubes are investigated by use of the tight-binding Green's function method. The Stone-Wales defects and the vacancies are considered. We find that the conductance sensitively depends on the realistic defect configurations for the metallic zigzag carbon nanotubes. Interestingly, the electronic transport properties of the nanotubes with three vacancies can be considered as the sum effect of two double-vacancies, while those with Stone-Wal... 相似文献