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Suspended single-walled carbon nanotube devices comprised of high-quality electrical contacts and two electrostatic gates per device have been prepared. Compared to nanotubes pinned on substrates, the suspended devices exhibit little hysteresis related to environmental factors and act as cleaner Fabry-Perot interferometers or single-electron transistors. The high-field saturation currents in the suspended nanotubes related to optical phonon or zone-boundary phonon scattering are significantly lower due to the lack of efficient heat sinking. The multiple-gate design may also facilitate future investigations into the electromechanical properties of nanotube quantum systems. 相似文献
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We investigate electronic transport in Josephson junctions formed by individual single-walled carbon nanotubes coupled to
superconducting electrodes. We observe enhanced zero-bias conductance (up to 10e
2/h) and pronounced sub-harmonic gap structures in differential conductance, which arise from the multiple Andreev reflections
at superconductor/nanotube interfaces. The voltage-current characteristics of these junctions display abrupt switching from
the supercurrent branch to the resistive branch, with a gate-tunable switching current ranging from 65 pA to 2.5 nA. The finite
resistance observed on the supercurrent branch and the magnitude of the switching current are in good agreement with the classical
phase diffusion model for resistively and capacitively shunted junctions. 相似文献
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To understand the electron transport properties of transition metal nitrides (MN), electronic structure relationship between metal and corresponding nitrides is important. In binary nitrides, when nitrogen atoms occupy interstitial sites of metal lattice, volume expansion started initially without changing structure of metal lattice. Above certain concentration of nitrogen into interstitial sites of lattice, the system starts stabilizing its energy to minimum that in turn changes to another crystal structure. The chemical bonding in MN is due to the mixing of d-orbitals of M and p-orbitals of N. This is confirmed theoretically and experimentally such as X-ray photoelectron spectroscopy. The Fermi energy is generally lowered by the introduction of vacancies. However, reports on the particle size effect in the electrical resistivity of nitrides are scanty. One reason is that the role of the particle size in resistivity is difficult to determine because there is a need to understand N concentration. It poses a challenge to the synthesis of nanostructured transition metal nitrides. The transition metal binary nitrides show unusual electron transport, optical and magnetic properties as compared to their metal counterparts. Electronic properties of all transition metal nitrides known till date are discussed. Different ways of synthesis of nitrides and their applications are mentioned. 相似文献
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Kronemeijer AJ Katsouras I Huisman EH van Hal PA Geuns TC Blom PW de Leeuw DM 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(11):1593-1598
Charge transport through alkanes and para-phenylene oligomers is investigated in large-area molecular junctions. The molecules are self-assembled in a monolayer and contacted with a top electrode consisting of poly(3,4-ethylenedioxythiophene)-poly(4-styrenesulfonic acid) (PEDOT:PSS). The complete set of J(V,T) characteristics of both saturated and π-conjugated molecules can be described quantitatively by a single equation with only two fit parameters. The derived parameters, in combination with a variation of the bulk conductivity of PEDOT:PSS, demonstrate that the absolute junction resistance is factorized with that of PEDOT:PSS. 相似文献
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《Journal of Experimental Nanoscience》2013,8(5):547-556
In this article, we report the synthesis of ultra-long carbon nanotubes (CNTs) by thermal chemical vapour deposition method. Ultra-long, individual and aligned CNTs were directly grown on a flat silicon substrate. The orientation of the nanotubes was found parallel to the gas flow direction. The ultra-long CNTs were grown with different transition metallic salts, such as nickel chloride, iron (III) chloride, cobalt acetate and ruthenium acetate, as the catalysts. The influence of the growth conditions, such as growth temperature, reactive gas flow on the length and alignment of the CNTs was studied in detail. By using different catalysts, ultra-long single-walled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) were successfully grown. These ultra-long CNTs were transferred to other substrates by two methods. (1) The first method is to use polydimethylsiloxane as a stamp. (2) The second method is to use KOH as an etching agent. The diameter and length of the CNTs were characterised by transmission electron microscope, scanning electron microscope, atomic force microscope and Raman spectroscopy. The results indicate that the length of the CNTs can reach up to 4?mm. The diameter of the SWCNTs is in the range of 0.7–2.1?nm and the diameter of the MWCNTs is approximately 150?nm. 相似文献
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碳纳米管的制备、表征及其在电子领域中的应用 总被引:2,自引:0,他引:2
碳纳米管的独特结构使它具有奇特的性质和广阔的应用前景。本文介绍了碳纳米管的结构和性质,对碳纳米管的制备现状、表征及其在电子领域的应用做了详细的回顾。 相似文献
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Jian Liu Xinchen Li Shaoqing Zhang Xingang Ren Jiaqi Cheng Lu Zhu Di Zhang Lijun Huo Jianhui Hou Wallace C. H. Choy 《Advanced Materials Interfaces》2015,2(17)
Currently, most of the promising organic solar cells (OSCs) are based on low bandgap polymer donors with deep‐lying highest occupied molecular orbit (HOMO) levels, which impose the challenges for device architecture design. In terms of fast charge extraction and suppression of bimolecular recombination, elaborate interface design in low bandgap OSCs is of significance to further boost their ultimate efficiency. In this work, a facile solution‐processed functionalized single wall carbon nanotube (f‐SWCNT) mesh/self‐assembled molecule (SAM) hybrid structure is reported as hole transport layer (HTL) in low bandgap OSCs. The effectiveness of such hybrid HTL originates from two aspects: (i) SAM layer can effectively realize Ohmic contact between f‐SWCNT and low bandgap polymer donors with deep‐lying HOMO levels due to the reduction of interface energy barrier; (ii) f‐SWCNT mesh can provide fast hole extraction pathways to quickly sweep out photogenerated charges. As a consequence of synergic effects of such hybrid HTL, both photocurrent and fill factor are greatly enhanced due to the reduced bimolecular recombination. Together with careful light management by using ZnO optical spacer, a high efficiency of 10.5% has been achieved. This work offers an excellent choice for large‐scale processable and effective HTL toward the application in low bandgap OSCs with deep‐lying energy levels. 相似文献
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碳纳米管的电化学性质及其应用研究 总被引:6,自引:1,他引:6
把碳纳米管作为一种新型的电极材料是开发碳纳米管应用的一个新的方向。本文研究了碳纳米管的化学修饰和电化学性质,发现决定碳纳米管电化学性质的两个重要因素。系统地总结了我们在碳纳米管电极的制备、碳纳米管电极的电化学响应、碳纳米管电极的生物电分析和电氧化有毒化成分应用方面的研究成果。 相似文献
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Jennifer E. Podesta Khuloud T. Al‐Jamal M. Antonia Herrero Bowen Tian Hanene Ali‐Boucetta Vikas Hegde Alberto Bianco Maurizio Prato Kostas Kostarelos 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(10):1176-1185
Carbon nanotubes are novel nanomaterials that are thought to offer potential benefits to a variety of biomedical and clinical applications. In this study, the treatment of a human lung carcinoma model in vivo using siRNA sequences leading to cytotoxicity and cell death is carried out using either cationic liposomes (DOTAP:cholesterol) or amino‐functionalized multi‐walled carbon nanotubes ( ). Validation for the most cytotoxic siRNA sequence using a panel of human carcinoma and murine cells reveals that the proprietary siTOX sequence is human specific and can lead to significant cytotoxic activities delivered both by liposome or in vitro. A comparative study using both types of vector indicates that only :siRNA complexes administered intratumorally can elicit delayed tumor growth and increased survival of xenograft‐bearing animals. siTOX delivery via the cationic is biologically active in vivo by triggering an apoptotic cascade, leading to extensive necrosis of the human tumor mass. This suggests that carbon‐nanotube‐mediated delivery of siRNA by intratumoral administration leads to successful and statistically significant suppression of tumor volume, followed by a concomitant prolongation of survival of human lung tumor‐bearing animals. The direct comparison between carbon nanotubes and liposomes demonstrates the potential advantages offered by carbon nanotubes for the intracellular delivery of therapeutic agents in vivo. The present work may act as the impetus for further studies to explore the therapeutic capacity of chemically functionalized carbon nanotubes to deliver siRNA directly into the cytoplasm of target cells and achieve effective therapeutic silencing in various disease indications where local delivery is feasible or desirable. 相似文献
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ChangLIU HuimingCHENG 《材料科学技术学报》2002,18(2):124-126
Single=walled carbon nanotubes(SWNTs) were synthesized by a hydrogen arc discharge method.A high yield of gram quantity of SWNTs per hour was achieved.Tow kinds of SWNT products:web-like substancea and thin films in large slices were obtained. Results of resonant Raman scattering measurements indicate that the SWNTs prepared have a wider diameter distribution and a larger mean diameter.Hydrogen uptake measurements of the two kinds of SWNT samples(both as prepared and pretreated) were carried out using a high pressure volumetric method,respectively.And a hydrogen storage capacity of 4 wt pct could be repeatedly achieved for the suitably pretreated SWMNTs,whicb indicates that SWNTs may be a promising hydrogen storge material. 相似文献
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Almut M. Schwenke Stephanie Hoeppener Ulrich S. Schubert 《Advanced materials (Deerfield Beach, Fla.)》2015,27(28):4113-4141
Microwave‐assisted synthesis and processing represents a growing field in materials research and successfully entered the field of carbon nanomaterials during the last decade. Due to the strong interaction of carbon materials with microwave radiation, fast heating rates and localized heating can be achieved. These features enable the acceleration of reaction processes, as well as the formation of nanostructures with special morphologies. A comprehensive overview is provided here on the possibilities and achievements in the field of carbon‐nanomaterial research when using microwave‐based heating approaches. This includes the synthesis and processing of carbon nanotubes and fibers, graphene materials, carbon nanoparticles, and capsules, as well as porous carbon materials. Additionally, the principles of microwave‐heating, in particular of carbon materials, are introduced and important issues, i.e., safety and reproducibility, are discussed. 相似文献
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J. Enrique Samaniego-Benitez J. Ramírez-Aparicio I. R. Chavez-Urbiola A. Garcia-Garcia J. Francisco Perez-Robles R. Ramirez-Bon 《Fullerenes, Nanotubes and Carbon Nanostructures》2018,26(6):370-378
Plumbonacrite films were used as support material for growth of carbon nanotubes and the resulting nanocomposite was tested as photocatalysts for the degradation of methylene blue dye. The plumbonacrite films were deposited on silicon substrates by a simple alkaline chemical bath deposition process. After the CNT growth process, the resulting nanocomposite samples were analyzed by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The high temperature during the CNT growth process decomposed the plumbonacrite material into lead microspheres, which were covered by the CNT constituting the nanocomposite films. Afterwards, the nanocomposite films were applied for the photodegradation of methylene blue molecules using natural sunlight. The nanocomposite films were reused for up to three cycles obtaining efficiencies in the degradation of the dye superior to 92% and a first order kinetics with rate constants of 8.9 × 10?3 min?1 in a maximum irradiation time of 240 minutes. 相似文献
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