Multichannel Ballistic Transport in Multiwall Carbon Nanotubes

Li, H. J.; Lü, Wei; Li, J. J.; Bai, Xuedong; Gu, Changzhi

doi:10.1103/physrevlett.95.086601

Cited by 456 publications

(261 citation statements)

References 27 publications

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“…This is the hallmark of ballistic electron transport, which has been theoretically predicted (13)(14)(15). Our work is one of the few that indicate ballistic nature of electron transport in MWCNT (16)(17)(18).…”

Section: Resultsmentioning

confidence: 85%

Electronic properties of nanoentities revealed by electrically driven rotation

Fan

Zhu

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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Direct electric measurement via small contacting pads on individual quasi-one-dimensional nanoentities, such as nanowires and carbon nanotubes, are usually required to access its electronic properties. We show in this work that 1D nanoentities in suspension can be driven to rotation by AC electric fields. The chirality of the resultantrotation unambiguously reveals whether the nanoentities are metal, semiconductor, or insulator due to the dependence of the Clausius-Mossotti factor on the material conductivity and frequency. This contactless method provides rapid and parallel identification of the electrical characteristics of 1D nanoentities.electric tweezers | nanoparticles | manipulation Q uasi 1D entities, such as carbon nanotubes and various nanowires (e.g., metallic Au, ferromagnetic Co, semiconducting ZnO, and insulating SiO 2 ), have been intensely explored in recent years owing to their remarkable properties. Particularly fascinating are carbon nanotubes (CNTs), which may be multiwall carbon nanotubes (MWCNTs) and single-wall carbon nanotubes (SWCNTs) with greatly different properties. Even among SWCNTs, they can be metallic or semiconducting depending on the manner with which the graphene sheet rolls into the cylindrical shape (1). In fact, during synthesis of CNTs, both MWCNTs and SWCNTs, either metallic or semiconducting, are indiscriminately produced (2). To access the electronic properties of 1D entities, one usually resorts to direct electrical measurements of a single entity via metallic contact pads painstakingly patterned by lithography (1). The task becomes daunting when there are a variety of entities.Freestanding nanoentities are typically suspended in a liquid to avoid adhesion to dry surfaces via the van der Waals forces. However, driven motion of suspended nanoentities is well known to be challenging because of the extremely low Reynolds number of 10 −5 where viscous force overwhelms. Nevertheless, it has recently been shown in a scheme termed "electric tweezers" that suspended quasi-1D objects, including CNTs and nanowires, can be compelled to execute translational and rotational motion with precision by DC and AC electric fields applied to patterned electrodes (3-6). In particular, a suitably administered AC electric field can rotate the suspended 1D entities (7), where the rotation speed, chirality and rotation angle can be precisely controlled by the strength and duration of the applied electric fields.In this work, we show that such electrically driven rotational motion can also reveal the electronic properties of the nanoentities. The chirality of the resultant rotation unambiguously reveals whether the nanoentities are metal, semiconductor, or insulator due to the dependence of the Clausius-Mossotti factor on the material conductivity and frequency. From the rotational characteristics, the imaginary part of the Clausius-Mossotti factor ImðKÞ, a key electronic property of the nanoentities, can be determined solely from their rotational motion. We have thus demonstrated contactless pr...

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Section: Resultsmentioning

confidence: 85%

Electronic properties of nanoentities revealed by electrically driven rotation

Fan

Zhu

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…[1][2][3][4][5][6][7][8][9][10][11][12] The current-voltage (IV) characteristics of individual metallic NTs are shown to be dependent not only on diameter and length, [1][2][3][4][5][6][7][8][9][10][11][12] but also on the substrate-NTs interaction. 1 Remarkable is that the current saturation have been observed for metallic as well as semiconducting single-walled NT (SWNT), [1][2][3][4][5][6][7][8] which is attributed to the electron back scattering by high energy phonon, 3 and interband zener tunneling. 11 However, a series of independent transport measurements on various length demonstrated the absence of current saturation in NTs shorter than 55 nm.…”

Section: Introductionmentioning

confidence: 99%

Electrical characteristics of multiwalled carbon nanotube arrays and influence of pressure

Singh

2012

AIP Advances

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We have investigated the current-voltage characteristics of carbon nanotube arrays and shown that the current through the arrays increases rapidly with applied voltage before the breakdown occurs. Simultaneous measurements of current and temperature at one end of the arrays suggest that the rapid increase of current is due to Joule heating. The current through the array and the threshold voltage are found to increase with decreasing pressure

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“…In some previous studies, multiwall carbon nanotube (MWNTs) interconnections with metal electrodes only occurred with the outermost wall of MWNTs (7). A robust mechanical connection in such a junction cannot be expected, nor can the inner walls of MWNTs participate considerably in charge transport (5). Therefore, detailed knowledge regarding the nature and strength of bonding as well as the morphology and electrical properties of contacts is important because it is vital to connect all concentric cylinders of a MWNT, across the entire cross-section of the nanotube, to a metal particle.…”

mentioning

confidence: 99%

“…To date, most results indicate that the properties of such a device are dominated by the electronic behavior at the nanotube-metal contact. For instance, the resistance of the ohmic contact (1,3,5) or Schottky barrier effects (6) are influenced by the type of interface between metal and the graphitic structure. In some previous studies, multiwall carbon nanotube (MWNTs) interconnections with metal electrodes only occurred with the outermost wall of MWNTs (7).…”

mentioning

confidence: 99%

Heterojunctions between metals and carbon nanotubes as ultimate nanocontacts

Rodríguez–Manzo

Banhart

Terrones

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

112

100

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We report the controlled formation and characterization of heterojunctions between carbon nanotubes and different metal nanocrystals (Fe, Co, Ni, and FeCo). The heterojunctions are formed from metal-filled multiwall carbon nanotubes (MWNTs) via intense electron beam irradiation at temperatures in the range of 450 -700°C and observed in situ in a transmission electron microscope. Under irradiation, the segregation of metal and carbon atoms occurs, leading to the formation of heterojunctions between metal and graphite. Metallic conductivity of the metal-nanotube junctions was found by using in situ transport measurements in an electron microscope. Density functional calculations show that these structures are mechanically strong, the bonding at the interface is covalent, and the electronic states at and around the Fermi level are delocalized across the entire system. These properties are essential for the application of such heterojunctions as contacts in electronic devices and vital for the fabrication of robust nanotube-metal composite materials.nanoelectronics ͉ interfacial interactions ͉ conductivity ͉ electron microscopy ͉ composites H eterojunctions between different materials are of increasing interest in nanotechnology. For creating devices at the nanoscale, different structures have to be joined so as to obtain junctions with predefined properties. Junctions between carbon nanotubes (CNTs) and metals (1-3) or semiconducting (1, 4) nanowires are highly desirable to exploit the excellent electronic and mechanical properties of CNTs. In electronic devices, conductive contacts between the graphitic network of CNTs and metallic electrodes need to be established to link the nanotubes with each other and their periphery. To date, most results indicate that the properties of such a device are dominated by the electronic behavior at the nanotube-metal contact. For instance, the resistance of the ohmic contact (1, 3, 5) or Schottky barrier effects (6) are influenced by the type of interface between metal and the graphitic structure. In some previous studies, multiwall carbon nanotube (MWNTs) interconnections with metal electrodes only occurred with the outermost wall of MWNTs (7). A robust mechanical connection in such a junction cannot be expected, nor can the inner walls of MWNTs participate considerably in charge transport (5). Therefore, detailed knowledge regarding the nature and strength of bonding as well as the morphology and electrical properties of contacts is important because it is vital to connect all concentric cylinders of a MWNT, across the entire cross-section of the nanotube, to a metal particle. In particular, a covalent nanotube-metal junction would allow one to attach nanotubes firmly to metal pieces, which is useful for achieving well-defined electrical contacts and also for attaching nanotubes firmly to metal supports for the realization of ultrastrong nanotube ropes in mechanical systems.Recent studies have reported examples of graphitic material interfaces with metal particles for Co crysta...

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Multichannel Ballistic Transport in Multiwall Carbon Nanotubes

Cited by 456 publications

References 27 publications

Electronic properties of nanoentities revealed by electrically driven rotation

Electronic properties of nanoentities revealed by electrically driven rotation

Electrical characteristics of multiwalled carbon nanotube arrays and influence of pressure

Heterojunctions between metals and carbon nanotubes as ultimate nanocontacts

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