Substitutional doping of carbon nanotubes to control their electromagnetic characteristics

Nemilentsau, Andrei; Шуба, М. В.; Slepyan, G. Ya.; Kuzhir, P.; Maksimenko, S. A.; D’yachkov, P. N.; Lakhtakia, Akhlesh

doi:10.1103/physrevb.82.235424

Cited by 37 publications

(23 citation statements)

References 53 publications

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“…Such CNT arrays form finite-thickness slabs which are used already as field emitters [17], biosensors [18] and antennas [19,20]. We assume that all nanotubes possess metallic properties that is a realistic assumption in view of recent studies of single-wall CNTs [21][22][23]. Usually carbon nanotubes form hexagonal lattices in arrays in processes of fabrication.…”

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Ultrabroadband electromagnetically indefinite medium formed by aligned carbon nanotubes

Nefedov

Tretyakov

2011

Phys. Rev. B

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Anisotropic materials with different signs of components of the permittivity tensor are called indefinite materials. Known realizations of indefinite media suffer of high absorption losses. We show that periodic arrays of parallel carbon nanotubes (CNTs) can behave as a low-loss indefinite medium in the infrared range. We show that a finite-thickness slab of CNTs supports the propagation of backward waves with small attenuation in an ultra-broad frequency band. In prospective, CNT arrays can be used for subwavelength focusing and detection, enhancing the radiation efficiency of small sources. PACS numbers: 78.67.Pt, 61.48.De, 77.84.Lf, 41.20.Jb Metal-dielectric nanostructures [1,2] have already brought applications to microscopy and sensing [3] and have the potential for realization of future nanosized optical devices and circuits [4]. In 2003 the authors of [5] noticed the potential of so-called indefinite metamaterials for subwavelength imaging of objects at electrically large distances from them (the concept of such imaging was first introduced in [6]). Indefinite metamaterials are artificial uniaxial materials in which the axial and tangential components of the permittivity and permeability tensors have different signs. In these materials the isofrequency surfaces have hyperbolic shape. This results in a possibility to design a "hyperlens", where evanescent near fields are transformed into propagating modes and can be transported at electrically long distances [7].The main challenge on the way to realize this and other effects is in the realization of low-loss indefinite materials. For waves of only one linear polarization (TM-polarized waves with respect to the axis of positive permittivity) it is enough to realize a layer of an indefinite dielectric metamaterial [8], whose permeability is unity and only components of the permittivity tensor have different signs. For the visible range such a metamaterial was designed in [8] as an array of parallel plasmonic (metal) nanowires. Since all plasmonic phenomena are related to strong dissipation, the axial component of the permittivity has a significant imaginary part which strongly restricts the subwavelength imaging property of the hyperlens [8]. In the microwave range, materials with negative permittivity can be realized as arrays of thin metal wires [9,10]. However, if the field varies along the wires, the properties of the structure are more complicated that those of a continuous medium due to strong spatial dispersion [11]. The spatial dispersion can be suppressed partially [12] or even totally [13][14][15]. However, manufacturing of structures [12-15] becomes a challenge already at millimeter waves as dimensions need to be quite small for high-frequency applications. For electromagnetic waves in the THz and mid infrared (MIR) range there are no known structures with an indefinite permittivity tensor. The imaginary and real parts of complex permittivity of metals in this range are of the same order and rather high.Here we show that arrays of metallic carb...

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confidence: 99%

Ultrabroadband electromagnetically indefinite medium formed by aligned carbon nanotubes

Nefedov

Tretyakov

2011

Phys. Rev. B

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“…Recently, the problem of the electromagnetic field diffraction by isolated CNTs, [3][4][5] bundles, and composites 6,7 containing CNTs received a lot of attention due to the potentiality of CNT-based materials for the effective manipulation of electromagnetic fields in the megahertz, gigahertz, and terahertz frequency ranges. The scattering of the electric near-fields by CNTs 8,9 has important applications in the near-field optical microscopy and spectroscopy with the CNT-based probes.…”

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confidence: 99%

Tutorial: Linear surface conductivity of an achiral single-wall carbon nanotube

Nemilentsau

2011

J. Nanophoton

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Abstract. Theoretical consideration of electromagnetic scattering by single-wall carbon nanotubes (SWNTs) and SWNT arrays requires knowledge of the linear surface conductivity of an SWNT. An expression for the surface conductivity of an infinitely long SWNT was derived by Slepyan et al. [Phys. Rev. B 60, 17136-17149 (1999)]. The twin purposes of this tutorial are to succinctly discuss the derivation using the density matrix formalism and to provide ready-to-use expressions. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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“…These findings are consistent with previous literature reports. 21,39,40 The band structure of TTF@CNT is consistent with n-type doping of the CNT, the flat dopant band meets the conduction band of the CNT close to the Fermi level.…”

Section: Elementmentioning

confidence: 71%

Formation of contacts between doped carbon nanotubes and aluminum electrodes

Jones¹,

Greer²

2013

Journal of Applied Physics

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A theoretical study of the a semiconducting carbon nanotube (CNT) bonding to an aluminum electrode is presented using density functional theory to determine the electronic structure, and charge transport across the junction is studied using non-equilibrium Green's functions. The properties of CNT-metal junctions are of interest for optimizing metal-semiconductor junctions for Schottky barrier transistors and for the formation of Ohmic contacts for nanoelectronics. We first consider the properties of an undoped (16,0) CNT bonded to an aluminum electrode, including an analysis of metal induced gap states and examination of the surface dipole. The junction is then modified by introduction of substitutional dopants into the CNT using nitrogen and boron to form n- and p-type semiconductors, respectively, and the resulting impact of the doping on current transport across the junctions is calculated. As an alternative doping strategy, tetrathiafulvalene is introduced endohedrally and found to act as an n-type dopant in agreement with previous experimental studies. From electron transmission and current voltage characteristics, it is found that the doped junctions can be engineered to have much lower onset resistances relative to the undoped junction. It is found that the current-voltage characteristics display increased resistance for larger forward and reverse biases: For one polarity, the resistance increase is associated with the introduction of the CNT band gap into the voltage bias window, whereas for the opposing voltage polarity, the resistance increase is due to large charge carrier-substitutional dopant scattering. For the case of the endohedral doping scheme, it is found that the carrier-dopant scattering is effectively absent. (C) 2013 AIP Publishing LLC

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Substitutional doping of carbon nanotubes to control their electromagnetic characteristics

Cited by 37 publications

References 53 publications

Ultrabroadband electromagnetically indefinite medium formed by aligned carbon nanotubes

Ultrabroadband electromagnetically indefinite medium formed by aligned carbon nanotubes

Tutorial: Linear surface conductivity of an achiral single-wall carbon nanotube

Formation of contacts between doped carbon nanotubes and aluminum electrodes

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