Carbon nanotube arrays

Taft BJ, Lazareck AD, Withey GD, Yin A, Xu JM, Kelley SO (2004) Site-specific assembly of DNA and appended cargo on arrayed carbon nanotubes. J Am Chem Soc 126 12750... 

Lebedev N, Trammell SA, Tsoi S, Spano A, Kim JH, Xu J, Twigg ME, Schnur JM. Increasing efficiency of photoelectronic conversion by encapsulation of photosynthetic reaction center proteins in arrayed carbon nanotube electrode. Langmuir 2008 24 8871. 

Whereas multi-wall carbon nanotubes require no catalyst for their growth, either by the laser vaporization or carbon arc methods, catalyst species are necessary for the growth of the single-wall nanotubes [156], while two different catalyst species seem to be needed to efficiently synthesize arrays of single wall carbon nanotubes by either the laser vaporization or arc methods. The detailed mechanisms responsible for the growth of carbon nanotubes are not yet well understood. Variations in the most probable diameter and the width of the diameter distribution is sensitively controlled by the composition of the catalyst, the growth temperature and other growth conditions. 

Early transport measurements on individual multi-wall nanotubes [187] were carried out on nanotubes with too large an outer diameter to be sensitive to ID quantum effects. Furthermore, contributions from the inner constituent shells which may not make electrical contact with the current source complicate the interpretation of the transport results, and in some cases the measurements were not made at low enough temperatures to be sensitive to 1D effects. Early transport measurements on multiple ropes (arrays) of single-wall armchair carbon nanotubes [188], addressed general issues such as the temperature dependence of the resistivity of nanotube bundles, each containing many single-wall nanotubes with a distribution of diameters d/ and chiral angles 6. Their results confirmed the theoretical prediction that many of the individual nanotubes are metallic. 

Abstract—The fundamental relations governing the geometry of carbon nanotubes are reviewed, and explicit examples are pre.sented. A framework is given for the symmetry properties of carbon nanotubes for both symmorphic and non-symmorphic tubules which have screw-axis symmetry. The implications of symmetry on the vibrational and electronic structure of ID carbon nanotube systems are considered. The corresponding properties of double-wall nanotubes and arrays of nanotubes are also discussed. 

Of particular importance to carbon nanotube physics are the many possible symmetries or geometries that can be realized on a cylindrical surface in carbon nanotubes without the introduction of strain. For ID systems on a cylindrical surface, translational symmetry with a screw axis could affect the electronic structure and related properties. The exotic electronic properties of ID carbon nanotubes are seen to arise predominately from intralayer interactions, rather than from interlayer interactions between multilayers within a single carbon nanotube or between two different nanotubes. Since the symmetry of a single nanotube is essential for understanding the basic physics of carbon nanotubes, most of this article focuses on the symmetry properties of single layer nanotubes, with a brief discussion also provided for two-layer nanotubes and an ordered array of similar nanotubes. 

Inspired by experimental observations on bundles of carbon nanotubes, calculations of the electronic structure have also been carried out on arrays of (6,6) armchair nanotubes to determine the crystalline structure of the arrays, the relative orientation of adjacent nanotubes, and the optimal spacing between them. Figure 5 shows one tetragonal and two hexagonal arrays that were considered, with space group symmetries P42/mmc P6/mmni Dh,), and P6/mcc... 

Fig. 5. Schematic representation of arrays of carbon nanotubes with a common tubule axial direction in the (a) tetragonal, (b) hexagonal I, and (c) hexagonal II arrangements. The reference nanotube is generated using a planar ring of twelve carbon atoms arranged in six pairs with the symmetry [16,17,30].

No superconductivity has yet been found in carbon nanotubes or nanotube arrays. Despite the prediction that ID electronic systems cannot support supercon-ductivity[33,34], it is not clear that such theories are applicable to carbon nanotubes, which are tubular with a hollow core and have several unit cells around the circumference. Doping of nanotube bundles by the insertion of alkali metal dopants between the tubules could lead to superconductivity. The doping of individual tubules may provide another possible approach to superconductivity for carbon nanotube systems. 

The electronic properties of single-walled carbon nanotubes have been studied theoretically using different methods[4-12. It is found that if n — wr is a multiple of 3, the nanotube will be metallic otherwise, it wiU exhibit a semiconducting behavior. Calculations on a 2D array of identical armchair nanotubes with parallel tube axes within the local density approximation framework indicate that a crystal with a hexagonal packing of the tubes is most stable, and that intertubule interactions render the system semiconducting with a zero energy gap[35]. 

Although random and irregular type GaN nanorods have been prepared by using transition metal nanoparticles, such as Ni, Co, and Fe as catalysts and carbon nanotubes as the template, the preparation of controllable regular array of strai t GaN nanorods has not yet been reported. Fabrication of well-ordered nano-structures with high density is very important for the application of nano-structures to practical devices. 

Gooding JJ, Wibowo R, Liu JQ, Yang WR, Losic D, Orbons S, Meams FJ, Shapter JG, Hibbert DB. 2003. Protein electrochemistry using aligned carbon nanotube arrays. J Am Chem Soc 125 9006-9007. 

Chemists have been working for a long time with particles having sizes of nanometers. The novelty of recent developments concerns the ability to make nanostructured substances with uniform particle sizes and in regular arrays. In this way it becomes feasible to produce materials that have definite and reproducible properties that depend on the particle size. The development began with the discovery of carbon nanotubes by Ijima in 1991 (Fig. 11.15, p. 116). 

Field emission displays are VFDs that use field emission cathodes as the electron source. The cathodes can be molybdenum microtips,33-35 carbon films,36,37 carbon nanotubes,38" 16 diamond tips,47 or other nanoscale-emitting materials.48 Niobium silicide applied as a protective layer on silicon tip field emission arrays has been claimed to improve the emission efficiency and stability.49 ZnO Zn is used in monochrome field emission device (FED) displays but its disadvantage is that it saturates at over 200 V.29... 

S. Sotiropoulou and N.A. Chaniotakis, Carbon nanotube array-based biosensor. Anal. Bioanal. Chem. 375,103-105 (2003). 

J. Li, C. Papadopoulos, and J. Xu, Highly-ordered carbon nanotube arrays for electronics applications. 

J. Liu, A. Chou, W. Rahmat, M.N. Paddon-Row, and J.J. Gooding, Achieving direct electrical connection to glucose oxidase using aligned single walled carbon nanotube arrays. Electroanalysis 17, 38—46 (2005). 

Kang, S. J. Kocabas, C. Ozel, T. Shim, M. Pimparkar, N. Muhammad, M. A. Rotkin, S. V. Rogers, J. A. 2007. Fligh-performance electronics using dense, perfectly aligned arrays of single-walled carbon nanotubes. Nature Nanotechnol. 2 230-236. 

APPLICATIONS USING NETWORKS AND ARRAYS OF CARBON NANOTUBES... 

Qi, P. Vermesh, O. Grecu, M. Javey, A. Wang, Q. Dai, H. Peng, S. Cho, K. J. 2003. Toward large arrays of multiplex functionalized carbon nanotube sensors for highly sensitive and selective molecular detection. Nano Lett. 3 347-351. 

Figure 13.7. (a) Schematic illustration of the dry transfer of CVD-grown single-walled carbon nanotubes onto plastic substrates, (b)-(e) Scanning electron micrographs of SWNT arrays transferred to plastic substrates, with repetitive transfer for crossed arrays. 

Kocabas, C. et al. 2005. Guided growth of large-scale, horizontally aligned arrays of single-walled carbon nanotubes and their use in thin-film transistors. Small 1 1110-1116. 

Kang, S. J. et al. 2007. High-performance electronics using dense, perfectly aligned arrays of single-walled carbon nanotubes. Nature Nanotechnol. 2 230-236. 

Nguyen CV, Delzeit L, Cassell AM, Li J, Flan J, Meyyappan M (2002) Preparation of nucleic acid functionalized carbon nanotube Arrays. Nano Lett. 2 1079-1081. 

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