Arrays of horizontal carbon nanotubes of controlled chirality grown using designed catalysts

Abstract

The semiconductor industry is increasingly of the view that Moore's law-which predicts the biennial doubling of the number of transistors per microprocessor chip-is nearing its end. Consequently, the pursuit of alternative semiconducting materials for nanoelectronic devices, including single-walled carbon nanotubes (SWNTs), continues. Arrays of horizontal nanotubes are particularly appealing for technological applications because they optimize current output. However, the direct growth of horizontal SWNT arrays with controlled chirality, that would enable the arrays to be adapted for a wider range of applications and ensure the uniformity of the fabricated devices, has not yet been achieved. Here we show that horizontal SWNT arrays with predicted chirality can be grown from the surfaces of solid carbide catalysts by controlling the symmetries of the active catalyst surface. We obtained horizontally aligned metallic SWNT arrays with an average density of more than 20 tubes per micrometre in which 90 per cent of the tubes had chiral indices of (12, 6), and semiconducting SWNT arrays with an average density of more than 10 tubes per micrometre in which 80 per cent of the nanotubes had chiral indices of (8, 4). The nanotubes were grown using uniform size MoC and WC solid catalysts. Thermodynamically, the SWNT was selectively nucleated by matching its structural symmetry and diameter with those of the catalyst. We grew nanotubes with chiral indices of (2m, m) (where m is a positive integer), the yield of which could be increased by raising the concentration of carbon to maximize the kinetic growth rate in the chemical vapour deposition process. Compared to previously reported methods, such as cloning, seeding and specific-structure-matching growth, our strategy of controlling the thermodynamics and kinetics offers more degrees of freedom, enabling the chirality of as-grown SWNTs in an array to be tuned, and can also be used to predict the growth conditions required to achieve the desired chiralities.

Plasmonic Chiral Nanostructures: Chiroptical Effects and Applications

“…Latest research showed that controlling the symmetry matching of carbon nanotubes arrays and catalyzer can assemble the horizontal singlewalled carbon nanotubes arrays with controlled chirality. [147] This idea can be used for reference for the future fabrication of plasmonic chiral nano structures. Based on artificial nanostructures, chiroptical effects such as CB, CD, and asymmetric transmission are excited and manipulated to stimulate potential applications, like chiral nanomotor, optical tweezer, chiral light detector, and biomo lecular sensor.…”

Single‐Walled Carbon Nanotubes in Emerging Solar Cells: Synthesis and Electrode Applications

“…In this work, they used Raman spectroscopy to check all SWNTs oneby-one and obtained statistical data that were difficult to achieve before. [82] There are also reports on the selective growth of other chiralities of SWNTs, particularly near the armchair, though the mechanism is not well understood. The mechanism was interpreted based on density functional theory (DFT) calculations, which revealed a facet-dependent energy match.…”

Detecting and Tuning the Interactions between Surfactants and Carbon Nanotubes for Their High‐Efficiency Structure Separation

“…[1][2][3][4][5][6][7][8][9] However, the current synthetic methods of SWCNTs difficultly produce a population of single-structure SWCNTs with identical properties despite recent creative breakthroughs in controlling the structural growth, [10][11][12][13] which seriously restricts the evaluation of their property and the corresponding technical applications. [1][2][3][4][5][6][7][8][9] However, the current synthetic methods of SWCNTs difficultly produce a population of single-structure SWCNTs with identical properties despite recent creative breakthroughs in controlling the structural growth, [10][11][12][13] which seriously restricts the evaluation of their property and the corresponding technical applications.…”