Transparent, highly percolated networks of regio-regular poly(3-hexylthiophene) (rr-P3HT) wrapped semiconducting single walled carbon nanotubes (s-SWNT) are deposited and the charge transfer processes of these nanohybrids are studied using spectroscopic and electrical measurements. The data discloses hole doping of s-SWNTs by the polymer, challenging the prevalent electron doping hypothesis. Through controlled fabrication, high to low-density

We report the high-rate and low-temperature growth of vertically aligned carbon nanotubes (CNTs) by a photo-thermal chemical vapour deposition (PTCVD) method using a Ti/Fe bi-layer film as the catalyst. The growth temperature is as low as 370 °C and the growth rate is up to 1.3 μm/min, at least 8 times faster than the reported values by traditional thermal CVD methods. Transmission electron microscopy observations reveal that as-grown CNTs are uniformly made of crystalline 5 − 6 graphene shells with an approximately 10 nm outer diameter and a 5 − 6 nm inner diameter. The low-temperature rapid growth of CNTs is strongly related with the unique top-down heating mode of PTCVD and the formation of Ti/Fe bimetallic solid solution. The present study will advance the deployment of CNTs as interconnects in nanoelectronics, through a CMOS-compatible low-temperature deposition method.

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Despite the “darker than black” association attributed to carbon nanotube forests, here is shown that it is also possible to grow these structures, over heat‐sensitive substrates, featuring highly transmissive characteristics from the UV to infrared wavelengths, for forest heights as high as 20 μm. The optical transmission is interpreted in terms of light propagation along channels that are self‐generated by localized bundling of tubes, acting as waveguides. A good correlation is shown between the distribution of diameter sizes of these sub‐wavelength voids and the transmission spectrum of the forests. For the shorter visible and near‐UV wavelengths, this model shows that light propagates by channeling along individual vertical voids in the forests, which elucidates the origin for the widely‐reported near‐zero reflectance values observed in forests. For the longer infrared wavelengths, the mode spreads over many nanotubes and voids, and propagates along a “homogeneous effective medium”. The strong absorption of the forest at the shorter wavelengths is correlated in terms of the stronger attenuation inside a waveguide cavity, according to the λ−1/2 attenuation dependency of standard waveguide theory. The realization of this material can lead to novel avenues in new optoelectronic device design, where the carbon nanotube forests can be used as highly conducting “scaffolds” for optically active materials, whilst also allowing light to penetrate to significant depths into the structure, in excess of 20 μm, enabling optical functionality.