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We have developed a low-cost and effective method to align single-walled carbon nanotubes (SWNTs) using a series of diamond wire drawing dies. The obtained SWNTs are highly dense and perfectly aligned. X-ray diffraction (XRD) indicates that the highly dense and perfectly aligned SWNTs (HDPA-SWNTs) form a two-dimensional triangular lattice with a lattice constant of 19.62 Å. We observe a sharp (002) reflection in the XRD pattern, which should be ascribed to an intertube spacing 3.39 Å of adjacent SWNTs. Raman spectra reveal that the radical breath mode (RBM) of SWNTs with larger diameter in the HDPA-SWNTs is suppressed compared with that of as-grown SWNTs. The HDPA-SWNTs have a large density, ∼1.09 g/cm 3, and a low resistivity, ∼2 mΩ cm, at room temperature, as well as a large response to light illumination. [ABSTRACT FROM AUTHOR]

The photocurrent generated in single-walled carbon nanotube bundles upon camera flash illumination has been studied under different ambient pressures and light intensities. The results show that the intensity of photocurrent depends closely on the ambient pressure and light intensity. With the ambient pressure reduced, the photocurrent exhibits a logarithmic growth behaviour. Meanwhile, the photocurrent increases with the increase in light intensity. In this work, a dynamic model is employed to unveil the origins of the observed photocurrent. A much smaller lifetime of photocarriers ([?]10 ms) is observed than that needed for gas molecular desorption or photodesorption (seconds or longer). Our results are consistent with the model of Schottky barriers being responsible for photocurrent generation. [ABSTRACT FROM AUTHOR]