Structuring of carbon nanotubes array under the action of pulsed laser radiation for nanoelectronics

摘要

The technology of modification of the CNT array on a silicon substrate using laser radiation of nanosecond duration hasbeen developed. The energy regime of irradiation of the array is determined with the aim of aligning the nanotubesperpendicular to the substrate. Structuring of CNTs at a given area using impulse nanosecond radiation moving using agalvanometric scanner system is obtained. Patterning was carried out using pulsed laser radiation with a wavelength of1064 nm, which was moved by means of galvanometric mirrors over the area of the CNT array. The spatial profile of thebeam was Gaussian. The energy density of the pulse was in the range 0.4-2.2 J/cm~2. In order to obtain a homogeneousregion of the CNT array after irradiation, the following parameters were set: the pulse duration was 100 ns, the radiationfrequency was 30 kHz, at which the overheating of CNTs was minimized. The diameter of the laser beam at the focus ofthe laser was 20 μm. The moving rate of the laser beam of 500 mm/s was chosen in such a way so that individual pulsesformed a continuous line with a laser beam overlap to compensate the changing in laser spot power along the diameter.Thus, the processed square 5x5 mm was formed by parallel lines 5 mm long, consisting of individual pulses located at adistance of 17 μm from each other. It is shown that the following effects are possible: CNT ablation, the effect of CNTalignment (straightening), singling, and “splicing” of individual CNTs in a single structure, as well as changing themorphology of the array itself. Nanotubes are less defective after laser modification. This is proved by Ramanspectroscopy. The effect of CNT array structuring can be used to create new sensitive elements of photodetectors, solarcells, chemical sensors, temperature and pressure sensors, probes in microscopy and emitters.