Experimental and theoretical analysis of carbon nanotubes grown from catalytic nanoparticles of defined size distribution

• We report use of a dip-coating method to prepare catalyst particles (mixture of iron and cobalt) with a controlled diameter distribution on silicon wafer substrates by changing the solution concentration and withdrawal velocity. The size and distribution of the prepared catalyst particles were analyzed by atomic force microscopy. Carbon nanotubes were grown by chemical vapor deposition, CVD, on the substrates with the prepared catalyst particles. By decreasing the particle size, the growth of carbon nanotubes can be tuned from few walled carbon nanotubes, with homogeneous diameters, to highly pure single walled carbon nanotubes, SWNT. Analysis of the Raman radial breathing mode, showed a relatively broad diameter distribution (0.8-1.4 nm) of single walled carbon nanotubes, SWNT, with different chiralities. By changing the size and composition of the catalyst particles but maintain the growth parameters, the chiralities of SWNT were reduced to mainly four different types: (12,1), (12.0), (8,5) and (7,5) of which quantity is 70 % of all the nanotubes.

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NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

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