E. Czerwosz et al., Atomic force microscopy and transmission electron microscopy investigations of catalytic formed nanotubes in C-60/C-70+Ni layers, APPL SURF S, 141(3-4), 1999, pp. 350-356
In this paper, atomic force microscopy (AFM) and transmission electron micr
oscopy (TEM) results of the investigations of nanotubes formation in anneal
ed C-60/C-70 + Ni layers are presented. The layers obtained by thermal evap
oration of fullerenes and Ni compound on Mo substrate were annealed in vacu
um at the pressure of 10(-5) Torr and at the temperature of 500 degrees C.
The initial layers (before annealing process) contained 2-5 wt.% of Ni. Thi
s process led to formation of nanotubes and extraction of Ni from the layer
to vacuum. The deposited layer did not posses any nanostructures what was
confirmed by AFM and TEM. In result of the annealing process, the nanotubes
were formed in the layer, The nanostructures formed in such manner were ob
served by TEM. The yield of the nanotubes formation process was estimated f
rom AFM images of the layers. The length, shape and structure of nanotubes
depended on Ni concentration in the initial layer. The length of nanotubes
was within the range of 100-1200 nm and was longer for the nanotubes formed
in layers with lower Ni contents. The shape of nanotubes was mostly cylind
rical and they had multishell structure. The catalytic reaction of Ni with
carbon structures in annealed C-60/C-70 + Ni layer is proposed as the mecha
nism forming nanotubes. (C) 1999 Elsevier Science B.V. All rights reserved.