Hybridization and Modification of the Ni/C60 Composites

Hybridization and thermal evolution of the Ni+C-60 composites, deposited on Si(001) at room temperature, were studied using Scanning Electron Microscopy, mu-Raman spectroscopy and Rutherford Backscattering. As-deposited, the hybrid films exhibited a granular nano-structure with Ni nano-particles encapsulated in C-60 polymerized rinds. The Ni and C (C-60) distributions in a top layer were found homogeneous with a stable Ni/C (C-60) ratio; in the larger depth the distributions were inhomogeneous and their ratio dramatically varied. At elevated temperatures, all structural parameters were changed. In the subsurface layer Ni - and C (C-60) - rich zones were formed (due to the induced phase separation), C-60 - molecules decayed and their fragments were transformed into amorphous carbon (a-C). The free volume distribution of the stressed hybrid matter was analyzed by the Hg marker that (in a form of vapors) in-diffused in to the samples. The RBS analysis showed that the Hg distribution of the as-deposited films followed the character of distribution of the C (C-60) component. At elevated temperatures, however, the Hg profiles decreased dramatically (especially in the subsurface layer) suggesting a significant drop-off of the free volume concentration due to the formation of the spatially compact a-C clusters.