Self-assembly of novel nanowires by thermolysis of fullerene and transition metal thin films

摘要

A wide range of nanomaterials has been grown by thermal treatment of patterned condensed-phase precursors. We present a systematic study of the thermolysis of fullerene, amorphous carbon and transition metal thin films, trying to bridge previously reported results in the high temperature regime (>900 deg C) and reporting novel structures for low temperature (<550 deg C) processing. The synthesis of crystals of single-walled carbon nanotubes from high temperature annealing of patterned, multilayered fullerene and nickel precursor films, could not be reproduced. A thicker fullerene layer in the presence of nickel was, however, transformed into a web-like carbon network. Low temperature processing of similar precursor patterns on sulfur-containing molybdenum grids resulted in the self-assembly of nickel sulfide nanowires and filled MoS_2 nanotubes. Cobalt was found to form cobalt sulfide structures. The strongly oxidizing behaviour of iron resulted in an abundance of needle-like molybdenum oxide crystals. None of the structural formations could be seen for amorphous carbon as a substitutional thin film precursor. Based on the ease of changing precursor materials, this simple, scaleable method addresses many nanomaterials, giving new insight into growth mechanisms as well as offering synthesis control for future applications.