The conduction mechanisms of Cu and Ni nanotubules at their different formation stages

Cu and Ni nanotubules have been created within etched tracks in suitable polymers as templates by electrodeless deposition (ELD). In the first stage of tubule formation, dispersed metallic crystallites are grown on the inner track walls by metal precipitation at previously preformed nucleation centers. The metal crystallites grow until they touch each other and form a continuous metal film. Upon further exposure of the sample to the ELD solution the tubule walls grow until either the ELD solution is exhausted, or until the tubules have been transformed into a massive nanowire. The tubules in their various stages of development have been characterized by scanning electron microscopy (SEM) and ion transmission spectrometry (ITS) to probe their geometrical parameters, and by conductivity measurements to understand in which stage of development which conductivity mechanism dominates. In the latter case, current/voltage measurements have been performed, and the temperature dependence of tubule conductivity was determined. This examination enables one to tailor better the metallic nanotubule production by choice of adequate ELD deposition conditions so that they exhibit any desired electric behavior, for future electronic applications.