Electrical Percolation during Codeposition of Fe and Si Clusters by a Dual Source PGCCD System

Abstract

Random assemblies of Fe and Si clusters have been prepared using a dual source plasma gas condensation cluster deposition system and their conductivities were measured for various compositional ratios. The size distributions of Fe and Si clusters are obtained by transmission electron microscopy (TEM) observations and the volume fraction of Fe clusters, f_Fe, is estimated from the chemical analysis and packing fraction of cluster assemblies. Electrical conductivity, σ, of Fe and Si cluster assemblies obeys a power law of f_Fe. The dramatic change at around f_Fe=f_c, indicates that the percolation of Fe clusters takes place at the threshold value, f_c=0.16. It is consistent with the Links-Nodes-Blobs model calculated for a three dimensional percolation network.