Electrical Conductivity of Composite Materials Based on n-InSe and Thermally Expanded Graphite

Abstract

The composite material was obtained based on InSe semiconductor powder and thermally expanded graphite (TEG). The TEG content varied from 4 wt. % up to 20 wt. %, the starting materials were pressed into disks using a hydraulic press. The percolation nature of the electrical conductivity of such composite materials was studied. Since the electrical conductivity of InSe powder is almost 9 orders of magnitude lower than the electrical conductivity of TEG, TEG can be considered as a conducting phase in this composite. The dependences of the electrical conductivity on the TEG content and temperature were measured. The value of the percolation threshold was estimated from the graphical dependence of the electrical conductivity on the TEG content. When studying the electrical conductivity of composite materials, it should be taken into account that the current flows both inside individual crystallites and through the interface between them. The theoretical model was proposed that describes the obtained experimental results of the temperature dependences of electrical conductivity. The conclusions were made about the dominant current flow mechanism on the basis of the analysis of the temperature dependence of electrical conductivity.