Electrical conductivity of carbon films obtained by thermal sputtering of type I shungite rocks of various deposits

Abstract

Amorphous carbon films were deposited by thermal evaporation of bulk samples of different shungites and graphite. Structural properties and the size of carbon nanoclusters in the films were determined from the analysis of their selected area electron diffraction (SAED) patterns and Raman spectra. To analyze the possible distribution of trace elements in the films, element mapping was performed using scanning electron microscopy. The electrical conductivity of the obtained films was measured at temperatures ranging from the liquid nitrogen to room temperature. The measurements showed differences in the type of dependence of electrical conductivity on temperature for different nano-crystalline films from monotonic, typical for semiconductors to complex, V-shaped curve containing sections of the metallic and semiconductor types.