Electrical conductivity of NaSi at elevated temperatures

The conductivity of sodium silicide (NaSi) was measured from 100 °C to 740 °C using a four-point DC method. NaSi was synthesized by heating a mixture of silicon powder and sodium liquid in an argon atmosphere at 550–650 °C. The formation of NaSi was followed by monitoring the conductivity and confirmed by post-experiment XRD analysis. The results showed semiconductor behaviour, with a shift in the conduction activation energy occurring near 460 °C, from 0.032 eV at the lower temperatures to 1.42 eV at higher temperatures. The room temperature conductivity of 0.22 S cm−1 was obtained by extrapolation, closely matching the results from simple two-point conductivity measurements.