Effect of Tunnelling on the Thermoelectric Efficiency of Bulk Nanostructured Bi₀.₅Sb₁.₅Te₃ Materials

This work investigates the influence of electron tunnelling on the kinetic and thermoelectric properties of nanostructured bulk materials based on Bi₀.₅Sb₁.₅Te₃. The study focuses on systems where electric transport occurs through a network of semiconducting grains separated by narrow dielectric barriers of nanometer-scale thickness. In this regime, the dominant conduction mechanism is tunnelling, and phonon heat transfer across the barriers can be neglected. Numerical evaluation of the electrical conductivity, thermal conductivity, Seebeck coefficient, and the effective thermoelectric figure of merit (ZT) demonstrates that tunnelling can significantly enhance the thermoelectric voltage and lead to ZT ≈ 1−2 at room temperature, even though the overall electrical conductivity remains relatively low. These results suggest that properly engineered tunnelling contacts can serve as an efficient mechanism for improving energy conversion in bulk thermoelectric composites.