2020/07/23 by M. Kockert, Kockert, M., R. Mitdank +17 · 1 citation
Engineering · Materials Science · #Advanced Thermoelectric Materials and Devices #Applied Physics (physics.app-ph) #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Gas Sensing Nanomaterials and Sensors
paper · pdf · doi:10.48550/arxiv.2007.11951
openalex publication_date 2020/07/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We demonstrate the full thermoelectric and structural characterization of individual bismuth-based (Bi-based) core/shell nanowires. The influence of strain on the temperature dependence of the electrical conductivity, the absolute Seebeck coefficient and the thermal conductivity of bismuth/titanium dioxide (Bi/TiO2) nanowires with different diameters is investigated and compared to bismuth (Bi) and bismuth/tellurium (Bi/Te) nanowires and bismuth bulk. Scattering at surfaces, crystal defects and interfaces between the core and the shell reduces the electrical conductivity to less than 5 % and the thermal conductivity to less than 25 % to 50 % of the bulk value at room temperature. On behalf of a compressive strain, Bi/TiO2 core/shell nanowires show a decreasing electrical conductivity with decreasing temperature opposed to that of Bi and Bi/Te nanowires. We find that the compressive strain induced by the TiO2 shell can lead to a band opening of bismuth increasing the absolute Seebeck coefficient by 10 % to 30 % compared to bulk at room temperature. In the semiconducting state, the activation energy is determined to |41.3±0.2| meV. We show that if the strain exceeds the elastic limit the semimetallic state is recovered due to the lattice relaxation.