Observation of anisotropy in thermoelectric properties of individual single-crystalline bismuth nanowires

The anisotropy in the thermoelectric-transport properties of single-crystalline Bi nanowires was systematically investigated. Bi nanowires were grown along the crystal orientations of the [-102] and [100] directions using the on-film formation of nanowires method. The electrical conductivity and Seebeck coefficient of Bi nanowires with different diameters were measured with respect to temperature in both directions. The temperature dependence in electrical conductivity exhibited a significant diameter dependence, and significant anisotropy was observed in the Seebeck coefficient. Anisotropy was also observed in the thermoelectric power factor. The thermoelectric figure of merit was estimated using our previously reported thermal-conductivity data, which indicate that [100]-oriented Bi nanowires are more suitable for thermoelectric applications than [-102] nanowires. This is the first report of the anisotropy investigating all the thermoelectric-transport properties of single-crystalline Bi nanowires. Published by AIP Publishing.