Fabrication of BiTe Se nanowires with tunable chemical compositions and enhanced thermoelectric properties.

Uniform BiTe Se nanowires (NWs) with tunable components are synthesized by a modified solution method free of any template, and inter-diffusion mechanism is proposed for the growth and transformation of ternary nanowires. Spark plasma sintering is adopted to fabricate the pellets of BiTe Se NWs and thermoelectric transport properties are measured. As compared to BiTe pellets, Se doping results in lowered electrical conductivity because of the reduced carrier concentration, both the Seebeck coefficient and the power factor are enhanced substantially. The BiTeSe pellet exhibits the highest power factor at room temperature as a result of optimized carrier concentration (4.37 × 10 cm) and mobility (60.22 cm V s). As compared to BiTe, the thermal conductivity of BiTe Se is lowered owing to the enhanced phonon scattering by dopants and grain boundaries. As a result, the ZT value at 300 K is substantially improved from 0.045 of BiTe to 0.42 of BiTeSe. It is suggested that Se doping is an effective way to enhance the thermoelectric performance of BiTe based materials.