Theoretical investigation of thermoelectric transport properties of cylindrical Bi nanowires

We report here a theoretical model for the transport properties of cylindrical Bi nanowires. Based on the band structure of Bi nanowires and the semiclassical transport model, the thermoelectric figure of merit Z(1D)T is calculated for Bi nanowires with various wire diameters and wire orientations. The results show the trigonal axis is the most favorable wire orientation for thermoelectric applications, and Z(1D)T>1 is predicted for n-type trigonal wires with diameters d(w)<10 nm. The effect of the T-point holes on Z(1D)T is also investigated. It is found that Z(1D)T can be significantly enhanced, especially for p-type Bi nanowires, if the T-point holes are removed or suppressed.