Evaluation of Thermoelectric Properties in Bi-Microwires by the Harman Method

We have improved the Harman method to evaluate all thermoelectric properties related to the figure of merit, ZT, not only in bulk materials but also in mesoscopic ones. By this method, the ZT of single microwires can also be determined. The minimum sample size is currently similar to 0.25 mm in length and similar to 10 mu m in diameter. The fabrication of our equipment based on the Harman method is described in detail. The enhancement of ZT can be achieved in the Bi-microwire array because of the homogeneous arrangement of the crystal orientation in each microwire. The results obtained in the Bi-microwire arrays are consistent with ZT behavior in the single microwires extracted from the arrays. [DOI: 10.1143/JJAP.47.3576]