Thermoelectric properties of semiconducting Bi-rich Bi-Sb alloys

H. Kitagawa, H .Noguchi, M. Itoh, Y. Noda

Department of Materials Science, ShimaneUniversityNishikawatsu 1060, Matsue,

Shimane 690-8504, Japan

The Bi_100-xSb_x (x=8-17) alloyswere prepared by quenching into LN₂ after melting the components.The semiconducting and thermoelectric properties of prepared samples wereinvestigated by measuring Hall coefficient,electrical resistivity and Seebeck coefficient in the temperature range from 20to 300K. The homogeneity and Sb concentration of prepared samples wereconfirmed by X-ray diffraction (XRD) and differential thermal analysis (DTA)measurements. The carrier concentration increases with increasing temperature,and also changes gradually with the Sb concentration x, which isattributed to the variation of the energy gap. In all samples, the electricalresistivity decreases with increasing temperature and the absolute value of theSeebeck coefficient takes a maximum value around 70K. As a result, the largevalues of power factor were observed in the temperature range from 100 to 200Kand the maximum value of 7.44 mWm^-1K^-2 was obtained at T=130K in x=12.