Thermoelectric properties of semiconducting Bi-rich Bi-Sb alloys

Bi100-xSbx (x=8similar to17) alloys were prepared by direct melting of constituent elements, which was followed by quenching and annealing. The semiconducting and thermoelectric properties of the samples were investigated by measuring Hall coefficient, electrical resistivity and Seebeck coefficient in the temperature range from 20 to 300K. The properties change gradually with the Sb concentration x, which is attributed to the variation of the energy gap. In all samples, the electrical resistivity decreases with increasing temperature and the absolute value of the Seebeck coefficient takes a maximum value around 70K. The large power factor was resulted in the temperature range from 100 to 200K. The Hall mobility was enhanced by annealing, which leads to a small electrical resistivity and a large Seebeck coefficient. Consequently, a large power factor about 8.5W/mK(2) was obtained in the annealed Bi88Sb12 alloy.