2005 Volume 46 Issue 4 Pages 761-764
We report room-temperature thermoelectric properties of polycrystalline (PbTe)100−x(Bi2Te3-Sb2Te3)x (0.1≤x≤5). At x≤0.25, with a decrease of x, the electrical resistivity increases dramatically whereas the Seebeck coefficient and the thermal conductivity nearly keep constant. At x≥0.5, the electrical conductivity, the thermal conductivity and the Seebeck coefficient in absolute value slightly decrease with increasing x. It is found that, the thermal conductivity of the PbTe sample with Bi2Te3 and Sb2Te3 as the sources of dopants is much smaller than that of doping with other dopants at the same carrier concentration. With an increase of x, the figure of merit, Z, which is calculated from the measured quantities, increases at first and then decreases and shows a maximum value of 8.97×10−4 K−1 at x=0.2. This value is several times higher than that of small grain-size PbTe containing other dopants.