Effect of heat treatment on the electrical and thermoelectric properties of Sb doped Bi2Se3

Polycrystalline samples of (Bi 0.95 Sb 0.05 ) 2 Se 3 were prepared using the conventional melting technique at 1273 K, followed by annealing at different temperatures (423, 473, 523 and 573 K) for different time intervals (4, 8, 12 and 16 h). The samples were crystallized in a single phase of Bi 2 Se 3 and no other phases or impurities were observed. The electrical and thermoelectric properties were studied by measuring the electrical conductivity and Seebeck coefficient as functions of temperature in the range 100–400 K. The results exhibited a metal–n-type semiconductor transition for all samples. The power factor (Pf) was calculated to determine the effect of the annealing treatment on the performance of the prepared material as a thermoelectric power generator. The highest room temperature value of the Pf was 6.9 μ WK −2 cm −1 and was recorded for the sample annealed at 573 K for 16 h. The results confirm the feasibility of using the annealing process to improve the performance of thermoelectric materials.