Enhanced thermoelectric properties of iron doped compound (Zn_{1 - x}Fe_x)₄Sb₃

The thermoelectric properties of Fe-doped compounds (Zn_{1 - x}Fe_x)₄Sb₃ (x = 0, 0.0025, 0.005, 0.01) have been studied at the temperatures from 7 K to 305 K. The results indicate that low-temperature (T < 300 K) thermal conductivity of the moderately doped (Zn_{1 - x}Fe_x)₄Sb₃ (x = 0.0025 and 0.005) reduces remarkably as compared with that of Zn₄Sb₃ due to enhanced impurity (dopant) scattering of phonons. Electrical resistivity and Seebeck coefficient are found to increase first and then decrease obviously with the increase in the Fe content. Moreover, the lightly doped compound (Zn_0.995Fe_0.005)₄Sb₃ exhibits the best thermoelectric performance due to the improvement in both its thermal conductivity and Seebeck coefficient, whose figure of merit (at 300 K), ZT, is about 1.3 times larger than that of β-Zn₄Sb₃ obtained in the present study.