Low Temperature Electrical Properties of β-In_2(1-x)Bi_2xTe₃ Semiconductors

　For a good thermoelectric material, the high electrical conductivity, high Seebeck coefficient and low thermal conductivity are naturally required. The electrical conductivity, Seebeck coefficient and electronic contribution to the thermal conductivity are closely related to the carrier concentration. An increase in the electrical conductivity leads to the decrease in the Seebeck coefficient and the increase in the electronic contribution to the thermal conductivity. This shows the difficulty in improving Ζ by controlling these parameters in conventional materials. On the other hand, a lattice contribution to the thermal conductivity is only related to the phonon energy and distribution [4]. This means that the lattice contribution to the thermal conductivity can be controllable without changing the electrical properties. Therefore, materials with low lattice thermal conductivity may achieve higher Ζ. In this paper low temperature electrical properties of β-In₂Te₃ were measured. The effects of Bi doping on their electrical properties were discussed. The thermoelectric figure of merit at 300K was estimated.