Thermoelectric properties of InzCo4Sb12-yTey skutterudites

In-filled and Te-doped CoSb₃ skutterudites were prepared by encapsulated induction melting, and their thermoelectric properties were investigated from 300 K to 700 K. Single delta-phase was successfully obtained by the subsequent heat treatment at 823 K for 5 days. In-filled and Te-doped In_zCo₄Sb_12-yTe_y showed the n-type conduction at all temperatures examined, indicating that Te atoms successfully acted as electron donors by substituting Sb atoms. Electrical resistivity was reduced by In filling and Te doping, and the Te doping effect on the resistivity decrease was predominant. Thermal conductivity was considerably reduced by In filling as well as Te doping due to the increase in phonon scattering, which shows that the lattice thermal conductivity is much larger than the electronic thermal conductivity in the In_zCo₄Sb_12-yTe_y systems.