Jae-Yong Jung

Electronic transport properties of Fe-doped CoSb3 prepared by hot pressing

Fe-doped CoSb3 skutterudites were prepared by hot pressing, and their thermoelectric and electronic transport properties were examined. The positive signs of the Seebeck and Hall coefficients for all Fe-doped specimens showed that Fe atoms acted as p-type dopants by substituting for Co atoms. The carrier concentration increased with increasing Fe doping content, and the Fe generated excess holes. The Seebeck coefficient showed a positive value at all temperatures examined, and increased with increasing temperature. The temperature dependence of electrical resistivity suggests that Co1?xFexSb3 is a highly degenerate semiconducting material. Fe doping reduced the thermal conductivity considerably, and the lattice contribution was dominant in Fe-doped CoSb3 skutterudites.

Electronic transport properties of In z Co 4 Sb 12-y Te y skutterudites

In_zCo₄Sb_12-yTe_y skutterudites were prepared by encapsulated induction melting and their electronic transport properties were investigated. Single phase delta-CoSb₃ was successfully obtained by the encapsulated induction melting and subsequent heat treatment at 823 K for 5 days. Te atoms acted as electron donors by substituting Sb atoms. The Hall coefficient and the Seebeck coefficient showed negative values, which confirms that In_zCo₄Sb_12-yTe_y skutterudites are n-type semiconductors. Electronic transport properties were considerably affected by Te doping rather than In filling. Carrier concentration was in the range of 7 times 10¹⁹ to 4 times 10²⁰ cm^-3, and carrier mobility was 2 to 22 cm²/Vs. The Seebeck coefficient negatively decreased and the electrical resistivity decreased by Te doping and In filling. The thermal conductivity was considerably reduced by doping as well as filling due to the phonon scattering, which is responsible for the lattice thermal conductivity reduction.

Thermoelectric properties of In z Co 4 Sb 12-y Te y 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 InzCo4Sb12-yTey 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 InzCo4Sb12-yTey systems.

Transport and Thermoelectric Properties of Sn‐filled/Ni‐doped CoSb3 Skutterudites

SnzCo3.7Ni0.3Sb12 skutterudites have been successfully synthesized by induction melting followed by annealing at 823 K for 120 h in a vacuum, and the Sn filling effects on the transport and thermoelectric properties were examined. Seebeck coefficient and Hall coefficient confirmed that electrical conduction type was changed from n‐type to p‐type if the filling fraction (z) is higher than 0.4. The temperature dependence of electrical resistivity suggests that SnzCo3.7Ni0.3Sb12 is a highly degenerate semiconducting material. The thermal conductivity was reduced by Sn filling and the lowest thermal conductivity was achieved for the compound Sn0.2Co3.7Ni0.3Sb12.

Thermoelectric Properties of SnzCo4Sb12-yTey Skutterudites

Sn-filled and Te-doped CoSb₃ skutterudites (Sn_zCo₄Sb_12-yTe_y) were synthesized 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 6 days. Intrinsic CoSb₃ showed n-type conductivity from 300 K to 400 K and there is a transition to p-type conductivity above 400 K. Sn-filled Sn _zCo₄Sb₁₂ showed p-type conductivity and Sn-filled/Te-doped Sn_zCo₄Sb_12-yTe_y showed n-type conductivity from 300 K to 700 K, indicating that Te atoms substituting for Sb atoms acted as electron donors. Thermal conductivity was considerably reduced by filling and doping due to the phonon scattering. Sn filling effect and Te doping effect are examined and compared in this study