PREPARATION AND THERMOELECTRIC PROPERTIES OF SEMICONDUCTING ZN4SB3

Hot-pressed samples of the semiconducting compound beta-Zn4Sb3 were pr epared and characterized by X-ray and microprobe analysis. Some physic al properties of beta-Zn4Sb3 were determined and its thermoelectric pr operties measured between room temperature and 650 K. Exceptionally lo w thermal conductivity values were obtained in the 300-650 K temperatu re range and the room temperature lattice thermal conductivity was est imated at 6.5 W cm(-1) K-1. High thermoelectric figures of merit (ZTs) were obtained between 450 and 670 K and a maximum of about 1.3 was ob tained at a temperature of 670 K, the highest known at this temperatur e. The stability of the compound was investigated by several technique s, including thermogravimetric studies. The results showed that the sa mples were stable under argon atmosphere and static vacuum up to about 670 K and up to 520 K in dynamic vacuum. The high thermoelectric perf ormance of beta-Zn4Sb3 in the 300-670 K temperature range fills the ex isting gap in the ZT spectrum of p-type state-of-the-art thermoelectri c materials between Bi2Te3-based alloys and PbTe-based alloys. This ma terial, relatively inexpensive, could be used in more efficient thermo electric generators for waste heat recovery and automobile industry ap plications, for example. (C) 1997 Elsevier Science Ltd. All rights res erved.