Lanthanide Refractory Semiconductors Based on the Th3P4 Structure

Abstract

ABSTRACTThe phase relationships and the important structural, electrical and thermal properties of the R3X4-R2X3 (where R = lanthanides and X = S, Se and Te) phases having the Th3P4 -type structure are reviewed. The room temperature electrical resistivity and Seebeck coefficient of these materials are independent of R and only slightly dependent on X, but critically dependent on the X:R ratio. The long term stability of these phases is also reviewed. Although these materials have good thermoelectric properties there are some problems which need to be solved before these phases can be utilized in thermoelectric devices. These problems include long term stability, higher than desirable thermal conductivities, and low electron mobilities.