Thermoelectric Properties of Nb3SbxTe7-x Compounds

Niobium antimony telluride, Nb3SbxTe7-x, was synthesized and tested for thermoelectric properties in the Thermoelectrics group at the Jet Propulsion Laboratory. The forty atoms per unit cell of Nb3Sb2Te5 and its varied mixture of atoms yield a complicated structure, suggesting that Nb3Sb2Te5 and related compounds may exhibit low thermal conductivity and hence a higher ZT value. Nb3SbxTe7-x compounds were synthesized and subsequently analyzed for their Seebeck voltage, heat conduction, and electrical resistivity. Results indicate that Nb3Sb2Te5 is a heavily doped semiconductor whose thermoelectric properties are compromised by compensating ntype and p-type carriers. Attempts to dope in favor of either carrier by varying the Sb:Te ratio yielded samples containing secondary metallic phases that dominated the transport properties of the resulting compounds.