Thermoelectric properties of Nb3SbxTe7-x compounds

Niobium antimony telluride, Nb₃Sb_xTe_7-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. Nb₃Sb_xTe_7-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 n-type 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.