Thermoelectric properties in nanostructured homologous series alloys GamSbnTe1.5(m+n).

In this paper we reported the thermoelectric (TE) properties in nanostructured homologous series alloys Ga_mSb_nTe_1.5(m+n) over the temperature range of 318–482 K and observed the maximum TE figure of merit (ZT) value of 0.98 for the alloy with m:n=1:10 at 482 K, which is approximately 0.24 higher than that of undoped Sb₂Te₃ at the corresponding temperature. This improvement is mainly attributed to the substantial reduction in lattice thermal conductivity due to the phonon scattering caused partly by the nanograins (<30 nm) and amorphous structure conceived in the matrix and partly by the lattice distortion resulted from an occupation of some Ga atoms in the Sb sites and a certain amount of Ga₂Te₃ precipitation. If in comparison with the TE properties for Ga directly doped Bi–Sb–Te solid solutions, we conclude that these Bi-free nanostructured homologous series alloys Ga_mSb_nTe_1.5(m+n) with proper compositions are of great potentiality for the improvement of TE performance. [ABSTRACT FROM AUTHOR]