The improvement of thermoelectric properties of heterophase alloys based on tin telluride

The method of improving thermoelectric properties by using heterophase composites formed under decomposition of oversaturated solid solutions is proposed and applied to tin telluride doped with the In/sub 2/Te/sub 3/ compound. Due to the partial decomposition of the solid solution this phase is precipitated in the form of dispersed particles, which resist coalescence and provide high heat resistance. The technique providing uniform spatial distribution and optimum size of the second phase (In/sub 2/Te/sub 3/) particles is developed. As a result, in the two-phase region figure of merit Z increases by /spl sim/40% reaching 1.2/spl middot/10/sup -3/ K/sup -1/. The experimental results are interpreted taking into account mechanical strains on interfaces, which significantly affect phonon scattering. The method proposed can be used for development of different thermoelectric materials.