Investigation of thermoelectric properties in binary Sb-Te and Sn-Te alloys during crystallization process

Abstract The nanometric phase-separation and crystal-growth behaviors occur continuously in Sb7Te3 alloy during phase-change process. It is strongly suggested that the phase separation hinders the improvement of Seebeck coefficient and power factor. Nevertheless, a dual-phase nanoprecipitate-embedded Sn7Te3 films with an improved thermoelectric performance is reported compared with Sb7Te3 films. Sn7Te3 alloy can significantly improve the thermopower factor from ~23.2 to ~ 1841.8 µW/mK2, which is attributed to the coexistence of dual-phase SnTe+Sn nanoprecipitates. This can effectively enhance the carrier transport and thus significantly enhance power factor. In this study, the basic phase separation mechanism in Sb7Te3 matrix is clarified, and the dual-phase engineering in Sn7Te3 is proved to be an effective way to improve the thermoelectric performance, which provides a new way to realize the high-performance properties of thermoelectric films.