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

摘要

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 similar to 23.2 to similar to 1841.8 mu W/mK(2), 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.