Phase diagram of thermoelectric Bi2S3-Bi2Se3-Bi2Te3 system

It is well known that the highest ZT value, at an optimized carrier concentration, is mainly determined by a material parameter $\beta =\mu $(m*/m0)3/2/$\kappa $lat, where $\mu $(m*/m0)3/2 and $\kappa $lat are the weighted carrier mobility and lattice thermal conductivity, respectively. In order to explore some new compositions in Bi2S3-Bi2Se3-Bi2Te3 system, we propose a compositional thermoelectric phase diagram (TPD), including weighted carrier mobility, lattice thermal conductivity, and material parameter, for the 1{\%} copper doped Bi2S3-Bi2Se3-Bi2Te3 solid solution fabricated by MA-HP method. Here, the $\mu $(m*/m0)3/2 and $\kappa $lat values could be deduced from the measured electrical resistivity, Seebeck coefficient, and thermal conductivity. The alloying effect on the thermoelectric phase diagram will be discussed from varying atomic size, chemical bond, lattice structure, etc.