Unravelling p-n Conduction Transition in High Thermoelectric Figure of Merit Gallium-Doped Bi2Te3 via Phase Diagram Engineering

Abstract

We revisit the well-established Bi2Te3 via phase diagram engineering. Along with a phase diagram in hand, it is realized that the solubility of Ga in Bi2Te3 is coincident with the p-n transition zone in Ga-Bi2Te3 alloys. The best-performing n-type (Bi2Te3)(0.93)(Ga2Te5)(0.07) possesses a peak zT similar to 1.5 at 300 K, which is attributed to the reduced kappa similar to 1.8 W m(-1) K-1 and the low-lying rho. The p-type Bi1.99Ga0.01Te3 also exhibits a peak zT of 1.2 at 300 K In other words, the addition of Ga leads to high-zT p-type or n-type bismuth-tellurides, which simplifies the conventional synthesis route that usually involves different dopants.