Thermoelectric properties of Te doped bulk Bi2Se3 system

Polycrystalline bulk samples of Bi-2(Se1-xTex)(3) system with x = 0.0-0.9 were prepared by the conventional melting method. Successfully and cheaply, Se atoms were replaced by Te atoms to get Bi2Se3-Bi2Te3 or even Bi2Te3 alone. Difference of mass and size between Te and Se atoms is expected to result in interesting properties in the Bi-2(Se1-xTex)(3) system. All compounds showed a metal-semiconductor conductivity transition. The electrical conduction in the pristine Bi2Se3 compound increases with the low Te doping ratio (x = 0.3) then decreases monotonically for further amounts of Te. The Seebeck coefficient of Bi2Se3 compound is positive showing up a p-type conduction. However, introducing Te content increases the n-type conduction with a decrease in the Seebeck coefficient absolute value. In addition, Bi2Se3 compound is found to exhibit relatively high room temperature power factor and figure of merit values of 2.13 mu W/m.k(2). In an attempt to determine the figure of merit ZT, Bi2Se3 seems to be the best for room temperature, whereas, Te addition at high values makes the system just suitable for high temperature application.