Thermal properties of high quality single crystals of bismuth telluride—Part I: Experimental characterization

A thermoelectric characterization of samples of bismuth telluride of both n- and p -type is carried out, as a function of stoichiometric deviation. Highly pure samples were prepared from single crystalline ingots, using an annealing saturation technique at temperatures between 560°C and the melting point 585.5°C. With the help of measurements of electrical and thermal conductivities, and Seebeck coefficients at room temperature, a sharp maximum in the figure of merit Z was determined. For n-type: Z = 2.9 10−3K−1. For P-type: Z = 2.3 10−3K−1 These values of Z correspond to an increase of nearly 50% from the usual values of Z for pure Bi2 Te3 samples.