Thermoelectric Properties of Ti Doping in Bismuth Telluride prepared by Powder Metallurgy Process

The Ti-doped Bi2Te3 with concentrations 1, 3, and 5 in % Ti were synthesized using a simple powder metallurgy method. It is revealed that the optimum Ti addition in parent material changes the conduction type from undoped n-type into p-type with 1 % Ti concentration. However, the Ti addition above 1 % affects on decreasing the absolute Seebeck coefficient. Furthermore, the conduction type returns to w-type again at 5 % Ti addition. A 70 % and 74 % reduction in the absolute Seebeck coefficient and the electrical resistivity value, respectively, were found in 5 % Ti-doped at near room temperature. Even though the 5 % Ti doping concentration does not give an enhancement effect in the power factor (PF) value at near room temperature, there is a possibility of 5 % Ti-doped achieves a higher PF value than undoped Bi2Te3 at the higher temperature above 500 K.