Synthesis and evaluation of thick films of electrochemically deposited Bi₂Te₃ and Sb₂Te₃ thermoelectric materials

This paper presents the results of the synthesis and evaluation of thick thermoelectric films that may be used for such applications as thermoelectric power generators. Two types of electrochemical deposition methods, constant and pulsed deposition with improved techniques for both N-type bismuth telluride (Bi₂Te₃) and P-type antimony telluride (Sb₂Te₃), are performed and compared. As a result, highly oriented Bi₂Te₃ and Sb₂Te₃ thick films with a bulk-like structure are successfully synthesized with high Seebeck coefficients and low electrical resistivities. Six hundred-micrometer-thick Bi₂Te₃ and 500-μm-thick Sb₂Te₃ films are obtained. The Seebeck coefficients for the Bi₂Te₃ and Sb₂Te₃ films are -150 ± 20 and 170 ± 20 μV/K, respectively. Additionally, the electrical resistivity for the Bi₂Te₃ is 15 ± 5 μΩm and is 25 ± 5 μΩm for the Sb₂Te₃. The power factors of each thermoelectric material can reach 15 × 10^-4 W/mK² for Bi₂Te₃ and 11.2 × 10^-4 W/mK² for Sb₂Te₃.