Effects of hydrogen annealing on the thermoelectric properties of electrodeposited Bi2Te3 for nanowire applications

Bi2Te3 films and nanowires were fabricated by electrodeposition, and the effects of hydrogen annealing on the thermoelectric properties of the electrodeposited Bi2Te3 were investigated. The power factor of the as-electrodeposited Te-rich Bi2Te3 film was maximized to 6.8 X 10-4 W/K2-m at a film composition of 35 %Bi - 65 %Te. With hydrogen annealing at 450 .deg. C, the Seebeck coefficient of the electrodeposited Te-rich Bi2Te3 films increased substantially up to -197 μV/K due to a reduction in the electron concentration. With hydrogen annealing at 450 .deg. C, the power factor of the Bi2Te3 film with a Bi/Bi + Te mole fraction of 0.35 was remarkably improved to 33 X 10-4 W/K2-m, which was equivalent to values of bulk (Bi,Sb)2(Te,Se)3. Bi2Te3 nanowires were successfully formed by using electrodeposition into nano pores of an alumina template.