Electrodeposition of BixTey thin films for thermoelectric application

Electrochemically deposited bismuth telluride (BixTey) thin films were grown from nitric acid baths on sputtered Au/Ni/Si substrates. The film compositions and morphology were strongly dependent on the deposition conditions. Surface morphologies varied from granular to needle-like structures depending on the Te content of the films. The power factor improved with the increase of Bi ions in electrolytes, and this may be due to the improvement of the crystal structure and no inclusion of excess Te phases. Annealing up to 200 °C in a reducing H2 atmosphere did not improve the power factor due to the interdependence of the Seebeck coefficient and the electrical conductivity.