Electrodeposition of thermoelectric Bi2Te3 thin films with added surfactant

• Bi2Te3 thin films were electrodeposited from electrolytes containing Bi(NO3)3.
• Nearly stoichiometric films were obtained when CTAB was added to the electrolyte.
• Added surfactant improved a film's surface morphology and mechanical properties.
• Electrical and thermoelectric properties were unaffected by CTAB.
• Electrical and thermoelectric properties unaffected by post-deposition annealing.

Bismuth telluride (Bi2Te3) thin films were electrodeposited at room temperature from nitric baths in the presence of a surfactant, cetyltrimethylammonium bromide (CTAB). Nearly stoichiometric Bi2Te3 thin films were obtained from electrolytes containing 7.5 mM Bi(NO3)3. The surface morphology and mechanical properties of the electrodeposited thin film were improved by the addition of CTAB to the electrolyte, while the electrical and thermoelectric properties were preserved. Post-deposition annealing in a reducing environment did not improve the electrical and thermoelectric properties, possibly because the change in the microstructure of the Bi2Te3 thin film was too small.