Additive-aided electrochemical deposition of bismuth telluride in a basic electrolyte

A new basic electrolyte with two cationic plating additives, polydiaminourea and polyaminosulfone, was investigated for the electrochemical deposition of the bismuth telluride film on a nickel-plated copper foil. Tellurium starts to deposit at a higher potential (−0.35 V) than bismuth (−0.5 V) in this electrolyte. The tellurium-to-bismuth ratio increases while the deposition potential declines from −1 to −1.25 V, indicating a kinetically quicker bismuth deposition at higher potentials. The as-deposited film features good adhesion to the substrate and smooth morphology, and has a nearly amorphous crystal structure disclosed by X-ray diffraction patterns.