Study of electrodeposition of bismuth telluride by voltammetric methods and in-situ electrochemical quartz crystal microbalance method

The authors examine Bi2Te3 deposition and stripping mechanisms by means of cyclic voltammetry and electrochemical quartz crystal microbalance (EQCM). Accumulated charges and related mass changes for Bi2Te3 deposition on working electrodes are measured in-situ. Linear scanning voltammetry and EQCM results are then used to propose a two-stage deposition process. During the initial stage, a thin layer of Bi-rich Bi2Te3 forms on the surface of the Au electrode, followed by a bulk deposition of Te-rich Bi2Te3. The composition variation is minor. During anodic linear stripping of a thin deposit, Bi2Te3 oxidation with a single peak was observed. Two oxidation peaks were detected during anodic stripping of a thick deposit-one corresponding to Bi2Te3 oxidation and the other to a combination of Bi2Te3 and Te oxidation. The Bi2Te3 deposit was synthesized via pulsed plating in order to study the effects of pulse parameters on deposit composition. Results indicate that Bi2Te3 film composition is affected by changes in pulse potential from potential pulse plating or by changes in current pulse plating relaxation time.