Electrodeposition of Bi2Te3 Nanowire Arrays with Uniform Length and Controlled Composition in Anodic Aluminum Templates

Abstract

Bismuth telluride (Bi2Te3) nanowire arrays with a uniform length and controlled composition were electrodeposited in anodic aluminum oxide (AAO) templates by controlling the applied potential and electrolytes concentration. The length and the contents of the electrodeposited nanowires were dependent on the ion ratio of Bi3+:HTeO2+ in the electrolyte as well as the applied potential. Te-rich BixTey nanowires could be obtained in a Te-rich electrolyte solution at relatively slow growth rates of 7.9–18.6 μm/h while both stoichiometric and Bi-rich deposits were prepared at high growth rates of 8.4–41.4 μm/h in Bi-rich electrolytes. Cyclic voltammetry (CV) was conducted for electrolytes with different ion ratios at voltages in the range of −0.7–0.8 V. Consequently, we found that slow nucleation and a steady growth rate in the underpotential deposition (UPD) region were needed to assure the uniformity and stoichiometry of as-deposited nanowires. The microstructure and crystallographic texture were examined by scanning electron microscopy and X-ray diffraction. This study can be extended to the electrodeposition of stoichiometric chalcogenide compounds derived by UPD with controlled length distribution.