Influence of surface modification on thermoelectric properties of Bi 2Te 3 nanowires

Abstract

Thermoelectric material bismuth telluride (Bi 2Te 3) nanowires were synthesized by pulsed-potential deposition using Bi(NO 3) 3·5H 2O and TeO 2 in 1.0 M HNO 3 in porous anodic alumina (PAA) template. Nanowires with various surface morphologies were obtained by changing the potential between -0.2 and -0.6 V vs. SCE (sat. KCl). The more negative pulse potentials than the reduction potential observed from cyclic voltammograms (CVs) were used for nanowires growth, delay potential was used in no current region between reduction and oxidation potentials of the compound. To obtain dense, highly oriented single-crystalline nanowires, the control of the growth rate is critical. Surface roughness and crystallinity of nanowires were affected by the pulsed-potential, and the pulsed-time. The microstructures and morphologies of nanowires were investigated by powder X-ray diffraction, FE-SEM, and HR-TEM. Thermoelectric properties of both smooth and rough surfaced nanowires are under investigation. © 2011 IEEE.