Insights into the Electrodeposition of Bi[sub 2]Te[sub 3]

Abstract

In this paper, the processes associated with the electrodeposition of bismuth telluride (Bi2Te3),(Bi2Te3), a thermoelectric material, are reported along with an analysis of the composition and crystallinity of the resulting films. The electrodeposition can be described by the general reaction 3HTeO2++2Bi3++18e−+9H+→Bi2Te3+6H2O.3HTeO2++2Bi3++18e−+9H+→Bi2Te3+6H2O. Cyclic voltammetry studies of Bi, Te, and Bi/Te dissolved in 1 M HNO3HNO3 reveal two different underlying processes depending on the deposition potential. One process involves the reduction of HTeO2+HTeO2+ to Te0Te0 and a subsequent interaction between reduced Te0Te0 and Bi3+Bi3+ to form Bi2Te3.Bi2Te3. A second process at more negative reduction potentials involves reduction of HTeO2+HTeO2+ to H2TeH2Te followed by the chemical interaction with Bi3+.Bi3+. Both processes result in the production of crystalline Bi2Te3Bi2Te3 films in the potential range −0.1<E<−0.52V−0.1vs. Ag/AgCl (3 M NaCl) on Pt substrates as determined by powder X-ray diffraction (XRD). Electron probe microanalyses and XRD reveal that the films are bismuth-rich and less oriented for more negative deposition potentials. © 2002 The Electrochemical Society. All rights reserved.