Electrodeposition of ZnTe Film with High Current Efficiency at Low Overpotential from a Citric Acid Bath

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Abstract
The cathodic electrodeposition of ZnTe film was studied using an aqueous citric acid bath (pH 4; temperature 368 K) in which Zn(II) and Te(IV) species were dissolved to form Zn(Cit)24−Zn(Cit)24− and HTeO2+HTeO2+ ions, respectively. The deposition mechanism was studied based on cyclic voltammetry. The influence of the deposition potential on the morphology, composition, and structure of the deposited film was also investigated. A smooth, dense polycrystalline ZnTe film with nearly stoichiometric composition was deposited at a constant cathode potential, ranging from −0.80 to −0.60 V vs. Ag/AgCl, from a solution containing 20 mmol dm−3 Zn(II), 0.16 mmol dm−3 Te(IV), 0.25 mol dm−3 H3Cit,H3Cit, and 0.25 mol dm−3 Na3CitNa3Cit (Cit=C6H5O7).(Cit=C6H5O7). Potentials in this range provided the deposited ZnTe film with high current efficiency (above 98%). During electrodeposition of the nearly stoichiometric crystalline ZnTe, the current density was approximately stationary. © 2004 The Electrochemical Society. All rights reserved.