Room-temperature ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (RTIL EMI-BF4) was used as the electrolyte to study the voltammetric behavior of Te(IV), Pb(II), and their mixtures. Te(IV) and Pb(II) were introduced into the IL by the addition of TeCl4 and PbCl2, respectively, with sufficient 1-ethyl-3-methylimidazolium chloride (EMIC). The electrodeposition of Te, Pb, and PbTe was achieved under constant applied potential at nickel electrodes. The nucleation mechanisms of Te and Pb were determined to be three-dimensional instantaneous nucleation with diffusion-controlled growth. Crystalline stoichiometric PbTe electrodeposits were obtained via Pb under-potential deposition at the continuously growing surface of Te. They exhibited an energy bandgap of 0.22 eV. (C) 2014 Elsevier Ltd. All rights reserved.