The reduction behaviors of unitary and binary bismuth cation (Bi-III), tellurium cation (Te-IV) in nitric acid and hydrochloric acid solutions were studied at different acid concentrations. Compared to the nitrate bath, the reduction of Bi-III was retarded and the reduction of Te-IV was promoted in hydrochloric acid. As a result, the difference in the reduction potential of Bi-III and Te-IV was markedly reduced in the presence of chloride ion. The acid concentration affected the morphologies of the Bi-Te deposit; specifically a rougher deposit was electroplated at higher acid concentrations. A 25 mu m Bi2Te3 film obtained from 0.7 M HNO3 at -20 mV versus saturated calomel electrode (SCE) had columnar structure with (110) preferred orientation and its Seebeck coefficient and power factor were -72.3 mu V/K and 732 mu W/m.K-2, respectively. A 25 Fun smooth, compact, nano-grained Bi2Te3 film was fabricated in 0.35 M HCl at -20 mV versus SCE and its Seebeck coefficient and power factor were -105.0 mu V/K and 169 mu W/m.K-2, respectively. (C) 2016 Elsevier B.V. All rights reserved.