Electrocrystallization process during deposition of Bi-Te films

The electrocrystallization process of Bi-Te films deposited from Bi3+ and HTeO2+ nitric acidic solution was studied with an emphasis on the impact of electrochemical conditions on film microstructure. Bi2Te3 films with a (110) preferential orientation and platelet grain morphology were obtained at the concentration of 7.5 mM Bi3+ and 10 mM HTeO2+. The grain morphology changed from single- to multiorder platelets, and the texture decreased when the deposition potential became more negative. This phenomenon was explained by considering geometrical selection growth and {11010} [1105] twinning of Bi2Te3 crystals. However, when the concentration ratio of [Bi3+] to [HTeO2+] was increased to 1.25, the film composition was changed to BiTe, and its preferential orientation was (014). The grain morphology changed from irregular polyhedron to spherulite, and the texture intensity decreased with more negative potentials. (c) 2008 The Electrochemical Society.