Investigation of electrodeposition kinetics of In, Sb, and Zn for advanced designing of InSb and ZnSb thin films

Abstract

In this work, the kinetics of indium, antimony, and zinc electrodepositions were investigated by using a gold rotating disc electrode (RDE). The performed studies shed light on the influence of electrodeposition parameters (i.e., working electrode potential and hydrodynamic conditions) on the chemical composition of In-Sb and Zn-Sb films. Stoichiometric InSb and ZnSb are one of the most promising thermoelectric materials, therefore a strictly controlled chemical composition of deposits is required. During electrochemical studies, as a primary electrolyte, a citrate bath with the addition of metal ion precursors, i.e., 0.06 M InCl 3 and/or 0.045 M SbCl 3 and/or 0.045 M ZnCl 2 , was applied. Based on the linear voltammetry measurements in the RDE system, the Koutecký-Levich analyses were performed. The diffusion coefficients ( D ) determined at 293 K for indium, antimony, and zinc ions equal to 1.45 × 10 −6 , 3.76 × 10 −6 , and 5.94 × 10 −6 cm 2 s −1 , respectively. The activation energy ( E A ) for the diffusion of metal ions was determined using D values calculated at different temperatures. E A of indium, antimony, and zinc ions equals to 25.1, 9.2, and 10.6 kJ mol −1 , respectively. The number of transferred electrons ( n ) and rate constant for heterogeneous reactions ( k ) occurring in the studied electrolytes at different potentials were also determined. • Electrodeposition of In, Sb, and Zn is under diffusion and kinetics control. • Diffusion coefficient of ion increase in line: In-citrate<Sb-citrate<Zn-citrate. • Adsorption of citrate ions on the RDE surface slows down electroreduction of In. • Indium-citrate ions have the highest E A of diffusion among studied species.