Influence of synthesis parameters on composition and morphology of electrodeposited Zn-Sb thin films

Abstract

The influence of bath concentration, electrodeposition potential, and hydrodynamic conditions in the electrolytic cell on the morphology, chemical composition, and crystal structure of synthesized Zn, Sb, and Zn-Sb thin films was demonstrated based on FE-SEM, EDS, XRD, and Raman measurements. It was found that an increase in the working electrode potential leads to the formation of thin films with a higher atomic percentage (at.%) of zinc. Contrary, increasing SbCl3 concentration in the citrate bath and application of electrolyte stirring, lead to the preferential electrodeposition of thin films containing a higher content of antimony. From the point of view of thermoelectric applications, the most promising material was that containing the ZnSb crystal phase with the Zn/Sb atomic ratio of 1. The best results for electrodeposition of Zn-Sb thin films were observed at −1.5V vs. Ag/AgCl (3M KCl) in the citrate bath containing 0.045M ZnCl2 and 0.045M SbCl3 in the absence of electrolyte stirring. As a result, an amorphous ZnSb thin film with the Zn/Sb atomic ratio of 1.03 was obtained. The sample with a composition very close to stoichiometric ZnSb was annealed in an inert atmosphere in order to transform it into a crystalline thin film.