Galvanostatic and potentiostatic deposition of bismuth telluride films from nitric acid solution: effect of chemical and electrochemical parameters

Composition modulated Bi2Te3 thin films have been deposited onto stainless-steel substrates using a potentiostatic or a galvanostatic process. The deposition potentials and current densities for different bath compositions and concentrations have been estimated from voltamperometric curves. Solutions with two Bi/Te ratios were studied. Only Bi3+ and HTeO2+ solutions in the volumetric proportion of 1:1 with equimolar solution concentrations of 0.01, 0.015 or 0.02 M allow one to obtain films with an excess or a deficiency of Bi in relation to stoichiometric Bi2Te3 (Bi=40 at%, Te=60 at%) by changing the deposition potential or the current density. The structure and the morphology of films have been studied as a function of the electrolyte concentration and the deposition conditions.