Electrodeposition of thin-film rare-earth-metal oxocuprates

Abstract

Cathodic deposition from an aqueous solution containing the simple nitrate salts of Nd³⁺ and Cu²⁺ yields insoluble thin-film oxyhydroxide layers. Variation of the electrode substrate, solute concentrations (absolute and relative, one to another), applied cathodic potential and cell geometry allows the production of films with a wide range of precursor compositions. Conditions were optimised to allow production of a solid thin film which, on firing at 940°C, yielded Nd₂CuO₄. Since the electrodeposited material comprises intimate mixtures of oxide, subsequent firing to yield the desired semiconductor requires a relatively low firing temperature. The compositions of the products formed are accounted for in terms of solubility constants and a reaction front between the electrogenerated material and cations in the bulk solution.