Angle-Resolved XPS Contribution to the Elucidation of the Mechanism of Cathodic Deposition of As-Sb Alloys.

AsSb alloys were deposited electrochemically onto flat, smooth Ni-plated Cu sheets from aqueous citric acid solutions and analysed by X-ray photoelectron spectroscopy (XPS) and angle-resolved (AR) XPS. Samples prepared and manipulated in air showed marked surface oxidation of both alloy elements, present as As2O3 and Sb2O3. Oxide-free samples were obtained when electrochemical synthesis and transfer to the ultrahigh vacuum XPS chamber were carried out in an inert atmosphere. ARXPS analysis of oxide-free alloy samples obtained at large negative potential showed an increase in intensity of the As(2p3 2) peak at grazing take off angles. This result, showing As surface enrichment, supports a previously proposed kinetic model of AsSb alloy electrodeposition.