ANGLE-RESOLVED X-RAY PHOTOELECTRON-SPECTROSCOPY CONTRIBUTION TO ELUCIDATION OF THE MECHANISM OF CATHODIC DEPOSITION OF AS-SB ALLOYS

As-Sb alloys were deposited electrochemically onto flat, smooth Ni-pla ted 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 bo th 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 ana lysis 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 pr eviously proposed kinetic model of As-Sb alloy electrodeposition.