Structure, morphology, and composition of nanometric Pd films deposited by dc magnetron sputtering on Cu, Ag, and Au foils

Abstract

The comprehension of atomic and electronic structures of bimetallic systems is important in several areas, such as catalysis, sensors, and microelectronics. The aim of this study is to investigate thin (10 nm) films of palladium deposited on polycrystalline copper, silver, and gold foils by dc magnetron sputtering. We employed atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) in order to characterize the morphology, structure, and surface composition of the films. AFM images revealed that the surfaces of Cu and, in a smaller degree, Ag foils were covered with small grains (particles). XPS results indicated that these particles were oxidized copper and silver. Gold substrate presented a flat morphology, with no detectable oxide formation. Pd films covered the small particles for both Cu and Ag substrates, presenting a flat morphology. In the case of Pd film deposited on Au, the morphology was similar to the substrate. For all three cases, XPS results indicated that Pd is mainly in the metallic state. XRD results showed the presence of a polycrystalline Pd film on top of Cu foil, but not for either Ag or Au foils.