Research on the Interfacial Properties of AlSb Thin Films with Air Molecules

AlSb film has attracted attention for its excellent properties, and many preparation methods have been explored. Herein, AlSb thin films were prepared by the DC magnetron co-sputtering method, and the interfacial behavior between the films and air molecules was investigated by X-ray diffraction (XRD), Auger electron spectroscopy (AES) testing, and density functional theory (DFT) calculations to elucidate the deliquescence process of AlSb thin films and its underlying mechanism. The results revealed that AlSb thin films exhibited Sb₂O₄ and Sb₂O₅ phases, while the thin films doped Cu no longer showed any Sb oxide phases after the film was exposed to air for one day. The chemical state of aluminum in the film remained stable along the depth direction, whereas antimony exhibited a pronounced gradient in chemical state from the surface to the interior. The oxidation state of Sb ions varied from -3 in the interior to +5 at the surface. The interaction between the (111) crystal plane of the AlSb film and air molecules is an exothermic process, with water molecules exhibiting the highest adsorption energy on the film surface, followed by oxygen molecules. The adsorption energies for nitrogen and carbon dioxide molecules were the lowest. Consequently, AlSb molecules readily combine with H₂O molecules. Furthermore, doping the AlSb film with copper or zinc atoms effectively reduced the adsorption energy for water and oxygen molecules, offering a new approach to suppress the deliquescence and oxidation of AlSb thin films. This study provides an important theoretical foundation for subsequent research on this material system.