title: H₂O Dissociation-Induced Aluminum Oxide Growth on Oxidized Al(111) Surfaces.
abstract: The interaction of water vapor with amorphous aluminum oxide films on Al(111) is studied using X-ray photoelectron spectroscopy to elucidate the passivation mechanism of the oxidized Al(111) surfaces. Exposure of the aluminum oxide film to water vapor results in self-limiting Al2O3/Al(OH)3 bilayer film growth via counter-diffusion of both ions, Al outward and OH inward, where a thinner starting aluminum oxide film is more reactive toward H2O dissociation-induced oxide growth because of the thickness-dependent ionic transport in the aluminum oxide film. The aluminum oxide film exhibits reactivity toward H2O dissociation in both low-vapor pressure [p(H2O) = 1 × 10(-6) Torr] and intermediate-vapor pressure [p(H2O) = 5 Torr] regimes. Compared to the oxide film growth by exposure to a p(H2O) of 1 × 10(-6) Torr, the exposure to a p(H2O) of 5 Torr results in the formation of a more open structure of the inner Al(OH)3 layer and a more compact outer Al2O3 layer, demonstrating the vapor-pressure-dependent atomic structure in the passivating layer.
authors.affiliation: Department of Mechanical Engineering and Multidisciplinary Program in Materials Science and Engineering, State University of New York , Binghamton, New York 13902, United States.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory , Upton, New York 11973, United States.
authors.forename: Xiao
authors.initials: X
authors.lastname: Tong
authors.affiliation: Department of Mechanical Engineering and Multidisciplinary Program in Materials Science and Engineering, State University of New York , Binghamton, New York 13902, United States.
authors.forename: Guangwen
authors.initials: G
authors.lastname: Zhou
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D004058:Diffusion; D056951:Photoelectron Spectroscopy; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D000537:Aluminum Oxide