H2O Dissociation-Induced Aluminum Oxide Growth on Oxidized Al(111) Surfaces

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• 作者：Qianqian Liu ; Xiao Tong ; Guangwen Zhou
• 刊名：Langmuir
• 出版年：2015
• 出版时间：December 8, 2015
• 年：2015
• 卷：31
• 期：48
• 页码：13117-13126
• 全文大小：540K
• ISSN：1520-5827

文摘

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 脳 10^鈥? Torr] and intermediate-vapor pressure [p(H₂O) = 5 Torr] regimes. Compared to the oxide film growth by exposure to a p(H₂O) of 1 脳 10^鈥? 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.