原子层沉积
无定形固体
水溶液
退火(玻璃)
薄膜
X射线光电子能谱
化学工程
材料科学
氧化物
热稳定性
氢氧化物
无机化学
化学
纳米技术
冶金
有机化学
结晶学
工程类
作者
Simon A. Willis,Emily K. McGuinness,Yi Li,Mark D. Losego
出处
期刊:Langmuir
[American Chemical Society]
日期:2021-12-01
卷期号:37 (49): 14509-14519
被引量:14
标识
DOI:10.1021/acs.langmuir.1c02574
摘要
Amorphous aluminum oxide (alumina) thin films are of interest as inert chemical barriers for various applications. However, the existing literature on the aqueous stability of atomic layer deposited (ALD) amorphous alumina thin films remains incomplete and, in some cases, inconsistent. Because these films have a metastable amorphous structure─which is likely partially hydrated in the as-deposited state─hydration and degradation behavior likely deviate from what is expected for the equilibrium, crystalline Al2O3 phase. Deposition conditions and the aqueous solution composition (ion content) appear to influence the reactivity and stability of amorphous ALD alumina films, but a full understanding of why these alumina films hydrate, solvate, and/or dissolve in near-neutral pH = 7 conditions, for which crystalline Al2O3 is expected to be stable, remains unsolved. In this work, we conduct an extensive X-ray photoelectron spectroscopy investigation of the surface chemistry as a function of water immersion time to reveal the formation of oxyhydroxide (AlOOH), hydroxide (Al(OH)3), and possible carbonate species. We further show that brief postdeposition exposures of these ALD alumina films to an air plasma anneal can significantly enhance the film's stability in near-neutral pH aqueous conditions. The simplicity and effectiveness of this plasma treatment may provide a new alternative to thermal annealing and capping treatments typically used to promote aqueous stability of low-temperature ALD metal oxide barrier layers.
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