Al2O3 on Black Phosphorus by Atomic Layer Deposition: An in Situ Interface Study

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• 作者：Hui Zhu ; Stephen McDonnell ; Xiaoye Qin ; Angelica Azcatl ; Lanxia Cheng ; Rafik Addou ; Jiyoung Kim ; Peide D. Ye ; Robert M. Wallace
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：June 17, 2015
• 年：2015
• 卷：7
• 期：23
• 页码：13038-13043
• 全文大小：357K
• ISSN：1944-8252

文摘

In situ 鈥渉alf cycle鈥?atomic layer deposition (ALD) of Al₂O₃ was carried out on black phosphorus (鈥渂lack-P鈥? surfaces with modified phosphorus oxide concentrations. X-ray photoelectron spectroscopy is employed to investigate the interfacial chemistry and the nucleation of the Al₂O₃ on black-P surfaces. This work suggests that exposing a sample that is initially free of phosphorus oxide to the ALD precursors does not result in detectable oxidation. However, when the phosphorus oxide is formed on the surface prior to deposition, the black-P can react with both the surface adventitious oxygen contamination and the H₂O precursor at a deposition temperature of 200 掳C. As a result, the concentration of the phosphorus oxide increases after both annealing and the atomic layer deposition process. The nucleation rate of Al₂O₃ on black-P is correlated with the amount of oxygen on samples prior to the deposition. The growth of Al₂O₃ follows a 鈥渟ubstrate inhibited growth鈥?behavior where an incubation period is required. Ex situ atomic force microscopy is also used to investigate the deposited Al₂O₃ morphologies on black-P where the Al₂O₃ tends to form islands on the exfoliated black-P samples. Therefore, surface functionalization may be needed to get a conformal coverage of Al₂O₃ on the phosphorus oxide free samples.