Investigation of the Mechanism of Nickel Electroless Deposition on Functionalized Self-Assembled Monolayers

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• 作者：Zhiwei Shi ; Amy V. Walker
• 刊名：Langmuir
• 出版年：2011
• 出版时间：June 7, 2011
• 年：2011
• 卷：27
• 期：11
• 页码：6932-6939
• 全文大小：859K
• 年卷期：v.27,no.11(June 7, 2011)
• ISSN：1520-5827

文摘

We have investigated the seedless electroless deposition (ELD) of Ni on functionalized self-assembled monolayers (SAMs) using scanning electron and optical microscopies, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. For all SAMs studied, the Ni deposition rate is dependent on the bath pH, deposition temperature, and complexing agent. In contrast to the physical vapor deposition of Ni on SAMs, electrolessly deposited Ni does not penetrate through the SAM. This behavior indicates that ELD is a suitable technique for the deposition of low-to-moderate reactivity on organic thin films. We demonstrate that Ni can be selectively deposited on SAMs using two different methods. First, selectivity can be imparted by the formation of Ni(II)鈥搒urface complexes. As a demonstration, we selectively deposited Ni on the 鈭扖OOH terminated SAM areas of patterned 鈭扖OOH/鈥揅H₃ or 鈭扖OOH/鈥揙H terminated SAMs. Here, Ni²⁺ ions form Ni²⁺鈥揷arboxylate complexes with the 鈭扖OOH terminal group, which comprise the nucleation sites for subsequent metal deposition. Second, we demonstrate that nickel is selectively deposited on the 鈭扖H₃ terminated SAM areas of a patterned 鈭扥H/鈥揅H₃ terminated SAM. In this case, the Ni²⁺ ion does not specifically interact with the 鈭扖H₃ terminal group. Rather, selectivity is imparted by the interaction of the reductant, dimethylamine borane (DMAB), with the 鈭扥H and 鈭扖H₃ terminal groups.