Thorman Rachel M, Matsuda Scott J, McElwee-White Lisa, Fairbrother D Howard
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218-2685, United States.
Department of Chemistry, University of Florida, Gainesville, Florida 32611-7200, United States.
J Phys Chem Lett. 2020 Mar 19;11(6):2006-2013. doi: 10.1021/acs.jpclett.0c00061. Epub 2020 Feb 26.
Surface reactions of electrons and ions with physisorbed organometallic precursors are fundamental processes in focused electron and ion beam-induced deposition (FEBID and FIBID, respectively) of metal-containing nanostructures. Markedly different surface reactions occur upon exposure of nanometer-scale films of (η-Cp)Fe(CO)Re(CO) to low-energy electrons (500 eV) compared to argon ions (860 eV). Electron-induced surface reactions are initiated by electronic excitation and fragmentation of (η-Cp)Fe(CO)Re(CO), causing half of the CO ligands to desorb. Residual CO ligands decompose under further electron irradiation. In contrast, Ar-induced surface reactions proceed by an ion-molecule momentum/energy transfer process, causing the desorption of all CO ligands without significant ion-induced precursor desorption. This initial decomposition step is followed by ion-induced sputtering of the deposited atoms. The fundamental insights derived from this study can be used not only to rationalize the composition of deposits made by FEBID and FIBID but also to inform the choice of a charged particle deposition strategy and the design of new precursors for these emerging nanofabrication tools.
电子和离子与物理吸附的有机金属前驱体的表面反应是聚焦电子束和离子束诱导沉积（分别为FEBID和FIBID）含金属纳米结构的基本过程。与氩离子（860 eV）相比，当将(η-Cp)Fe(CO)Re(CO)的纳米级薄膜暴露于低能电子（500 eV）时，会发生明显不同的表面反应。电子诱导的表面反应由(η-Cp)Fe(CO)Re(CO)的电子激发和碎片化引发，导致一半的CO配体解吸。残余的CO配体在进一步的电子辐照下分解。相比之下，氩离子诱导的表面反应通过离子-分子动量/能量转移过程进行，导致所有CO配体解吸，而没有明显的离子诱导前驱体解吸。这个初始分解步骤之后是离子诱导的沉积原子溅射。从这项研究中获得的基本见解不仅可以用于解释FEBID和FIBID制备的沉积物的组成，还可以为带电粒子沉积策略的选择以及这些新兴纳米制造工具的新前驱体设计提供参考。
