title: Rapid Focused Ion Beam Milling Based Fabrication of Plasmonic Nanoparticles and Assemblies via "Sketch and Peel" Strategy.
abstract: Focused ion beam (FIB) milling is a versatile maskless and resistless patterning technique and has been widely used for the fabrication of inverse plasmonic structures such as nanoholes and nanoslits for various applications. However, due to its subtractive milling nature, it is an impractical method to fabricate isolated plasmonic nanoparticles and assemblies which are more commonly adopted in applications. In this work, we propose and demonstrate an approach to reliably and rapidly define plasmonic nanoparticles and their assemblies using FIB milling via a simple "sketch and peel" strategy. Systematic experimental investigations and mechanism studies reveal that the high reliability of this fabrication approach is enabled by a conformally formed sidewall coating due to the ion-milling-induced redeposition. Particularly, we demonstrated that this strategy is also applicable to the state-of-the-art helium ion beam milling technology, with which high-fidelity plasmonic dimers with tiny gaps could be directly and rapidly prototyped. Because the proposed approach enables rapid and reliable patterning of arbitrary plasmonic nanostructures that are not feasible to fabricate via conventional FIB milling process, our work provides the FIB milling technology an additional nanopatterning capability and thus could greatly increase its popularity for utilization in fundamental research and device prototyping.
authors.forename: Yiqin
authors.identifier: 0000-0003-4635-0666
authors.initials: Y
authors.lastname: Chen
authors.affiliation: College of Science, National University of Defense Technology , Changsha 410073, People's Republic of China.
authors.forename: Kaixi
authors.initials: K
authors.lastname: Bi
authors.affiliation: College of Engineering and Applied Sciences, Nanjing University , Nanjing 210093, People's Republic of China.
authors.forename: Qianjin
authors.initials: Q
authors.lastname: Wang
authors.forename: Mengjie
authors.initials: M
authors.lastname: Zheng
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: College of Science, National University of Defense Technology , Changsha 410073, People's Republic of China.
authors.forename: Yunxin
authors.initials: Y
authors.lastname: Han
authors.affiliation: College of Science, National University of Defense Technology , Changsha 410073, People's Republic of China.
authors.forename: Junbo
authors.initials: J
authors.lastname: Yang
authors.affiliation: College of Science, National University of Defense Technology , Changsha 410073, People's Republic of China.
authors.forename: Shengli
authors.initials: S
authors.lastname: Chang
authors.forename: Guanhua
authors.initials: G
authors.lastname: Zhang
authors.forename: Huigao
authors.initials: H
authors.lastname: Duan
keywords: FIB milling; helium ion beam; nanofabrication; plasmonics; sketch and peel