College of Science, National University of Defense Technology , Changsha 410073, People's Republic of China.
College of Engineering and Applied Sciences, Nanjing University , Nanjing 210093, People's Republic of China.
ACS Nano. 2016 Dec 27;10(12):11228-11236. doi: 10.1021/acsnano.6b06290. Epub 2016 Nov 23.
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.
聚焦离子束（FIB）铣削是一种通用的无掩模、无抗蚀剂的图案化技术，已广泛用于各种应用的反等离子体结构的制造，如纳米孔和纳米狭缝。然而，由于其减法铣削的性质，它是一种不切实际的方法来制造孤立的等离子体纳米粒子和组装体，这些在应用中更为常见。在这项工作中，我们提出并证明了一种使用 FIB 铣削通过简单的“草图和剥离”策略可靠且快速地定义等离子体纳米粒子及其组装体的方法。系统的实验研究和机理研究表明，由于离子铣削诱导的再沉积，形成了一个共形的侧壁涂层，从而实现了这种制造方法的高可靠性。特别是，我们证明了这种策略也适用于最先进的氦离子束铣削技术，通过该技术可以直接快速原型化具有微小间隙的高保真等离子体二聚体。由于所提出的方法能够快速可靠地对通过传统 FIB 铣削工艺无法制造的任意等离子体纳米结构进行图案化，因此我们的工作为 FIB 铣削技术提供了额外的纳米图案化能力，从而可以极大地增加其在基础研究和器件原型制作中的应用。
