Superplastic Formation of Metal Nanostructure Arrays with Ultrafine Gaps

Abstract

Laser shock compression of plasmonic nanoarrays results in ultrafine tunable line-gaps at sub-10 nm scale by collaborative superplastic flow. From molecular dynamics analysis, the metal nanostructures change from crystalline to liquid-like metals, expanding quickly but never fusing together, even when they are very close. This technique enables good tunability of surface plasmon resonances and significantly enhanced local fields.

Ultralarge Area Sub-10 nm Plasmonic Nanogap Array by Block Copolymer Self-Assembly for Reliable High-Sensitivity SERS

“…Surface enhancement of Raman scattering (SERS) exploiting metal nanostructures may successfully broaden the cross section of scattering and thereby enhance the Raman signal intensity even for a tiny amount of sample. − Typically, such an augmentation of Raman intensity is enabled by the radiative field enhancement at the “hot spot”, such as metal nanoscale gaps − or sharp tips . In this regard, various approaches, including colloidal assembly, − E-beam writing, and photolithography, − have been exploited thus far. Nevertheless, sophisticated time-consuming process, undesired metal aggregation, and random distribution of hot spots have remained significant bottlenecks for reliable sensing.…”

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

“…For friction welding, the low efficiency and welding defects are concerning. Alternatively, highpower-density laser has attracted enormous research interest and found its wide application in a broad branch of manufacturing areas including selective laser sintering and three-dimensional printing [1][2][3][4][5][6], surface nanostructuring [7][8][9][10][11][12], multimaterial joining and integration [13][14][15][16][17], material removal [18,19], and mechanical/optical property enhancements [20][21][22][23]. Characteristics, such as contact-free processing, good flexibility and tunablity, high efficiency, and throughput, make laser a feasible route for welding of 42CrMo [24,25].…”

Light–Matter Interaction within Extreme Dimensions: From Nanomanufacturing to Applications

“…The gap can further be narrowed down (Fig. 2b) by combined use of EBL and LSI [32] at laser fluence on the order of 1 KJ/m 2 . The geometries and crystallinity are dependent on laser parameters and the mechanical properties of the shock wave transmission media.…”

“…The intensity of such a shock wave can be increased by up to two orders of magnitude by using a transparent overlay. Although it has been decades since the development of laser shock processing of metals for surface engineering [29,30] in 1970s, the recent integration of laser shock generation with sheet metal shaping has generated a strong impetus for laser-shock based nanomanufacturing of plasmonic metal nanostructures [31,32], as well as shaped or strained 1D nanowires [33,34] and 2D materials [31,35]. For instance, LSI of sheet metals against a predefined silicon mold yields large-scale ordered nanogaps at dimensions around 10 nm [31].…”