Ag Nanotwin-Assisted Grain Growth-Induced by Stress in SiO2/Ag/SiO2 Nanocap Arrays

Abstract

A trilayer SiO2/Ag/SiO2 nanocap array was prepared on a two-dimensional template. When annealed at different temperatures, the curvature of the SiO2/Ag/SiO2 nanocap arrays increased, which led to Ag nanocap shrinkage. The stress provided by the curved SiO2 layer induced the formation of Ag nanotwins. Ag nanotwins assisted the growth of nanoparticles when the neighboring nanotwins changed the local misorientations. Nanocap shrinkage reduced the surface plasmon resonance (SPR) coupling between neighboring nanocaps; concurrently, grain growth decreased the SPR coupling between the particles in each nanocap, which led to a red shift of the localized surface plasmon resonance (LSPR) bands and decreased the surface-enhanced Raman scattering (SERS) signals.

Controlling the 3D Electromagnetic Coupling in Co-Sputtered Ag–SiO2 Nanomace Arrays by Lateral Sizes

“…In Figure 2 E, the HRTEM image shows that the distance of the lattice fringes is approximately 0.230 nm, which is in agreement with the (111) plane of Ag. The surrounding semitransparent areas are amorphous SiO 2 [ 32 ], which was confirmed by XPS ( Figure S1 ).…”

Manipulation and Applications of Hotspots in Nanostructured Surfaces and Thin Films

“…With increasing deposition time, the surface roughness of the SiO 2 −Ag nanocaps increases, and the nanogaps between the units of bridged knobby units gradually decrease ( Figure 4 b–d). The results of FDTD simulations indicate that the hotspots where the EM field is coupling are mostly distributed on the surface of the SiO 2 -isolated Ag nanoparticles on the nanocaps and the bridges between nanocaps, as shown in Figure 4 e. In addition, the trilayer or multilayer Ag/SiO 2 composite shell or 3D pillar-cap arrays also significantly improve the enhancement of the EM field, which manipulates the distribution of hotspots [ 29 , 45 , 51 ]. The SiO 2 addition not only immensely increases the surface roughness of the designed nanostructure surfaces and thin films but also improves the enhancement of the EM field at the nanogaps, which manipulates the formation and evolution of hotspots.…”

“…Various nanostructured surfaces and thin films can be achieved by the combination of NSL and physical vapor deposition, such as periodic nanocaps [ 14 , 15 , 16 , 17 , 18 ], nanotriangles [ 19 , 20 , 21 , 22 ], nanobowls [ 23 , 24 , 25 ], nanorings [ 26 , 27 , 28 ], nanopillars [ 29 , 30 ], nanocones [ 31 , 32 , 33 ], and other complex nanostructured surfaces and thin films, including nanohoneycomb, bridged knobby units, nanoparticle cluster-in-bowl arrays, and so on [ 2 , 25 , 34 , 35 , 36 , 37 , 38 , 39 , 40 ]. These architectural designs of nanostructured surfaces and thin films can be obtained by controlling a series of deposition processes (the deposition time, angle, distance, and so on), PS colloid sphere etching, transfer, and their combination steps, which manipulate the formation, distribution, and evolution of hotspots and have significant implications in broad applications [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 …”

Linearly Tunable Fano Resonance Modes in a Plasmonic Nanostructure with a Waveguide Loaded with Two Rectangular Cavities Coupled by a Circular Cavity

“…The collective electromagnetic oscillation due to the interaction of free electrons in a metal nanostructure with an electromagnetic wave, known as surface plasmon polariton (SPP), has been considered as one of the most promising effects for building highly integrated photonic circuits owing to its capabilities in overcoming diffraction limit of light wave, manipulating wave at a deep subwavelength scale, and producing extremely strong local field near the metal-dielectric surface [1,2,3,4,5,6]. By now, various kinds of nanoscale devices based on SPPs have been investigated theoretically and experimentally, such as optical filters, optoelectronic switches, optical amplifiers, and modulators [7,8,9].…”