Self-Organized Freestanding One-Dimensional Au Nanoparticle Arrays

Abstract

One-dimensional Au nanoparticle arrays encapsulated within freestanding SiO nanowires are fabricated by thermal oxidation of Au-coated Si nanowires with controlled diameter and surface modulation. The nanoparticle diameter is determined by the Si nanowire diameter and Au film thickness, while the interparticle spacing is independently controlled by the Si nanowire modulation. The optical absorption of randomly oriented Au nanoparticle arrays exhibits a strong plasmonic response at 550 nm. Scanning transmission electron microscopy (STEM)-electron energy loss spectrum (EELS) of nanoparticle arrays confirmed the same plasmonic response and demonstrated uniform optical properties of the Au nanoparticles. The plasmonic response in the STEM-EELS maps is primarily confined around the vicinity of the nanoparticles. On the other hand, examination of the same nanowires by energy-filtered transmission electron microscopy also revealed significant enhancement in the plasmonic excitation in the regions in between the nanoparticles. This versatile route to synthesize one-dimensional Au nanoparticle arrays with independently tailorable nanoparticle diameter and interparticle spacing opens up opportunities to exploit enhanced design flexibility and cost-effectiveness for future plasmonic devices.

Tin Nanoparticles–Enhanced Optical Transportation in Branched CdS Nanowire Waveguides

“…Similar to the copper wire annealed at 400 °C, the surface roughness of the Sn nanowires grows with increasing temperature. Keeping temperature at a high level, based on the Rayleigh thermodynamic instability principle, the Sn nanowire is fragmented into a row of spherical and uniformly sized nanoparticles via atomic diffusion—to minimize the interfacial energy—forming core–shell superlattice structures (Figure e,f) . The scanning electron microscopy (SEM) image and corresponding selected area element mappings of the cross section of the wire are shown in the inset of Figure e and Figure S1 (Supporting Information), indicating that the core and shell are composed of Sn and CdS, respectively.…”

Optically Programmable Plateau–Rayleigh Instability for High-Resolution and Scalable Morphology Manipulation of Silver Nanowires for Flexible Optoelectronics

“…The key to PRI-based nanofabrication is the introduction of specific disturbance to trigger or control the morphology formation. One approach is to directly define periodic geometrical shapes on NWs using EBL or FIB to control the PRI evolution, which can produce periodic NP array and nanobead chain. − Another frequently used routine is to employ templates, including surface anisotropic substrates, , diameter-modulated supporting NWs, and nanotubes, , to guide the shape evolution. More recently, Lieber et al formulated diameter-modulated semiconductor NWs by regulating the surface atom diffusion to induce “Plateau–Rayleigh crystal growth”, which provides a new engineering strategy in reshaping NW .…”

1-D Metal Nanobead Arrays within Encapsulated Nanowires via a Red-Ox-Induced Dewetting: Mechanism Study by Atom-Probe Tomography

“…These highly ordered metal nanoparticle arrays may be suitable for various applications, including plasmonic and electro-optical device applications such as biosensing, optical waveguides, SERS, negative index materials, and more. 6,13,14 Noble metals, such as Au, 15 Pt, 16 and Ag, 17 are well-known for their plasmonic properties, which can be tuned by controlling their morphology 18 and spatial positions. 19 The spatial patterns are traditionally achieved using top-down lithography, which can be applied to various materials in a highly controlled manner.…”

“…Nanowire (NW) building blocks are central to numerous emerging applications including electronics, , biological applications, and thermoelectric devices , owing to the one-dimensional (1-D) morphology of the nanowire, which can channel electrons, phonons, and photons in the propagation direction. The confined motion of charge carriers in metal and semiconductor nanowires makes them novel platforms for sensing, plasmonic waveguides, and laser applications, while confining phonon transport within nanowires reduces their thermal conductivity and renders them promising candidates for thermo-electric devices . The 1-D morphology confers unique physical phenomena, which differentiate them from their bulk or 2-D counterparts.…”

“…We term the 1-D periodic metal nanoparticles we observe embedded within a nanowire nanobeads (NBs). These highly ordered metal nanoparticle arrays may be suitable for various applications, including plasmonic and electro-optical device applications such as biosensing, optical waveguides, SERS, negative index materials, and more. ,, …”