Fabrication of self-assembled spherical Gold Particles by pulsed UV Laser Treatment

Abstract

We report on the fabrication of spherical Au spheres by pulsed laser treatment using a KrF excimer laser (248 nm, 25 ns) under ambient conditions as a fast and high throughput fabrication technique. The presented experiments were realized using initial Au layers of 100 nm thickness deposited on optically transparent and low cost Borofloat glass or single-crystalline SrTiO3 substrates, respectively. High (111)-orientation and smoothness (RMS ≈ 1 nm) are the properties of the deposited Au layers before laser treatment. After laser treatment, spheres with size distribution ranging from hundreds of nanometers up to several micrometers were produced. Single-particle scattering spectra with distinct plasmonic resonance peaks are presented to reveal the critical role of optimal irradiation parameters in the process of laser induced particle self-assembly. The variation of irradiation parameters like fluence and number of laser pulses influences the melting, dewetting and solidification process of the Au layers and thus the formation of extremely well shaped spherical particles. The gold layers on Borofloat glass and SrTiO3 are found to show a slightly different behavior under laser treatment. We also discuss the effect of substrates.

Porous spherical gold nanoparticles via a laser induced process

“…The sample position is achieved using an XY-translational stage. 24,28 Selective chemical etching For the etching process of the mixed Ag/Au particles, a solution of 65% HNO 3 + H 2 O with a volume ratio of 1 : 2 (e.g. 5 ml 65% HNO 3 + 10 ml H 2 O) was used.…”

“…[18][19][20] Another new high-potential synthesis route for pure or multicomponent nanoparticle fabrication represents the laser synthesis of colloids 21,22 or the NP fabrication by Nd-YAG or excimer lasers via dewetting or melting of layer systems or ablation. 23,24 In contrast to colloidal synthesis, this laser induced method allows fabrication of spherical single alloy particles under ambient conditions without time consuming and complex chemical synthesis steps, which adhere on lowcost glass substrates and do not require a chemical shell to avoid agglomeration.…”

“…These extensive relationships have been demonstrated in various literature studies and previous publications for different material systems. [23][24][25][26][27][28] A material mixture in particles based on a multilayer system deposited on a substrate is very well realizable with this method, since excimer laser irradiation is characterized by fast heating, up to melting or evaporation in the ns range. The fast cooling rate can suppress phase separation during solidication.…”

Amplitude-Resolved Single Particle Spectrophotometry: A Robust Tool for High-Throughput Size Characterization of Plasmonic Nanoparticles

“…Several methods, including both bottom-up 12 and top-down 13,14 approaches, can be used to fabricate plasmonic nanoparticles and are being continuously improved to produce nanoparticle populations with very narrow size distributions. However, achieving greater precision in nanoparticle size typically requires more costly synthesis processes, and the coe cient of size variation can vary by up to 50% between batches.…”

Fabrication and Characterization of Biplasmonic Substrates Obtained by Picosecond Laser Pulses

“…Moreover, many methods of obtaining SERS-active nanostructures have been tested and proven throughout the years. Just to name a few: self-assembling techniques [11], electron beam lithography, ion beam irradiation [12], nanotransfer printing [13], femtosecond laser irradiation and picosecond laser irradiation [14][15][16][17].…”