Gold nanoparticle array formation on dimpled Ta templates using pulsed laser-induced thin film dewetting

Abstract

Here we show that pulsed laser-induced dewetting (PLiD) of a thin Au metallic film on a nano-scale ordered dimpled tantalum (DT) surface results in the formation of a high quality Au nanoparticle (NP) array. In contrast to thermal dewetting, PLiD does not result in deformation of the substrate, even when the Au film is heated to above its melting point. PLiD causes local heating of only the metal film and thus thermal oxidation of the Ta substrate can be avoided, also because of the high vacuum (low pO2) environment employed. Therefore, this technique can potentially be used to fabricate NP arrays composed of high melting point metals, such as Pt, not previously possible using conventional thermal annealing methods. We also show that the Au NPs formed by PLiD are more spherical in shape than those formed by thermal dewetting, likely demonstrating a different dewetting mechanism in the two cases. As the metallic NPs formed on DT templates are electrochemically addressable, a longer-term objective of this work is to determine the effect of NP size and shape (formed by laser vs. thermal dewetting) on their electrocatalytic properties.

Gold nanoparticle assembly on porous silicon by pulsed laser induced dewetting

“…However, substrate deformation due to the extended exposure at high temperatures needed for the dewetting of high-melting-point metals limits its use mainly to low-melting-point metals. 24,25 In addition, there are potential metal-substrate chemical interactions and metal diffusion into the substrate, complicating the dewetting process. 26 An alternative dewetting technique is liquid-state dewetting induced by pulsed laser irradiation.…”

“…29 As a result, the PLiD method prevents any detrimental effect to the underlying substrates, thanks to the instantaneous heating within the short width of laser pulses. It is therefore suitable for making NPs of high-melting-point metals such as Pt, 30 Fe, 31 and Co-Pt, 32 in addition to lowmelting-point metal NPs, e.g., Au, 24,33 Ag, 33,34 and Cu. 27,35 PLiD via liquid-state dewetting is able to produce spatially ordered metal NPs, which have more uniform distributions than those obtained from solid-state thermal dewetting.…”

Approach for fine‐tuning of hybrid dimer antennas via laser melting at the nanoscale

“…Recently laser‐assiated methods have become a powerful platform for plasmonic nanostructures fabrication and tuning . More specifically, it has recently been experimentally demonstrated that asymmetric hybrid metal‐dielectric (Au/Si) nanoparticles consisting of a gold (Au) nanodisk placed on an upper base of truncated silicon (Si) nanocone, can be tuned via fs‐laser induced melting at the nanometer scale .…”

Templated dewetting: designing entirely self-organized platforms for photocatalysis

“…67,69 Fine control of the NP size can thus be achieved by film thickness and substrate topography. 42,68,70–77 …”

“…76,77 This method allows also for dewetting of high melting point metals and avoids substrate deterioration ( e.g. , by thermal oxidation).…”