Building Interfacial Nanostructures by Size-Controlled Chemical Etching

Abstract

Development of soft chemical processes for the synthesis of interfacial architectures with well-defined structural nano-motifs organized over large areas in two dimensions is an important branch of nanotechnology. The present study deals with the fabrication of gold nanostructures using size-selective chemical etching of continuous gold films on glass support with titanium and chromium adhesive layers. In this process, which is called self-passivated surface etching, a gold film is etched in the presence of citric acid, resulting in gold nanostructures adhering to the metal support. The size-controlled chemical dissolution of gold is driven by a competing reaction between self-organized passivation of surface nano-motifs by citric acid shells and soft etching by a nonoxidative composition containing hydrochloric acid and hydrogen peroxide in water. According to these results, the presence of a chemically stable adhesive layer (titanium), citric acid in solution, and agitation are critical factors to be considered. However, the nature of the adhesive layer is the most influential factor. The following technique presents a simple method for the rapid fabrication of a nanostructured gold substrate that has the ability to support both propagating and localized surface plasmon resonances simultaneously.

Plasmon Waveguide Resonance Raman Spectroscopy

“…Previously, a reduction in the prism background was reported using a 50-nm Au film between the sapphire and analyte layer because of the limited transparency of the Au film. 30 A reduction in the prism background is also expected at the plasmon waveguide interface. On the other hand, several hundred nanometers of silica may contribute to the spectral background since the electric field intensity is high in the waveguide supporting medium (i.e., SiO 2 ).…”

Gold surface cleaning by etching polishing: Optimization of polycrystalline film topography and surface functionality for biosensing

“…After ~30 min of additional process (probably, texture etching in the inter-crystalline regions) the differential spectrum takes a shape typical for gold nano-structures with an absorption peak of a local surface plasmon resonance excitations above 510 nm. Such nanostructuring of a continuous polycrystalline gold films has been described earlier [55]. Nanostructures can induce additional scattering of propagating plasmon-polariton excitations, including a radioactive emission [59] which lead to a broadening of the SPR resonance curve and a decrease in the efficiency of the SPR transducer.…”

Nanostructuring of Continuous Gold Film by Laser Radiation Under Surface Plasmon Polariton Resonance Conditions

“…The results obtained create a base for the further development and application of a laser-assisted resonance method of metallic nanoparticles generation. Contrary to the wet chemical etching procedures [27], the proposed technique open a way for fabricating the well-defined structural nanomotifs organized over large areas in two dimensions both on initial metal films substrate and on remote surfaces due to a laser transfer, similarly to the laserinduced film transfer technology [28].…”