IR Laser‐Induced Functionalization of Au‐Coated Oxide Glass via Formation of Shell‐Like Nanostructures

ABSTRACT

Functionalization of oxide glass through Au plasmonic nanostructures enabled by IR laser‐induced 2D modification under different environmental conditions is reported. Under nonthermal plasma conditions, the as‐deposited continuous Au film (200 ± 15 nm thick) disintegrates into hollow shell‐like nanostructures. In contrast, for the film annealed at 400°C in argon gas, the laser energy induces high thermal stress and mechanical strain at the glass–film interface, and it therefore undergoes cracking, buckling and spallation, with ultimate disintegration into large flake‐like structures. The porous and apparently hollow shell‐like structures predominantly originate from laser‐induced thermoelastic effects that trigger spinodal dewetting in the irradiated film. The morphology, size and spatial organization of the nanostructures were strongly dependent on the ablation conditions: Strong confinement with a soda‐lime glass yielded modification with densely populated smaller sized particles, whereas relatively sparse particle distributions were obtained in both ambient air and plasma environments. The self‐organized plasmonic structures obtained under nonthermal plasma were used as a model SERS substrate and showed excellent SERS activity towards an aqueous Rhodamine 6G (10 ⁻⁵  M) solution. This result confirms the induced surface functionality for potential optical chemical sensing and molecular identification. Such engineered modification and functionalization of metal surfaces are highly efficient and suitable for advanced plasmonic sensing devices and energy‐harvesting devices such as photovoltaic systems.