Fabrication of gold nanoparticle decorated surfaces for controlled nucleation of plasmonic microbubbles

Abstract

Plasmonic bubbles produced by water-immersed gold nanoparticles (GNPs) under a laser irradiation are of great relevance in numerous applications. Normally, plasmonic bubbles are produced on a well-fabricated GNP decorated sample surfaces, which rely on expensive devices and complex fabrication processes. In this study, we systematically investigate the fabrication of GNP decorated sample surfaces for optimized production of plasmonic bubbles. Sample surfaces are fabricated by thermal dewetting of a gold film coated on fused silica substrates under an annealing temperature up to 1200 °C. Both the size and density of GNPs can be well tuned by adjusting gold film thickness and annealing temperature. The optical absorption of sample surfaces is also experimentally and numerically investigated, from which the optimal parameters of fabrication are determined. More importantly, for the first time, we find that the high annealing temperature leads to the formation of nanoindents beneath GNPs, resulting in the partial enwrapment of GNPs into fused silica substrates. This helps to stabilize GNPs on sample surfaces. With the fabricated sample surfaces, the nucleation and growth dynamics of giant initial bubbles and ordinary plasmonic bubbles can be well tuned. No apparent damage has been observed on the sample surfaces after the violent bubble nucleation. The increased stability of GNPs is important for plasmonic bubble related applications.