Engineering plasmonic nanostructured surfaces by pulsed laser deposition

Abstract

The synthesis and the optical response of gold nanoparticles (NPs) and thin nanostructured films grown by pulsed laser deposition (PLD) are here studied. Different PLD process parameters – including background gas pressure and the number of laser shots as well as post-deposition annealing treatments – have been varied to control the growth of Au NPs and films, thus tuning the surface plasmon characteristics. The mechanisms of NPs and film growth have been explored performing a morphological characterization by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM), and the correlation with the optical behavior is investigated. We show that the size distribution and the morphology of the as deposited Au NPs depend on growth mechanisms which are controlled by tuning the deposition process, while the optical behavior is strongly affected by the average size and surface density of NPs or by the length of percolated Au domains. Furthermore, nucleation in gas phase has been reported at high (1000 Pa Ar) background pressures, enabling independent control of NP size and coverage, contrary to surface driven NP growth by diffusion and aggregation on substrate.